should not use unkeyed fields anyway.

.gitignore

@@ -1,19 +1 @@
-# Binaries for programs and plugins
-*.exe
-*.dll
-*.so
-*.dylib
-
-# Test binary, build with `go test -c`
-*.test
-
-# Output of the go coverage tool, specifically when used with LiteIDE
-*.out
-
-# Project-local glide cache, RE: https://github.com/Masterminds/glide/issues/736
-.glide/
-
-# Other
 .vscode
-.DS_Store
-coverage.html

.travis.yml

@@ -0,0 +1,13 @@
+language: go
+
+go:
+  - 1.6.2
+
+sudo: false
+
+before_script:
+  - go get -u github.com/blendlabs/go-assert
+  - go get ./...
+
+script:
+  - go test ./...

COVERAGE

@@ -1 +0,0 @@
-70.89

Makefile

@@ -0,0 +1,9 @@
+all: test
+
+test:
+	@go test ./...
+
+cover:
+	@go test -short -covermode=set -coverprofile=profile.cov
+	@go tool cover -html=profile.cov
+	@rm profile.cov

README.md

@@ -0,0 +1,99 @@
+go-chart
+========
+[![Build Status](https://travis-ci.org/wcharczuk/go-chart.svg?branch=master)](https://travis-ci.org/wcharczuk/go-chart)[![Go Report Card](https://goreportcard.com/badge/github.com/wcharczuk/go-chart)](https://goreportcard.com/report/github.com/wcharczuk/go-chart)
+
+Package `chart` is a very simple golang native charting library that supports timeseries and continuous
+line charts. 
+
+The v1.0 release has been tagged so things should be more or less stable, if something changes please log an issue.
+
+Master should now be on the v2.x codebase, which brings a couple new features and better handling of basics like axes labeling etc. Per usual, see `_examples` for more information.
+
+# Installation
+
+To install `chart` run the following:
+
+```bash
+> go get -u github.com/wcharczuk/go-chart
+```
+
+Most of the components are interchangeable so feel free to crib whatever you want. 
+
+# Output Examples 
+
+Spark Lines:
+
+![](https://raw.githubusercontent.com/wcharczuk/go-chart/master/_images/tvix_ltm.png)
+
+Single axis:
+
+![](https://raw.githubusercontent.com/wcharczuk/go-chart/master/_images/goog_ltm.png)
+
+Two axis:
+
+![](https://raw.githubusercontent.com/wcharczuk/go-chart/master/_images/two_axis.png)
+
+# Other Chart Types
+
+Pie Chart:
+
+![](https://raw.githubusercontent.com/wcharczuk/go-chart/master/_images/pie_chart.png)
+
+The code for this chart can be found in `_examples/pie_chart/main.go`.
+
+Stacked Bar:
+
+![](https://raw.githubusercontent.com/wcharczuk/go-chart/master/_images/stacked_bar.png)
+
+The code for this chart can be found in `_examples/stacked_bar/main.go`.
+
+# Code Examples
+
+Actual chart configurations and examples can be found in the `./_examples/` directory. They are web servers, so start them with `go run main.go` then access `http://localhost:8080` to see the output.
+
+# Usage
+
+Everything starts with the `chart.Chart` object. The bare minimum to draw a chart would be the following:
+
+```golang
+
+import (
+    ...
+    "bytes"
+    ...
+    "github.com/wcharczuk/go-chart" //exposes "chart"
+)
+
+graph := chart.Chart{
+    Series: []chart.Series{
+        chart.ContinuousSeries{
+            XValues: []float64{1.0, 2.0, 3.0, 4.0},
+            YValues: []float64{1.0, 2.0, 3.0, 4.0},
+        },
+    },
+}
+
+buffer := bytes.NewBuffer([]byte{})
+err := graph.Render(chart.PNG, buffer)
+```
+
+Explanation of the above: A `chart` can have many `Series`, a `Series` is a collection of things that need to be drawn according to the X range and the Y range(s).
+
+Here, we have a single series with x range values as float64s, rendered to a PNG. Note; we can pass any type of `io.Writer` into `Render(...)`, meaning that we can render the chart to a file or a resonse or anything else that implements `io.Writer`.
+
+# API Overview
+
+Everything on the `chart.Chart` object has defaults that can be overriden. Whenever a developer sets a property on the chart object, it is to be assumed that value will be used instead of the default. One complication here
+is any object's root `chart.Style` object (i.e named `Style`) and the `Show` property specifically, if any other property is set and the `Show` property is unset, it is assumed to be it's default value of `False`.
+
+The best way to see the api in action is to look at the examples in the `./_examples/` directory.
+
+# Design Philosophy
+
+I wanted to make a charting library that used only native golang, that could be stood up on a server (i.e. it had built in fonts).
+
+The goal with the API itself is to have the "zero value be useful", and to require the user to not code more than they absolutely needed.
+
+# Contributions
+
+This library is super early but contributions are welcome.

_examples/annotations/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {

_examples/axes/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -15,10 +15,14 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	graph := chart.Chart{
 		XAxis: chart.XAxis{
-			Style: chart.StyleShow(), //enables / displays the x-axis
+			Style: chart.Style{
+				Show: true, //enables / displays the x-axis
+			},
 		},
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(), //enables / displays the y-axis
+			Style: chart.Style{
+				Show: true, //enables / displays the y-axis
+			},
 		},
 		Series: []chart.Series{
 			chart.ContinuousSeries{

_examples/axes_labels/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {

_examples/bar_chart/main.go

@@ -6,23 +6,20 @@ import (
 	"net/http"
 	"os"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
 	sbc := chart.BarChart{
-		Title:      "Test Bar Chart",
-		TitleStyle: chart.StyleShow(),
-		Background: chart.Style{
-			Padding: chart.Box{
-				Top: 40,
-			},
-		},
 		Height:   512,
 		BarWidth: 60,
-		XAxis:    chart.StyleShow(),
+		XAxis: chart.Style{
+			Show: true,
+		},
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 		},
 		Bars: []chart.Value{
 			{Value: 5.25, Label: "Blue"},

_examples/bar_chart_base_value/main.go

@@ -1,88 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"log"
-	"net/http"
-	"os"
-
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/drawing"
-)
-
-func drawChart(res http.ResponseWriter, req *http.Request) {
-	profitStyle := chart.Style{
-		Show:        true,
-		FillColor:   drawing.ColorFromHex("13c158"),
-		StrokeColor: drawing.ColorFromHex("13c158"),
-		StrokeWidth: 0,
-	}
-
-	lossStyle := chart.Style{
-		Show:        true,
-		FillColor:   drawing.ColorFromHex("c11313"),
-		StrokeColor: drawing.ColorFromHex("c11313"),
-		StrokeWidth: 0,
-	}
-
-	sbc := chart.BarChart{
-		Title:      "Bar Chart Using BaseValue",
-		TitleStyle: chart.StyleShow(),
-		Background: chart.Style{
-			Padding: chart.Box{
-				Top: 40,
-			},
-		},
-		Height:   512,
-		BarWidth: 60,
-		XAxis: chart.Style{
-			Show: true,
-		},
-		YAxis: chart.YAxis{
-			Style: chart.Style{
-				Show: true,
-			},
-			Ticks: []chart.Tick{
-				{-4.0, "-4"},
-				{-2.0, "-2"},
-				{0, "0"},
-				{2.0, "2"},
-				{4.0, "4"},
-				{6.0, "6"},
-				{8.0, "8"},
-				{10.0, "10"},
-				{12.0, "12"},
-			},
-		},
-		UseBaseValue: true,
-		BaseValue:    0.0,
-		Bars: []chart.Value{
-			{Value: 10.0, Style: profitStyle, Label: "Profit"},
-			{Value: 12.0, Style: profitStyle, Label: "More Profit"},
-			{Value: 8.0, Style: profitStyle, Label: "Still Profit"},
-			{Value: -4.0, Style: lossStyle, Label: "Loss!"},
-			{Value: 3.0, Style: profitStyle, Label: "Phew Ok"},
-			{Value: -2.0, Style: lossStyle, Label: "Oh No!"},
-		},
-	}
-
-	res.Header().Set("Content-Type", "image/png")
-	err := sbc.Render(chart.PNG, res)
-	if err != nil {
-		fmt.Printf("Error rendering chart: %v\n", err)
-	}
-}
-
-func port() string {
-	if len(os.Getenv("PORT")) > 0 {
-		return os.Getenv("PORT")
-	}
-	return "8080"
-}
-
-func main() {
-	listenPort := fmt.Sprintf(":%s", port())
-	fmt.Printf("Listening on %s\n", listenPort)
-	http.HandleFunc("/", drawChart)
-	log.Fatal(http.ListenAndServe(listenPort, nil))
-}

_examples/basic/main.go

@@ -4,7 +4,7 @@ import (
 	"log"
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -26,8 +26,8 @@ func drawChartWide(res http.ResponseWriter, req *http.Request) {
 		Width: 1920, //this overrides the default.
 		Series: []chart.Series{
 			chart.ContinuousSeries{
-				XValues: []float64{1.0, 2.0, 3.0, 4.0},
-				YValues: []float64{1.0, 2.0, 3.0, 4.0},
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
 			},
 		},
 	}

_examples/benchmark_line_charts/main.go

@@ -1,79 +0,0 @@
-// Usage: http://localhost:8080?series=100&values=1000
-package main
-
-import (
-	"fmt"
-	"math/rand"
-	"net/http"
-	"strconv"
-	"time"
-
-	"git.fireandbrimst.one/aw/go-chart"
-)
-
-func random(min, max float64) float64 {
-	return rand.Float64()*(max-min) + min
-}
-
-func drawLargeChart(res http.ResponseWriter, r *http.Request) {
-	numSeriesInt64, err := strconv.ParseInt(r.FormValue("series"), 10, 64)
-	if err != nil {
-		numSeriesInt64 = int64(1)
-	}
-	if numSeriesInt64 == 0 {
-		numSeriesInt64 = 1
-	}
-	numSeries := int(numSeriesInt64)
-
-	numValuesInt64, err := strconv.ParseInt(r.FormValue("values"), 10, 64)
-	if err != nil {
-		numValuesInt64 = int64(100)
-	}
-	if numValuesInt64 == 0 {
-		numValuesInt64 = int64(100)
-	}
-	numValues := int(numValuesInt64)
-
-	series := make([]chart.Series, numSeries)
-
-	for i := 0; i < numSeries; i++ {
-		xValues := make([]time.Time, numValues)
-		yValues := make([]float64, numValues)
-
-		for j := 0; j < numValues; j++ {
-			xValues[j] = time.Now().AddDate(0, 0, (numValues-j)*-1)
-			yValues[j] = random(float64(-500), float64(500))
-		}
-
-		series[i] = chart.TimeSeries{
-			Name:    fmt.Sprintf("aaa.bbb.hostname-%v.ccc.ddd.eee.fff.ggg.hhh.iii.jjj.kkk.lll.mmm.nnn.value", i),
-			XValues: xValues,
-			YValues: yValues,
-		}
-	}
-
-	graph := chart.Chart{
-		XAxis: chart.XAxis{
-			Name:      "Time",
-			NameStyle: chart.StyleShow(),
-			Style:     chart.StyleShow(),
-		},
-		YAxis: chart.YAxis{
-			Name:      "Value",
-			NameStyle: chart.StyleShow(),
-			Style:     chart.StyleShow(),
-		},
-		Series: series,
-	}
-
-	res.Header().Set("Content-Type", "image/png")
-	graph.Render(chart.PNG, res)
-}
-
-func main() {
-	http.HandleFunc("/", drawLargeChart)
-	http.HandleFunc("/favico.ico", func(res http.ResponseWriter, req *http.Request) {
-		res.Write([]byte{})
-	})
-	http.ListenAndServe(":8080", nil)
-}

_examples/css_classes/main.go

@@ -1,58 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"log"
-	"net/http"
-
-	"git.fireandbrimst.one/aw/go-chart"
-)
-
-// Note: Additional examples on how to add Stylesheets are in the custom_stylesheets example
-
-func inlineSVGWithClasses(res http.ResponseWriter, req *http.Request) {
-	res.Write([]byte(
-		"<!DOCTYPE html><html><head>" +
-			"<link rel=\"stylesheet\" type=\"text/css\" href=\"/main.css\">" +
-			"</head>" +
-			"<body>"))
-
-	pie := chart.PieChart{
-		// Note that setting ClassName will cause all other inline styles to be dropped!
-		Background: chart.Style{ClassName: "background"},
-		Canvas: chart.Style{
-			ClassName: "canvas",
-		},
-		Width:  512,
-		Height: 512,
-		Values: []chart.Value{
-			{Value: 5, Label: "Blue", Style: chart.Style{ClassName: "blue"}},
-			{Value: 5, Label: "Green", Style: chart.Style{ClassName: "green"}},
-			{Value: 4, Label: "Gray", Style: chart.Style{ClassName: "gray"}},
-		},
-	}
-
-	err := pie.Render(chart.SVG, res)
-	if err != nil {
-		fmt.Printf("Error rendering pie chart: %v\n", err)
-	}
-	res.Write([]byte("</body>"))
-}
-
-func css(res http.ResponseWriter, req *http.Request) {
-	res.Header().Set("Content-Type", "text/css")
-	res.Write([]byte("svg .background { fill: white; }" +
-		"svg .canvas { fill: white; }" +
-		"svg path.blue { fill: blue; stroke: lightblue; }" +
-		"svg path.green { fill: green; stroke: lightgreen; }" +
-		"svg path.gray { fill: gray; stroke: lightgray; }" +
-		"svg text.blue { fill: white; }" +
-		"svg text.green { fill: white; }" +
-		"svg text.gray { fill: white; }"))
-}
-
-func main() {
-	http.HandleFunc("/", inlineSVGWithClasses)
-	http.HandleFunc("/main.css", css)
-	log.Fatal(http.ListenAndServe(":8080", nil))
-}

_examples/custom_formatters/main.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -16,7 +16,9 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	graph := chart.Chart{
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 			ValueFormatter: func(v interface{}) string {
 				if vf, isFloat := v.(float64); isFloat {
 					return fmt.Sprintf("%0.6f", vf)

_examples/custom_padding/main.go

@@ -3,9 +3,8 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/drawing"
-	"git.fireandbrimst.one/aw/go-chart/seq"
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/drawing"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -20,15 +19,19 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 			FillColor: drawing.ColorFromHex("efefef"),
 		},
 		XAxis: chart.XAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 		},
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 		},
 		Series: []chart.Series{
 			chart.ContinuousSeries{
-				XValues: seq.Range(1.0, 100.0),
-				YValues: seq.RandomValuesWithMax(100, 512),
+				XValues: chart.Sequence.Float64(1.0, 100.0),
+				YValues: chart.Sequence.Random(100.0, 256.0),
 			},
 		},
 	}
@@ -43,15 +46,19 @@ func drawChartDefault(res http.ResponseWriter, req *http.Request) {
 			FillColor: drawing.ColorFromHex("efefef"),
 		},
 		XAxis: chart.XAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 		},
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 		},
 		Series: []chart.Series{
 			chart.ContinuousSeries{
-				XValues: seq.Range(1.0, 100.0),
-				YValues: seq.RandomValuesWithMax(100, 512),
+				XValues: chart.Sequence.Float64(1.0, 100.0),
+				YValues: chart.Sequence.Random(100.0, 256.0),
 			},
 		},
 	}

_examples/custom_ranges/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -14,7 +14,9 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	graph := chart.Chart{
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 			Range: &chart.ContinuousRange{
 				Min: 0.0,
 				Max: 10.0,

_examples/custom_styles/main.go

@@ -3,8 +3,8 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/drawing"
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/drawing"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {

_examples/custom_stylesheets/inlineOutput.svg

@@ -1,21 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="512" height="512">\n<style type="text/css"><![CDATA[svg .background { fill: white; }svg .canvas { fill: white; }svg path.blue { fill: blue; stroke: lightblue; }svg path.green { fill: green; stroke: lightgreen; }svg path.gray { fill: gray; stroke: lightgray; }svg text.blue { fill: white; }svg text.green { fill: white; }svg text.gray { fill: white; }]]></style><path  d="M 0 0
-L 512 0
-L 512 512
-L 0 512
-L 0 0" class="background"/><path  d="M 5 5
-L 507 5
-L 507 507
-L 5 507
-L 5 5" class="canvas"/><path  d="M 256 256
-L 507 256
-A 251 251 128.56 0 1 100 452
-L 256 256
-Z" class="blue"/><path  d="M 256 256
-L 100 452
-A 251 251 128.56 0 1 201 12
-L 256 256
-Z" class="green"/><path  d="M 256 256
-L 201 12
-A 251 251 102.85 0 1 506 256
-L 256 256
-Z" class="gray"/><text x="313" y="413" class="blue">Blue</text><text x="73" y="226" class="green">Green</text><text x="344" y="133" class="gray">Gray</text></svg>

_examples/custom_stylesheets/main.go

@@ -1,87 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"github.com/hashworks/go-chart"
-	"log"
-	"net/http"
-)
-
-const style = "svg .background { fill: white; }" +
-	"svg .canvas { fill: white; }" +
-	"svg path.blue { fill: blue; stroke: lightblue; }" +
-	"svg path.green { fill: green; stroke: lightgreen; }" +
-	"svg path.gray { fill: gray; stroke: lightgray; }" +
-	"svg text.blue { fill: white; }" +
-	"svg text.green { fill: white; }" +
-	"svg text.gray { fill: white; }"
-
-func svgWithCustomInlineCSS(res http.ResponseWriter, _ *http.Request) {
-	res.Header().Set("Content-Type", chart.ContentTypeSVG)
-
-	// Render the CSS with custom css
-	err := pieChart().Render(chart.SVGWithCSS(style, ""), res)
-	if err != nil {
-		fmt.Printf("Error rendering pie chart: %v\n", err)
-	}
-}
-
-func svgWithCustomInlineCSSNonce(res http.ResponseWriter, _ *http.Request) {
-	// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src
-	// This should be randomly generated on every request!
-	const nonce = "RAND0MBASE64"
-
-	res.Header().Set("Content-Security-Policy", fmt.Sprintf("style-src 'nonce-%s'", nonce))
-	res.Header().Set("Content-Type", chart.ContentTypeSVG)
-
-	// Render the CSS with custom css and a nonce.
-	// Try changing the nonce to a different string - your browser should block the CSS.
-	err := pieChart().Render(chart.SVGWithCSS(style, nonce), res)
-	if err != nil {
-		fmt.Printf("Error rendering pie chart: %v\n", err)
-	}
-}
-
-func svgWithCustomExternalCSS(res http.ResponseWriter, _ *http.Request) {
-	// Add external CSS
-	res.Write([]byte(
-		`<?xml version="1.0" standalone="no"?>`+
-		`<?xml-stylesheet href="/main.css" type="text/css"?>`+
-		`<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">`))
-
-	res.Header().Set("Content-Type", chart.ContentTypeSVG)
-	err := pieChart().Render(chart.SVG, res)
-	if err != nil {
-		fmt.Printf("Error rendering pie chart: %v\n", err)
-	}
-}
-
-func pieChart() chart.PieChart {
-	return chart.PieChart{
-		// Note that setting ClassName will cause all other inline styles to be dropped!
-		Background: chart.Style{ClassName: "background"},
-		Canvas: chart.Style{
-			ClassName: "canvas",
-		},
-		Width:  512,
-		Height: 512,
-		Values: []chart.Value{
-			{Value: 5, Label: "Blue", Style: chart.Style{ClassName: "blue"}},
-			{Value: 5, Label: "Green", Style: chart.Style{ClassName: "green"}},
-			{Value: 4, Label: "Gray", Style: chart.Style{ClassName: "gray"}},
-		},
-	}
-}
-
-func css(res http.ResponseWriter, req *http.Request) {
-	res.Header().Set("Content-Type", "text/css")
-	res.Write([]byte(style))
-}
-
-func main() {
-	http.HandleFunc("/", svgWithCustomInlineCSS)
-	http.HandleFunc("/nonce", svgWithCustomInlineCSSNonce)
-	http.HandleFunc("/external", svgWithCustomExternalCSS)
-	http.HandleFunc("/main.css", css)
-	log.Fatal(http.ListenAndServe(":8080", nil))
-}

_examples/custom_ticks/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -14,7 +14,9 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	graph := chart.Chart{
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 			Range: &chart.ContinuousRange{
 				Min: 0.0,
 				Max: 4.0,

_examples/descending/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -20,13 +20,17 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 		Height: 500,
 		Width:  500,
 		XAxis: chart.XAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 			/*Range: &chart.ContinuousRange{
 				Descending: true,
 			},*/
 		},
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 			Range: &chart.ContinuousRange{
 				Descending: true,
 			},

_examples/image_writer/main.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"log"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func main() {

_examples/legend/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -16,10 +16,10 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	graph := chart.Chart{
 		XAxis: chart.XAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{Show: true},
 		},
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{Show: true},
 		},
 		Background: chart.Style{
 			Padding: chart.Box{

_examples/legend_left/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -16,10 +16,10 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	graph := chart.Chart{
 		XAxis: chart.XAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{Show: true},
 		},
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{Show: true},
 		},
 		Background: chart.Style{
 			Padding: chart.Box{

_examples/linear_regression/main.go

@@ -3,21 +3,20 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/seq"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	/*
 		In this example we add a new type of series, a `SimpleMovingAverageSeries` that takes another series as a required argument.
-		InnerSeries only needs to implement `ValuesProvider`, so really you could chain `SimpleMovingAverageSeries` together if you wanted.
+		InnerSeries only needs to implement `ValueProvider`, so really you could chain `SimpleMovingAverageSeries` together if you wanted.
 	*/
 
 	mainSeries := chart.ContinuousSeries{
 		Name:    "A test series",
-		XValues: seq.Range(1.0, 100.0),             //generates a []float64 from 1.0 to 100.0 in 1.0 step increments, or 100 elements.
-		YValues: seq.RandomValuesWithMax(100, 100), //generates a []float64 randomly from 0 to 100 with 100 elements.
+		XValues: chart.Sequence.Float64(1.0, 100.0), //generates a []float64 from 1.0 to 100.0 in 1.0 step increments, or 100 elements.
+		YValues: chart.Sequence.Random(100, 100),    //generates a []float64 randomly from 0 to 100 with 100 elements.
 	}
 
 	// note we create a LinearRegressionSeries series by assignin the inner series.

_examples/market_hours/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"net/http"
+
+	"github.com/wcharczuk/go-chart"
+)
+
+func drawChart(res http.ResponseWriter, req *http.Request) {
+	start := chart.Date.Date(2016, 7, 01, chart.Date.Eastern())
+	end := chart.Date.Date(2016, 07, 21, chart.Date.Eastern())
+	xv := chart.Sequence.MarketHours(start, end, chart.NYSEOpen, chart.NYSEClose, chart.Date.IsNYSEHoliday)
+	yv := chart.Sequence.RandomWithAverage(len(xv), 200, 10)
+
+	graph := chart.Chart{
+		XAxis: chart.XAxis{
+			Style:          chart.StyleShow(),
+			TickPosition:   chart.TickPositionBetweenTicks,
+			ValueFormatter: chart.TimeHourValueFormatter,
+			Range: &chart.MarketHoursRange{
+				MarketOpen:      chart.NYSEOpen,
+				MarketClose:     chart.NYSEClose,
+				HolidayProvider: chart.Date.IsNYSEHoliday,
+			},
+		},
+		YAxis: chart.YAxis{
+			Style: chart.StyleShow(),
+		},
+		Series: []chart.Series{
+			chart.TimeSeries{
+				XValues: xv,
+				YValues: yv,
+			},
+		},
+	}
+
+	res.Header().Set("Content-Type", "image/png")
+	graph.Render(chart.PNG, res)
+}
+
+func main() {
+	http.HandleFunc("/", drawChart)
+	http.ListenAndServe(":8080", nil)
+}

_examples/min_max/main.go

@@ -3,15 +3,14 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/seq"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
 	mainSeries := chart.ContinuousSeries{
 		Name:    "A test series",
-		XValues: seq.Range(1.0, 100.0),
-		YValues: seq.New(seq.NewRandom().WithLen(100).WithMax(150).WithMin(50)).Array(),
+		XValues: chart.Sequence.Float64(1.0, 100.0),
+		YValues: chart.Sequence.RandomWithAverage(100, 100, 50),
 	}
 
 	minSeries := &chart.MinSeries{

_examples/pie_chart/main.go

@@ -5,7 +5,7 @@ import (
 	"log"
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -30,26 +30,7 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 	}
 }
 
-func drawChartRegression(res http.ResponseWriter, req *http.Request) {
-	pie := chart.PieChart{
-		Width:  512,
-		Height: 512,
-		Values: []chart.Value{
-			{Value: 5, Label: "Blue"},
-			{Value: 2, Label: "Two"},
-			{Value: 1, Label: "One"},
-		},
-	}
-
-	res.Header().Set("Content-Type", chart.ContentTypeSVG)
-	err := pie.Render(chart.SVG, res)
-	if err != nil {
-		fmt.Printf("Error rendering pie chart: %v\n", err)
-	}
-}
-
 func main() {
 	http.HandleFunc("/", drawChart)
-	http.HandleFunc("/reg", drawChartRegression)
 	log.Fatal(http.ListenAndServe(":8080", nil))
 }

_examples/pie_chart/reg.svg

@@ -1,17 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="512" height="512">
-<path  d="M 256 256
-L 507 256
-A 251 251 225.00 1 1 79 79
-L 256 256
-Z" style="stroke-width:5;stroke:rgba(255,255,255,1.0);fill:rgba(106,195,203,1.0)"/>
-<path  d="M 256 256
-L 79 79
-A 251 251 90.00 0 1 433 79
-L 256 256
-Z" style="stroke-width:5;stroke:rgba(255,255,255,1.0);fill:rgba(42,190,137,1.0)"/>
-<path  d="M 256 256
-L 433 79
-A 251 251 45.00 0 1 507 256
-L 256 256
-Z" style="stroke-width:5;stroke:rgba(255,255,255,1.0);fill:rgba(110,128,139,1.0)"/>
-</svg>

_examples/poly_regression/main.go

@@ -1,42 +0,0 @@
-package main
-
-import (
-	"net/http"
-
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/seq"
-)
-
-func drawChart(res http.ResponseWriter, req *http.Request) {
-
-	/*
-		In this example we add a new type of series, a `PolynomialRegressionSeries` that takes another series as a required argument.
-		InnerSeries only needs to implement `ValuesProvider`, so really you could chain `PolynomialRegressionSeries` together if you wanted.
-	*/
-
-	mainSeries := chart.ContinuousSeries{
-		Name:    "A test series",
-		XValues: seq.Range(1.0, 100.0),             //generates a []float64 from 1.0 to 100.0 in 1.0 step increments, or 100 elements.
-		YValues: seq.RandomValuesWithMax(100, 100), //generates a []float64 randomly from 0 to 100 with 100 elements.
-	}
-
-	polyRegSeries := &chart.PolynomialRegressionSeries{
-		Degree:      3,
-		InnerSeries: mainSeries,
-	}
-
-	graph := chart.Chart{
-		Series: []chart.Series{
-			mainSeries,
-			polyRegSeries,
-		},
-	}
-
-	res.Header().Set("Content-Type", "image/png")
-	graph.Render(chart.PNG, res)
-}
-
-func main() {
-	http.HandleFunc("/", drawChart)
-	http.ListenAndServe(":8080", nil)
-}

_examples/request_timings/main.go

@@ -7,8 +7,7 @@ import (
 	"strings"
 	"time"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	util "git.fireandbrimst.one/aw/go-chart/util"
+	"github.com/wcharczuk/go-chart"
 )
 
 func parseInt(str string) int {
@@ -24,7 +23,7 @@ func parseFloat64(str string) float64 {
 func readData() ([]time.Time, []float64) {
 	var xvalues []time.Time
 	var yvalues []float64
-	err := util.File.ReadByLines("requests.csv", func(line string) error {
+	err := chart.File.ReadByLines("requests.csv", func(line string) {
 		parts := strings.Split(line, ",")
 		year := parseInt(parts[0])
 		month := parseInt(parts[1])
@@ -33,7 +32,6 @@ func readData() ([]time.Time, []float64) {
 		elapsedMillis := parseFloat64(parts[4])
 		xvalues = append(xvalues, time.Date(year, time.Month(month), day, hour, 0, 0, 0, time.UTC))
 		yvalues = append(yvalues, elapsedMillis)
-		return nil
 	})
 	if err != nil {
 		fmt.Println(err.Error())
@@ -43,12 +41,12 @@ func readData() ([]time.Time, []float64) {
 
 func releases() []chart.GridLine {
 	return []chart.GridLine{
-		{Value: util.Time.ToFloat64(time.Date(2016, 8, 1, 9, 30, 0, 0, time.UTC))},
-		{Value: util.Time.ToFloat64(time.Date(2016, 8, 2, 9, 30, 0, 0, time.UTC))},
-		{Value: util.Time.ToFloat64(time.Date(2016, 8, 2, 15, 30, 0, 0, time.UTC))},
-		{Value: util.Time.ToFloat64(time.Date(2016, 8, 4, 9, 30, 0, 0, time.UTC))},
-		{Value: util.Time.ToFloat64(time.Date(2016, 8, 5, 9, 30, 0, 0, time.UTC))},
-		{Value: util.Time.ToFloat64(time.Date(2016, 8, 6, 9, 30, 0, 0, time.UTC))},
+		{Value: chart.Time.ToFloat64(time.Date(2016, 8, 1, 9, 30, 0, 0, time.UTC))},
+		{Value: chart.Time.ToFloat64(time.Date(2016, 8, 2, 9, 30, 0, 0, time.UTC))},
+		{Value: chart.Time.ToFloat64(time.Date(2016, 8, 2, 15, 30, 0, 0, time.UTC))},
+		{Value: chart.Time.ToFloat64(time.Date(2016, 8, 4, 9, 30, 0, 0, time.UTC))},
+		{Value: chart.Time.ToFloat64(time.Date(2016, 8, 5, 9, 30, 0, 0, time.UTC))},
+		{Value: chart.Time.ToFloat64(time.Date(2016, 8, 6, 9, 30, 0, 0, time.UTC))},
 	}
 }
 
@@ -105,7 +103,9 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 			},
 		},
 		XAxis: chart.XAxis{
-			Style:          chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 			ValueFormatter: chart.TimeHourValueFormatter,
 			GridMajorStyle: chart.Style{
 				Show:        true,
@@ -125,7 +125,7 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	graph.Elements = []chart.Renderable{chart.LegendThin(&graph)}
 
-	res.Header().Set("Content-Type", chart.ContentTypePNG)
+	res.Header().Set("Content-Type", "image/png")
 	graph.Render(chart.PNG, res)
 }
 

_examples/rerender/main.go

@@ -1,50 +0,0 @@
-package main
-
-import (
-	"log"
-	"net/http"
-	"sync"
-	"time"
-
-	"git.fireandbrimst.one/aw/go-chart/util"
-
-	chart "git.fireandbrimst.one/aw/go-chart"
-)
-
-var lock sync.Mutex
-var graph *chart.Chart
-var ts *chart.TimeSeries
-
-func addData(t time.Time, e time.Duration) {
-	lock.Lock()
-	ts.XValues = append(ts.XValues, t)
-	ts.YValues = append(ts.YValues, util.Time.Millis(e))
-	lock.Unlock()
-}
-
-func drawChart(res http.ResponseWriter, req *http.Request) {
-	start := time.Now()
-	defer func() {
-		addData(start, time.Since(start))
-	}()
-	if len(ts.XValues) == 0 {
-		http.Error(res, "no data (yet)", http.StatusBadRequest)
-		return
-	}
-	res.Header().Set("Content-Type", "image/png")
-	if err := graph.Render(chart.PNG, res); err != nil {
-		log.Printf("%v", err)
-	}
-}
-
-func main() {
-	ts = &chart.TimeSeries{
-		XValues: []time.Time{},
-		YValues: []float64{},
-	}
-	graph = &chart.Chart{
-		Series: []chart.Series{ts},
-	}
-	http.HandleFunc("/", drawChart)
-	log.Fatal(http.ListenAndServe(":8080", nil))
-}

_examples/scatter/main.go

@@ -4,39 +4,48 @@ import (
 	"log"
 	"net/http"
 
-	_ "net/http/pprof"
-
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/drawing"
-	"git.fireandbrimst.one/aw/go-chart/seq"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
-
-	viridisByY := func(xr, yr chart.Range, index int, x, y float64) drawing.Color {
-		return chart.Viridis(y, yr.GetMin(), yr.GetMax())
-	}
-
 	graph := chart.Chart{
 		Series: []chart.Series{
 			chart.ContinuousSeries{
 				Style: chart.Style{
-					Show:             true,
-					StrokeWidth:      chart.Disabled,
-					DotWidth:         5,
-					DotColorProvider: viridisByY,
+					Show:        true,
+					StrokeWidth: chart.Disabled,
+					DotWidth:    3,
 				},
-				XValues: seq.Range(0, 127),
-				YValues: seq.New(seq.NewRandom().WithLen(128).WithMax(1024)).Array(),
+				XValues: chart.Sequence.Random(32, 1024),
+				YValues: chart.Sequence.Random(32, 1024),
+			},
+			chart.ContinuousSeries{
+				Style: chart.Style{
+					Show:        true,
+					StrokeWidth: chart.Disabled,
+					DotWidth:    5,
+				},
+				XValues: chart.Sequence.Random(16, 1024),
+				YValues: chart.Sequence.Random(16, 1024),
+			},
+			chart.ContinuousSeries{
+				Style: chart.Style{
+					Show:        true,
+					StrokeWidth: chart.Disabled,
+					DotWidth:    7,
+				},
+				XValues: chart.Sequence.Random(8, 1024),
+				YValues: chart.Sequence.Random(8, 1024),
 			},
 		},
 	}
 
-	res.Header().Set("Content-Type", chart.ContentTypePNG)
+	res.Header().Set("Content-Type", "image/png")
 	err := graph.Render(chart.PNG, res)
 	if err != nil {
 		log.Println(err.Error())
 	}
+
 }
 
 func unit(res http.ResponseWriter, req *http.Request) {
@@ -44,20 +53,20 @@ func unit(res http.ResponseWriter, req *http.Request) {
 		Height: 50,
 		Width:  50,
 		Canvas: chart.Style{
-			Padding: chart.BoxZero,
+			Padding: chart.Box{IsSet: true},
 		},
 		Background: chart.Style{
-			Padding: chart.BoxZero,
+			Padding: chart.Box{IsSet: true},
 		},
 		Series: []chart.Series{
 			chart.ContinuousSeries{
-				XValues: seq.RangeWithStep(0, 4, 1),
-				YValues: seq.RangeWithStep(0, 4, 1),
+				XValues: chart.Sequence.Float64(0, 4, 1),
+				YValues: chart.Sequence.Float64(0, 4, 1),
 			},
 		},
 	}
 
-	res.Header().Set("Content-Type", chart.ContentTypePNG)
+	res.Header().Set("Content-Type", "image/png")
 	err := graph.Render(chart.PNG, res)
 	if err != nil {
 		log.Println(err.Error())

_examples/simple_moving_average/main.go

@@ -3,16 +3,20 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/seq"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
 
+	/*
+		In this example we add a new type of series, a `SimpleMovingAverageSeries` that takes another series as a required argument.
+		InnerSeries only needs to implement `ValueProvider`, so really you could chain `SimpleMovingAverageSeries` together if you wanted.
+	*/
+
 	mainSeries := chart.ContinuousSeries{
 		Name:    "A test series",
-		XValues: seq.Range(1.0, 100.0),             //generates a []float64 from 1.0 to 100.0 in 1.0 step increments, or 100 elements.
-		YValues: seq.RandomValuesWithMax(100, 100), //generates a []float64 randomly from 0 to 100 with 100 elements.
+		XValues: chart.Sequence.Float64(1.0, 100.0), //generates a []float64 from 1.0 to 100.0 in 1.0 step increments, or 100 elements.
+		YValues: chart.Sequence.Random(100, 100),    //generates a []float64 randomly from 0 to 100 with 100 elements.
 	}
 
 	// note we create a SimpleMovingAverage series by assignin the inner series.

_examples/stacked_bar/main.go

@@ -5,21 +5,18 @@ import (
 	"log"
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
 	sbc := chart.StackedBarChart{
-		Title:      "Test Stacked Bar Chart",
-		TitleStyle: chart.StyleShow(),
-		Background: chart.Style{
-			Padding: chart.Box{
-				Top: 40,
-			},
-		},
 		Height: 512,
-		XAxis:  chart.StyleShow(),
-		YAxis:  chart.StyleShow(),
+		XAxis: chart.Style{
+			Show: true,
+		},
+		YAxis: chart.Style{
+			Show: true,
+		},
 		Bars: []chart.StackedBar{
 			{
 				Name: "This is a very long string to test word break wrapping.",

_examples/stock_analysis/main.go

@@ -4,8 +4,8 @@ import (
 	"net/http"
 	"time"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/drawing"
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/drawing"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -43,11 +43,11 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	graph := chart.Chart{
 		XAxis: chart.XAxis{
-			Style:        chart.StyleShow(),
+			Style:        chart.Style{Show: true},
 			TickPosition: chart.TickPositionBetweenTicks,
 		},
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{Show: true},
 			Range: &chart.ContinuousRange{
 				Max: 220.0,
 				Min: 180.0,

_examples/text_rotation/main.go

@@ -3,8 +3,8 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/drawing"
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/drawing"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {

_examples/timeseries/main.go

@@ -4,17 +4,19 @@ import (
 	"net/http"
 	"time"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
 	/*
 	   This is an example of using the `TimeSeries` to automatically coerce time.Time values into a continuous xrange.
-	   Note: chart.TimeSeries implements `ValueFormatterProvider` and as a result gives the XAxis the appropriate formatter to use for the ticks.
+	   Note: chart.TimeSeries implements `ValueFormatterProvider` and as a result gives the XAxis the appropariate formatter to use for the ticks.
 	*/
 	graph := chart.Chart{
 		XAxis: chart.XAxis{
-			Style: chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 		},
 		Series: []chart.Series{
 			chart.TimeSeries{
@@ -46,7 +48,9 @@ func drawCustomChart(res http.ResponseWriter, req *http.Request) {
 	*/
 	graph := chart.Chart{
 		XAxis: chart.XAxis{
-			Style:          chart.StyleShow(),
+			Style: chart.Style{
+				Show: true,
+			},
 			ValueFormatter: chart.TimeHourValueFormatter,
 		},
 		Series: []chart.Series{
@@ -75,7 +79,7 @@ func drawCustomChart(res http.ResponseWriter, req *http.Request) {
 
 func main() {
 	http.HandleFunc("/", drawChart)
-	http.HandleFunc("/favicon.ico", func(res http.ResponseWriter, req *http.Request) {
+	http.HandleFunc("/favico.ico", func(res http.ResponseWriter, req *http.Request) {
 		res.Write([]byte{})
 	})
 	http.HandleFunc("/custom", drawCustomChart)

_examples/twoaxis/main.go

@@ -4,8 +4,7 @@ import (
 	"fmt"
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	util "git.fireandbrimst.one/aw/go-chart/util"
+	"github.com/wcharczuk/go-chart"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -18,19 +17,25 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	graph := chart.Chart{
 		XAxis: chart.XAxis{
-			Style:        chart.StyleShow(), //enables / displays the x-axis
+			Style: chart.Style{
+				Show: true, //enables / displays the x-axis
+			},
 			TickPosition: chart.TickPositionBetweenTicks,
 			ValueFormatter: func(v interface{}) string {
 				typed := v.(float64)
-				typedDate := util.Time.FromFloat64(typed)
+				typedDate := chart.Time.FromFloat64(typed)
 				return fmt.Sprintf("%d-%d\n%d", typedDate.Month(), typedDate.Day(), typedDate.Year())
 			},
 		},
 		YAxis: chart.YAxis{
-			Style: chart.StyleShow(), //enables / displays the y-axis
+			Style: chart.Style{
+				Show: true, //enables / displays the y-axis
+			},
 		},
 		YAxisSecondary: chart.YAxis{
-			Style: chart.StyleShow(), //enables / displays the secondary y-axis
+			Style: chart.Style{
+				Show: true, //enables / displays the secondary y-axis
+			},
 		},
 		Series: []chart.Series{
 			chart.ContinuousSeries{

_examples/twopoint/main.go

@@ -4,8 +4,8 @@ import (
 	"bytes"
 	"log"
 	"os"
-
-	"git.fireandbrimst.one/aw/go-chart"
+	//"time"
+	"github.com/wcharczuk/go-chart" //exposes "chart"
 )
 
 func main() {
@@ -14,8 +14,12 @@ func main() {
 	b = 1000
 
 	ts1 := chart.ContinuousSeries{ //TimeSeries{
-		Name:    "Time Series",
-		Style:   chart.StyleShow(),
+		Name: "Time Series",
+		Style: chart.Style{
+			Show: true,
+		},
+
+		//XValues: []time.Time{time.Unix(3*b,0),time.Unix(4*b,0),time.Unix(5*b,0),time.Unix(6*b,0),time.Unix(7*b,0),time.Unix(8*b,0),time.Unix(9*b,0),time.Unix(10*b,0)},
 		XValues: []float64{10 * b, 20 * b, 30 * b, 40 * b, 50 * b, 60 * b, 70 * b, 80 * b},
 		YValues: []float64{1.0, 2.0, 30.0, 4.0, 50.0, 6.0, 7.0, 88.0},
 	}

annotation_series.go

@@ -3,13 +3,6 @@ package chart
 import (
 	"fmt"
 	"math"
-
-	util "git.fireandbrimst.one/aw/go-chart/util"
-)
-
-// Interface Assertions.
-var (
-	_ Series = (*AnnotationSeries)(nil)
 )
 
 // AnnotationSeries is a series of labels on the chart.
@@ -62,10 +55,10 @@ func (as AnnotationSeries) Measure(r Renderer, canvasBox Box, xrange, yrange Ran
 			lx := canvasBox.Left + xrange.Translate(a.XValue)
 			ly := canvasBox.Bottom - yrange.Translate(a.YValue)
 			ab := Draw.MeasureAnnotation(r, canvasBox, style, lx, ly, a.Label)
-			box.Top = util.Math.MinInt(box.Top, ab.Top)
-			box.Left = util.Math.MinInt(box.Left, ab.Left)
-			box.Right = util.Math.MaxInt(box.Right, ab.Right)
-			box.Bottom = util.Math.MaxInt(box.Bottom, ab.Bottom)
+			box.Top = Math.MinInt(box.Top, ab.Top)
+			box.Left = Math.MinInt(box.Left, ab.Left)
+			box.Right = Math.MaxInt(box.Right, ab.Right)
+			box.Bottom = Math.MaxInt(box.Bottom, ab.Bottom)
 		}
 	}
 	return box

annotation_series_test.go

@@ -0,0 +1,119 @@
+package chart
+
+import (
+	"image/color"
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/drawing"
+)
+
+func TestAnnotationSeriesMeasure(t *testing.T) {
+	assert := assert.New(t)
+
+	as := AnnotationSeries{
+		Style: Style{
+			Show: true,
+		},
+		Annotations: []Value2{
+			{XValue: 1.0, YValue: 1.0, Label: "1.0"},
+			{XValue: 2.0, YValue: 2.0, Label: "2.0"},
+			{XValue: 3.0, YValue: 3.0, Label: "3.0"},
+			{XValue: 4.0, YValue: 4.0, Label: "4.0"},
+		},
+	}
+
+	r, err := PNG(110, 110)
+	assert.Nil(err)
+
+	f, err := GetDefaultFont()
+	assert.Nil(err)
+
+	xrange := &ContinuousRange{
+		Min:    1.0,
+		Max:    4.0,
+		Domain: 100,
+	}
+	yrange := &ContinuousRange{
+		Min:    1.0,
+		Max:    4.0,
+		Domain: 100,
+	}
+
+	cb := Box{
+		Top:    5,
+		Left:   5,
+		Right:  105,
+		Bottom: 105,
+	}
+	sd := Style{
+		FontSize: 10.0,
+		Font:     f,
+	}
+
+	box := as.Measure(r, cb, xrange, yrange, sd)
+	assert.False(box.IsZero())
+	assert.Equal(-5.0, box.Top)
+	assert.Equal(5.0, box.Left)
+	assert.Equal(146.0, box.Right) //the top,left annotation sticks up 5px and out ~44px.
+	assert.Equal(115.0, box.Bottom)
+}
+
+func TestAnnotationSeriesRender(t *testing.T) {
+	assert := assert.New(t)
+
+	as := AnnotationSeries{
+		Style: Style{
+			Show:        true,
+			FillColor:   drawing.ColorWhite,
+			StrokeColor: drawing.ColorBlack,
+		},
+		Annotations: []Value2{
+			{XValue: 1.0, YValue: 1.0, Label: "1.0"},
+			{XValue: 2.0, YValue: 2.0, Label: "2.0"},
+			{XValue: 3.0, YValue: 3.0, Label: "3.0"},
+			{XValue: 4.0, YValue: 4.0, Label: "4.0"},
+		},
+	}
+
+	r, err := PNG(110, 110)
+	assert.Nil(err)
+
+	f, err := GetDefaultFont()
+	assert.Nil(err)
+
+	xrange := &ContinuousRange{
+		Min:    1.0,
+		Max:    4.0,
+		Domain: 100,
+	}
+	yrange := &ContinuousRange{
+		Min:    1.0,
+		Max:    4.0,
+		Domain: 100,
+	}
+
+	cb := Box{
+		Top:    5,
+		Left:   5,
+		Right:  105,
+		Bottom: 105,
+	}
+	sd := Style{
+		FontSize: 10.0,
+		Font:     f,
+	}
+
+	as.Render(r, cb, xrange, yrange, sd)
+
+	rr, isRaster := r.(*rasterRenderer)
+	assert.True(isRaster)
+	assert.NotNil(rr)
+
+	c := rr.i.At(38, 70)
+	converted, isRGBA := color.RGBAModel.Convert(c).(color.RGBA)
+	assert.True(isRGBA)
+	assert.Equal(0, converted.R)
+	assert.Equal(0, converted.G)
+	assert.Equal(0, converted.B)
+}

bar_chart.go

@@ -6,8 +6,7 @@ import (
 	"io"
 	"math"
 
-	util "git.fireandbrimst.one/aw/go-chart/util"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/truetype"
 )
 
 // BarChart is a chart that draws bars on a range.
@@ -15,8 +14,6 @@ type BarChart struct {
 	Title      string
 	TitleStyle Style
 
-	ColorPalette ColorPalette
-
 	Width  int
 	Height int
 	DPI    float64
@@ -31,9 +28,6 @@ type BarChart struct {
 
 	BarSpacing int
 
-	UseBaseValue bool
-	BaseValue    float64
-
 	Font        *truetype.Font
 	defaultFont *truetype.Font
 
@@ -129,7 +123,7 @@ func (bc BarChart) Render(rp RendererProvider, w io.Writer) error {
 		canvasBox = bc.getAdjustedCanvasBox(r, canvasBox, yr, yt)
 		yr = bc.setRangeDomains(canvasBox, yr)
 	}
-	bc.drawCanvas(r, canvasBox)
+
 	bc.drawBars(r, canvasBox, yr)
 	bc.drawXAxis(r, canvasBox)
 	bc.drawYAxis(r, canvasBox, yr, yt)
@@ -142,10 +136,6 @@ func (bc BarChart) Render(rp RendererProvider, w io.Writer) error {
 	return r.Save(w)
 }
 
-func (bc BarChart) drawCanvas(r Renderer, canvasBox Box) {
-	Draw.Box(r, canvasBox, bc.getCanvasStyle())
-}
-
 func (bc BarChart) getRanges() Range {
 	var yrange Range
 	if bc.YAxis.Range != nil && !bc.YAxis.Range.IsZero() {
@@ -202,20 +192,11 @@ func (bc BarChart) drawBars(r Renderer, canvasBox Box, yr Range) {
 
 		by = canvasBox.Bottom - yr.Translate(bar.Value)
 
-		if bc.UseBaseValue {
-			barBox = Box{
-				Top:    by,
-				Left:   bxl,
-				Right:  bxr,
-				Bottom: canvasBox.Bottom - yr.Translate(bc.BaseValue),
-			}
-		} else {
-			barBox = Box{
-				Top:    by,
-				Left:   bxl,
-				Right:  bxr,
-				Bottom: canvasBox.Bottom,
-			}
+		barBox = Box{
+			Top:    by,
+			Left:   bxl,
+			Right:  bxr,
+			Bottom: canvasBox.Bottom,
 		}
 
 		Draw.Box(r, barBox, bar.Style.InheritFrom(bc.styleDefaultsBar(index)))
@@ -296,32 +277,7 @@ func (bc BarChart) drawYAxis(r Renderer, canvasBox Box, yr Range, ticks []Tick)
 
 func (bc BarChart) drawTitle(r Renderer) {
 	if len(bc.Title) > 0 && bc.TitleStyle.Show {
-		r.SetFont(bc.TitleStyle.GetFont(bc.GetFont()))
-		r.SetFontColor(bc.TitleStyle.GetFontColor(bc.GetColorPalette().TextColor()))
-		titleFontSize := bc.TitleStyle.GetFontSize(bc.getTitleFontSize())
-		r.SetFontSize(titleFontSize)
-
-		textBox := r.MeasureText(bc.Title)
-
-		textWidth := textBox.Width()
-		textHeight := textBox.Height()
-
-		titleX := (bc.GetWidth() >> 1) - (textWidth >> 1)
-		titleY := bc.TitleStyle.Padding.GetTop(DefaultTitleTop) + textHeight
-
-		r.Text(bc.Title, titleX, titleY)
-	}
-}
-
-func (bc BarChart) getCanvasStyle() Style {
-	return bc.Canvas.InheritFrom(bc.styleDefaultsCanvas())
-}
-
-func (bc BarChart) styleDefaultsCanvas() Style {
-	return Style{
-		FillColor:   bc.GetColorPalette().CanvasColor(),
-		StrokeColor: bc.GetColorPalette().CanvasStrokeColor(),
-		StrokeWidth: DefaultCanvasStrokeWidth,
+		Draw.TextWithin(r, bc.Title, bc.box(), bc.styleDefaultsTitle())
 	}
 }
 
@@ -410,7 +366,7 @@ func (bc BarChart) getAdjustedCanvasBox(r Renderer, canvasBox Box, yrange Range,
 				lines := Text.WrapFit(r, bar.Label, barLabelBox.Width(), axisStyle)
 				linesBox := Text.MeasureLines(r, lines, axisStyle)
 
-				xaxisHeight = util.Math.MinInt(linesBox.Height()+(2*DefaultXAxisMargin), xaxisHeight)
+				xaxisHeight = Math.MinInt(linesBox.Height()+(2*DefaultXAxisMargin), xaxisHeight)
 			}
 		}
 
@@ -438,8 +394,8 @@ func (bc BarChart) box() Box {
 	dpb := bc.Background.Padding.GetBottom(50)
 
 	return Box{
-		Top:    bc.Background.Padding.GetTop(20),
-		Left:   bc.Background.Padding.GetLeft(20),
+		Top:    20,
+		Left:   20,
 		Right:  bc.GetWidth() - dpr,
 		Bottom: bc.GetHeight() - dpb,
 	}
@@ -451,23 +407,23 @@ func (bc BarChart) getBackgroundStyle() Style {
 
 func (bc BarChart) styleDefaultsBackground() Style {
 	return Style{
-		FillColor:   bc.GetColorPalette().BackgroundColor(),
-		StrokeColor: bc.GetColorPalette().BackgroundStrokeColor(),
+		FillColor:   DefaultBackgroundColor,
+		StrokeColor: DefaultBackgroundStrokeColor,
 		StrokeWidth: DefaultStrokeWidth,
 	}
 }
 
 func (bc BarChart) styleDefaultsBar(index int) Style {
 	return Style{
-		StrokeColor: bc.GetColorPalette().GetSeriesColor(index),
+		StrokeColor: GetAlternateColor(index),
 		StrokeWidth: 3.0,
-		FillColor:   bc.GetColorPalette().GetSeriesColor(index),
+		FillColor:   GetAlternateColor(index),
 	}
 }
 
 func (bc BarChart) styleDefaultsTitle() Style {
 	return bc.TitleStyle.InheritFrom(Style{
-		FontColor:           bc.GetColorPalette().TextColor(),
+		FontColor:           DefaultTextColor,
 		Font:                bc.GetFont(),
 		FontSize:            bc.getTitleFontSize(),
 		TextHorizontalAlign: TextHorizontalAlignCenter,
@@ -477,7 +433,7 @@ func (bc BarChart) styleDefaultsTitle() Style {
 }
 
 func (bc BarChart) getTitleFontSize() float64 {
-	effectiveDimension := util.Math.MinInt(bc.GetWidth(), bc.GetHeight())
+	effectiveDimension := Math.MinInt(bc.GetWidth(), bc.GetHeight())
 	if effectiveDimension >= 2048 {
 		return 48
 	} else if effectiveDimension >= 1024 {
@@ -492,10 +448,10 @@ func (bc BarChart) getTitleFontSize() float64 {
 
 func (bc BarChart) styleDefaultsAxes() Style {
 	return Style{
-		StrokeColor:         bc.GetColorPalette().AxisStrokeColor(),
+		StrokeColor:         DefaultAxisColor,
 		Font:                bc.GetFont(),
 		FontSize:            DefaultAxisFontSize,
-		FontColor:           bc.GetColorPalette().TextColor(),
+		FontColor:           DefaultAxisColor,
 		TextHorizontalAlign: TextHorizontalAlignCenter,
 		TextVerticalAlign:   TextVerticalAlignTop,
 		TextWrap:            TextWrapWord,
@@ -507,11 +463,3 @@ func (bc BarChart) styleDefaultsElements() Style {
 		Font: bc.GetFont(),
 	}
 }
-
-// GetColorPalette returns the color palette for the chart.
-func (bc BarChart) GetColorPalette() ColorPalette {
-	if bc.ColorPalette != nil {
-		return bc.ColorPalette
-	}
-	return AlternateColorPalette
-}

bar_chart_test.go

@@ -0,0 +1,320 @@
+package chart
+
+import (
+	"bytes"
+	"math"
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+func TestBarChartRender(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		Width:      1024,
+		Title:      "Test Title",
+		TitleStyle: StyleShow(),
+		XAxis:      StyleShow(),
+		YAxis: YAxis{
+			Style: StyleShow(),
+		},
+		Bars: []Value{
+			{Value: 1.0, Label: "One"},
+			{Value: 2.0, Label: "Two"},
+			{Value: 3.0, Label: "Three"},
+			{Value: 4.0, Label: "Four"},
+			{Value: 5.0, Label: "Five"},
+		},
+	}
+
+	buf := bytes.NewBuffer([]byte{})
+	err := bc.Render(PNG, buf)
+	assert.Nil(err)
+	assert.NotZero(buf.Len())
+}
+
+func TestBarChartRenderZero(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		Width:      1024,
+		Title:      "Test Title",
+		TitleStyle: StyleShow(),
+		XAxis:      StyleShow(),
+		YAxis: YAxis{
+			Style: StyleShow(),
+		},
+		Bars: []Value{
+			{Value: 0.0, Label: "One"},
+			{Value: 0.0, Label: "Two"},
+		},
+	}
+
+	buf := bytes.NewBuffer([]byte{})
+	err := bc.Render(PNG, buf)
+	assert.NotNil(err)
+}
+
+func TestBarChartProps(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+
+	assert.Equal(DefaultDPI, bc.GetDPI())
+	bc.DPI = 100
+	assert.Equal(100, bc.GetDPI())
+
+	assert.Nil(bc.GetFont())
+	f, err := GetDefaultFont()
+	assert.Nil(err)
+	bc.Font = f
+	assert.NotNil(bc.GetFont())
+
+	assert.Equal(DefaultChartWidth, bc.GetWidth())
+	bc.Width = DefaultChartWidth - 1
+	assert.Equal(DefaultChartWidth-1, bc.GetWidth())
+
+	assert.Equal(DefaultChartHeight, bc.GetHeight())
+	bc.Height = DefaultChartHeight - 1
+	assert.Equal(DefaultChartHeight-1, bc.GetHeight())
+
+	assert.Equal(DefaultBarSpacing, bc.GetBarSpacing())
+	bc.BarSpacing = 150
+	assert.Equal(150, bc.GetBarSpacing())
+
+	assert.Equal(DefaultBarWidth, bc.GetBarWidth())
+	bc.BarWidth = 75
+	assert.Equal(75, bc.GetBarWidth())
+}
+
+func TestBarChartRenderNoBars(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+	err := bc.Render(PNG, bytes.NewBuffer([]byte{}))
+	assert.NotNil(err)
+}
+
+func TestBarChartGetRanges(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+
+	yr := bc.getRanges()
+	assert.NotNil(yr)
+	assert.False(yr.IsZero())
+
+	assert.Equal(-math.MaxFloat64, yr.GetMax())
+	assert.Equal(math.MaxFloat64, yr.GetMin())
+}
+
+func TestBarChartGetRangesBarsMinMax(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		Bars: []Value{
+			{Value: 1.0},
+			{Value: 10.0},
+		},
+	}
+
+	yr := bc.getRanges()
+	assert.NotNil(yr)
+	assert.False(yr.IsZero())
+
+	assert.Equal(10, yr.GetMax())
+	assert.Equal(1, yr.GetMin())
+}
+
+func TestBarChartGetRangesMinMax(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		YAxis: YAxis{
+			Range: &ContinuousRange{
+				Min: 5.0,
+				Max: 15.0,
+			},
+			Ticks: []Tick{
+				{Value: 7.0, Label: "Foo"},
+				{Value: 11.0, Label: "Foo2"},
+			},
+		},
+		Bars: []Value{
+			{Value: 1.0},
+			{Value: 10.0},
+		},
+	}
+
+	yr := bc.getRanges()
+	assert.NotNil(yr)
+	assert.False(yr.IsZero())
+
+	assert.Equal(15, yr.GetMax())
+	assert.Equal(5, yr.GetMin())
+}
+
+func TestBarChartGetRangesTicksMinMax(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		YAxis: YAxis{
+			Ticks: []Tick{
+				{Value: 7.0, Label: "Foo"},
+				{Value: 11.0, Label: "Foo2"},
+			},
+		},
+		Bars: []Value{
+			{Value: 1.0},
+			{Value: 10.0},
+		},
+	}
+
+	yr := bc.getRanges()
+	assert.NotNil(yr)
+	assert.False(yr.IsZero())
+
+	assert.Equal(11, yr.GetMax())
+	assert.Equal(7, yr.GetMin())
+}
+
+func TestBarChartHasAxes(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+	assert.False(bc.hasAxes())
+	bc.YAxis = YAxis{
+		Style: StyleShow(),
+	}
+
+	assert.True(bc.hasAxes())
+}
+
+func TestBarChartGetDefaultCanvasBox(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+	b := bc.getDefaultCanvasBox()
+	assert.False(b.IsZero())
+}
+
+func TestBarChartSetRangeDomains(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+	cb := bc.box()
+	yr := bc.getRanges()
+	yr2 := bc.setRangeDomains(cb, yr)
+	assert.NotZero(yr2.GetDomain())
+}
+
+func TestBarChartGetValueFormatters(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{}
+	vf := bc.getValueFormatters()
+	assert.NotNil(vf)
+	assert.Equal("1234.00", vf(1234.0))
+
+	bc.YAxis.ValueFormatter = func(_ interface{}) string { return "test" }
+	assert.Equal("test", bc.getValueFormatters()(1234))
+}
+
+func TestBarChartGetAxesTicks(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		Bars: []Value{
+			{Value: 1.0},
+			{Value: 2.0},
+			{Value: 3.0},
+		},
+	}
+
+	r, err := PNG(128, 128)
+	assert.Nil(err)
+	yr := bc.getRanges()
+	yf := bc.getValueFormatters()
+
+	ticks := bc.getAxesTicks(r, yr, yf)
+	assert.Empty(ticks)
+
+	bc.YAxis.Style.Show = true
+	ticks = bc.getAxesTicks(r, yr, yf)
+	assert.Len(ticks, 2)
+}
+
+func TestBarChartCalculateEffectiveBarSpacing(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		Width:    1024,
+		BarWidth: 10,
+		Bars: []Value{
+			{Value: 1.0, Label: "One"},
+			{Value: 2.0, Label: "Two"},
+			{Value: 3.0, Label: "Three"},
+			{Value: 4.0, Label: "Four"},
+			{Value: 5.0, Label: "Five"},
+		},
+	}
+
+	spacing := bc.calculateEffectiveBarSpacing(bc.box())
+	assert.NotZero(spacing)
+
+	bc.BarWidth = 250
+	spacing = bc.calculateEffectiveBarSpacing(bc.box())
+	assert.Zero(spacing)
+}
+
+func TestBarChartCalculateEffectiveBarWidth(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BarChart{
+		Width:    1024,
+		BarWidth: 10,
+		Bars: []Value{
+			{Value: 1.0, Label: "One"},
+			{Value: 2.0, Label: "Two"},
+			{Value: 3.0, Label: "Three"},
+			{Value: 4.0, Label: "Four"},
+			{Value: 5.0, Label: "Five"},
+		},
+	}
+
+	cb := bc.box()
+
+	spacing := bc.calculateEffectiveBarSpacing(bc.box())
+	assert.NotZero(spacing)
+
+	barWidth := bc.calculateEffectiveBarWidth(bc.box(), spacing)
+	assert.Equal(10, barWidth)
+
+	bc.BarWidth = 250
+	spacing = bc.calculateEffectiveBarSpacing(bc.box())
+	assert.Zero(spacing)
+	barWidth = bc.calculateEffectiveBarWidth(bc.box(), spacing)
+	assert.Equal(199, barWidth)
+
+	assert.Equal(cb.Width()+1, bc.calculateTotalBarWidth(barWidth, spacing))
+
+	bw, bs, total := bc.calculateScaledTotalWidth(cb)
+	assert.Equal(spacing, bs)
+	assert.Equal(barWidth, bw)
+	assert.Equal(cb.Width()+1, total)
+}
+
+func TestBarChatGetTitleFontSize(t *testing.T) {
+	assert := assert.New(t)
+	size := BarChart{Width: 2049, Height: 2049}.getTitleFontSize()
+	assert.Equal(48, size)
+	size = BarChart{Width: 1025, Height: 1025}.getTitleFontSize()
+	assert.Equal(24, size)
+	size = BarChart{Width: 513, Height: 513}.getTitleFontSize()
+	assert.Equal(18, size)
+	size = BarChart{Width: 257, Height: 257}.getTitleFontSize()
+	assert.Equal(12, size)
+	size = BarChart{Width: 128, Height: 128}.getTitleFontSize()
+	assert.Equal(10, size)
+}

bollinger_band_series.go

@@ -2,13 +2,7 @@ package chart
 
 import (
 	"fmt"
-
-	"git.fireandbrimst.one/aw/go-chart/seq"
-)
-
-// Interface Assertions.
-var (
-	_ Series = (*BollingerBandsSeries)(nil)
+	"math"
 )
 
 // BollingerBandsSeries draws bollinger bands for an inner series.
@@ -20,9 +14,9 @@ type BollingerBandsSeries struct {
 
 	Period      int
 	K           float64
-	InnerSeries ValuesProvider
+	InnerSeries ValueProvider
 
-	valueBuffer *seq.Buffer
+	valueBuffer *RingBuffer
 }
 
 // GetName returns the name of the time series.
@@ -48,9 +42,7 @@ func (bbs BollingerBandsSeries) GetPeriod() int {
 	return bbs.Period
 }
 
-// GetK returns the K value, or the number of standard deviations above and below
-// to band the simple moving average with.
-// Typical K value is 2.0.
+// GetK returns the K value.
 func (bbs BollingerBandsSeries) GetK(defaults ...float64) float64 {
 	if bbs.K == 0 {
 		if len(defaults) > 0 {
@@ -62,35 +54,35 @@ func (bbs BollingerBandsSeries) GetK(defaults ...float64) float64 {
 }
 
 // Len returns the number of elements in the series.
-func (bbs BollingerBandsSeries) Len() int {
+func (bbs *BollingerBandsSeries) Len() int {
 	return bbs.InnerSeries.Len()
 }
 
-// GetBoundedValues gets the bounded value for the series.
-func (bbs *BollingerBandsSeries) GetBoundedValues(index int) (x, y1, y2 float64) {
+// GetBoundedValue gets the bounded value for the series.
+func (bbs *BollingerBandsSeries) GetBoundedValue(index int) (x, y1, y2 float64) {
 	if bbs.InnerSeries == nil {
 		return
 	}
 	if bbs.valueBuffer == nil || index == 0 {
-		bbs.valueBuffer = seq.NewBufferWithCapacity(bbs.GetPeriod())
+		bbs.valueBuffer = NewRingBufferWithCapacity(bbs.GetPeriod())
 	}
 	if bbs.valueBuffer.Len() >= bbs.GetPeriod() {
 		bbs.valueBuffer.Dequeue()
 	}
-	px, py := bbs.InnerSeries.GetValues(index)
+	px, py := bbs.InnerSeries.GetValue(index)
 	bbs.valueBuffer.Enqueue(py)
 	x = px
 
-	ay := seq.New(bbs.valueBuffer).Average()
-	std := seq.New(bbs.valueBuffer).StdDev()
+	ay := bbs.getAverage(bbs.valueBuffer)
+	std := bbs.getStdDev(bbs.valueBuffer)
 
 	y1 = ay + (bbs.GetK() * std)
 	y2 = ay - (bbs.GetK() * std)
 	return
 }
 
-// GetBoundedLastValues returns the last bounded value for the series.
-func (bbs *BollingerBandsSeries) GetBoundedLastValues() (x, y1, y2 float64) {
+// GetBoundedLastValue returns the last bounded value for the series.
+func (bbs *BollingerBandsSeries) GetBoundedLastValue() (x, y1, y2 float64) {
 	if bbs.InnerSeries == nil {
 		return
 	}
@@ -101,15 +93,15 @@ func (bbs *BollingerBandsSeries) GetBoundedLastValues() (x, y1, y2 float64) {
 		startAt = 0
 	}
 
-	vb := seq.NewBufferWithCapacity(period)
+	vb := NewRingBufferWithCapacity(period)
 	for index := startAt; index < seriesLength; index++ {
-		xn, yn := bbs.InnerSeries.GetValues(index)
+		xn, yn := bbs.InnerSeries.GetValue(index)
 		vb.Enqueue(yn)
 		x = xn
 	}
 
-	ay := seq.Seq{Provider: vb}.Average()
-	std := seq.Seq{Provider: vb}.StdDev()
+	ay := bbs.getAverage(vb)
+	std := bbs.getStdDev(vb)
 
 	y1 = ay + (bbs.GetK() * std)
 	y2 = ay - (bbs.GetK() * std)
@@ -128,6 +120,37 @@ func (bbs *BollingerBandsSeries) Render(r Renderer, canvasBox Box, xrange, yrang
 	Draw.BoundedSeries(r, canvasBox, xrange, yrange, s, bbs, bbs.GetPeriod())
 }
 
+func (bbs BollingerBandsSeries) getAverage(valueBuffer *RingBuffer) float64 {
+	var accum float64
+	valueBuffer.Each(func(v interface{}) {
+		if typed, isTyped := v.(float64); isTyped {
+			accum += typed
+		}
+	})
+	return accum / float64(valueBuffer.Len())
+}
+
+func (bbs BollingerBandsSeries) getVariance(valueBuffer *RingBuffer) float64 {
+	if valueBuffer.Len() == 0 {
+		return 0
+	}
+
+	var variance float64
+	m := bbs.getAverage(valueBuffer)
+
+	valueBuffer.Each(func(v interface{}) {
+		if n, isTyped := v.(float64); isTyped {
+			variance += (float64(n) - m) * (float64(n) - m)
+		}
+	})
+
+	return variance / float64(valueBuffer.Len())
+}
+
+func (bbs BollingerBandsSeries) getStdDev(valueBuffer *RingBuffer) float64 {
+	return math.Pow(bbs.getVariance(valueBuffer), 0.5)
+}
+
 // Validate validates the series.
 func (bbs BollingerBandsSeries) Validate() error {
 	if bbs.InnerSeries == nil {

bollinger_band_series_test.go

@@ -0,0 +1,51 @@
+package chart
+
+import (
+	"math"
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+)
+
+func TestBollingerBandSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	s1 := mockValueProvider{
+		X: Sequence.Float64(1.0, 100.0),
+		Y: Sequence.Random(100, 1024),
+	}
+
+	bbs := &BollingerBandsSeries{
+		InnerSeries: s1,
+	}
+
+	xvalues := make([]float64, 100)
+	y1values := make([]float64, 100)
+	y2values := make([]float64, 100)
+
+	for x := 0; x < 100; x++ {
+		xvalues[x], y1values[x], y2values[x] = bbs.GetBoundedValue(x)
+	}
+
+	for x := bbs.GetPeriod(); x < 100; x++ {
+		assert.True(y1values[x] > y2values[x])
+	}
+}
+
+func TestBollingerBandLastValue(t *testing.T) {
+	assert := assert.New(t)
+
+	s1 := mockValueProvider{
+		X: Sequence.Float64(1.0, 100.0),
+		Y: Sequence.Float64(1.0, 100.0),
+	}
+
+	bbs := &BollingerBandsSeries{
+		InnerSeries: s1,
+	}
+
+	x, y1, y2 := bbs.GetBoundedLastValue()
+	assert.Equal(100.0, x)
+	assert.Equal(101, math.Floor(y1))
+	assert.Equal(83, math.Floor(y2))
+}

box.go

@@ -3,8 +3,6 @@ package chart
 import (
 	"fmt"
 	"math"
-
-	util "git.fireandbrimst.one/aw/go-chart/util"
 )
 
 var (
@@ -91,12 +89,12 @@ func (b Box) GetBottom(defaults ...int) int {
 
 // Width returns the width
 func (b Box) Width() int {
-	return util.Math.AbsInt(b.Right - b.Left)
+	return Math.AbsInt(b.Right - b.Left)
 }
 
 // Height returns the height
 func (b Box) Height() int {
-	return util.Math.AbsInt(b.Bottom - b.Top)
+	return Math.AbsInt(b.Bottom - b.Top)
 }
 
 // Center returns the center of the box
@@ -148,10 +146,10 @@ func (b Box) Equals(other Box) bool {
 // Grow grows a box based on another box.
 func (b Box) Grow(other Box) Box {
 	return Box{
-		Top:    util.Math.MinInt(b.Top, other.Top),
-		Left:   util.Math.MinInt(b.Left, other.Left),
-		Right:  util.Math.MaxInt(b.Right, other.Right),
-		Bottom: util.Math.MaxInt(b.Bottom, other.Bottom),
+		Top:    Math.MinInt(b.Top, other.Top),
+		Left:   Math.MinInt(b.Left, other.Left),
+		Right:  Math.MaxInt(b.Right, other.Right),
+		Bottom: Math.MaxInt(b.Bottom, other.Bottom),
 	}
 }
 
@@ -222,10 +220,10 @@ func (b Box) Fit(other Box) Box {
 func (b Box) Constrain(other Box) Box {
 	newBox := b.Clone()
 
-	newBox.Top = util.Math.MaxInt(newBox.Top, other.Top)
-	newBox.Left = util.Math.MaxInt(newBox.Left, other.Left)
-	newBox.Right = util.Math.MinInt(newBox.Right, other.Right)
-	newBox.Bottom = util.Math.MinInt(newBox.Bottom, other.Bottom)
+	newBox.Top = Math.MaxInt(newBox.Top, other.Top)
+	newBox.Left = Math.MaxInt(newBox.Left, other.Left)
+	newBox.Right = Math.MinInt(newBox.Right, other.Right)
+	newBox.Bottom = Math.MinInt(newBox.Bottom, other.Bottom)
 
 	return newBox
 }
@@ -264,36 +262,36 @@ type BoxCorners struct {
 // Box return the BoxCorners as a regular box.
 func (bc BoxCorners) Box() Box {
 	return Box{
-		Top:    util.Math.MinInt(bc.TopLeft.Y, bc.TopRight.Y),
-		Left:   util.Math.MinInt(bc.TopLeft.X, bc.BottomLeft.X),
-		Right:  util.Math.MaxInt(bc.TopRight.X, bc.BottomRight.X),
-		Bottom: util.Math.MaxInt(bc.BottomLeft.Y, bc.BottomRight.Y),
+		Top:    Math.MinInt(bc.TopLeft.Y, bc.TopRight.Y),
+		Left:   Math.MinInt(bc.TopLeft.X, bc.BottomLeft.X),
+		Right:  Math.MaxInt(bc.TopRight.X, bc.BottomRight.X),
+		Bottom: Math.MaxInt(bc.BottomLeft.Y, bc.BottomRight.Y),
 	}
 }
 
 // Width returns the width
 func (bc BoxCorners) Width() int {
-	minLeft := util.Math.MinInt(bc.TopLeft.X, bc.BottomLeft.X)
-	maxRight := util.Math.MaxInt(bc.TopRight.X, bc.BottomRight.X)
+	minLeft := Math.MinInt(bc.TopLeft.X, bc.BottomLeft.X)
+	maxRight := Math.MaxInt(bc.TopRight.X, bc.BottomRight.X)
 	return maxRight - minLeft
 }
 
 // Height returns the height
 func (bc BoxCorners) Height() int {
-	minTop := util.Math.MinInt(bc.TopLeft.Y, bc.TopRight.Y)
-	maxBottom := util.Math.MaxInt(bc.BottomLeft.Y, bc.BottomRight.Y)
+	minTop := Math.MinInt(bc.TopLeft.Y, bc.TopRight.Y)
+	maxBottom := Math.MaxInt(bc.BottomLeft.Y, bc.BottomRight.Y)
 	return maxBottom - minTop
 }
 
 // Center returns the center of the box
 func (bc BoxCorners) Center() (x, y int) {
 
-	left := util.Math.MeanInt(bc.TopLeft.X, bc.BottomLeft.X)
-	right := util.Math.MeanInt(bc.TopRight.X, bc.BottomRight.X)
+	left := Math.MeanInt(bc.TopLeft.X, bc.BottomLeft.X)
+	right := Math.MeanInt(bc.TopRight.X, bc.BottomRight.X)
 	x = ((right - left) >> 1) + left
 
-	top := util.Math.MeanInt(bc.TopLeft.Y, bc.TopRight.Y)
-	bottom := util.Math.MeanInt(bc.BottomLeft.Y, bc.BottomRight.Y)
+	top := Math.MeanInt(bc.TopLeft.Y, bc.TopRight.Y)
+	bottom := Math.MeanInt(bc.BottomLeft.Y, bc.BottomRight.Y)
 	y = ((bottom - top) >> 1) + top
 
 	return
@@ -303,12 +301,12 @@ func (bc BoxCorners) Center() (x, y int) {
 func (bc BoxCorners) Rotate(thetaDegrees float64) BoxCorners {
 	cx, cy := bc.Center()
 
-	thetaRadians := util.Math.DegreesToRadians(thetaDegrees)
+	thetaRadians := Math.DegreesToRadians(thetaDegrees)
 
-	tlx, tly := util.Math.RotateCoordinate(cx, cy, bc.TopLeft.X, bc.TopLeft.Y, thetaRadians)
-	trx, try := util.Math.RotateCoordinate(cx, cy, bc.TopRight.X, bc.TopRight.Y, thetaRadians)
-	brx, bry := util.Math.RotateCoordinate(cx, cy, bc.BottomRight.X, bc.BottomRight.Y, thetaRadians)
-	blx, bly := util.Math.RotateCoordinate(cx, cy, bc.BottomLeft.X, bc.BottomLeft.Y, thetaRadians)
+	tlx, tly := Math.RotateCoordinate(cx, cy, bc.TopLeft.X, bc.TopLeft.Y, thetaRadians)
+	trx, try := Math.RotateCoordinate(cx, cy, bc.TopRight.X, bc.TopRight.Y, thetaRadians)
+	brx, bry := Math.RotateCoordinate(cx, cy, bc.BottomRight.X, bc.BottomRight.Y, thetaRadians)
+	blx, bly := Math.RotateCoordinate(cx, cy, bc.BottomLeft.X, bc.BottomLeft.Y, thetaRadians)
 
 	return BoxCorners{
 		TopLeft:     Point{tlx, tly},

box_test.go

@@ -0,0 +1,188 @@
+package chart
+
+import (
+	"math"
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+)
+
+func TestBoxClone(t *testing.T) {
+	assert := assert.New(t)
+	a := Box{Top: 5, Left: 5, Right: 15, Bottom: 15}
+	b := a.Clone()
+	assert.True(a.Equals(b))
+	assert.True(b.Equals(a))
+}
+
+func TestBoxEquals(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 5, Left: 5, Right: 15, Bottom: 15}
+	b := Box{Top: 10, Left: 10, Right: 30, Bottom: 30}
+	c := Box{Top: 5, Left: 5, Right: 15, Bottom: 15}
+	assert.True(a.Equals(a))
+	assert.True(a.Equals(c))
+	assert.True(c.Equals(a))
+	assert.False(a.Equals(b))
+	assert.False(c.Equals(b))
+	assert.False(b.Equals(a))
+	assert.False(b.Equals(c))
+}
+
+func TestBoxIsBiggerThan(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 5, Left: 5, Right: 25, Bottom: 25}
+	b := Box{Top: 10, Left: 10, Right: 20, Bottom: 20} // only half bigger
+	c := Box{Top: 1, Left: 1, Right: 30, Bottom: 30}   //bigger
+	assert.True(a.IsBiggerThan(b))
+	assert.False(a.IsBiggerThan(c))
+	assert.True(c.IsBiggerThan(a))
+}
+
+func TestBoxIsSmallerThan(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 5, Left: 5, Right: 25, Bottom: 25}
+	b := Box{Top: 10, Left: 10, Right: 20, Bottom: 20} // only half bigger
+	c := Box{Top: 1, Left: 1, Right: 30, Bottom: 30}   //bigger
+	assert.False(a.IsSmallerThan(b))
+	assert.True(a.IsSmallerThan(c))
+	assert.False(c.IsSmallerThan(a))
+}
+
+func TestBoxGrow(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 1, Left: 2, Right: 15, Bottom: 15}
+	b := Box{Top: 4, Left: 5, Right: 30, Bottom: 35}
+	c := a.Grow(b)
+	assert.False(c.Equals(b))
+	assert.False(c.Equals(a))
+	assert.Equal(1, c.Top)
+	assert.Equal(2, c.Left)
+	assert.Equal(30, c.Right)
+	assert.Equal(35, c.Bottom)
+}
+
+func TestBoxFit(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 64, Left: 64, Right: 192, Bottom: 192}
+	b := Box{Top: 16, Left: 16, Right: 256, Bottom: 170}
+	c := Box{Top: 16, Left: 16, Right: 170, Bottom: 256}
+
+	fab := a.Fit(b)
+	assert.Equal(a.Left, fab.Left)
+	assert.Equal(a.Right, fab.Right)
+	assert.True(fab.Top < fab.Bottom)
+	assert.True(fab.Left < fab.Right)
+	assert.True(math.Abs(b.Aspect()-fab.Aspect()) < 0.02)
+
+	fac := a.Fit(c)
+	assert.Equal(a.Top, fac.Top)
+	assert.Equal(a.Bottom, fac.Bottom)
+	assert.True(math.Abs(c.Aspect()-fac.Aspect()) < 0.02)
+}
+
+func TestBoxConstrain(t *testing.T) {
+	assert := assert.New(t)
+
+	a := Box{Top: 64, Left: 64, Right: 192, Bottom: 192}
+	b := Box{Top: 16, Left: 16, Right: 256, Bottom: 170}
+	c := Box{Top: 16, Left: 16, Right: 170, Bottom: 256}
+
+	cab := a.Constrain(b)
+	assert.Equal(64, cab.Top)
+	assert.Equal(64, cab.Left)
+	assert.Equal(192, cab.Right)
+	assert.Equal(170, cab.Bottom)
+
+	cac := a.Constrain(c)
+	assert.Equal(64, cac.Top)
+	assert.Equal(64, cac.Left)
+	assert.Equal(170, cac.Right)
+	assert.Equal(192, cac.Bottom)
+}
+
+func TestBoxOuterConstrain(t *testing.T) {
+	assert := assert.New(t)
+
+	box := NewBox(0, 0, 100, 100)
+	canvas := NewBox(5, 5, 95, 95)
+	taller := NewBox(-10, 5, 50, 50)
+
+	c := canvas.OuterConstrain(box, taller)
+	assert.Equal(15, c.Top, c.String())
+	assert.Equal(5, c.Left, c.String())
+	assert.Equal(95, c.Right, c.String())
+	assert.Equal(95, c.Bottom, c.String())
+
+	wider := NewBox(5, 5, 110, 50)
+	d := canvas.OuterConstrain(box, wider)
+	assert.Equal(5, d.Top, d.String())
+	assert.Equal(5, d.Left, d.String())
+	assert.Equal(85, d.Right, d.String())
+	assert.Equal(95, d.Bottom, d.String())
+}
+
+func TestBoxShift(t *testing.T) {
+	assert := assert.New(t)
+
+	b := Box{
+		Top:    5,
+		Left:   5,
+		Right:  10,
+		Bottom: 10,
+	}
+
+	shifted := b.Shift(1, 2)
+	assert.Equal(7, shifted.Top)
+	assert.Equal(6, shifted.Left)
+	assert.Equal(11, shifted.Right)
+	assert.Equal(12, shifted.Bottom)
+}
+
+func TestBoxCenter(t *testing.T) {
+	assert := assert.New(t)
+
+	b := Box{
+		Top:    10,
+		Left:   10,
+		Right:  20,
+		Bottom: 30,
+	}
+	cx, cy := b.Center()
+	assert.Equal(15, cx)
+	assert.Equal(20, cy)
+}
+
+func TestBoxCornersCenter(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BoxCorners{
+		TopLeft:     Point{5, 5},
+		TopRight:    Point{15, 5},
+		BottomRight: Point{15, 15},
+		BottomLeft:  Point{5, 15},
+	}
+
+	cx, cy := bc.Center()
+	assert.Equal(10, cx)
+	assert.Equal(10, cy)
+}
+
+func TestBoxCornersRotate(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := BoxCorners{
+		TopLeft:     Point{5, 5},
+		TopRight:    Point{15, 5},
+		BottomRight: Point{15, 15},
+		BottomLeft:  Point{5, 15},
+	}
+
+	rotated := bc.Rotate(45)
+	assert.True(rotated.TopLeft.Equals(Point{10, 3}), rotated.String())
+}

chart.go

@@ -6,8 +6,7 @@ import (
 	"io"
 	"math"
 
-	util "git.fireandbrimst.one/aw/go-chart/util"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/truetype"
 )
 
 // Chart is what we're drawing.
@@ -15,8 +14,6 @@ type Chart struct {
 	Title      string
 	TitleStyle Style
 
-	ColorPalette ColorPalette
-
 	Width  int
 	Height int
 	DPI    float64
@@ -101,11 +98,11 @@ func (c Chart) Render(rp RendererProvider, w io.Writer) error {
 	xr, yr, yra := c.getRanges()
 	canvasBox := c.getDefaultCanvasBox()
 	xf, yf, yfa := c.getValueFormatters()
-
 	xr, yr, yra = c.setRangeDomains(canvasBox, xr, yr, yra)
 
 	err = c.checkRanges(xr, yr, yra)
 	if err != nil {
+		// (try to) dump the raw background to the stream.
 		r.Save(w)
 		return err
 	}
@@ -178,10 +175,10 @@ func (c Chart) getRanges() (xrange, yrange, yrangeAlt Range) {
 	for _, s := range c.Series {
 		if s.GetStyle().IsZero() || s.GetStyle().Show {
 			seriesAxis := s.GetYAxis()
-			if bvp, isBoundedValuesProvider := s.(BoundedValuesProvider); isBoundedValuesProvider {
+			if bvp, isBoundedValueProvider := s.(BoundedValueProvider); isBoundedValueProvider {
 				seriesLength := bvp.Len()
 				for index := 0; index < seriesLength; index++ {
-					vx, vy1, vy2 := bvp.GetBoundedValues(index)
+					vx, vy1, vy2 := bvp.GetBoundedValue(index)
 
 					minx = math.Min(minx, vx)
 					maxx = math.Max(maxx, vx)
@@ -199,10 +196,10 @@ func (c Chart) getRanges() (xrange, yrange, yrangeAlt Range) {
 						seriesMappedToSecondaryAxis = true
 					}
 				}
-			} else if vp, isValuesProvider := s.(ValuesProvider); isValuesProvider {
+			} else if vp, isValueProvider := s.(ValueProvider); isValueProvider {
 				seriesLength := vp.Len()
 				for index := 0; index < seriesLength; index++ {
-					vx, vy := vp.GetValues(index)
+					vx, vy := vp.GetValue(index)
 
 					minx = math.Min(minx, vx)
 					maxx = math.Max(maxx, vx)
@@ -263,15 +260,11 @@ func (c Chart) getRanges() (xrange, yrange, yrangeAlt Range) {
 		yrange.SetMin(miny)
 		yrange.SetMax(maxy)
 
-		// only round if we're showing the axis
-		if c.YAxis.Style.Show {
-			delta := yrange.GetDelta()
-			roundTo := util.Math.GetRoundToForDelta(delta)
-			rmin, rmax := util.Math.RoundDown(yrange.GetMin(), roundTo), util.Math.RoundUp(yrange.GetMax(), roundTo)
-
-			yrange.SetMin(rmin)
-			yrange.SetMax(rmax)
-		}
+		delta := yrange.GetDelta()
+		roundTo := Math.GetRoundToForDelta(delta)
+		rmin, rmax := Math.RoundDown(yrange.GetMin(), roundTo), Math.RoundUp(yrange.GetMax(), roundTo)
+		yrange.SetMin(rmin)
+		yrange.SetMax(rmax)
 	}
 
 	if len(c.YAxisSecondary.Ticks) > 0 {
@@ -286,13 +279,11 @@ func (c Chart) getRanges() (xrange, yrange, yrangeAlt Range) {
 		yrangeAlt.SetMin(minya)
 		yrangeAlt.SetMax(maxya)
 
-		if c.YAxisSecondary.Style.Show {
-			delta := yrangeAlt.GetDelta()
-			roundTo := util.Math.GetRoundToForDelta(delta)
-			rmin, rmax := util.Math.RoundDown(yrangeAlt.GetMin(), roundTo), util.Math.RoundUp(yrangeAlt.GetMax(), roundTo)
-			yrangeAlt.SetMin(rmin)
-			yrangeAlt.SetMax(rmax)
-		}
+		delta := yrangeAlt.GetDelta()
+		roundTo := Math.GetRoundToForDelta(delta)
+		rmin, rmax := Math.RoundDown(yrangeAlt.GetMin(), roundTo), Math.RoundUp(yrangeAlt.GetMax(), roundTo)
+		yrangeAlt.SetMin(rmin)
+		yrangeAlt.SetMax(rmax)
 	}
 
 	return
@@ -349,13 +340,13 @@ func (c Chart) getValueFormatters() (x, y, ya ValueFormatter) {
 		}
 	}
 	if c.XAxis.ValueFormatter != nil {
-		x = c.XAxis.GetValueFormatter()
+		x = c.XAxis.ValueFormatter
 	}
 	if c.YAxis.ValueFormatter != nil {
-		y = c.YAxis.GetValueFormatter()
+		y = c.YAxis.ValueFormatter
 	}
 	if c.YAxisSecondary.ValueFormatter != nil {
-		ya = c.YAxisSecondary.GetValueFormatter()
+		ya = c.YAxisSecondary.ValueFormatter
 	}
 	return
 }
@@ -487,7 +478,7 @@ func (c Chart) drawSeries(r Renderer, canvasBox Box, xrange, yrange, yrangeAlt R
 func (c Chart) drawTitle(r Renderer) {
 	if len(c.Title) > 0 && c.TitleStyle.Show {
 		r.SetFont(c.TitleStyle.GetFont(c.GetFont()))
-		r.SetFontColor(c.TitleStyle.GetFontColor(c.GetColorPalette().TextColor()))
+		r.SetFontColor(c.TitleStyle.GetFontColor(DefaultTextColor))
 		titleFontSize := c.TitleStyle.GetFontSize(DefaultTitleFontSize)
 		r.SetFontSize(titleFontSize)
 
@@ -505,24 +496,25 @@ func (c Chart) drawTitle(r Renderer) {
 
 func (c Chart) styleDefaultsBackground() Style {
 	return Style{
-		FillColor:   c.GetColorPalette().BackgroundColor(),
-		StrokeColor: c.GetColorPalette().BackgroundStrokeColor(),
+		FillColor:   DefaultBackgroundColor,
+		StrokeColor: DefaultBackgroundStrokeColor,
 		StrokeWidth: DefaultBackgroundStrokeWidth,
 	}
 }
 
 func (c Chart) styleDefaultsCanvas() Style {
 	return Style{
-		FillColor:   c.GetColorPalette().CanvasColor(),
-		StrokeColor: c.GetColorPalette().CanvasStrokeColor(),
+		FillColor:   DefaultCanvasColor,
+		StrokeColor: DefaultCanvasStrokeColor,
 		StrokeWidth: DefaultCanvasStrokeWidth,
 	}
 }
 
 func (c Chart) styleDefaultsSeries(seriesIndex int) Style {
+	strokeColor := GetDefaultColor(seriesIndex)
 	return Style{
-		DotColor:    c.GetColorPalette().GetSeriesColor(seriesIndex),
-		StrokeColor: c.GetColorPalette().GetSeriesColor(seriesIndex),
+		DotColor:    strokeColor,
+		StrokeColor: strokeColor,
 		StrokeWidth: DefaultSeriesLineWidth,
 		Font:        c.GetFont(),
 		FontSize:    DefaultFontSize,
@@ -532,9 +524,9 @@ func (c Chart) styleDefaultsSeries(seriesIndex int) Style {
 func (c Chart) styleDefaultsAxes() Style {
 	return Style{
 		Font:        c.GetFont(),
-		FontColor:   c.GetColorPalette().TextColor(),
+		FontColor:   DefaultAxisColor,
 		FontSize:    DefaultAxisFontSize,
-		StrokeColor: c.GetColorPalette().AxisStrokeColor(),
+		StrokeColor: DefaultAxisColor,
 		StrokeWidth: DefaultAxisLineWidth,
 	}
 }
@@ -545,14 +537,6 @@ func (c Chart) styleDefaultsElements() Style {
 	}
 }
 
-// GetColorPalette returns the color palette for the chart.
-func (c Chart) GetColorPalette() ColorPalette {
-	if c.ColorPalette != nil {
-		return c.ColorPalette
-	}
-	return DefaultColorPalette
-}
-
 // Box returns the chart bounds as a box.
 func (c Chart) Box() Box {
 	dpr := c.Background.Padding.GetRight(DefaultBackgroundPadding.Right)

chart_test.go

@@ -0,0 +1,575 @@
+package chart
+
+import (
+	"bytes"
+	"image"
+	"image/png"
+	"math"
+	"testing"
+	"time"
+
+	"github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/drawing"
+)
+
+func TestChartGetDPI(t *testing.T) {
+	assert := assert.New(t)
+
+	unset := Chart{}
+	assert.Equal(DefaultDPI, unset.GetDPI())
+	assert.Equal(192, unset.GetDPI(192))
+
+	set := Chart{DPI: 128}
+	assert.Equal(128, set.GetDPI())
+	assert.Equal(128, set.GetDPI(192))
+}
+
+func TestChartGetFont(t *testing.T) {
+	assert := assert.New(t)
+
+	f, err := GetDefaultFont()
+	assert.Nil(err)
+
+	unset := Chart{}
+	assert.Nil(unset.GetFont())
+
+	set := Chart{Font: f}
+	assert.NotNil(set.GetFont())
+}
+
+func TestChartGetWidth(t *testing.T) {
+	assert := assert.New(t)
+
+	unset := Chart{}
+	assert.Equal(DefaultChartWidth, unset.GetWidth())
+
+	set := Chart{Width: DefaultChartWidth + 10}
+	assert.Equal(DefaultChartWidth+10, set.GetWidth())
+}
+
+func TestChartGetHeight(t *testing.T) {
+	assert := assert.New(t)
+
+	unset := Chart{}
+	assert.Equal(DefaultChartHeight, unset.GetHeight())
+
+	set := Chart{Height: DefaultChartHeight + 10}
+	assert.Equal(DefaultChartHeight+10, set.GetHeight())
+}
+
+func TestChartGetRanges(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Series: []Series{
+			ContinuousSeries{
+				XValues: []float64{-2.0, -1.0, 0, 1.0, 2.0},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 4.5},
+			},
+			ContinuousSeries{
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{-2.1, -1.0, 0, 1.0, 2.0},
+			},
+			ContinuousSeries{
+				YAxis:   YAxisSecondary,
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{10.0, 11.0, 12.0, 13.0, 14.0},
+			},
+		},
+	}
+
+	xrange, yrange, yrangeAlt := c.getRanges()
+	assert.Equal(-2.0, xrange.GetMin())
+	assert.Equal(5.0, xrange.GetMax())
+
+	assert.Equal(-2.1, yrange.GetMin())
+	assert.Equal(4.5, yrange.GetMax())
+
+	assert.Equal(10.0, yrangeAlt.GetMin())
+	assert.Equal(14.0, yrangeAlt.GetMax())
+
+	cSet := Chart{
+		XAxis: XAxis{
+			Range: &ContinuousRange{Min: 9.8, Max: 19.8},
+		},
+		YAxis: YAxis{
+			Range: &ContinuousRange{Min: 9.9, Max: 19.9},
+		},
+		YAxisSecondary: YAxis{
+			Range: &ContinuousRange{Min: 9.7, Max: 19.7},
+		},
+		Series: []Series{
+			ContinuousSeries{
+				XValues: []float64{-2.0, -1.0, 0, 1.0, 2.0},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 4.5},
+			},
+			ContinuousSeries{
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{-2.1, -1.0, 0, 1.0, 2.0},
+			},
+			ContinuousSeries{
+				YAxis:   YAxisSecondary,
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{10.0, 11.0, 12.0, 13.0, 14.0},
+			},
+		},
+	}
+
+	xr2, yr2, yra2 := cSet.getRanges()
+	assert.Equal(9.8, xr2.GetMin())
+	assert.Equal(19.8, xr2.GetMax())
+
+	assert.Equal(9.9, yr2.GetMin())
+	assert.Equal(19.9, yr2.GetMax())
+
+	assert.Equal(9.7, yra2.GetMin())
+	assert.Equal(19.7, yra2.GetMax())
+}
+
+func TestChartGetRangesUseTicks(t *testing.T) {
+	assert := assert.New(t)
+
+	// this test asserts that ticks should supercede manual ranges when generating the overall ranges.
+
+	c := Chart{
+		YAxis: YAxis{
+			Ticks: []Tick{
+				{0.0, "Zero"},
+				{1.0, "1.0"},
+				{2.0, "2.0"},
+				{3.0, "3.0"},
+				{4.0, "4.0"},
+				{5.0, "Five"},
+			},
+			Range: &ContinuousRange{
+				Min: -5.0,
+				Max: 5.0,
+			},
+		},
+		Series: []Series{
+			ContinuousSeries{
+				XValues: []float64{-2.0, -1.0, 0, 1.0, 2.0},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 4.5},
+			},
+		},
+	}
+
+	xr, yr, yar := c.getRanges()
+	assert.Equal(-2.0, xr.GetMin())
+	assert.Equal(2.0, xr.GetMax())
+	assert.Equal(0.0, yr.GetMin())
+	assert.Equal(5.0, yr.GetMax())
+	assert.True(yar.IsZero(), yar.String())
+}
+
+func TestChartGetRangesUseUserRanges(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		YAxis: YAxis{
+			Range: &ContinuousRange{
+				Min: -5.0,
+				Max: 5.0,
+			},
+		},
+		Series: []Series{
+			ContinuousSeries{
+				XValues: []float64{-2.0, -1.0, 0, 1.0, 2.0},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 4.5},
+			},
+		},
+	}
+
+	xr, yr, yar := c.getRanges()
+	assert.Equal(-2.0, xr.GetMin())
+	assert.Equal(2.0, xr.GetMax())
+	assert.Equal(-5.0, yr.GetMin())
+	assert.Equal(5.0, yr.GetMax())
+	assert.True(yar.IsZero(), yar.String())
+}
+
+func TestChartGetBackgroundStyle(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Background: Style{
+			FillColor: drawing.ColorBlack,
+		},
+	}
+
+	bs := c.getBackgroundStyle()
+	assert.Equal(bs.FillColor.String(), drawing.ColorBlack.String())
+}
+
+func TestChartGetCanvasStyle(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Canvas: Style{
+			FillColor: drawing.ColorBlack,
+		},
+	}
+
+	bs := c.getCanvasStyle()
+	assert.Equal(bs.FillColor.String(), drawing.ColorBlack.String())
+}
+
+func TestChartGetDefaultCanvasBox(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{}
+	canvasBoxDefault := c.getDefaultCanvasBox()
+	assert.False(canvasBoxDefault.IsZero())
+	assert.Equal(DefaultBackgroundPadding.Top, canvasBoxDefault.Top)
+	assert.Equal(DefaultBackgroundPadding.Left, canvasBoxDefault.Left)
+	assert.Equal(c.GetWidth()-DefaultBackgroundPadding.Right, canvasBoxDefault.Right)
+	assert.Equal(c.GetHeight()-DefaultBackgroundPadding.Bottom, canvasBoxDefault.Bottom)
+
+	custom := Chart{
+		Background: Style{
+			Padding: Box{
+				Top:    DefaultBackgroundPadding.Top + 1,
+				Left:   DefaultBackgroundPadding.Left + 1,
+				Right:  DefaultBackgroundPadding.Right + 1,
+				Bottom: DefaultBackgroundPadding.Bottom + 1,
+			},
+		},
+	}
+	canvasBoxCustom := custom.getDefaultCanvasBox()
+	assert.False(canvasBoxCustom.IsZero())
+	assert.Equal(DefaultBackgroundPadding.Top+1, canvasBoxCustom.Top)
+	assert.Equal(DefaultBackgroundPadding.Left+1, canvasBoxCustom.Left)
+	assert.Equal(c.GetWidth()-(DefaultBackgroundPadding.Right+1), canvasBoxCustom.Right)
+	assert.Equal(c.GetHeight()-(DefaultBackgroundPadding.Bottom+1), canvasBoxCustom.Bottom)
+}
+
+func TestChartGetValueFormatters(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Series: []Series{
+			ContinuousSeries{
+				XValues: []float64{-2.0, -1.0, 0, 1.0, 2.0},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 4.5},
+			},
+			ContinuousSeries{
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{-2.1, -1.0, 0, 1.0, 2.0},
+			},
+			ContinuousSeries{
+				YAxis:   YAxisSecondary,
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{10.0, 11.0, 12.0, 13.0, 14.0},
+			},
+		},
+	}
+
+	dxf, dyf, dyaf := c.getValueFormatters()
+	assert.NotNil(dxf)
+	assert.NotNil(dyf)
+	assert.NotNil(dyaf)
+}
+
+func TestChartHasAxes(t *testing.T) {
+	assert := assert.New(t)
+
+	assert.False(Chart{}.hasAxes())
+
+	x := Chart{
+		XAxis: XAxis{
+			Style: Style{
+				Show: true,
+			},
+		},
+	}
+	assert.True(x.hasAxes())
+
+	y := Chart{
+		YAxis: YAxis{
+			Style: Style{
+				Show: true,
+			},
+		},
+	}
+	assert.True(y.hasAxes())
+
+	ya := Chart{
+		YAxisSecondary: YAxis{
+			Style: Style{
+				Show: true,
+			},
+		},
+	}
+	assert.True(ya.hasAxes())
+}
+
+func TestChartGetAxesTicks(t *testing.T) {
+	assert := assert.New(t)
+
+	r, err := PNG(1024, 1024)
+	assert.Nil(err)
+
+	c := Chart{
+		XAxis: XAxis{
+			Style: Style{Show: true},
+			Range: &ContinuousRange{Min: 9.8, Max: 19.8},
+		},
+		YAxis: YAxis{
+			Style: Style{Show: true},
+			Range: &ContinuousRange{Min: 9.9, Max: 19.9},
+		},
+		YAxisSecondary: YAxis{
+			Style: Style{Show: true},
+			Range: &ContinuousRange{Min: 9.7, Max: 19.7},
+		},
+	}
+	xr, yr, yar := c.getRanges()
+
+	xt, yt, yat := c.getAxesTicks(r, xr, yr, yar, FloatValueFormatter, FloatValueFormatter, FloatValueFormatter)
+	assert.NotEmpty(xt)
+	assert.NotEmpty(yt)
+	assert.NotEmpty(yat)
+}
+
+func TestChartSingleSeries(t *testing.T) {
+	assert := assert.New(t)
+	now := time.Now()
+	c := Chart{
+		Title:      "Hello!",
+		TitleStyle: StyleShow(),
+		Width:      1024,
+		Height:     400,
+		YAxis: YAxis{
+			Style: StyleShow(),
+			Range: &ContinuousRange{
+				Min: 0.0,
+				Max: 4.0,
+			},
+		},
+		XAxis: XAxis{
+			Style: StyleShow(),
+		},
+		Series: []Series{
+			TimeSeries{
+				Name:    "goog",
+				XValues: []time.Time{now.AddDate(0, 0, -3), now.AddDate(0, 0, -2), now.AddDate(0, 0, -1)},
+				YValues: []float64{1.0, 2.0, 3.0},
+			},
+		},
+	}
+
+	buffer := bytes.NewBuffer([]byte{})
+	c.Render(PNG, buffer)
+	assert.NotEmpty(buffer.Bytes())
+}
+
+func TestChartRegressionBadRanges(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Series: []Series{
+			ContinuousSeries{
+				XValues: []float64{math.Inf(1), math.Inf(1), math.Inf(1), math.Inf(1), math.Inf(1)},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 4.5},
+			},
+		},
+	}
+	buffer := bytes.NewBuffer([]byte{})
+	c.Render(PNG, buffer)
+	assert.True(true, "Render needs to finish.")
+}
+
+func TestChartRegressionBadRangesByUser(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		YAxis: YAxis{
+			Range: &ContinuousRange{
+				Min: math.Inf(-1),
+				Max: math.Inf(1), // this could really happen? eh.
+			},
+		},
+		Series: []Series{
+			ContinuousSeries{
+				XValues: Sequence.Float64(1.0, 10.0),
+				YValues: Sequence.Float64(1.0, 10.0),
+			},
+		},
+	}
+	buffer := bytes.NewBuffer([]byte{})
+	c.Render(PNG, buffer)
+	assert.True(true, "Render needs to finish.")
+}
+
+func TestChartValidatesSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Series: []Series{
+			ContinuousSeries{
+				XValues: Sequence.Float64(1.0, 10.0),
+				YValues: Sequence.Float64(1.0, 10.0),
+			},
+		},
+	}
+
+	assert.Nil(c.validateSeries())
+
+	c = Chart{
+		Series: []Series{
+			ContinuousSeries{
+				XValues: Sequence.Float64(1.0, 10.0),
+			},
+		},
+	}
+
+	assert.NotNil(c.validateSeries())
+}
+
+func TestChartCheckRanges(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Series: []Series{
+			ContinuousSeries{
+				XValues: []float64{1.0, 2.0},
+				YValues: []float64{3.10, 3.14},
+			},
+		},
+	}
+
+	xr, yr, yra := c.getRanges()
+	assert.Nil(c.checkRanges(xr, yr, yra))
+}
+
+func TestChartCheckRangesFailure(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Series: []Series{
+			ContinuousSeries{
+				XValues: []float64{1.0, 2.0},
+				YValues: []float64{3.14, 3.14},
+			},
+		},
+	}
+
+	xr, yr, yra := c.getRanges()
+	assert.NotNil(c.checkRanges(xr, yr, yra))
+}
+
+func TestChartCheckRangesWithRanges(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		XAxis: XAxis{
+			Range: &ContinuousRange{
+				Min: 0,
+				Max: 10,
+			},
+		},
+		YAxis: YAxis{
+			Range: &ContinuousRange{
+				Min: 0,
+				Max: 5,
+			},
+		},
+		Series: []Series{
+			ContinuousSeries{
+				XValues: []float64{1.0, 2.0},
+				YValues: []float64{3.14, 3.14},
+			},
+		},
+	}
+
+	xr, yr, yra := c.getRanges()
+	assert.Nil(c.checkRanges(xr, yr, yra))
+}
+
+func at(i image.Image, x, y int) drawing.Color {
+	return drawing.ColorFromAlphaMixedRGBA(i.At(x, y).RGBA())
+}
+
+func TestChartE2ELine(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Height: 50,
+		Width:  50,
+		Canvas: Style{
+			Padding: Box{IsSet: true},
+		},
+		Background: Style{
+			Padding: Box{IsSet: true},
+		},
+		Series: []Series{
+			ContinuousSeries{
+				XValues: Sequence.Float64(0, 4, 1),
+				YValues: Sequence.Float64(0, 4, 1),
+			},
+		},
+	}
+
+	var buffer = &bytes.Buffer{}
+	err := c.Render(PNG, buffer)
+	assert.Nil(err)
+
+	// do color tests ...
+
+	i, err := png.Decode(buffer)
+	assert.Nil(err)
+
+	// test the bottom and top of the line
+	assert.Equal(drawing.ColorWhite, at(i, 0, 0))
+	assert.Equal(drawing.ColorWhite, at(i, 49, 49))
+
+	// test a line mid point
+	defaultSeriesColor := GetDefaultColor(0)
+	assert.Equal(defaultSeriesColor, at(i, 0, 49))
+	assert.Equal(defaultSeriesColor, at(i, 49, 0))
+	assert.Equal(drawing.ColorFromHex("bddbf6"), at(i, 24, 24))
+}
+
+func TestChartE2ELineWithFill(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Height: 50,
+		Width:  50,
+		Canvas: Style{
+			Padding: Box{IsSet: true},
+		},
+		Background: Style{
+			Padding: Box{IsSet: true},
+		},
+		Series: []Series{
+			ContinuousSeries{
+				Style: Style{
+					Show:        true,
+					StrokeColor: drawing.ColorBlue,
+					FillColor:   drawing.ColorRed,
+				},
+				XValues: Sequence.Float64(0, 4, 1),
+				YValues: Sequence.Float64(0, 4, 1),
+			},
+		},
+	}
+
+	var buffer = &bytes.Buffer{}
+	err := c.Render(PNG, buffer)
+	assert.Nil(err)
+
+	// do color tests ...
+
+	i, err := png.Decode(buffer)
+	assert.Nil(err)
+
+	// test the bottom and top of the line
+	assert.Equal(drawing.ColorWhite, at(i, 0, 0))
+	assert.Equal(drawing.ColorRed, at(i, 49, 49))
+
+	// test a line mid point
+	defaultSeriesColor := drawing.ColorBlue
+	assert.Equal(defaultSeriesColor, at(i, 0, 49))
+	assert.Equal(defaultSeriesColor, at(i, 49, 0))
+}

colors.go

@@ -1,184 +0,0 @@
-package chart
-
-import "git.fireandbrimst.one/aw/go-chart/drawing"
-
-var (
-	// ColorWhite is white.
-	ColorWhite = drawing.Color{R: 255, G: 255, B: 255, A: 255}
-	// ColorBlue is the basic theme blue color.
-	ColorBlue = drawing.Color{R: 0, G: 116, B: 217, A: 255}
-	// ColorCyan is the basic theme cyan color.
-	ColorCyan = drawing.Color{R: 0, G: 217, B: 210, A: 255}
-	// ColorGreen is the basic theme green color.
-	ColorGreen = drawing.Color{R: 0, G: 217, B: 101, A: 255}
-	// ColorRed is the basic theme red color.
-	ColorRed = drawing.Color{R: 217, G: 0, B: 116, A: 255}
-	// ColorOrange is the basic theme orange color.
-	ColorOrange = drawing.Color{R: 217, G: 101, B: 0, A: 255}
-	// ColorYellow is the basic theme yellow color.
-	ColorYellow = drawing.Color{R: 217, G: 210, B: 0, A: 255}
-	// ColorBlack is the basic theme black color.
-	ColorBlack = drawing.Color{R: 51, G: 51, B: 51, A: 255}
-	// ColorLightGray is the basic theme light gray color.
-	ColorLightGray = drawing.Color{R: 239, G: 239, B: 239, A: 255}
-
-	// ColorAlternateBlue is a alternate theme color.
-	ColorAlternateBlue = drawing.Color{R: 106, G: 195, B: 203, A: 255}
-	// ColorAlternateGreen is a alternate theme color.
-	ColorAlternateGreen = drawing.Color{R: 42, G: 190, B: 137, A: 255}
-	// ColorAlternateGray is a alternate theme color.
-	ColorAlternateGray = drawing.Color{R: 110, G: 128, B: 139, A: 255}
-	// ColorAlternateYellow is a alternate theme color.
-	ColorAlternateYellow = drawing.Color{R: 240, G: 174, B: 90, A: 255}
-	// ColorAlternateLightGray is a alternate theme color.
-	ColorAlternateLightGray = drawing.Color{R: 187, G: 190, B: 191, A: 255}
-
-	// ColorTransparent is a transparent (alpha zero) color.
-	ColorTransparent = drawing.Color{R: 1, G: 1, B: 1, A: 0}
-)
-
-var (
-	// DefaultBackgroundColor is the default chart background color.
-	// It is equivalent to css color:white.
-	DefaultBackgroundColor = ColorWhite
-	// DefaultBackgroundStrokeColor is the default chart border color.
-	// It is equivalent to color:white.
-	DefaultBackgroundStrokeColor = ColorWhite
-	// DefaultCanvasColor is the default chart canvas color.
-	// It is equivalent to css color:white.
-	DefaultCanvasColor = ColorWhite
-	// DefaultCanvasStrokeColor is the default chart canvas stroke color.
-	// It is equivalent to css color:white.
-	DefaultCanvasStrokeColor = ColorWhite
-	// DefaultTextColor is the default chart text color.
-	// It is equivalent to #333333.
-	DefaultTextColor = ColorBlack
-	// DefaultAxisColor is the default chart axis line color.
-	// It is equivalent to #333333.
-	DefaultAxisColor = ColorBlack
-	// DefaultStrokeColor is the default chart border color.
-	// It is equivalent to #efefef.
-	DefaultStrokeColor = ColorLightGray
-	// DefaultFillColor is the default fill color.
-	// It is equivalent to #0074d9.
-	DefaultFillColor = ColorBlue
-	// DefaultAnnotationFillColor is the default annotation background color.
-	DefaultAnnotationFillColor = ColorWhite
-	// DefaultGridLineColor is the default grid line color.
-	DefaultGridLineColor = ColorLightGray
-)
-
-var (
-	// DefaultColors are a couple default series colors.
-	DefaultColors = []drawing.Color{
-		ColorBlue,
-		ColorGreen,
-		ColorRed,
-		ColorCyan,
-		ColorOrange,
-	}
-
-	// DefaultAlternateColors are a couple alternate colors.
-	DefaultAlternateColors = []drawing.Color{
-		ColorAlternateBlue,
-		ColorAlternateGreen,
-		ColorAlternateGray,
-		ColorAlternateYellow,
-		ColorBlue,
-		ColorGreen,
-		ColorRed,
-		ColorCyan,
-		ColorOrange,
-	}
-)
-
-// GetDefaultColor returns a color from the default list by index.
-// NOTE: the index will wrap around (using a modulo).
-func GetDefaultColor(index int) drawing.Color {
-	finalIndex := index % len(DefaultColors)
-	return DefaultColors[finalIndex]
-}
-
-// GetAlternateColor returns a color from the default list by index.
-// NOTE: the index will wrap around (using a modulo).
-func GetAlternateColor(index int) drawing.Color {
-	finalIndex := index % len(DefaultAlternateColors)
-	return DefaultAlternateColors[finalIndex]
-}
-
-// ColorPalette is a set of colors that.
-type ColorPalette interface {
-	BackgroundColor() drawing.Color
-	BackgroundStrokeColor() drawing.Color
-	CanvasColor() drawing.Color
-	CanvasStrokeColor() drawing.Color
-	AxisStrokeColor() drawing.Color
-	TextColor() drawing.Color
-	GetSeriesColor(index int) drawing.Color
-}
-
-// DefaultColorPalette represents the default palatte.
-var DefaultColorPalette defaultColorPalette
-
-type defaultColorPalette struct{}
-
-func (dp defaultColorPalette) BackgroundColor() drawing.Color {
-	return DefaultBackgroundColor
-}
-
-func (dp defaultColorPalette) BackgroundStrokeColor() drawing.Color {
-	return DefaultBackgroundStrokeColor
-}
-
-func (dp defaultColorPalette) CanvasColor() drawing.Color {
-	return DefaultCanvasColor
-}
-
-func (dp defaultColorPalette) CanvasStrokeColor() drawing.Color {
-	return DefaultCanvasStrokeColor
-}
-
-func (dp defaultColorPalette) AxisStrokeColor() drawing.Color {
-	return DefaultAxisColor
-}
-
-func (dp defaultColorPalette) TextColor() drawing.Color {
-	return DefaultTextColor
-}
-
-func (dp defaultColorPalette) GetSeriesColor(index int) drawing.Color {
-	return GetDefaultColor(index)
-}
-
-// AlternateColorPalette represents the default palatte.
-var AlternateColorPalette alternateColorPalette
-
-type alternateColorPalette struct{}
-
-func (ap alternateColorPalette) BackgroundColor() drawing.Color {
-	return DefaultBackgroundColor
-}
-
-func (ap alternateColorPalette) BackgroundStrokeColor() drawing.Color {
-	return DefaultBackgroundStrokeColor
-}
-
-func (ap alternateColorPalette) CanvasColor() drawing.Color {
-	return DefaultCanvasColor
-}
-
-func (ap alternateColorPalette) CanvasStrokeColor() drawing.Color {
-	return DefaultCanvasStrokeColor
-}
-
-func (ap alternateColorPalette) AxisStrokeColor() drawing.Color {
-	return DefaultAxisColor
-}
-
-func (ap alternateColorPalette) TextColor() drawing.Color {
-	return DefaultTextColor
-}
-
-func (ap alternateColorPalette) GetSeriesColor(index int) drawing.Color {
-	return GetAlternateColor(index)
-}

concat_series.go

@@ -7,7 +7,7 @@ type ConcatSeries []Series
 func (cs ConcatSeries) Len() int {
 	total := 0
 	for _, s := range cs {
-		if typed, isValuesProvider := s.(ValuesProvider); isValuesProvider {
+		if typed, isValueProvider := s.(ValueProvider); isValueProvider {
 			total += typed.Len()
 		}
 	}
@@ -19,10 +19,10 @@ func (cs ConcatSeries) Len() int {
 func (cs ConcatSeries) GetValue(index int) (x, y float64) {
 	cursor := 0
 	for _, s := range cs {
-		if typed, isValuesProvider := s.(ValuesProvider); isValuesProvider {
+		if typed, isValueProvider := s.(ValueProvider); isValueProvider {
 			len := typed.Len()
 			if index < cursor+len {
-				x, y = typed.GetValues(index - cursor) //FENCEPOSTS.
+				x, y = typed.GetValue(index - cursor) //FENCEPOSTS.
 				return
 			}
 			cursor += typed.Len()

concat_series_test.go

@@ -0,0 +1,41 @@
+package chart
+
+import (
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+func TestConcatSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	s1 := ContinuousSeries{
+		XValues: Sequence.Float64(1.0, 10.0),
+		YValues: Sequence.Float64(1.0, 10.0),
+	}
+
+	s2 := ContinuousSeries{
+		XValues: Sequence.Float64(11, 20.0),
+		YValues: Sequence.Float64(10.0, 1.0),
+	}
+
+	s3 := ContinuousSeries{
+		XValues: Sequence.Float64(21, 30.0),
+		YValues: Sequence.Float64(1.0, 10.0),
+	}
+
+	cs := ConcatSeries([]Series{s1, s2, s3})
+	assert.Equal(30, cs.Len())
+
+	x0, y0 := cs.GetValue(0)
+	assert.Equal(1.0, x0)
+	assert.Equal(1.0, y0)
+
+	xm, ym := cs.GetValue(19)
+	assert.Equal(20.0, xm)
+	assert.Equal(1.0, ym)
+
+	xn, yn := cs.GetValue(29)
+	assert.Equal(30.0, xn)
+	assert.Equal(10.0, yn)
+}

continuous_range_test.go

@@ -0,0 +1,22 @@
+package chart
+
+import (
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+)
+
+func TestRangeTranslate(t *testing.T) {
+	assert := assert.New(t)
+	values := []float64{1.0, 2.0, 2.5, 2.7, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0}
+	r := ContinuousRange{Domain: 1000}
+	r.Min, r.Max = Math.MinAndMax(values...)
+
+	// delta = ~7.0
+	// value = ~5.0
+	// domain = ~1000
+	// 5/8 * 1000 ~=
+	assert.Equal(0, r.Translate(1.0))
+	assert.Equal(1000, r.Translate(8.0))
+	assert.Equal(572, r.Translate(5.0))
+}

continuous_series.go

@@ -2,13 +2,6 @@ package chart
 
 import "fmt"
 
-// Interface Assertions.
-var (
-	_ Series              = (*ContinuousSeries)(nil)
-	_ FirstValuesProvider = (*ContinuousSeries)(nil)
-	_ LastValuesProvider  = (*ContinuousSeries)(nil)
-)
-
 // ContinuousSeries represents a line on a chart.
 type ContinuousSeries struct {
 	Name  string
@@ -38,18 +31,13 @@ func (cs ContinuousSeries) Len() int {
 	return len(cs.XValues)
 }
 
-// GetValues gets the x,y values at a given index.
-func (cs ContinuousSeries) GetValues(index int) (float64, float64) {
+// GetValue gets a value at a given index.
+func (cs ContinuousSeries) GetValue(index int) (float64, float64) {
 	return cs.XValues[index], cs.YValues[index]
 }
 
-// GetFirstValues gets the first x,y values.
-func (cs ContinuousSeries) GetFirstValues() (float64, float64) {
-	return cs.XValues[0], cs.YValues[0]
-}
-
-// GetLastValues gets the last x,y values.
-func (cs ContinuousSeries) GetLastValues() (float64, float64) {
+// GetLastValue gets the last value.
+func (cs ContinuousSeries) GetLastValue() (float64, float64) {
 	return cs.XValues[len(cs.XValues)-1], cs.YValues[len(cs.YValues)-1]
 }
 

continuous_series_test.go

@@ -0,0 +1,72 @@
+package chart
+
+import (
+	"fmt"
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+func TestContinuousSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	cs := ContinuousSeries{
+		Name:    "Test Series",
+		XValues: Sequence.Float64(1.0, 10.0),
+		YValues: Sequence.Float64(1.0, 10.0),
+	}
+
+	assert.Equal("Test Series", cs.GetName())
+	assert.Equal(10, cs.Len())
+	x0, y0 := cs.GetValue(0)
+	assert.Equal(1.0, x0)
+	assert.Equal(1.0, y0)
+
+	xn, yn := cs.GetValue(9)
+	assert.Equal(10.0, xn)
+	assert.Equal(10.0, yn)
+
+	xn, yn = cs.GetLastValue()
+	assert.Equal(10.0, xn)
+	assert.Equal(10.0, yn)
+}
+
+func TestContinuousSeriesValueFormatter(t *testing.T) {
+	assert := assert.New(t)
+
+	cs := ContinuousSeries{
+		XValueFormatter: func(v interface{}) string {
+			return fmt.Sprintf("%f foo", v)
+		},
+		YValueFormatter: func(v interface{}) string {
+			return fmt.Sprintf("%f bar", v)
+		},
+	}
+
+	xf, yf := cs.GetValueFormatters()
+	assert.Equal("0.100000 foo", xf(0.1))
+	assert.Equal("0.100000 bar", yf(0.1))
+}
+
+func TestContinuousSeriesValidate(t *testing.T) {
+	assert := assert.New(t)
+
+	cs := ContinuousSeries{
+		Name:    "Test Series",
+		XValues: Sequence.Float64(1.0, 10.0),
+		YValues: Sequence.Float64(1.0, 10.0),
+	}
+	assert.Nil(cs.Validate())
+
+	cs = ContinuousSeries{
+		Name:    "Test Series",
+		XValues: Sequence.Float64(1.0, 10.0),
+	}
+	assert.NotNil(cs.Validate())
+
+	cs = ContinuousSeries{
+		Name:    "Test Series",
+		YValues: Sequence.Float64(1.0, 10.0),
+	}
+	assert.NotNil(cs.Validate())
+}

date.go

@@ -0,0 +1,426 @@
+package chart
+
+import (
+	"sync"
+	"time"
+)
+
+const (
+	// AllDaysMask is a bitmask of all the days of the week.
+	AllDaysMask = 1<<uint(time.Sunday) | 1<<uint(time.Monday) | 1<<uint(time.Tuesday) | 1<<uint(time.Wednesday) | 1<<uint(time.Thursday) | 1<<uint(time.Friday) | 1<<uint(time.Saturday)
+	// WeekDaysMask is a bitmask of all the weekdays of the week.
+	WeekDaysMask = 1<<uint(time.Monday) | 1<<uint(time.Tuesday) | 1<<uint(time.Wednesday) | 1<<uint(time.Thursday) | 1<<uint(time.Friday)
+	//WeekendDaysMask is a bitmask of the weekend days of the week.
+	WeekendDaysMask = 1<<uint(time.Sunday) | 1<<uint(time.Saturday)
+)
+
+var (
+	// DaysOfWeek are all the time.Weekday in an array for utility purposes.
+	DaysOfWeek = []time.Weekday{
+		time.Sunday,
+		time.Monday,
+		time.Tuesday,
+		time.Wednesday,
+		time.Thursday,
+		time.Friday,
+		time.Saturday,
+	}
+
+	// WeekDays are the business time.Weekday in an array.
+	WeekDays = []time.Weekday{
+		time.Monday,
+		time.Tuesday,
+		time.Wednesday,
+		time.Thursday,
+		time.Friday,
+	}
+
+	// WeekendDays are the weekend time.Weekday in an array.
+	WeekendDays = []time.Weekday{
+		time.Sunday,
+		time.Saturday,
+	}
+
+	//Epoch is unix epoc saved for utility purposes.
+	Epoch = time.Unix(0, 0)
+)
+
+var (
+	_easternLock sync.Mutex
+	_eastern     *time.Location
+)
+
+// NYSEOpen is when the NYSE opens.
+func NYSEOpen() time.Time { return Date.Time(9, 30, 0, 0, Date.Eastern()) }
+
+// NYSEClose is when the NYSE closes.
+func NYSEClose() time.Time { return Date.Time(16, 0, 0, 0, Date.Eastern()) }
+
+// NASDAQOpen is when NASDAQ opens.
+func NASDAQOpen() time.Time { return Date.Time(9, 30, 0, 0, Date.Eastern()) }
+
+// NASDAQClose is when NASDAQ closes.
+func NASDAQClose() time.Time { return Date.Time(16, 0, 0, 0, Date.Eastern()) }
+
+// NYSEArcaOpen is when NYSEARCA opens.
+func NYSEArcaOpen() time.Time { return Date.Time(4, 0, 0, 0, Date.Eastern()) }
+
+// NYSEArcaClose is when NYSEARCA closes.
+func NYSEArcaClose() time.Time { return Date.Time(20, 0, 0, 0, Date.Eastern()) }
+
+// HolidayProvider is a function that returns if a given time falls on a holiday.
+type HolidayProvider func(time.Time) bool
+
+// defaultHolidayProvider implements `HolidayProvider` and just returns false.
+func defaultHolidayProvider(_ time.Time) bool { return false }
+
+var (
+	// Date contains utility functions that operate on dates.
+	Date = &date{}
+)
+
+type date struct{}
+
+// IsNYSEHoliday returns if a date was/is on a nyse holiday day.
+func (d date) IsNYSEHoliday(t time.Time) bool {
+	te := t.In(d.Eastern())
+	if te.Year() == 2013 {
+		if te.Month() == 1 {
+			return te.Day() == 1 || te.Day() == 21
+		} else if te.Month() == 2 {
+			return te.Day() == 18
+		} else if te.Month() == 3 {
+			return te.Day() == 29
+		} else if te.Month() == 5 {
+			return te.Day() == 27
+		} else if te.Month() == 7 {
+			return te.Day() == 4
+		} else if te.Month() == 9 {
+			return te.Day() == 2
+		} else if te.Month() == 11 {
+			return te.Day() == 28
+		} else if te.Month() == 12 {
+			return te.Day() == 25
+		}
+	} else if te.Year() == 2014 {
+		if te.Month() == 1 {
+			return te.Day() == 1 || te.Day() == 20
+		} else if te.Month() == 2 {
+			return te.Day() == 17
+		} else if te.Month() == 4 {
+			return te.Day() == 18
+		} else if te.Month() == 5 {
+			return te.Day() == 26
+		} else if te.Month() == 7 {
+			return te.Day() == 4
+		} else if te.Month() == 9 {
+			return te.Day() == 1
+		} else if te.Month() == 11 {
+			return te.Day() == 27
+		} else if te.Month() == 12 {
+			return te.Day() == 25
+		}
+	} else if te.Year() == 2015 {
+		if te.Month() == 1 {
+			return te.Day() == 1 || te.Day() == 19
+		} else if te.Month() == 2 {
+			return te.Day() == 16
+		} else if te.Month() == 4 {
+			return te.Day() == 3
+		} else if te.Month() == 5 {
+			return te.Day() == 25
+		} else if te.Month() == 7 {
+			return te.Day() == 3
+		} else if te.Month() == 9 {
+			return te.Day() == 7
+		} else if te.Month() == 11 {
+			return te.Day() == 26
+		} else if te.Month() == 12 {
+			return te.Day() == 25
+		}
+	} else if te.Year() == 2016 {
+		if te.Month() == 1 {
+			return te.Day() == 1 || te.Day() == 18
+		} else if te.Month() == 2 {
+			return te.Day() == 15
+		} else if te.Month() == 3 {
+			return te.Day() == 25
+		} else if te.Month() == 5 {
+			return te.Day() == 30
+		} else if te.Month() == 7 {
+			return te.Day() == 4
+		} else if te.Month() == 9 {
+			return te.Day() == 5
+		} else if te.Month() == 11 {
+			return te.Day() == 24 || te.Day() == 25
+		} else if te.Month() == 12 {
+			return te.Day() == 26
+		}
+	} else if te.Year() == 2017 {
+		if te.Month() == 1 {
+			return te.Day() == 1 || te.Day() == 16
+		} else if te.Month() == 2 {
+			return te.Day() == 20
+		} else if te.Month() == 4 {
+			return te.Day() == 15
+		} else if te.Month() == 5 {
+			return te.Day() == 29
+		} else if te.Month() == 7 {
+			return te.Day() == 4
+		} else if te.Month() == 9 {
+			return te.Day() == 4
+		} else if te.Month() == 11 {
+			return te.Day() == 23
+		} else if te.Month() == 12 {
+			return te.Day() == 25
+		}
+	} else if te.Year() == 2018 {
+		if te.Month() == 1 {
+			return te.Day() == 1 || te.Day() == 15
+		} else if te.Month() == 2 {
+			return te.Day() == 19
+		} else if te.Month() == 3 {
+			return te.Day() == 30
+		} else if te.Month() == 5 {
+			return te.Day() == 28
+		} else if te.Month() == 7 {
+			return te.Day() == 4
+		} else if te.Month() == 9 {
+			return te.Day() == 3
+		} else if te.Month() == 11 {
+			return te.Day() == 22
+		} else if te.Month() == 12 {
+			return te.Day() == 25
+		}
+	}
+	return false
+}
+
+// IsNYSEArcaHoliday returns that returns if a given time falls on a holiday.
+func (d date) IsNYSEArcaHoliday(t time.Time) bool {
+	return d.IsNYSEHoliday(t)
+}
+
+// IsNASDAQHoliday returns if a date was a NASDAQ holiday day.
+func (d date) IsNASDAQHoliday(t time.Time) bool {
+	return d.IsNYSEHoliday(t)
+}
+
+// Time returns a new time.Time for the given clock components.
+func (d date) Time(hour, min, sec, nsec int, loc *time.Location) time.Time {
+	return time.Date(0, 0, 0, hour, min, sec, nsec, loc)
+}
+
+func (d date) Date(year, month, day int, loc *time.Location) time.Time {
+	return time.Date(year, time.Month(month), day, 12, 0, 0, 0, loc)
+}
+
+// On returns the clock components of clock (hour,minute,second) on the date components of d.
+func (d date) On(clock, cd time.Time) time.Time {
+	tzAdjusted := cd.In(clock.Location())
+	return time.Date(tzAdjusted.Year(), tzAdjusted.Month(), tzAdjusted.Day(), clock.Hour(), clock.Minute(), clock.Second(), clock.Nanosecond(), clock.Location())
+}
+
+// NoonOn is a shortcut for On(Time(12,0,0), cd) a.k.a. noon on a given date.
+func (d date) NoonOn(cd time.Time) time.Time {
+	return time.Date(cd.Year(), cd.Month(), cd.Day(), 12, 0, 0, 0, cd.Location())
+}
+
+// Optional returns a pointer reference to a given time.
+func (d date) Optional(t time.Time) *time.Time {
+	return &t
+}
+
+// IsWeekDay returns if the day is a monday->friday.
+func (d date) IsWeekDay(day time.Weekday) bool {
+	return !d.IsWeekendDay(day)
+}
+
+// IsWeekendDay returns if the day is a monday->friday.
+func (d date) IsWeekendDay(day time.Weekday) bool {
+	return day == time.Saturday || day == time.Sunday
+}
+
+// Before returns if a timestamp is strictly before another date (ignoring hours, minutes etc.)
+func (d date) Before(before, reference time.Time) bool {
+	tzAdjustedBefore := before.In(reference.Location())
+	if tzAdjustedBefore.Year() < reference.Year() {
+		return true
+	}
+	if tzAdjustedBefore.Month() < reference.Month() {
+		return true
+	}
+	return tzAdjustedBefore.Year() == reference.Year() && tzAdjustedBefore.Month() == reference.Month() && tzAdjustedBefore.Day() < reference.Day()
+}
+
+// NextMarketOpen returns the next market open after a given time.
+func (d date) NextMarketOpen(after, openTime time.Time, isHoliday HolidayProvider) time.Time {
+	afterLocalized := after.In(openTime.Location())
+	todaysOpen := d.On(openTime, afterLocalized)
+
+	if isHoliday == nil {
+		isHoliday = defaultHolidayProvider
+	}
+
+	todayIsValidTradingDay := d.IsWeekDay(todaysOpen.Weekday()) && !isHoliday(todaysOpen)
+
+	if (afterLocalized.Equal(todaysOpen) || afterLocalized.Before(todaysOpen)) && todayIsValidTradingDay {
+		return todaysOpen
+	}
+
+	for cursorDay := 1; cursorDay < 7; cursorDay++ {
+		newDay := todaysOpen.AddDate(0, 0, cursorDay)
+		isValidTradingDay := d.IsWeekDay(newDay.Weekday()) && !isHoliday(newDay)
+		if isValidTradingDay {
+			return d.On(openTime, newDay)
+		}
+	}
+	panic("Have exhausted day window looking for next market open.")
+}
+
+// NextMarketClose returns the next market close after a given time.
+func (d date) NextMarketClose(after, closeTime time.Time, isHoliday HolidayProvider) time.Time {
+	afterLocalized := after.In(closeTime.Location())
+
+	if isHoliday == nil {
+		isHoliday = defaultHolidayProvider
+	}
+
+	todaysClose := d.On(closeTime, afterLocalized)
+	if afterLocalized.Before(todaysClose) && d.IsWeekDay(todaysClose.Weekday()) && !isHoliday(todaysClose) {
+		return todaysClose
+	}
+
+	if afterLocalized.Equal(todaysClose) { //rare but it might happen.
+		return todaysClose
+	}
+
+	for cursorDay := 1; cursorDay < 6; cursorDay++ {
+		newDay := todaysClose.AddDate(0, 0, cursorDay)
+		if d.IsWeekDay(newDay.Weekday()) && !isHoliday(newDay) {
+			return d.On(closeTime, newDay)
+		}
+	}
+	panic("Have exhausted day window looking for next market close.")
+}
+
+// CalculateMarketSecondsBetween calculates the number of seconds the market was open between two dates.
+func (d date) CalculateMarketSecondsBetween(start, end, marketOpen, marketClose time.Time, isHoliday HolidayProvider) (seconds int64) {
+	startEastern := start.In(d.Eastern())
+	endEastern := end.In(d.Eastern())
+
+	startMarketOpen := d.On(marketOpen, startEastern)
+	startMarketClose := d.On(marketClose, startEastern)
+
+	if !d.IsWeekendDay(startMarketOpen.Weekday()) && !isHoliday(startMarketOpen) {
+		if (startEastern.Equal(startMarketOpen) || startEastern.After(startMarketOpen)) && startEastern.Before(startMarketClose) {
+			if endEastern.Before(startMarketClose) {
+				seconds += int64(endEastern.Sub(startEastern) / time.Second)
+			} else {
+				seconds += int64(startMarketClose.Sub(startEastern) / time.Second)
+			}
+		}
+	}
+
+	cursor := d.NextMarketOpen(startMarketClose, marketOpen, isHoliday)
+	for d.Before(cursor, endEastern) {
+		if d.IsWeekDay(cursor.Weekday()) && !isHoliday(cursor) {
+			close := d.NextMarketClose(cursor, marketClose, isHoliday)
+			seconds += int64(close.Sub(cursor) / time.Second)
+		}
+		cursor = cursor.AddDate(0, 0, 1)
+	}
+
+	finalMarketOpen := d.NextMarketOpen(cursor, marketOpen, isHoliday)
+	finalMarketClose := d.NextMarketClose(cursor, marketClose, isHoliday)
+	if endEastern.After(finalMarketOpen) {
+		if endEastern.Before(finalMarketClose) {
+			seconds += int64(endEastern.Sub(finalMarketOpen) / time.Second)
+		} else {
+			seconds += int64(finalMarketClose.Sub(finalMarketOpen) / time.Second)
+		}
+	}
+
+	return
+}
+
+const (
+	_secondsPerHour = 60 * 60
+	_secondsPerDay  = 60 * 60 * 24
+)
+
+func (d date) DiffDays(t1, t2 time.Time) (days int) {
+	t1n := t1.Unix()
+	t2n := t2.Unix()
+	diff := t2n - t1n //yields seconds
+	return int(diff / (_secondsPerDay))
+}
+
+func (d date) DiffHours(t1, t2 time.Time) (hours int) {
+	t1n := t1.Unix()
+	t2n := t2.Unix()
+	diff := t2n - t1n //yields seconds
+	return int(diff / (_secondsPerHour))
+}
+
+// NextDay returns the timestamp advanced a day.
+func (d date) NextDay(ts time.Time) time.Time {
+	return ts.AddDate(0, 0, 1)
+}
+
+// NextHour returns the next timestamp on the hour.
+func (d date) NextHour(ts time.Time) time.Time {
+	//advance a full hour ...
+	advanced := ts.Add(time.Hour)
+	minutes := time.Duration(advanced.Minute()) * time.Minute
+	final := advanced.Add(-minutes)
+	return time.Date(final.Year(), final.Month(), final.Day(), final.Hour(), 0, 0, 0, final.Location())
+}
+
+// NextDayOfWeek returns the next instance of a given weekday after a given timestamp.
+func (d date) NextDayOfWeek(after time.Time, dayOfWeek time.Weekday) time.Time {
+	afterWeekday := after.Weekday()
+	if afterWeekday == dayOfWeek {
+		return after.AddDate(0, 0, 7)
+	}
+
+	// 1 vs 5 ~ add 4 days
+	if afterWeekday < dayOfWeek {
+		dayDelta := int(dayOfWeek - afterWeekday)
+		return after.AddDate(0, 0, dayDelta)
+	}
+
+	// 5 vs 1, add 7-(5-1) ~ 3 days
+	dayDelta := 7 - int(afterWeekday-dayOfWeek)
+	return after.AddDate(0, 0, dayDelta)
+}
+
+// Start returns the earliest (min) time in a list of times.
+func (d date) Start(times []time.Time) time.Time {
+	if len(times) == 0 {
+		return time.Time{}
+	}
+
+	start := times[0]
+	for _, t := range times[1:] {
+		if t.Before(start) {
+			start = t
+		}
+	}
+	return start
+}
+
+// Start returns the earliest (min) time in a list of times.
+func (d date) End(times []time.Time) time.Time {
+	if len(times) == 0 {
+		return time.Time{}
+	}
+
+	end := times[0]
+	for _, t := range times[1:] {
+		if t.After(end) {
+			end = t
+		}
+	}
+	return end
+}

date_posix.go

@@ -0,0 +1,17 @@
+// +build !windows
+
+package chart
+
+import "time"
+
+// Eastern returns the eastern timezone.
+func (d date) Eastern() *time.Location {
+	if _eastern == nil {
+		_easternLock.Lock()
+		defer _easternLock.Unlock()
+		if _eastern == nil {
+			_eastern, _ = time.LoadLocation("America/New_York")
+		}
+	}
+	return _eastern
+}

date_test.go

@@ -0,0 +1,288 @@
+package chart
+
+import (
+	"testing"
+	"time"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+func parse(v string) time.Time {
+	ts, _ := time.Parse("2006-01-02", v)
+	return ts
+}
+
+func TestDateTime(t *testing.T) {
+	assert := assert.New(t)
+
+	ts := Date.Time(5, 6, 7, 8, time.UTC)
+	assert.Equal(05, ts.Hour())
+	assert.Equal(06, ts.Minute())
+	assert.Equal(07, ts.Second())
+	assert.Equal(8, ts.Nanosecond())
+	assert.Equal(time.UTC, ts.Location())
+}
+
+func TestDateDate(t *testing.T) {
+	assert := assert.New(t)
+
+	ts := Date.Date(2015, 5, 6, time.UTC)
+	assert.Equal(2015, ts.Year())
+	assert.Equal(5, ts.Month())
+	assert.Equal(6, ts.Day())
+	assert.Equal(time.UTC, ts.Location())
+}
+
+func TestDateOn(t *testing.T) {
+	assert := assert.New(t)
+
+	ts := Date.On(Date.Time(5, 4, 3, 2, time.UTC), Date.Date(2016, 6, 7, Date.Eastern()))
+	assert.Equal(2016, ts.Year())
+	assert.Equal(6, ts.Month())
+	assert.Equal(7, ts.Day())
+	assert.Equal(5, ts.Hour())
+	assert.Equal(4, ts.Minute())
+	assert.Equal(3, ts.Second())
+	assert.Equal(2, ts.Nanosecond())
+	assert.Equal(time.UTC, ts.Location())
+}
+
+func TestDateNoonOn(t *testing.T) {
+	assert := assert.New(t)
+	noon := Date.NoonOn(time.Date(2016, 04, 03, 02, 01, 0, 0, time.UTC))
+
+	assert.Equal(2016, noon.Year())
+	assert.Equal(4, noon.Month())
+	assert.Equal(3, noon.Day())
+	assert.Equal(12, noon.Hour())
+	assert.Equal(0, noon.Minute())
+	assert.Equal(time.UTC, noon.Location())
+}
+
+func TestDateBefore(t *testing.T) {
+	assert := assert.New(t)
+
+	assert.True(Date.Before(parse("2015-07-02"), parse("2016-07-01")))
+	assert.True(Date.Before(parse("2016-06-01"), parse("2016-07-01")))
+	assert.True(Date.Before(parse("2016-07-01"), parse("2016-07-02")))
+
+	assert.False(Date.Before(parse("2016-07-01"), parse("2016-07-01")))
+	assert.False(Date.Before(parse("2016-07-03"), parse("2016-07-01")))
+	assert.False(Date.Before(parse("2016-08-03"), parse("2016-07-01")))
+	assert.False(Date.Before(parse("2017-08-03"), parse("2016-07-01")))
+}
+
+func TestDateBeforeHandlesTimezones(t *testing.T) {
+	assert := assert.New(t)
+
+	tuesdayUTC := time.Date(2016, 8, 02, 22, 00, 0, 0, time.UTC)
+	mondayUTC := time.Date(2016, 8, 01, 1, 00, 0, 0, time.UTC)
+	sundayEST := time.Date(2016, 7, 31, 22, 00, 0, 0, Date.Eastern())
+
+	assert.True(Date.Before(sundayEST, tuesdayUTC))
+	assert.False(Date.Before(sundayEST, mondayUTC))
+}
+
+func TestNextMarketOpen(t *testing.T) {
+	assert := assert.New(t)
+
+	beforeOpen := time.Date(2016, 07, 18, 9, 0, 0, 0, Date.Eastern())
+	todayOpen := time.Date(2016, 07, 18, 9, 30, 0, 0, Date.Eastern())
+
+	afterOpen := time.Date(2016, 07, 18, 9, 31, 0, 0, Date.Eastern())
+	tomorrowOpen := time.Date(2016, 07, 19, 9, 30, 0, 0, Date.Eastern())
+
+	afterFriday := time.Date(2016, 07, 22, 9, 31, 0, 0, Date.Eastern())
+	mondayOpen := time.Date(2016, 07, 25, 9, 30, 0, 0, Date.Eastern())
+
+	weekend := time.Date(2016, 07, 23, 9, 31, 0, 0, Date.Eastern())
+
+	assert.True(todayOpen.Equal(Date.NextMarketOpen(beforeOpen, NYSEOpen(), Date.IsNYSEHoliday)))
+	assert.True(tomorrowOpen.Equal(Date.NextMarketOpen(afterOpen, NYSEOpen(), Date.IsNYSEHoliday)))
+	assert.True(mondayOpen.Equal(Date.NextMarketOpen(afterFriday, NYSEOpen(), Date.IsNYSEHoliday)))
+	assert.True(mondayOpen.Equal(Date.NextMarketOpen(weekend, NYSEOpen(), Date.IsNYSEHoliday)))
+
+	assert.Equal(Date.Eastern(), todayOpen.Location())
+	assert.Equal(Date.Eastern(), tomorrowOpen.Location())
+	assert.Equal(Date.Eastern(), mondayOpen.Location())
+
+	testRegression := time.Date(2016, 07, 18, 16, 0, 0, 0, Date.Eastern())
+	shouldbe := time.Date(2016, 07, 19, 9, 30, 0, 0, Date.Eastern())
+
+	assert.True(shouldbe.Equal(Date.NextMarketOpen(testRegression, NYSEOpen(), Date.IsNYSEHoliday)))
+}
+
+func TestNextMarketClose(t *testing.T) {
+	assert := assert.New(t)
+
+	beforeClose := time.Date(2016, 07, 18, 15, 0, 0, 0, Date.Eastern())
+	todayClose := time.Date(2016, 07, 18, 16, 00, 0, 0, Date.Eastern())
+
+	afterClose := time.Date(2016, 07, 18, 16, 1, 0, 0, Date.Eastern())
+	tomorrowClose := time.Date(2016, 07, 19, 16, 00, 0, 0, Date.Eastern())
+
+	afterFriday := time.Date(2016, 07, 22, 16, 1, 0, 0, Date.Eastern())
+	mondayClose := time.Date(2016, 07, 25, 16, 0, 0, 0, Date.Eastern())
+
+	weekend := time.Date(2016, 07, 23, 9, 31, 0, 0, Date.Eastern())
+
+	assert.True(todayClose.Equal(Date.NextMarketClose(beforeClose, NYSEClose(), Date.IsNYSEHoliday)))
+	assert.True(tomorrowClose.Equal(Date.NextMarketClose(afterClose, NYSEClose(), Date.IsNYSEHoliday)))
+	assert.True(mondayClose.Equal(Date.NextMarketClose(afterFriday, NYSEClose(), Date.IsNYSEHoliday)))
+	assert.True(mondayClose.Equal(Date.NextMarketClose(weekend, NYSEClose(), Date.IsNYSEHoliday)))
+
+	assert.Equal(Date.Eastern(), todayClose.Location())
+	assert.Equal(Date.Eastern(), tomorrowClose.Location())
+	assert.Equal(Date.Eastern(), mondayClose.Location())
+}
+
+func TestCalculateMarketSecondsBetween(t *testing.T) {
+	assert := assert.New(t)
+
+	start := time.Date(2016, 07, 18, 9, 30, 0, 0, Date.Eastern())
+	end := time.Date(2016, 07, 22, 16, 00, 0, 0, Date.Eastern())
+
+	shouldbe := 5 * 6.5 * 60 * 60
+
+	assert.Equal(shouldbe, Date.CalculateMarketSecondsBetween(start, end, NYSEOpen(), NYSEClose(), Date.IsNYSEHoliday))
+}
+
+func TestCalculateMarketSecondsBetween1D(t *testing.T) {
+	assert := assert.New(t)
+
+	start := time.Date(2016, 07, 22, 9, 45, 0, 0, Date.Eastern())
+	end := time.Date(2016, 07, 22, 15, 45, 0, 0, Date.Eastern())
+
+	shouldbe := 6 * 60 * 60
+
+	assert.Equal(shouldbe, Date.CalculateMarketSecondsBetween(start, end, NYSEOpen(), NYSEClose(), Date.IsNYSEHoliday))
+}
+
+func TestCalculateMarketSecondsBetweenLTM(t *testing.T) {
+	assert := assert.New(t)
+
+	start := time.Date(2015, 07, 01, 9, 30, 0, 0, Date.Eastern())
+	end := time.Date(2016, 07, 01, 9, 30, 0, 0, Date.Eastern())
+
+	shouldbe := 253 * 6.5 * 60 * 60 //253 full market days since this date last year.
+	assert.Equal(shouldbe, Date.CalculateMarketSecondsBetween(start, end, NYSEOpen(), NYSEClose(), Date.IsNYSEHoliday))
+}
+
+func TestDateNextHour(t *testing.T) {
+	assert := assert.New(t)
+
+	start := time.Date(2015, 07, 01, 9, 30, 0, 0, Date.Eastern())
+	next := Date.NextHour(start)
+	assert.Equal(2015, next.Year())
+	assert.Equal(07, next.Month())
+	assert.Equal(01, next.Day())
+	assert.Equal(10, next.Hour())
+	assert.Equal(00, next.Minute())
+
+	next = Date.NextHour(next)
+	assert.Equal(11, next.Hour())
+
+	next = Date.NextHour(next)
+	assert.Equal(12, next.Hour())
+
+}
+
+func TestDateNextDayOfWeek(t *testing.T) {
+	assert := assert.New(t)
+
+	weds := Date.Date(2016, 8, 10, time.UTC)
+	fri := Date.Date(2016, 8, 12, time.UTC)
+	sun := Date.Date(2016, 8, 14, time.UTC)
+	mon := Date.Date(2016, 8, 15, time.UTC)
+	weds2 := Date.Date(2016, 8, 17, time.UTC)
+
+	nextFri := Date.NextDayOfWeek(weds, time.Friday)
+	nextSunday := Date.NextDayOfWeek(weds, time.Sunday)
+	nextMonday := Date.NextDayOfWeek(weds, time.Monday)
+	nextWeds := Date.NextDayOfWeek(weds, time.Wednesday)
+
+	assert.Equal(fri.Year(), nextFri.Year())
+	assert.Equal(fri.Month(), nextFri.Month())
+	assert.Equal(fri.Day(), nextFri.Day())
+
+	assert.Equal(sun.Year(), nextSunday.Year())
+	assert.Equal(sun.Month(), nextSunday.Month())
+	assert.Equal(sun.Day(), nextSunday.Day())
+
+	assert.Equal(mon.Year(), nextMonday.Year())
+	assert.Equal(mon.Month(), nextMonday.Month())
+	assert.Equal(mon.Day(), nextMonday.Day())
+
+	assert.Equal(weds2.Year(), nextWeds.Year())
+	assert.Equal(weds2.Month(), nextWeds.Month())
+	assert.Equal(weds2.Day(), nextWeds.Day())
+
+	assert.Equal(time.UTC, nextFri.Location())
+	assert.Equal(time.UTC, nextSunday.Location())
+	assert.Equal(time.UTC, nextMonday.Location())
+}
+
+func TestDateIsNYSEHoliday(t *testing.T) {
+	assert := assert.New(t)
+
+	cursor := time.Date(2013, 01, 01, 0, 0, 0, 0, time.UTC)
+	end := time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC)
+	var holidays int
+	for Date.Before(cursor, end) {
+		if Date.IsNYSEHoliday(cursor) {
+			holidays++
+		}
+		cursor = cursor.AddDate(0, 0, 1)
+	}
+	assert.Equal(holidays, 55)
+}
+
+func TestTimeStart(t *testing.T) {
+	assert := assert.New(t)
+
+	times := []time.Time{
+		time.Now().AddDate(0, 0, -4),
+		time.Now().AddDate(0, 0, -2),
+		time.Now().AddDate(0, 0, -1),
+		time.Now().AddDate(0, 0, -3),
+		time.Now().AddDate(0, 0, -5),
+	}
+
+	assert.InTimeDelta(Date.Start(times), times[4], time.Millisecond)
+}
+
+func TestTimeEnd(t *testing.T) {
+	assert := assert.New(t)
+
+	times := []time.Time{
+		time.Now().AddDate(0, 0, -4),
+		time.Now().AddDate(0, 0, -2),
+		time.Now().AddDate(0, 0, -1),
+		time.Now().AddDate(0, 0, -3),
+		time.Now().AddDate(0, 0, -5),
+	}
+
+	assert.InTimeDelta(Date.End(times), times[2], time.Millisecond)
+}
+
+func TestDateDiffDays(t *testing.T) {
+	assert := assert.New(t)
+
+	t1 := time.Date(2017, 02, 27, 12, 0, 0, 0, time.UTC)
+	t2 := time.Date(2017, 01, 10, 3, 0, 0, 0, time.UTC)
+	t3 := time.Date(2017, 02, 24, 16, 0, 0, 0, time.UTC)
+
+	assert.Equal(48, Date.DiffDays(t2, t1))
+	assert.Equal(2, Date.DiffDays(t3, t1)) // technically we should round down.
+}
+
+func TestDateDiffHours(t *testing.T) {
+	assert := assert.New(t)
+
+	t1 := time.Date(2017, 02, 27, 12, 0, 0, 0, time.UTC)
+	t2 := time.Date(2017, 02, 24, 16, 0, 0, 0, time.UTC)
+	t3 := time.Date(2017, 02, 28, 12, 0, 0, 0, time.UTC)
+
+	assert.Equal(68, Date.DiffHours(t2, t1))
+	assert.Equal(24, Date.DiffHours(t1, t3))
+}

date_windows.go

@@ -0,0 +1,17 @@
+// +build windows
+
+package chart
+
+import "time"
+
+// Eastern returns the eastern timezone.
+func (d date) Eastern() *time.Location {
+	if _eastern == nil {
+		_easternLock.Lock()
+		defer _easternLock.Unlock()
+		if _eastern == nil {
+			_eastern, _ = time.LoadLocation("EST")
+		}
+	}
+	return _eastern
+}

defaults.go

@@ -1,5 +1,12 @@
 package chart
 
+import (
+	"sync"
+
+	"github.com/golang/freetype/truetype"
+	"github.com/wcharczuk/go-chart/drawing"
+)
+
 const (
 	// DefaultChartHeight is the default chart height.
 	DefaultChartHeight = 400
@@ -75,6 +82,96 @@ const (
 	DefaultBarWidth = 50
 )
 
+var (
+	// ColorWhite is white.
+	ColorWhite = drawing.Color{R: 255, G: 255, B: 255, A: 255}
+	// ColorBlue is the basic theme blue color.
+	ColorBlue = drawing.Color{R: 0, G: 116, B: 217, A: 255}
+	// ColorCyan is the basic theme cyan color.
+	ColorCyan = drawing.Color{R: 0, G: 217, B: 210, A: 255}
+	// ColorGreen is the basic theme green color.
+	ColorGreen = drawing.Color{R: 0, G: 217, B: 101, A: 255}
+	// ColorRed is the basic theme red color.
+	ColorRed = drawing.Color{R: 217, G: 0, B: 116, A: 255}
+	// ColorOrange is the basic theme orange color.
+	ColorOrange = drawing.Color{R: 217, G: 101, B: 0, A: 255}
+	// ColorYellow is the basic theme yellow color.
+	ColorYellow = drawing.Color{R: 217, G: 210, B: 0, A: 255}
+	// ColorBlack is the basic theme black color.
+	ColorBlack = drawing.Color{R: 51, G: 51, B: 51, A: 255}
+	// ColorLightGray is the basic theme light gray color.
+	ColorLightGray = drawing.Color{R: 239, G: 239, B: 239, A: 255}
+
+	// ColorAlternateBlue is a alternate theme color.
+	ColorAlternateBlue = drawing.Color{R: 106, G: 195, B: 203, A: 255}
+	// ColorAlternateGreen is a alternate theme color.
+	ColorAlternateGreen = drawing.Color{R: 42, G: 190, B: 137, A: 255}
+	// ColorAlternateGray is a alternate theme color.
+	ColorAlternateGray = drawing.Color{R: 110, G: 128, B: 139, A: 255}
+	// ColorAlternateYellow is a alternate theme color.
+	ColorAlternateYellow = drawing.Color{R: 240, G: 174, B: 90, A: 255}
+	// ColorAlternateLightGray is a alternate theme color.
+	ColorAlternateLightGray = drawing.Color{R: 187, G: 190, B: 191, A: 255}
+
+	// ColorTransparent is a transparent (alpha zero) color.
+	ColorTransparent = drawing.Color{R: 1, G: 1, B: 1, A: 0}
+)
+
+var (
+	// DefaultBackgroundColor is the default chart background color.
+	// It is equivalent to css color:white.
+	DefaultBackgroundColor = ColorWhite
+	// DefaultBackgroundStrokeColor is the default chart border color.
+	// It is equivalent to color:white.
+	DefaultBackgroundStrokeColor = ColorWhite
+	// DefaultCanvasColor is the default chart canvas color.
+	// It is equivalent to css color:white.
+	DefaultCanvasColor = ColorWhite
+	// DefaultCanvasStrokeColor is the default chart canvas stroke color.
+	// It is equivalent to css color:white.
+	DefaultCanvasStrokeColor = ColorWhite
+	// DefaultTextColor is the default chart text color.
+	// It is equivalent to #333333.
+	DefaultTextColor = ColorBlack
+	// DefaultAxisColor is the default chart axis line color.
+	// It is equivalent to #333333.
+	DefaultAxisColor = ColorBlack
+	// DefaultStrokeColor is the default chart border color.
+	// It is equivalent to #efefef.
+	DefaultStrokeColor = ColorLightGray
+	// DefaultFillColor is the default fill color.
+	// It is equivalent to #0074d9.
+	DefaultFillColor = ColorBlue
+	// DefaultAnnotationFillColor is the default annotation background color.
+	DefaultAnnotationFillColor = ColorWhite
+	// DefaultGridLineColor is the default grid line color.
+	DefaultGridLineColor = ColorLightGray
+)
+
+var (
+	// DefaultColors are a couple default series colors.
+	DefaultColors = []drawing.Color{
+		ColorBlue,
+		ColorGreen,
+		ColorRed,
+		ColorCyan,
+		ColorOrange,
+	}
+
+	// DefaultAlternateColors are a couple alternate colors.
+	DefaultAlternateColors = []drawing.Color{
+		ColorAlternateBlue,
+		ColorAlternateGreen,
+		ColorAlternateGray,
+		ColorAlternateYellow,
+		ColorBlue,
+		ColorGreen,
+		ColorRed,
+		ColorCyan,
+		ColorOrange,
+	}
+)
+
 var (
 	// DashArrayDots is a dash array that represents '....' style stroke dashes.
 	DashArrayDots = []int{1, 1}
@@ -86,18 +183,49 @@ var (
 	DashArrayDashesLarge = []int{10, 10}
 )
 
+// NewColor returns a new color.
+func NewColor(r, g, b, a uint8) drawing.Color {
+	return drawing.Color{R: r, G: g, B: b, A: a}
+}
+
+// GetDefaultColor returns a color from the default list by index.
+// NOTE: the index will wrap around (using a modulo).
+func GetDefaultColor(index int) drawing.Color {
+	finalIndex := index % len(DefaultColors)
+	return DefaultColors[finalIndex]
+}
+
+// GetAlternateColor returns a color from the default list by index.
+// NOTE: the index will wrap around (using a modulo).
+func GetAlternateColor(index int) drawing.Color {
+	finalIndex := index % len(DefaultAlternateColors)
+	return DefaultAlternateColors[finalIndex]
+}
+
 var (
 	// DefaultAnnotationPadding is the padding around an annotation.
 	DefaultAnnotationPadding = Box{Top: 5, Left: 5, Right: 5, Bottom: 5}
-
 	// DefaultBackgroundPadding is the default canvas padding config.
 	DefaultBackgroundPadding = Box{Top: 5, Left: 5, Right: 5, Bottom: 5}
 )
 
-const (
-	// ContentTypePNG is the png mime type.
-	ContentTypePNG = "image/png"
-
-	// ContentTypeSVG is the svg mime type.
-	ContentTypeSVG = "image/svg+xml"
+var (
+	_defaultFontLock sync.Mutex
+	_defaultFont     *truetype.Font
 )
+
+// GetDefaultFont returns the default font (Roboto-Medium).
+func GetDefaultFont() (*truetype.Font, error) {
+	if _defaultFont == nil {
+		_defaultFontLock.Lock()
+		defer _defaultFontLock.Unlock()
+		if _defaultFont == nil {
+			font, err := truetype.Parse(roboto)
+			if err != nil {
+				return nil, err
+			}
+			_defaultFont = font
+		}
+	}
+	return _defaultFont, nil
+}

draw.go

@@ -1,10 +1,6 @@
 package chart
 
-import (
-	"math"
-
-	util "git.fireandbrimst.one/aw/go-chart/util"
-)
+import "math"
 
 var (
 	// Draw contains helpers for drawing common objects.
@@ -14,7 +10,7 @@ var (
 type draw struct{}
 
 // LineSeries draws a line series with a renderer.
-func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValuesProvider) {
+func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValueProvider) {
 	if vs.Len() == 0 {
 		return
 	}
@@ -22,7 +18,7 @@ func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style
 	cb := canvasBox.Bottom
 	cl := canvasBox.Left
 
-	v0x, v0y := vs.GetValues(0)
+	v0x, v0y := vs.GetValue(0)
 	x0 := cl + xrange.Translate(v0x)
 	y0 := cb - yrange.Translate(v0y)
 
@@ -35,13 +31,13 @@ func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style
 		style.GetFillOptions().WriteDrawingOptionsToRenderer(r)
 		r.MoveTo(x0, y0)
 		for i := 1; i < vs.Len(); i++ {
-			vx, vy = vs.GetValues(i)
+			vx, vy = vs.GetValue(i)
 			x = cl + xrange.Translate(vx)
 			y = cb - yrange.Translate(vy)
 			r.LineTo(x, y)
 		}
-		r.LineTo(x, util.Math.MinInt(cb, cb-yv0))
-		r.LineTo(x0, util.Math.MinInt(cb, cb-yv0))
+		r.LineTo(x, Math.MinInt(cb, cb-yv0))
+		r.LineTo(x0, Math.MinInt(cb, cb-yv0))
 		r.LineTo(x0, y0)
 		r.Fill()
 	}
@@ -51,7 +47,7 @@ func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style
 
 		r.MoveTo(x0, y0)
 		for i := 1; i < vs.Len(); i++ {
-			vx, vy = vs.GetValues(i)
+			vx, vy = vs.GetValue(i)
 			x = cl + xrange.Translate(vx)
 			y = cb - yrange.Translate(vy)
 			r.LineTo(x, y)
@@ -60,34 +56,23 @@ func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style
 	}
 
 	if style.ShouldDrawDot() {
-		defaultDotWidth := style.GetDotWidth()
+		dotWidth := style.GetDotWidth()
 
 		style.GetDotOptions().WriteDrawingOptionsToRenderer(r)
+
 		for i := 0; i < vs.Len(); i++ {
-			vx, vy = vs.GetValues(i)
+			vx, vy = vs.GetValue(i)
 			x = cl + xrange.Translate(vx)
 			y = cb - yrange.Translate(vy)
 
-			dotWidth := defaultDotWidth
-			if style.DotWidthProvider != nil {
-				dotWidth = style.DotWidthProvider(xrange, yrange, i, vx, vy)
-			}
-
-			if style.DotColorProvider != nil {
-				dotColor := style.DotColorProvider(xrange, yrange, i, vx, vy)
-
-				r.SetFillColor(dotColor)
-				r.SetStrokeColor(dotColor)
-			}
-
 			r.Circle(dotWidth, x, y)
 			r.FillStroke()
 		}
 	}
 }
 
-// BoundedSeries draws a series that implements BoundedValuesProvider.
-func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, bbs BoundedValuesProvider, drawOffsetIndexes ...int) {
+// BoundedSeries draws a series that implements BoundedValueProvider.
+func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, bbs BoundedValueProvider, drawOffsetIndexes ...int) {
 	drawOffsetIndex := 0
 	if len(drawOffsetIndexes) > 0 {
 		drawOffsetIndex = drawOffsetIndexes[0]
@@ -96,7 +81,7 @@ func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, sty
 	cb := canvasBox.Bottom
 	cl := canvasBox.Left
 
-	v0x, v0y1, v0y2 := bbs.GetBoundedValues(0)
+	v0x, v0y1, v0y2 := bbs.GetBoundedValue(0)
 	x0 := cl + xrange.Translate(v0x)
 	y0 := cb - yrange.Translate(v0y1)
 
@@ -111,7 +96,7 @@ func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, sty
 	style.GetFillAndStrokeOptions().WriteToRenderer(r)
 	r.MoveTo(x0, y0)
 	for i := 1; i < bbs.Len(); i++ {
-		vx, vy1, vy2 = bbs.GetBoundedValues(i)
+		vx, vy1, vy2 = bbs.GetBoundedValue(i)
 
 		xvalues[i] = vx
 		y2values[i] = vy2
@@ -137,7 +122,7 @@ func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, sty
 }
 
 // HistogramSeries draws a value provider as boxes from 0.
-func (d draw) HistogramSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValuesProvider, barWidths ...int) {
+func (d draw) HistogramSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValueProvider, barWidths ...int) {
 	if vs.Len() == 0 {
 		return
 	}
@@ -154,7 +139,7 @@ func (d draw) HistogramSeries(r Renderer, canvasBox Box, xrange, yrange Range, s
 
 	//foreach datapoint, draw a box.
 	for index := 0; index < seriesLength; index++ {
-		vx, vy := vs.GetValues(index)
+		vx, vy := vs.GetValue(index)
 		y0 := yrange.Translate(0)
 		x := cl + xrange.Translate(vx)
 		y := yrange.Translate(vy)

drawing/color.go

@@ -57,11 +57,6 @@ func ColorFromAlphaMixedRGBA(r, g, b, a uint32) Color {
 	return c
 }
 
-// ColorChannelFromFloat returns a normalized byte from a given float value.
-func ColorChannelFromFloat(v float64) uint8 {
-	return uint8(v * 255)
-}
-
 // Color is our internal color type because color.Color is bullshit.
 type Color struct {
 	R, G, B, A uint8

drawing/color_test.go

@@ -0,0 +1,53 @@
+package drawing
+
+import (
+	"testing"
+
+	"image/color"
+
+	"github.com/blendlabs/go-assert"
+)
+
+func TestColorFromHex(t *testing.T) {
+	assert := assert.New(t)
+
+	white := ColorFromHex("FFFFFF")
+	assert.Equal(ColorWhite, white)
+
+	shortWhite := ColorFromHex("FFF")
+	assert.Equal(ColorWhite, shortWhite)
+
+	black := ColorFromHex("000000")
+	assert.Equal(ColorBlack, black)
+
+	shortBlack := ColorFromHex("000")
+	assert.Equal(ColorBlack, shortBlack)
+
+	red := ColorFromHex("FF0000")
+	assert.Equal(ColorRed, red)
+
+	shortRed := ColorFromHex("F00")
+	assert.Equal(ColorRed, shortRed)
+
+	green := ColorFromHex("00FF00")
+	assert.Equal(ColorGreen, green)
+
+	shortGreen := ColorFromHex("0F0")
+	assert.Equal(ColorGreen, shortGreen)
+
+	blue := ColorFromHex("0000FF")
+	assert.Equal(ColorBlue, blue)
+
+	shortBlue := ColorFromHex("00F")
+	assert.Equal(ColorBlue, shortBlue)
+}
+
+func TestColorFromAlphaMixedRGBA(t *testing.T) {
+	assert := assert.New(t)
+
+	black := ColorFromAlphaMixedRGBA(color.Black.RGBA())
+	assert.True(black.Equals(ColorBlack), black.String())
+
+	white := ColorFromAlphaMixedRGBA(color.White.RGBA())
+	assert.True(white.Equals(ColorWhite), white.String())
+}

drawing/curve_test.go

@@ -0,0 +1,35 @@
+package drawing
+
+import (
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+type point struct {
+	X, Y float64
+}
+
+type mockLine struct {
+	inner []point
+}
+
+func (ml *mockLine) LineTo(x, y float64) {
+	ml.inner = append(ml.inner, point{x, y})
+}
+
+func (ml mockLine) Len() int {
+	return len(ml.inner)
+}
+
+func TestTraceQuad(t *testing.T) {
+	assert := assert.New(t)
+
+	// Quad
+	// x1, y1, cpx1, cpy2, x2, y2 float64
+	// do the 9->12 circle segment
+	quad := []float64{10, 20, 20, 20, 20, 10}
+	liner := &mockLine{}
+	TraceQuad(liner, quad, 0.5)
+	assert.NotZero(liner.Len())
+}

drawing/drawing.go

@@ -3,7 +3,7 @@ package drawing
 import (
 	"image/color"
 
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/truetype"
 )
 
 // FillRule defines the type for fill rules

drawing/free_type_path.go

@@ -1,8 +1,8 @@
 package drawing
 
 import (
-	"git.fireandbrimst.one/aw/golang-freetype/raster"
-	"git.fireandbrimst.one/aw/golang-image/math/fixed"
+	"github.com/golang/freetype/raster"
+	"golang.org/x/image/math/fixed"
 )
 
 // FtLineBuilder is a builder for freetype raster glyphs.

drawing/graphic_context.go

@@ -4,7 +4,7 @@ import (
 	"image"
 	"image/color"
 
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/truetype"
 )
 
 // GraphicContext describes the interface for the various backends (images, pdf, opengl, ...)

drawing/painter.go

@@ -4,10 +4,10 @@ import (
 	"image"
 	"image/color"
 
-	"git.fireandbrimst.one/aw/golang-image/draw"
-	"git.fireandbrimst.one/aw/golang-image/math/f64"
+	"golang.org/x/image/draw"
+	"golang.org/x/image/math/f64"
 
-	"git.fireandbrimst.one/aw/golang-freetype/raster"
+	"github.com/golang/freetype/raster"
 )
 
 // Painter implements the freetype raster.Painter and has a SetColor method like the RGBAPainter

drawing/raster_graphic_context.go

@@ -6,11 +6,11 @@ import (
 	"image/color"
 	"math"
 
-	"git.fireandbrimst.one/aw/golang-freetype/raster"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
-	"git.fireandbrimst.one/aw/golang-image/draw"
-	"git.fireandbrimst.one/aw/golang-image/font"
-	"git.fireandbrimst.one/aw/golang-image/math/fixed"
+	"github.com/golang/freetype/raster"
+	"github.com/golang/freetype/truetype"
+	"golang.org/x/image/draw"
+	"golang.org/x/image/font"
+	"golang.org/x/image/math/fixed"
 )
 
 // NewRasterGraphicContext creates a new Graphic context from an image.
@@ -206,7 +206,7 @@ func (rgc *RasterGraphicContext) GetFont() *truetype.Font {
 	return rgc.current.Font
 }
 
-// SetFontSize sets the font size in points (as in “a 12 point font”).
+// SetFontSize sets the font size in points (as in ``a 12 point font'').
 func (rgc *RasterGraphicContext) SetFontSize(fontSizePoints float64) {
 	rgc.current.FontSizePoints = fontSizePoints
 	rgc.recalc()

drawing/stack_graphic_context.go

@@ -4,7 +4,7 @@ import (
 	"image"
 	"image/color"
 
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/truetype"
 )
 
 // StackGraphicContext is a context that does thngs.

drawing/text.go

@@ -1,8 +1,8 @@
 package drawing
 
 import (
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
-	"git.fireandbrimst.one/aw/golang-image/math/fixed"
+	"github.com/golang/freetype/truetype"
+	"golang.org/x/image/math/fixed"
 )
 
 // DrawContour draws the given closed contour at the given sub-pixel offset.

drawing/util.go

@@ -3,10 +3,10 @@ package drawing
 import (
 	"math"
 
-	"git.fireandbrimst.one/aw/golang-image/math/fixed"
+	"golang.org/x/image/math/fixed"
 
-	"git.fireandbrimst.one/aw/golang-freetype/raster"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/raster"
+	"github.com/golang/freetype/truetype"
 )
 
 // PixelsToPoints returns the points for a given number of pixels at a DPI.

ema_series.go

@@ -7,13 +7,6 @@ const (
 	DefaultEMAPeriod = 12
 )
 
-// Interface Assertions.
-var (
-	_ Series              = (*EMASeries)(nil)
-	_ FirstValuesProvider = (*EMASeries)(nil)
-	_ LastValuesProvider  = (*EMASeries)(nil)
-)
-
 // EMASeries is a computed series.
 type EMASeries struct {
 	Name  string
@@ -21,7 +14,7 @@ type EMASeries struct {
 	YAxis YAxisType
 
 	Period      int
-	InnerSeries ValuesProvider
+	InnerSeries ValueProvider
 
 	cache []float64
 }
@@ -59,36 +52,23 @@ func (ema EMASeries) GetSigma() float64 {
 	return 2.0 / (float64(ema.GetPeriod()) + 1)
 }
 
-// GetValues gets a value at a given index.
-func (ema *EMASeries) GetValues(index int) (x, y float64) {
+// GetValue gets a value at a given index.
+func (ema *EMASeries) GetValue(index int) (x, y float64) {
 	if ema.InnerSeries == nil {
 		return
 	}
 	if len(ema.cache) == 0 {
 		ema.ensureCachedValues()
 	}
-	vx, _ := ema.InnerSeries.GetValues(index)
+	vx, _ := ema.InnerSeries.GetValue(index)
 	x = vx
 	y = ema.cache[index]
 	return
 }
 
-// GetFirstValues computes the first moving average value.
-func (ema *EMASeries) GetFirstValues() (x, y float64) {
-	if ema.InnerSeries == nil {
-		return
-	}
-	if len(ema.cache) == 0 {
-		ema.ensureCachedValues()
-	}
-	x, _ = ema.InnerSeries.GetValues(0)
-	y = ema.cache[0]
-	return
-}
-
-// GetLastValues computes the last moving average value but walking back window size samples,
+// GetLastValue computes the last moving average value but walking back window size samples,
 // and recomputing the last moving average chunk.
-func (ema *EMASeries) GetLastValues() (x, y float64) {
+func (ema *EMASeries) GetLastValue() (x, y float64) {
 	if ema.InnerSeries == nil {
 		return
 	}
@@ -96,7 +76,7 @@ func (ema *EMASeries) GetLastValues() (x, y float64) {
 		ema.ensureCachedValues()
 	}
 	lastIndex := ema.InnerSeries.Len() - 1
-	x, _ = ema.InnerSeries.GetValues(lastIndex)
+	x, _ = ema.InnerSeries.GetValue(lastIndex)
 	y = ema.cache[lastIndex]
 	return
 }
@@ -106,7 +86,7 @@ func (ema *EMASeries) ensureCachedValues() {
 	ema.cache = make([]float64, seriesLength)
 	sigma := ema.GetSigma()
 	for x := 0; x < seriesLength; x++ {
-		_, y := ema.InnerSeries.GetValues(x)
+		_, y := ema.InnerSeries.GetValue(x)
 		if x == 0 {
 			ema.cache[x] = y
 			continue

ema_series_test.go

@@ -0,0 +1,105 @@
+package chart
+
+import (
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+)
+
+var (
+	emaXValues = Sequence.Float64(1.0, 50.0)
+	emaYValues = []float64{
+		1, 2, 3, 4, 5, 4, 3, 2,
+		1, 2, 3, 4, 5, 4, 3, 2,
+		1, 2, 3, 4, 5, 4, 3, 2,
+		1, 2, 3, 4, 5, 4, 3, 2,
+		1, 2, 3, 4, 5, 4, 3, 2,
+		1, 2, 3, 4, 5, 4, 3, 2,
+		1, 2,
+	}
+	emaExpected = []float64{
+		1,
+		1.074074074,
+		1.216735254,
+		1.422903013,
+		1.68787316,
+		1.859141815,
+		1.943649828,
+		1.947823915,
+		1.877614736,
+		1.886680311,
+		1.969148437,
+		2.119581886,
+		2.33294619,
+		2.456431658,
+		2.496695979,
+		2.459903685,
+		2.351762671,
+		2.325706177,
+		2.375653867,
+		2.495975803,
+		2.681459077,
+		2.779128775,
+		2.795489607,
+		2.73656445,
+		2.607930047,
+		2.562898191,
+		2.595276103,
+		2.699329725,
+		2.869749746,
+		2.953471987,
+		2.956918506,
+		2.886035654,
+		2.746329309,
+		2.691045657,
+		2.713931163,
+		2.809195522,
+		2.971477335,
+		3.047664199,
+		3.044133518,
+		2.966790294,
+		2.821102124,
+		2.760279745,
+		2.778036801,
+		2.868552593,
+		3.026437586,
+		3.098553321,
+		3.091253075,
+		3.010419514,
+		2.86149955,
+		2.797684768,
+	}
+	emaDelta = 0.0001
+)
+
+func TestEMASeries(t *testing.T) {
+	assert := assert.New(t)
+
+	mockSeries := mockValueProvider{
+		emaXValues,
+		emaYValues,
+	}
+	assert.Equal(50, mockSeries.Len())
+
+	ema := &EMASeries{
+		InnerSeries: mockSeries,
+		Period:      26,
+	}
+
+	sig := ema.GetSigma()
+	assert.Equal(2.0/(26.0+1), sig)
+
+	var yvalues []float64
+	for x := 0; x < ema.Len(); x++ {
+		_, y := ema.GetValue(x)
+		yvalues = append(yvalues, y)
+	}
+
+	for index, yv := range yvalues {
+		assert.InDelta(yv, emaExpected[index], emaDelta)
+	}
+
+	lvx, lvy := ema.GetLastValue()
+	assert.Equal(50.0, lvx)
+	assert.InDelta(lvy, emaExpected[49], emaDelta)
+}

file_util.go

@@ -1,4 +1,4 @@
-package util
+package chart
 
 import (
 	"bufio"
@@ -14,30 +14,24 @@ var (
 type fileUtil struct{}
 
 // ReadByLines reads a file and calls the handler for each line.
-func (fu fileUtil) ReadByLines(filePath string, handler func(line string) error) error {
-	var f *os.File
-	var err error
-	if f, err = os.Open(filePath); err == nil {
+func (fu fileUtil) ReadByLines(filePath string, handler func(line string)) error {
+	if f, err := os.Open(filePath); err == nil {
 		defer f.Close()
-		var line string
+
 		scanner := bufio.NewScanner(f)
 		for scanner.Scan() {
-			line = scanner.Text()
-			err = handler(line)
-			if err != nil {
-				return err
-			}
+			line := scanner.Text()
+			handler(line)
 		}
+	} else {
+		return err
 	}
-	return err
-
+	return nil
 }
 
 // ReadByChunks reads a file in `chunkSize` pieces, dispatched to the handler.
-func (fu fileUtil) ReadByChunks(filePath string, chunkSize int, handler func(line []byte) error) error {
-	var f *os.File
-	var err error
-	if f, err = os.Open(filePath); err == nil {
+func (fu fileUtil) ReadByChunks(filePath string, chunkSize int, handler func(line []byte)) error {
+	if f, err := os.Open(filePath); err == nil {
 		defer f.Close()
 
 		chunk := make([]byte, chunkSize)
@@ -47,11 +41,10 @@ func (fu fileUtil) ReadByChunks(filePath string, chunkSize int, handler func(lin
 				break
 			}
 			readData := chunk[:readBytes]
-			err = handler(readData)
-			if err != nil {
-				return err
-			}
+			handler(readData)
 		}
+	} else {
+		return err
 	}
-	return err
+	return nil
 }

first_value_annotation.go

@@ -1,37 +0,0 @@
-package chart
-
-import "fmt"
-
-// FirstValueAnnotation returns an annotation series of just the first value of a value provider as an annotation.
-func FirstValueAnnotation(innerSeries ValuesProvider, vfs ...ValueFormatter) AnnotationSeries {
-	var vf ValueFormatter
-	if len(vfs) > 0 {
-		vf = vfs[0]
-	} else if typed, isTyped := innerSeries.(ValueFormatterProvider); isTyped {
-		_, vf = typed.GetValueFormatters()
-	} else {
-		vf = FloatValueFormatter
-	}
-
-	var firstValue Value2
-	if typed, isTyped := innerSeries.(FirstValuesProvider); isTyped {
-		firstValue.XValue, firstValue.YValue = typed.GetFirstValues()
-		firstValue.Label = vf(firstValue.YValue)
-	} else {
-		firstValue.XValue, firstValue.YValue = innerSeries.GetValues(0)
-		firstValue.Label = vf(firstValue.YValue)
-	}
-
-	var seriesName string
-	var seriesStyle Style
-	if typed, isTyped := innerSeries.(Series); isTyped {
-		seriesName = fmt.Sprintf("%s - First Value", typed.GetName())
-		seriesStyle = typed.GetStyle()
-	}
-
-	return AnnotationSeries{
-		Name:        seriesName,
-		Style:       seriesStyle,
-		Annotations: []Value2{firstValue},
-	}
-}

font.go

@@ -1,29 +0,0 @@
-package chart
-
-import (
-	"sync"
-
-	"git.fireandbrimst.one/aw/go-chart/roboto"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
-)
-
-var (
-	_defaultFontLock sync.Mutex
-	_defaultFont     *truetype.Font
-)
-
-// GetDefaultFont returns the default font (Roboto-Medium).
-func GetDefaultFont() (*truetype.Font, error) {
-	if _defaultFont == nil {
-		_defaultFontLock.Lock()
-		defer _defaultFontLock.Unlock()
-		if _defaultFont == nil {
-			font, err := truetype.Parse(roboto.Roboto)
-			if err != nil {
-				return nil, err
-			}
-			_defaultFont = font
-		}
-	}
-	return _defaultFont, nil
-}

grid_line_test.go

@@ -0,0 +1,24 @@
+package chart
+
+import (
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+)
+
+func TestGenerateGridLines(t *testing.T) {
+	assert := assert.New(t)
+
+	ticks := []Tick{
+		{Value: 1.0, Label: "1.0"},
+		{Value: 2.0, Label: "2.0"},
+		{Value: 3.0, Label: "3.0"},
+		{Value: 4.0, Label: "4.0"},
+	}
+
+	gl := GenerateGridLines(ticks, Style{}, Style{})
+	assert.Len(gl, 2)
+
+	assert.Equal(2.0, gl[0].Value)
+	assert.Equal(3.0, gl[1].Value)
+}