updates

.gitignore

@@ -1,19 +1,2 @@
-# 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:
+  - 1.8.1
+
+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) {

_examples/benchmark_line_charts/main.go

@@ -8,7 +8,7 @@ import (
 	"strconv"
 	"time"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func random(min, max float64) float64 {

_examples/candlestick_series/main.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"math/rand"
+	"net/http"
+	"time"
+
+	chart "github.com/wcharczuk/go-chart"
+	util "github.com/wcharczuk/go-chart/util"
+)
+
+func stockData() (times []time.Time, prices []float64) {
+	start := time.Date(2017, 05, 15, 9, 30, 0, 0, util.Date.Eastern())
+	price := 256.0
+	for day := 0; day < 60; day++ {
+		cursor := start.AddDate(0, 0, day)
+
+		if util.Date.IsNYSEHoliday(cursor) {
+			continue
+		}
+
+		for minute := 0; minute < ((6 * 60) + 30); minute++ {
+			cursor = cursor.Add(time.Minute)
+
+			if rand.Float64() >= 0.5 {
+				price = price + (rand.Float64() * (price * 0.01))
+			} else {
+				price = price - (rand.Float64() * (price * 0.01))
+			}
+
+			times = append(times, cursor)
+			prices = append(prices, price)
+		}
+	}
+	return
+}
+
+func drawChart(res http.ResponseWriter, req *http.Request) {
+	xv, yv := stockData()
+
+	priceSeries := chart.TimeSeries{
+		Name: "SPY",
+		Style: chart.Style{
+			Show:        false,
+			StrokeColor: chart.GetDefaultColor(0),
+		},
+		XValues: xv,
+		YValues: yv,
+	}
+
+	candleSeries := chart.CandlestickSeries{
+		Name:    "SPY",
+		XValues: xv,
+		YValues: yv,
+	}
+
+	graph := chart.Chart{
+		XAxis: chart.XAxis{
+			Style:        chart.Style{Show: true, FontSize: 8, TextRotationDegrees: 45},
+			TickPosition: chart.TickPositionUnderTick,
+			Range:        &chart.MarketHoursRange{},
+		},
+		YAxis: chart.YAxis{
+			Style: chart.Style{Show: true},
+		},
+		Series: []chart.Series{
+			candleSeries,
+			priceSeries,
+		},
+	}
+
+	res.Header().Set("Content-Type", "image/png")
+	err := graph.Render(chart.PNG, res)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func main() {
+	http.HandleFunc("/", drawChart)
+	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 +3,9 @@ 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"
+	"github.com/wcharczuk/go-chart/seq"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -20,10 +20,14 @@ 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{
@@ -43,10 +47,14 @@ 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{

_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

@@ -3,8 +3,8 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/seq"
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/seq"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -16,8 +16,8 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	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: 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.RandomValuesWithAverage(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 +1,46 @@
+package main
+
+import (
+	"net/http"
+
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/seq"
+	"github.com/wcharczuk/go-chart/util"
+)
+
+func drawChart(res http.ResponseWriter, req *http.Request) {
+	start := util.Date.Date(2016, 7, 01, util.Date.Eastern())
+	end := util.Date.Date(2016, 07, 21, util.Date.Eastern())
+	xv := seq.Time.MarketHours(start, end, util.NYSEOpen(), util.NYSEClose(), util.Date.IsNYSEHoliday)
+	yv := seq.New(seq.NewRandom().WithLen(len(xv)).WithAverage(200).WithScale(10)).Array()
+
+	graph := chart.Chart{
+		XAxis: chart.XAxis{
+			Style:          chart.StyleShow(),
+			TickPosition:   chart.TickPositionBetweenTicks,
+			ValueFormatter: chart.TimeHourValueFormatter,
+			Range: &chart.MarketHoursRange{
+				MarketOpen:      util.NYSEOpen(),
+				MarketClose:     util.NYSEClose(),
+				HolidayProvider: util.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 +3,15 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/seq"
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/seq"
 )
 
 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(),
+		YValues: seq.New(seq.NewRandom().WithLen(100).WithAverage(100).WithScale(50)).Array(),
 	}
 
 	minSeries := &chart.MinSeries{

_examples/overlap/main.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"net/http"
+
+	chart "github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/drawing"
+)
+
+func conditionalColor(condition bool, trueColor drawing.Color, falseColor drawing.Color) drawing.Color {
+	if condition {
+		return trueColor
+	}
+	return falseColor
+}
+
+func drawChart(res http.ResponseWriter, req *http.Request) {
+	r, _ := chart.PNG(1024, 1024)
+
+	b0 := chart.Box{Left: 100, Top: 100, Right: 400, Bottom: 200}
+	b1 := chart.Box{Left: 500, Top: 100, Right: 900, Bottom: 200}
+	b0r := b0.Corners().Rotate(45).Shift(0, 200)
+
+	chart.Draw.Box(r, b0, chart.Style{
+		StrokeColor: drawing.ColorRed,
+		StrokeWidth: 2,
+		FillColor:   conditionalColor(b0.Corners().Overlaps(b1.Corners()), drawing.ColorRed, drawing.ColorTransparent),
+	})
+
+	chart.Draw.Box(r, b1, chart.Style{
+		StrokeColor: drawing.ColorBlue,
+		StrokeWidth: 2,
+		FillColor:   conditionalColor(b1.Corners().Overlaps(b0.Corners()), drawing.ColorRed, drawing.ColorTransparent),
+	})
+
+	chart.Draw.Box2d(r, b0r, chart.Style{
+		StrokeColor: drawing.ColorGreen,
+		StrokeWidth: 2,
+		FillColor:   conditionalColor(b0r.Overlaps(b0.Corners()), drawing.ColorRed, drawing.ColorTransparent),
+	})
+
+	res.Header().Set("Content-Type", "image/png")
+	r.Save(res)
+}
+
+func main() {
+	http.HandleFunc("/", drawChart)
+	http.ListenAndServe(":8080", nil)
+}

_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

@@ -3,8 +3,8 @@ package main
 import (
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	"git.fireandbrimst.one/aw/go-chart/seq"
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/seq"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -16,8 +16,8 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	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: 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.RandomValuesWithAverage(100, 100), //generates a []float64 randomly from 0 to 100 with 100 elements.
 	}
 
 	polyRegSeries := &chart.PolynomialRegressionSeries{

_examples/request_timings/main.go

@@ -7,8 +7,8 @@ import (
 	"strings"
 	"time"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	util "git.fireandbrimst.one/aw/go-chart/util"
+	"github.com/wcharczuk/go-chart"
+	util "github.com/wcharczuk/go-chart/util"
 )
 
 func parseInt(str string) int {
@@ -105,7 +105,9 @@ 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,

_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

@@ -6,9 +6,9 @@ import (
 
 	_ "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"
+	"github.com/wcharczuk/go-chart/drawing"
+	"github.com/wcharczuk/go-chart/seq"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -44,10 +44,10 @@ 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{

_examples/simple_moving_average/main.go

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

_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) {
@@ -32,11 +32,17 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 	tbc := tb.Corners().Rotate(45)
 
-	chart.Draw.BoxCorners(r, tbc, chart.Style{
+	chart.Draw.Box2d(r, tbc, chart.Style{
 		StrokeColor: drawing.ColorRed,
 		StrokeWidth: 2,
 	})
 
+	tbc2 := tbc.Shift(tbc.Height(), 0)
+	chart.Draw.Box2d(r, tbc2, chart.Style{
+		StrokeColor: drawing.ColorGreen,
+		StrokeWidth: 2,
+	})
+
 	tbcb := tbc.Box()
 	chart.Draw.Box(r, tbcb, chart.Style{
 		StrokeColor: drawing.ColorBlue,

_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 +4,8 @@ import (
 	"fmt"
 	"net/http"
 
-	"git.fireandbrimst.one/aw/go-chart"
-	util "git.fireandbrimst.one/aw/go-chart/util"
+	"github.com/wcharczuk/go-chart"
+	util "github.com/wcharczuk/go-chart/util"
 )
 
 func drawChart(res http.ResponseWriter, req *http.Request) {
@@ -18,7 +18,9 @@ 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)
@@ -27,10 +29,14 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 			},
 		},
 		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

@@ -5,7 +5,7 @@ import (
 	"log"
 	"os"
 
-	"git.fireandbrimst.one/aw/go-chart"
+	"github.com/wcharczuk/go-chart"
 )
 
 func main() {
@@ -14,8 +14,10 @@ func main() {
 	b = 1000
 
 	ts1 := chart.ContinuousSeries{ //TimeSeries{
-		Name:    "Time Series",
-		Style:   chart.StyleShow(),
+		Name: "Time Series",
+		Style: chart.Style{
+			Show: true,
+		},
 		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

@@ -4,12 +4,7 @@ import (
 	"fmt"
 	"math"
 
-	util "git.fireandbrimst.one/aw/go-chart/util"
-)
-
-// Interface Assertions.
-var (
-	_ Series = (*AnnotationSeries)(nil)
+	util "github.com/wcharczuk/go-chart/util"
 )
 
 // AnnotationSeries is a series of labels on the chart.

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 +6,8 @@ import (
 	"io"
 	"math"
 
-	util "git.fireandbrimst.one/aw/go-chart/util"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/truetype"
+	util "github.com/wcharczuk/go-chart/util"
 )
 
 // BarChart is a chart that draws bars on a range.
@@ -31,9 +31,6 @@ type BarChart struct {
 
 	BarSpacing int
 
-	UseBaseValue bool
-	BaseValue    float64
-
 	Font        *truetype.Font
 	defaultFont *truetype.Font
 
@@ -129,7 +126,7 @@ 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 +139,6 @@ 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 +195,11 @@ 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)))
@@ -277,7 +261,7 @@ func (bc BarChart) drawYAxis(r Renderer, canvasBox Box, yr Range, ticks []Tick)
 		r.Stroke()
 
 		var ty int
-		var tb Box
+		var tb Box2d
 		for _, t := range ticks {
 			ty = canvasBox.Bottom - yr.Translate(t.Value)
 
@@ -288,7 +272,7 @@ func (bc BarChart) drawYAxis(r Renderer, canvasBox Box, yr Range, ticks []Tick)
 
 			axisStyle.GetTextOptions().WriteToRenderer(r)
 			tb = r.MeasureText(t.Label)
-			Draw.Text(r, t.Label, canvasBox.Right+DefaultYAxisMargin+5, ty+(tb.Height()>>1), axisStyle)
+			Draw.Text(r, t.Label, canvasBox.Right+DefaultYAxisMargin+5, ty+(int(tb.Height())>>1), axisStyle)
 		}
 
 	}
@@ -296,32 +280,7 @@ 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 +369,7 @@ 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 = util.Math.MinInt(int(linesBox.Height())+(2*DefaultXAxisMargin), xaxisHeight)
 			}
 		}
 
@@ -438,8 +397,8 @@ 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,
 	}

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

@@ -3,12 +3,7 @@ package chart
 import (
 	"fmt"
 
-	"git.fireandbrimst.one/aw/go-chart/seq"
-)
-
-// Interface Assertions.
-var (
-	_ Series = (*BollingerBandsSeries)(nil)
+	"github.com/wcharczuk/go-chart/seq"
 )
 
 // BollingerBandsSeries draws bollinger bands for an inner series.

bollinger_band_series_test.go

@@ -0,0 +1,53 @@
+package chart
+
+import (
+	"fmt"
+	"math"
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/seq"
+)
+
+func TestBollingerBandSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	s1 := mockValuesProvider{
+		X: seq.Range(1.0, 100.0),
+		Y: seq.RandomValuesWithMax(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.GetBoundedValues(x)
+	}
+
+	for x := bbs.GetPeriod(); x < 100; x++ {
+		assert.True(y1values[x] > y2values[x], fmt.Sprintf("%v vs. %v", y1values[x], y2values[x]))
+	}
+}
+
+func TestBollingerBandLastValue(t *testing.T) {
+	assert := assert.New(t)
+
+	s1 := mockValuesProvider{
+		X: seq.Range(1.0, 100.0),
+		Y: seq.Range(1.0, 100.0),
+	}
+
+	bbs := &BollingerBandsSeries{
+		InnerSeries: s1,
+	}
+
+	x, y1, y2 := bbs.GetBoundedLastValues()
+	assert.Equal(100.0, x)
+	assert.Equal(101, math.Floor(y1))
+	assert.Equal(83, math.Floor(y2))
+}

box.go

@@ -2,9 +2,8 @@ package chart
 
 import (
 	"fmt"
-	"math"
 
-	util "git.fireandbrimst.one/aw/go-chart/util"
+	util "github.com/wcharczuk/go-chart/util"
 )
 
 var (
@@ -166,12 +165,12 @@ func (b Box) Shift(x, y int) Box {
 }
 
 // Corners returns the box as a set of corners.
-func (b Box) Corners() BoxCorners {
-	return BoxCorners{
-		TopLeft:     Point{b.Left, b.Top},
-		TopRight:    Point{b.Right, b.Top},
-		BottomRight: Point{b.Right, b.Bottom},
-		BottomLeft:  Point{b.Left, b.Bottom},
+func (b Box) Corners() Box2d {
+	return Box2d{
+		TopLeft:     Point{float64(b.Left), float64(b.Top)},
+		TopRight:    Point{float64(b.Right), float64(b.Top)},
+		BottomRight: Point{float64(b.Right), float64(b.Bottom)},
+		BottomLeft:  Point{float64(b.Left), float64(b.Bottom)},
 	}
 }
 
@@ -255,99 +254,3 @@ func (b Box) OuterConstrain(bounds, other Box) Box {
 	}
 	return newBox
 }
-
-// BoxCorners is a box with independent corners.
-type BoxCorners struct {
-	TopLeft, TopRight, BottomRight, BottomLeft Point
-}
-
-// 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),
-	}
-}
-
-// 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)
-	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)
-	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)
-	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)
-	y = ((bottom - top) >> 1) + top
-
-	return
-}
-
-// Rotate rotates the box.
-func (bc BoxCorners) Rotate(thetaDegrees float64) BoxCorners {
-	cx, cy := bc.Center()
-
-	thetaRadians := util.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)
-
-	return BoxCorners{
-		TopLeft:     Point{tlx, tly},
-		TopRight:    Point{trx, try},
-		BottomRight: Point{brx, bry},
-		BottomLeft:  Point{blx, bly},
-	}
-}
-
-// Equals returns if the box equals another box.
-func (bc BoxCorners) Equals(other BoxCorners) bool {
-	return bc.TopLeft.Equals(other.TopLeft) &&
-		bc.TopRight.Equals(other.TopRight) &&
-		bc.BottomRight.Equals(other.BottomRight) &&
-		bc.BottomLeft.Equals(other.BottomLeft)
-}
-
-func (bc BoxCorners) String() string {
-	return fmt.Sprintf("BoxC{%s,%s,%s,%s}", bc.TopLeft.String(), bc.TopRight.String(), bc.BottomRight.String(), bc.BottomLeft.String())
-}
-
-// Point is an X,Y pair
-type Point struct {
-	X, Y int
-}
-
-// DistanceTo calculates the distance to another point.
-func (p Point) DistanceTo(other Point) float64 {
-	dx := math.Pow(float64(p.X-other.X), 2)
-	dy := math.Pow(float64(p.Y-other.Y), 2)
-	return math.Pow(dx+dy, 0.5)
-}
-
-// Equals returns if a point equals another point.
-func (p Point) Equals(other Point) bool {
-	return p.X == other.X && p.Y == other.Y
-}
-
-// String returns a string representation of the point.
-func (p Point) String() string {
-	return fmt.Sprintf("P{%d,%d}", p.X, p.Y)
-}

box_2d.go

@@ -0,0 +1,183 @@
+package chart
+
+import (
+	"fmt"
+	"math"
+
+	util "github.com/wcharczuk/go-chart/util"
+)
+
+// Box2d is a box with (4) independent corners.
+// It is used when dealing with ~rotated~ boxes.
+type Box2d struct {
+	TopLeft, TopRight, BottomRight, BottomLeft Point
+}
+
+// Points returns the constituent points of the box.
+func (bc Box2d) Points() []Point {
+	return []Point{
+		bc.TopRight,
+		bc.BottomRight,
+		bc.BottomLeft,
+		bc.TopLeft,
+	}
+}
+
+// Box return the Box2d as a regular box.
+func (bc Box2d) Box() Box {
+	return Box{
+		Top:    int(bc.Top()),
+		Left:   int(bc.Left()),
+		Right:  int(bc.Right()),
+		Bottom: int(bc.Bottom()),
+	}
+}
+
+// Top returns the top-most corner y value.
+func (bc Box2d) Top() float64 {
+	return math.Min(bc.TopLeft.Y, bc.TopRight.Y)
+}
+
+// Left returns the left-most corner x value.
+func (bc Box2d) Left() float64 {
+	return math.Min(bc.TopLeft.X, bc.BottomLeft.X)
+}
+
+// Right returns the right-most corner x value.
+func (bc Box2d) Right() float64 {
+	return math.Max(bc.TopRight.X, bc.BottomRight.X)
+}
+
+// Bottom returns the bottom-most corner y value.
+func (bc Box2d) Bottom() float64 {
+	return math.Max(bc.BottomLeft.Y, bc.BottomLeft.Y)
+}
+
+// Width returns the width
+func (bc Box2d) Width() float64 {
+	minLeft := math.Min(bc.TopLeft.X, bc.BottomLeft.X)
+	maxRight := math.Max(bc.TopRight.X, bc.BottomRight.X)
+	return maxRight - minLeft
+}
+
+// Height returns the height
+func (bc Box2d) Height() float64 {
+	minTop := math.Min(bc.TopLeft.Y, bc.TopRight.Y)
+	maxBottom := math.Max(bc.BottomLeft.Y, bc.BottomRight.Y)
+	return maxBottom - minTop
+}
+
+// Center returns the center of the box
+func (bc Box2d) Center() (x, y float64) {
+	left := util.Math.Mean(bc.TopLeft.X, bc.BottomLeft.X)
+	right := util.Math.Mean(bc.TopRight.X, bc.BottomRight.X)
+	x = ((right - left) / 2.0) + left
+
+	top := util.Math.Mean(bc.TopLeft.Y, bc.TopRight.Y)
+	bottom := util.Math.Mean(bc.BottomLeft.Y, bc.BottomRight.Y)
+	y = ((bottom - top) / 2.0) + top
+
+	return
+}
+
+// Rotate rotates the box.
+func (bc Box2d) Rotate(thetaDegrees float64) Box2d {
+	cx, cy := bc.Center()
+
+	thetaRadians := util.Math.DegreesToRadians(thetaDegrees)
+
+	tlx, tly := util.Math.RotateCoordinate(int(cx), int(cy), int(bc.TopLeft.X), int(bc.TopLeft.Y), thetaRadians)
+	trx, try := util.Math.RotateCoordinate(int(cx), int(cy), int(bc.TopRight.X), int(bc.TopRight.Y), thetaRadians)
+	brx, bry := util.Math.RotateCoordinate(int(cx), int(cy), int(bc.BottomRight.X), int(bc.BottomRight.Y), thetaRadians)
+	blx, bly := util.Math.RotateCoordinate(int(cx), int(cy), int(bc.BottomLeft.X), int(bc.BottomLeft.Y), thetaRadians)
+
+	return Box2d{
+		TopLeft:     Point{float64(tlx), float64(tly)},
+		TopRight:    Point{float64(trx), float64(try)},
+		BottomRight: Point{float64(brx), float64(bry)},
+		BottomLeft:  Point{float64(blx), float64(bly)},
+	}
+}
+
+// Shift shifts a box by a given x and y value.
+func (bc Box2d) Shift(x, y float64) Box2d {
+	return Box2d{
+		TopLeft:     bc.TopLeft.Shift(x, y),
+		TopRight:    bc.TopRight.Shift(x, y),
+		BottomRight: bc.BottomRight.Shift(x, y),
+		BottomLeft:  bc.BottomLeft.Shift(x, y),
+	}
+}
+
+// Equals returns if the box equals another box.
+func (bc Box2d) Equals(other Box2d) bool {
+	return bc.TopLeft.Equals(other.TopLeft) &&
+		bc.TopRight.Equals(other.TopRight) &&
+		bc.BottomRight.Equals(other.BottomRight) &&
+		bc.BottomLeft.Equals(other.BottomLeft)
+}
+
+// Overlaps returns if two boxes overlap.
+func (bc Box2d) Overlaps(other Box2d) bool {
+	pa := bc.Points()
+	pb := other.Points()
+	for i := 0; i < 4; i++ {
+		for j := 0; j < 4; j++ {
+			pa0 := pa[i]
+			pa1 := pa[(i+1)%4]
+
+			pb0 := pb[j]
+			pb1 := pb[(j+1)%4]
+
+			if util.Math.LinesIntersect(pa0.X, pa0.Y, pa1.X, pa1.Y, pb0.X, pb0.Y, pb1.X, pb1.Y) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// Grow grows a box by a given set of dimensions.
+func (bc Box2d) Grow(by Box) Box2d {
+	top, left, right, bottom := float64(by.Top), float64(by.Left), float64(by.Right), float64(by.Bottom)
+	return Box2d{
+		TopLeft:     Point{X: bc.TopLeft.X - left, Y: bc.TopLeft.Y - top},
+		TopRight:    Point{X: bc.TopRight.X + right, Y: bc.TopRight.Y - top},
+		BottomRight: Point{X: bc.BottomRight.X + right, Y: bc.BottomRight.Y + bottom},
+		BottomLeft:  Point{X: bc.BottomLeft.X - left, Y: bc.BottomLeft.Y + bottom},
+	}
+}
+
+func (bc Box2d) String() string {
+	return fmt.Sprintf("Box2d{%s,%s,%s,%s}", bc.TopLeft.String(), bc.TopRight.String(), bc.BottomRight.String(), bc.BottomLeft.String())
+}
+
+// Point is an X,Y pair
+type Point struct {
+	X, Y float64
+}
+
+// Shift shifts a point.
+func (p Point) Shift(x, y float64) Point {
+	return Point{
+		X: p.X + x,
+		Y: p.Y + y,
+	}
+}
+
+// DistanceTo calculates the distance to another point.
+func (p Point) DistanceTo(other Point) float64 {
+	dx := math.Pow(p.X-other.X, 2)
+	dy := math.Pow(p.Y-other.Y, 2)
+	return math.Pow(dx+dy, 0.5)
+}
+
+// Equals returns if a point equals another point.
+func (p Point) Equals(other Point) bool {
+	return p.X == other.X && p.Y == other.Y
+}
+
+// String returns a string representation of the point.
+func (p Point) String() string {
+	return fmt.Sprintf("(%.2f,%.2f)", p.X, p.Y)
+}

box_2d_test.go

@@ -0,0 +1,66 @@
+package chart
+
+import (
+	"fmt"
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+func TestBox2dCenter(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := Box2d{
+		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 TestBox2dRotate(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := Box2d{
+		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())
+}
+
+func TestBox2dOverlaps(t *testing.T) {
+	assert := assert.New(t)
+
+	bc := Box2d{
+		TopLeft:     Point{5, 5},
+		TopRight:    Point{15, 5},
+		BottomRight: Point{15, 15},
+		BottomLeft:  Point{5, 15},
+	}
+
+	// shift meaningfully the full width of bc right.
+	bc2 := bc.Shift(bc.Width()+1, 0)
+	assert.False(bc.Overlaps(bc2), fmt.Sprintf("%v\n\t\tshould not overlap\n\t%v", bc, bc2))
+
+	// shift meaningfully the full height of bc down.
+	bc3 := bc.Shift(0, bc.Height()+1)
+	assert.False(bc.Overlaps(bc3), fmt.Sprintf("%v\n\t\tshould not overlap\n\t%v", bc, bc3))
+
+	bc4 := bc.Shift(5, 0)
+	assert.True(bc.Overlaps(bc4))
+
+	bc5 := bc.Shift(0, 5)
+	assert.True(bc.Overlaps(bc5))
+
+	bcr := bc.Rotate(45)
+	bcr2 := bc.Rotate(45).Shift(bc.Width()/2.0, 0)
+	assert.True(bcr.Overlaps(bcr2), fmt.Sprintf("%v\n\t\tshould overlap\n\t%v", bcr, bcr2))
+}

box_test.go

@@ -0,0 +1,159 @@
+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)
+}

candlestick_series.go

@@ -0,0 +1,157 @@
+package chart
+
+import (
+	"fmt"
+	"time"
+
+	"math"
+
+	"github.com/wcharczuk/go-chart/util"
+)
+
+// CandleValue is a day's data for a candlestick plot.
+type CandleValue struct {
+	Timestamp time.Time
+	High      float64
+	Low       float64
+	Open      float64
+	Close     float64
+}
+
+// String returns a string value for the candle value.
+func (cv CandleValue) String() string {
+	return fmt.Sprintf("candle %s high: %.2f low: %.2f open: %.2f close: %.2f", cv.Timestamp.Format("2006-01-02"), cv.High, cv.Low, cv.Open, cv.Close)
+}
+
+// IsZero returns if the value is zero or not.
+func (cv CandleValue) IsZero() bool {
+	return cv.Timestamp.IsZero()
+}
+
+// CandlestickSeries is a special type of series that takes a norma value provider
+// and maps it to day value stats (high, low, open, close).
+type CandlestickSeries struct {
+	Name  string
+	Style Style
+	YAxis YAxisType
+
+	// CandleValues will be used in place of creating them from the `InnerSeries`.
+	CandleValues []CandleValue
+
+	// InnerSeries is used if the `CandleValues` are not set.
+	InnerSeries ValuesProvider
+}
+
+// GetName implements Series.GetName.
+func (cs *CandlestickSeries) GetName() string {
+	return cs.Name
+}
+
+// GetStyle implements Series.GetStyle.
+func (cs *CandlestickSeries) GetStyle() Style {
+	return cs.Style
+}
+
+// GetYAxis returns which yaxis the series is mapped to.
+func (cs *CandlestickSeries) GetYAxis() YAxisType {
+	return cs.YAxis
+}
+
+// Len returns the length of the series.
+func (cs *CandlestickSeries) Len() int {
+	return len(cs.GetCandleValues())
+}
+
+// GetBoundedValues returns the bounded values at a given index.
+func (cs *CandlestickSeries) GetBoundedValues(index int) (x, y0, y1 float64) {
+	value := cs.GetCandleValues()[index]
+	return util.Time.ToFloat64(value.Timestamp), value.Low, value.High
+}
+
+// GetCandleValues returns the candle values.
+func (cs CandlestickSeries) GetCandleValues() []CandleValue {
+	if cs.CandleValues == nil {
+		cs.CandleValues = cs.GenerateCandleValues()
+	}
+	return cs.CandleValues
+}
+
+// GenerateCandleValues returns the candlestick values for each day represented by the inner series.
+func (cs CandlestickSeries) GenerateCandleValues() []CandleValue {
+	if cs.InnerSeries == nil {
+		return nil
+	}
+
+	totalValues := cs.InnerSeries.Len()
+	if totalValues == 0 {
+		return nil
+	}
+
+	var values []CandleValue
+	var lastYear, lastMonth, lastDay int
+	var year, month, day int
+
+	var t time.Time
+	var tv, lv, v float64
+
+	tv, v = cs.InnerSeries.GetValues(0)
+	t = util.Time.FromFloat64(tv)
+	year, month, day = t.Year(), int(t.Month()), t.Day()
+
+	lastYear, lastMonth, lastDay = year, month, day
+
+	value := CandleValue{
+		Timestamp: cs.newTimestamp(year, month, day),
+		Open:      v,
+		Low:       v,
+		High:      v,
+	}
+	lv = v
+
+	for i := 1; i < totalValues; i++ {
+		tv, v = cs.InnerSeries.GetValues(i)
+		t = util.Time.FromFloat64(tv)
+		year, month, day = t.Year(), int(t.Month()), t.Day()
+
+		// if we've transitioned to a new day or we're on the last value
+		if lastYear != year || lastMonth != month || lastDay != day || i == (totalValues-1) {
+			value.Close = lv
+			values = append(values, value)
+
+			value = CandleValue{
+				Timestamp: cs.newTimestamp(year, month, day),
+				Open:      v,
+				High:      v,
+				Low:       v,
+			}
+
+			lastYear = year
+			lastMonth = month
+			lastDay = day
+		} else {
+			value.Low = math.Min(value.Low, v)
+			value.High = math.Max(value.High, v)
+		}
+		lv = v
+	}
+
+	return values
+}
+
+func (cs CandlestickSeries) newTimestamp(year, month, day int) time.Time {
+	return time.Date(year, time.Month(month), day, 12, 0, 0, 0, util.Date.Eastern())
+}
+
+// Render implements Series.Render.
+func (cs CandlestickSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
+	style := cs.Style.InheritFrom(defaults)
+	Draw.CandlestickSeries(r, canvasBox, xrange, yrange, style, cs)
+}
+
+// Validate validates the series.
+func (cs CandlestickSeries) Validate() error {
+	if cs.CandleValues == nil && cs.InnerSeries == nil {
+		return fmt.Errorf("candlestick series requires either `CandleValues` or `InnerSeries` to be set")
+	}
+	return nil
+}

candlestick_series_test.go

@@ -0,0 +1,52 @@
+package chart
+
+import (
+	"math/rand"
+	"testing"
+	"time"
+
+	assert "github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/util"
+)
+
+func generateDummyStockData() (times []time.Time, prices []float64) {
+	start := util.Date.On(util.NYSEOpen(), time.Date(2017, 05, 15, 0, 0, 0, 0, util.Date.Eastern()))
+	cursor := start
+	for day := 0; day < 60; day++ {
+
+		if util.Date.IsWeekendDay(cursor.Weekday()) {
+			cursor = start.AddDate(0, 0, day)
+			continue
+		}
+
+		for hour := 0; hour < 7; hour++ {
+			for minute := 0; minute < 60; minute++ {
+				times = append(times, cursor)
+				prices = append(prices, rand.Float64()*256)
+				cursor = cursor.Add(time.Minute)
+			}
+
+			cursor = cursor.Add(time.Hour)
+		}
+
+		cursor = start.AddDate(0, 0, day)
+	}
+
+	return
+}
+
+func TestCandlestickSeriesCandleValues(t *testing.T) {
+	assert := assert.New(t)
+
+	xdata, ydata := generateDummyStockData()
+
+	candleSeries := &CandlestickSeries{
+		InnerSeries: TimeSeries{
+			XValues: xdata,
+			YValues: ydata,
+		},
+	}
+
+	values := candleSeries.GetCandleValues()
+	assert.Len(values, 43) // should be 60 days per the generator.
+}

chart.go

@@ -6,8 +6,8 @@ import (
 	"io"
 	"math"
 
-	util "git.fireandbrimst.one/aw/go-chart/util"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/truetype"
+	util "github.com/wcharczuk/go-chart/util"
 )
 
 // Chart is what we're drawing.
@@ -317,6 +317,9 @@ func (c Chart) checkRanges(xr, yr, yra Range) error {
 	if math.IsNaN(yDelta) {
 		return errors.New("nan y-range delta")
 	}
+	if yDelta == 0 {
+		return errors.New("zero y-range delta")
+	}
 
 	if c.hasSecondarySeries() {
 		yraDelta := yra.GetDelta()
@@ -326,6 +329,9 @@ func (c Chart) checkRanges(xr, yr, yra Range) error {
 		if math.IsNaN(yraDelta) {
 			return errors.New("nan secondary y-range delta")
 		}
+		if yraDelta == 0 {
+			return errors.New("zero secondary y-range delta")
+		}
 	}
 
 	return nil
@@ -496,8 +502,8 @@ func (c Chart) drawTitle(r Renderer) {
 		textWidth := textBox.Width()
 		textHeight := textBox.Height()
 
-		titleX := (c.GetWidth() >> 1) - (textWidth >> 1)
-		titleY := c.TitleStyle.Padding.GetTop(DefaultTitleTop) + textHeight
+		titleX := (int(c.GetWidth()) >> 1) - (int(textWidth) >> 1)
+		titleY := c.TitleStyle.Padding.GetTop(DefaultTitleTop) + int(textHeight)
 
 		r.Text(c.Title, titleX, titleY)
 	}

chart_test.go

@@ -0,0 +1,576 @@
+package chart
+
+import (
+	"bytes"
+	"image"
+	"image/png"
+	"math"
+	"testing"
+	"time"
+
+	"github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/drawing"
+	"github.com/wcharczuk/go-chart/seq"
+)
+
+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: seq.Range(1.0, 10.0),
+				YValues: seq.Range(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: seq.Range(1.0, 10.0),
+				YValues: seq.Range(1.0, 10.0),
+			},
+		},
+	}
+
+	assert.Nil(c.validateSeries())
+
+	c = Chart{
+		Series: []Series{
+			ContinuousSeries{
+				XValues: seq.Range(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: seq.RangeWithStep(0, 4, 1),
+				YValues: seq.RangeWithStep(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: seq.RangeWithStep(0, 4, 1),
+				YValues: seq.RangeWithStep(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

@@ -1,6 +1,6 @@
 package chart
 
-import "git.fireandbrimst.one/aw/go-chart/drawing"
+import "github.com/wcharczuk/go-chart/drawing"
 
 var (
 	// ColorWhite is white.

concat_series_test.go

@@ -0,0 +1,42 @@
+package chart
+
+import (
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/seq"
+)
+
+func TestConcatSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	s1 := ContinuousSeries{
+		XValues: seq.Range(1.0, 10.0),
+		YValues: seq.Range(1.0, 10.0),
+	}
+
+	s2 := ContinuousSeries{
+		XValues: seq.Range(11, 20.0),
+		YValues: seq.Range(10.0, 1.0),
+	}
+
+	s3 := ContinuousSeries{
+		XValues: seq.Range(21, 30.0),
+		YValues: seq.Range(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 +1,23 @@
+package chart
+
+import (
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/util"
+)
+
+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 = util.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
@@ -43,11 +36,6 @@ func (cs ContinuousSeries) GetValues(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) {
 	return cs.XValues[len(cs.XValues)-1], cs.YValues[len(cs.YValues)-1]

continuous_series_test.go

@@ -0,0 +1,73 @@
+package chart
+
+import (
+	"fmt"
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/seq"
+)
+
+func TestContinuousSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	cs := ContinuousSeries{
+		Name:    "Test Series",
+		XValues: seq.Range(1.0, 10.0),
+		YValues: seq.Range(1.0, 10.0),
+	}
+
+	assert.Equal("Test Series", cs.GetName())
+	assert.Equal(10, cs.Len())
+	x0, y0 := cs.GetValues(0)
+	assert.Equal(1.0, x0)
+	assert.Equal(1.0, y0)
+
+	xn, yn := cs.GetValues(9)
+	assert.Equal(10.0, xn)
+	assert.Equal(10.0, yn)
+
+	xn, yn = cs.GetLastValues()
+	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: seq.Range(1.0, 10.0),
+		YValues: seq.Range(1.0, 10.0),
+	}
+	assert.Nil(cs.Validate())
+
+	cs = ContinuousSeries{
+		Name:    "Test Series",
+		XValues: seq.Range(1.0, 10.0),
+	}
+	assert.NotNil(cs.Validate())
+
+	cs = ContinuousSeries{
+		Name:    "Test Series",
+		YValues: seq.Range(1.0, 10.0),
+	}
+	assert.NotNil(cs.Validate())
+}

draw.go

@@ -3,7 +3,7 @@ package chart
 import (
 	"math"
 
-	util "git.fireandbrimst.one/aw/go-chart/util"
+	util "github.com/wcharczuk/go-chart/util"
 )
 
 var (
@@ -168,14 +168,73 @@ func (d draw) HistogramSeries(r Renderer, canvasBox Box, xrange, yrange Range, s
 	}
 }
 
+func (d draw) CandlestickSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, cs CandlestickSeries) {
+	if cs.Len() == 0 {
+		return
+	}
+
+	candleValues := cs.GetCandleValues()
+
+	cb := canvasBox.Bottom
+	cl := canvasBox.Left
+
+	var cv CandleValue
+	for index := 0; index < len(candleValues); index++ {
+		cv = candleValues[index]
+
+		y0 := yrange.Translate(cv.Open)
+		y1 := yrange.Translate(cv.Close)
+
+		x0 := cl + xrange.Translate(util.Time.ToFloat64(util.Date.On(util.NYSEOpen(), cv.Timestamp)))
+		x1 := cl + xrange.Translate(util.Time.ToFloat64(util.Date.On(util.NYSEClose(), cv.Timestamp)))
+
+		x := x0 + ((x1 - x0) >> 1)
+
+		// draw open / close box.
+		if cv.Open < cv.Close {
+			d.Box(r, Box{
+				Top:    cb - y0,
+				Left:   x0,
+				Right:  x1,
+				Bottom: cb - y1,
+			}, style.InheritFrom(Style{FillColor: ColorAlternateGreen}))
+		} else {
+			d.Box(r, Box{
+				Top:    cb - y1,
+				Left:   x0,
+				Right:  x1,
+				Bottom: cb - y0,
+			}, style.InheritFrom(Style{FillColor: ColorRed}))
+		}
+
+		// draw high / low t bars
+		y0 = yrange.Translate(cv.High)
+		y1 = yrange.Translate(cv.Low)
+
+		style.InheritFrom(Style{StrokeColor: DefaultStrokeColor}).WriteToRenderer(r)
+
+		r.MoveTo(x0, cb-y0)
+		r.LineTo(x1, cb-y0)
+		r.Stroke()
+
+		r.MoveTo(x, cb-y0)
+		r.LineTo(x, cb-y1)
+		r.Stroke()
+
+		r.MoveTo(x0, cb-y1)
+		r.LineTo(x1, cb-y1)
+		r.Stroke()
+	}
+}
+
 // MeasureAnnotation measures how big an annotation would be.
 func (d draw) MeasureAnnotation(r Renderer, canvasBox Box, style Style, lx, ly int, label string) Box {
 	style.WriteToRenderer(r)
 	defer r.ResetStyle()
 
 	textBox := r.MeasureText(label)
-	textWidth := textBox.Width()
-	textHeight := textBox.Height()
+	textWidth := int(textBox.Width())
+	textHeight := int(textBox.Height())
 	halfTextHeight := textHeight >> 1
 
 	pt := style.Padding.GetTop(DefaultAnnotationPadding.Top)
@@ -203,8 +262,8 @@ func (d draw) Annotation(r Renderer, canvasBox Box, style Style, lx, ly int, lab
 	defer r.ResetStyle()
 
 	textBox := r.MeasureText(label)
-	textWidth := textBox.Width()
-	halfTextHeight := textBox.Height() >> 1
+	textWidth := int(textBox.Width())
+	halfTextHeight := int(textBox.Height()) >> 1
 
 	style.GetFillAndStrokeOptions().WriteToRenderer(r)
 
@@ -255,17 +314,17 @@ func (d draw) Box(r Renderer, b Box, s Style) {
 }
 
 func (d draw) BoxRotated(r Renderer, b Box, thetaDegrees float64, s Style) {
-	d.BoxCorners(r, b.Corners().Rotate(thetaDegrees), s)
+	d.Box2d(r, b.Corners().Rotate(thetaDegrees), s)
 }
 
-func (d draw) BoxCorners(r Renderer, bc BoxCorners, s Style) {
+func (d draw) Box2d(r Renderer, bc Box2d, s Style) {
 	s.GetFillAndStrokeOptions().WriteToRenderer(r)
 	defer r.ResetStyle()
 
-	r.MoveTo(bc.TopLeft.X, bc.TopLeft.Y)
-	r.LineTo(bc.TopRight.X, bc.TopRight.Y)
-	r.LineTo(bc.BottomRight.X, bc.BottomRight.Y)
-	r.LineTo(bc.BottomLeft.X, bc.BottomLeft.Y)
+	r.MoveTo(int(bc.TopLeft.X), int(bc.TopLeft.Y))
+	r.LineTo(int(bc.TopRight.X), int(bc.TopRight.Y))
+	r.LineTo(int(bc.BottomRight.X), int(bc.BottomRight.Y))
+	r.LineTo(int(bc.BottomLeft.X), int(bc.BottomLeft.Y))
 	r.Close()
 	r.FillStroke()
 }
@@ -278,7 +337,7 @@ func (d draw) Text(r Renderer, text string, x, y int, style Style) {
 	r.Text(text, x, y)
 }
 
-func (d draw) MeasureText(r Renderer, text string, style Style) Box {
+func (d draw) MeasureText(r Renderer, text string, style Style) Box2d {
 	style.GetTextOptions().WriteToRenderer(r)
 	defer r.ResetStyle()
 
@@ -297,9 +356,9 @@ func (d draw) TextWithin(r Renderer, text string, box Box, style Style) {
 
 	switch style.GetTextVerticalAlign() {
 	case TextVerticalAlignBottom, TextVerticalAlignBaseline: // i have to build better baseline handling into measure text
-		y = y - linesBox.Height()
+		y = y - int(linesBox.Height())
 	case TextVerticalAlignMiddle, TextVerticalAlignMiddleBaseline:
-		y = (y - linesBox.Height()) >> 1
+		y = (y - int(linesBox.Height())) >> 1
 	}
 
 	var tx, ty int
@@ -307,19 +366,19 @@ func (d draw) TextWithin(r Renderer, text string, box Box, style Style) {
 		lineBox := r.MeasureText(line)
 		switch style.GetTextHorizontalAlign() {
 		case TextHorizontalAlignCenter:
-			tx = box.Left + ((box.Width() - lineBox.Width()) >> 1)
+			tx = box.Left + ((int(box.Width()) - int(lineBox.Width())) >> 1)
 		case TextHorizontalAlignRight:
-			tx = box.Right - lineBox.Width()
+			tx = box.Right - int(lineBox.Width())
 		default:
 			tx = box.Left
 		}
 		if style.TextRotationDegrees == 0 {
-			ty = y + lineBox.Height()
+			ty = y + int(lineBox.Height())
 		} else {
 			ty = y
 		}
 
 		r.Text(line, tx, ty)
-		y += lineBox.Height() + style.GetTextLineSpacing()
+		y += int(lineBox.Height()) + style.GetTextLineSpacing()
 	}
 }

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
@@ -73,19 +66,6 @@ func (ema *EMASeries) GetValues(index int) (x, y float64) {
 	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,
 // and recomputing the last moving average chunk.
 func (ema *EMASeries) GetLastValues() (x, y float64) {

ema_series_test.go

@@ -0,0 +1,106 @@
+package chart
+
+import (
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/seq"
+)
+
+var (
+	emaXValues = seq.Range(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 := mockValuesProvider{
+		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.GetValues(x)
+		yvalues = append(yvalues, y)
+	}
+
+	for index, yv := range yvalues {
+		assert.InDelta(yv, emaExpected[index], emaDelta)
+	}
+
+	lvx, lvy := ema.GetLastValues()
+	assert.Equal(50.0, lvx)
+	assert.InDelta(lvy, emaExpected[49], emaDelta)
+}

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

@@ -3,8 +3,8 @@ package chart
 import (
 	"sync"
 
-	"git.fireandbrimst.one/aw/go-chart/roboto"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/truetype"
+	"github.com/wcharczuk/go-chart/roboto"
 )
 
 var (

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)
+}

histogram_series_test.go

@@ -0,0 +1,32 @@
+package chart
+
+import (
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/seq"
+)
+
+func TestHistogramSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	cs := ContinuousSeries{
+		Name:    "Test Series",
+		XValues: seq.Range(1.0, 20.0),
+		YValues: seq.Range(10.0, -10.0),
+	}
+
+	hs := HistogramSeries{
+		InnerSeries: cs,
+	}
+
+	for x := 0; x < hs.Len(); x++ {
+		csx, csy := cs.GetValues(0)
+		hsx, hsy1, hsy2 := hs.GetBoundedValues(0)
+		assert.Equal(csx, hsx)
+		assert.True(hsy1 > 0)
+		assert.True(hsy2 <= 0)
+		assert.True(csy < 0 || (csy > 0 && csy == hsy1))
+		assert.True(csy > 0 || (csy < 0 && csy == hsy2))
+	}
+}

jet.go

@@ -1,6 +1,6 @@
 package chart
 
-import "git.fireandbrimst.one/aw/go-chart/drawing"
+import "github.com/wcharczuk/go-chart/drawing"
 
 // Jet is a color map provider based on matlab's jet color map.
 func Jet(v, vmin, vmax float64) drawing.Color {

legend.go

@@ -1,8 +1,8 @@
 package chart
 
 import (
-	"git.fireandbrimst.one/aw/go-chart/drawing"
-	"git.fireandbrimst.one/aw/go-chart/util"
+	"github.com/wcharczuk/go-chart/drawing"
+	"github.com/wcharczuk/go-chart/util"
 )
 
 // Legend returns a legend renderable function.
@@ -67,8 +67,8 @@ func Legend(c *Chart, userDefaults ...Style) Renderable {
 				if labelCount > 0 {
 					legendContent.Bottom += DefaultMinimumTickVerticalSpacing
 				}
-				legendContent.Bottom += tb.Height()
-				right := legendContent.Left + tb.Width() + lineTextGap + lineLengthMinimum
+				legendContent.Bottom += int(tb.Height())
+				right := legendContent.Left + int(tb.Width()) + lineTextGap + lineLengthMinimum
 				legendContent.Right = util.Math.MaxInt(legendContent.Right, right)
 				labelCount++
 			}
@@ -95,12 +95,12 @@ func Legend(c *Chart, userDefaults ...Style) Renderable {
 
 				tb := r.MeasureText(label)
 
-				ty := ycursor + tb.Height()
+				ty := ycursor + int(tb.Height())
 				r.Text(label, tx, ty)
 
-				th2 := tb.Height() >> 1
+				th2 := int(tb.Height()) >> 1
 
-				lx := tx + tb.Width() + lineTextGap
+				lx := tx + int(tb.Width()) + lineTextGap
 				ly := ty - th2
 				lx2 := legendContent.Right - legendPadding.Right
 
@@ -112,7 +112,7 @@ func Legend(c *Chart, userDefaults ...Style) Renderable {
 				r.LineTo(lx2, ly)
 				r.Stroke()
 
-				ycursor += tb.Height()
+				ycursor += int(tb.Height())
 				legendCount++
 			}
 		}
@@ -160,12 +160,12 @@ func LegendThin(c *Chart, userDefaults ...Style) Renderable {
 
 		var textHeight int
 		var textWidth int
-		var textBox Box
+		var textBox Box2d
 		for x := 0; x < len(labels); x++ {
 			if len(labels[x]) > 0 {
 				textBox = r.MeasureText(labels[x])
-				textHeight = util.Math.MaxInt(textBox.Height(), textHeight)
-				textWidth = util.Math.MaxInt(textBox.Width(), textWidth)
+				textHeight = util.Math.MaxInt(int(textBox.Height()), textHeight)
+				textWidth = util.Math.MaxInt(int(textBox.Width()), textWidth)
 			}
 		}
 
@@ -200,7 +200,7 @@ func LegendThin(c *Chart, userDefaults ...Style) Renderable {
 				textBox = r.MeasureText(label)
 				r.Text(label, tx, ty)
 
-				lx = tx + textBox.Width() + lineTextGap
+				lx = tx + int(textBox.Width()) + lineTextGap
 				ly = ty - th2
 
 				r.SetStrokeColor(lines[index].GetStrokeColor())
@@ -211,7 +211,7 @@ func LegendThin(c *Chart, userDefaults ...Style) Renderable {
 				r.LineTo(lx+lineLengthMinimum, ly)
 				r.Stroke()
 
-				tx += textBox.Width() + DefaultMinimumTickHorizontalSpacing + lineTextGap + lineLengthMinimum
+				tx += int(textBox.Width()) + DefaultMinimumTickHorizontalSpacing + lineTextGap + lineLengthMinimum
 			}
 		}
 	}
@@ -279,8 +279,8 @@ func LegendLeft(c *Chart, userDefaults ...Style) Renderable {
 				if labelCount > 0 {
 					legendContent.Bottom += DefaultMinimumTickVerticalSpacing
 				}
-				legendContent.Bottom += tb.Height()
-				right := legendContent.Left + tb.Width() + lineTextGap + lineLengthMinimum
+				legendContent.Bottom += int(tb.Height())
+				right := legendContent.Left + int(tb.Width()) + lineTextGap + lineLengthMinimum
 				legendContent.Right = util.Math.MaxInt(legendContent.Right, right)
 				labelCount++
 			}
@@ -307,12 +307,12 @@ func LegendLeft(c *Chart, userDefaults ...Style) Renderable {
 
 				tb := r.MeasureText(label)
 
-				ty := ycursor + tb.Height()
+				ty := ycursor + int(tb.Height())
 				r.Text(label, tx, ty)
 
-				th2 := tb.Height() >> 1
+				th2 := int(tb.Height()) >> 1
 
-				lx := tx + tb.Width() + lineTextGap
+				lx := tx + int(tb.Width()) + lineTextGap
 				ly := ty - th2
 				lx2 := legendContent.Right - legendPadding.Right
 
@@ -324,7 +324,7 @@ func LegendLeft(c *Chart, userDefaults ...Style) Renderable {
 				r.LineTo(lx2, ly)
 				r.Stroke()
 
-				ycursor += tb.Height()
+				ycursor += int(tb.Height())
 				legendCount++
 			}
 		}

legend_test.go

@@ -0,0 +1,31 @@
+package chart
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+)
+
+func TestLegend(t *testing.T) {
+	assert := assert.New(t)
+
+	graph := Chart{
+		Series: []Series{
+			ContinuousSeries{
+				Name:    "A test series",
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+			},
+		},
+	}
+
+	//note we have to do this as a separate step because we need a reference to graph
+	graph.Elements = []Renderable{
+		Legend(&graph),
+	}
+	buf := bytes.NewBuffer([]byte{})
+	err := graph.Render(PNG, buf)
+	assert.Nil(err)
+	assert.NotZero(buf.Len())
+}

linear_coefficient_provider.go

@@ -1,42 +0,0 @@
-package chart
-
-// LinearCoefficientProvider is a type that returns linear cofficients.
-type LinearCoefficientProvider interface {
-	Coefficients() (m, b, stdev, avg float64)
-}
-
-// LinearCoefficients returns a fixed linear coefficient pair.
-func LinearCoefficients(m, b float64) LinearCoefficientSet {
-	return LinearCoefficientSet{
-		M: m,
-		B: b,
-	}
-}
-
-// NormalizedLinearCoefficients returns a fixed linear coefficient pair.
-func NormalizedLinearCoefficients(m, b, stdev, avg float64) LinearCoefficientSet {
-	return LinearCoefficientSet{
-		M:      m,
-		B:      b,
-		StdDev: stdev,
-		Avg:    avg,
-	}
-}
-
-// LinearCoefficientSet is the m and b values for the linear equation in the form:
-// y = (m*x) + b
-type LinearCoefficientSet struct {
-	M      float64
-	B      float64
-	StdDev float64
-	Avg    float64
-}
-
-// Coefficients returns the coefficients.
-func (lcs LinearCoefficientSet) Coefficients() (m, b, stdev, avg float64) {
-	m = lcs.M
-	b = lcs.B
-	stdev = lcs.StdDev
-	avg = lcs.Avg
-	return
-}

linear_regression_series.go

@@ -3,16 +3,8 @@ package chart
 import (
 	"fmt"
 
-	"git.fireandbrimst.one/aw/go-chart/seq"
-	util "git.fireandbrimst.one/aw/go-chart/util"
-)
-
-// Interface Assertions.
-var (
-	_ Series                    = (*LinearRegressionSeries)(nil)
-	_ FirstValuesProvider       = (*LinearRegressionSeries)(nil)
-	_ LastValuesProvider        = (*LinearRegressionSeries)(nil)
-	_ LinearCoefficientProvider = (*LinearRegressionSeries)(nil)
+	"github.com/wcharczuk/go-chart/seq"
+	util "github.com/wcharczuk/go-chart/util"
 )
 
 // LinearRegressionSeries is a series that plots the n-nearest neighbors
@@ -32,19 +24,6 @@ type LinearRegressionSeries struct {
 	stddevx float64
 }
 
-// Coefficients returns the linear coefficients for the series.
-func (lrs LinearRegressionSeries) Coefficients() (m, b, stdev, avg float64) {
-	if lrs.IsZero() {
-		lrs.computeCoefficients()
-	}
-
-	m = lrs.m
-	b = lrs.b
-	stdev = lrs.stddevx
-	avg = lrs.avgx
-	return
-}
-
 // GetName returns the name of the time series.
 func (lrs LinearRegressionSeries) GetName() string {
 	return lrs.Name
@@ -93,7 +72,7 @@ func (lrs *LinearRegressionSeries) GetValues(index int) (x, y float64) {
 	if lrs.InnerSeries == nil || lrs.InnerSeries.Len() == 0 {
 		return
 	}
-	if lrs.IsZero() {
+	if lrs.m == 0 && lrs.b == 0 {
 		lrs.computeCoefficients()
 	}
 	offset := lrs.GetOffset()
@@ -103,25 +82,12 @@ func (lrs *LinearRegressionSeries) GetValues(index int) (x, y float64) {
 	return
 }
 
-// GetFirstValues computes the first linear regression value.
-func (lrs *LinearRegressionSeries) GetFirstValues() (x, y float64) {
-	if lrs.InnerSeries == nil || lrs.InnerSeries.Len() == 0 {
-		return
-	}
-	if lrs.IsZero() {
-		lrs.computeCoefficients()
-	}
-	x, y = lrs.InnerSeries.GetValues(0)
-	y = (lrs.m * lrs.normalize(x)) + lrs.b
-	return
-}
-
 // GetLastValues computes the last linear regression value.
 func (lrs *LinearRegressionSeries) GetLastValues() (x, y float64) {
 	if lrs.InnerSeries == nil || lrs.InnerSeries.Len() == 0 {
 		return
 	}
-	if lrs.IsZero() {
+	if lrs.m == 0 && lrs.b == 0 {
 		lrs.computeCoefficients()
 	}
 	endIndex := lrs.GetEndIndex()
@@ -130,29 +96,6 @@ func (lrs *LinearRegressionSeries) GetLastValues() (x, y float64) {
 	return
 }
 
-// Render renders the series.
-func (lrs *LinearRegressionSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
-	style := lrs.Style.InheritFrom(defaults)
-	Draw.LineSeries(r, canvasBox, xrange, yrange, style, lrs)
-}
-
-// Validate validates the series.
-func (lrs *LinearRegressionSeries) Validate() error {
-	if lrs.InnerSeries == nil {
-		return fmt.Errorf("linear regression series requires InnerSeries to be set")
-	}
-	return nil
-}
-
-// IsZero returns if we've computed the coefficients or not.
-func (lrs *LinearRegressionSeries) IsZero() bool {
-	return lrs.m == 0 && lrs.b == 0
-}
-
-//
-// internal helpers
-//
-
 func (lrs *LinearRegressionSeries) normalize(xvalue float64) float64 {
 	return (xvalue - lrs.avgx) / lrs.stddevx
 }
@@ -188,3 +131,17 @@ func (lrs *LinearRegressionSeries) computeCoefficients() {
 	lrs.m = (p*sumxy - sumx*sumy) / (p*sumxx - sumx*sumx)
 	lrs.b = (sumy / p) - (lrs.m * sumx / p)
 }
+
+// Render renders the series.
+func (lrs *LinearRegressionSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
+	style := lrs.Style.InheritFrom(defaults)
+	Draw.LineSeries(r, canvasBox, xrange, yrange, style, lrs)
+}
+
+// Validate validates the series.
+func (lrs *LinearRegressionSeries) Validate() error {
+	if lrs.InnerSeries == nil {
+		return fmt.Errorf("linear regression series requires InnerSeries to be set")
+	}
+	return nil
+}

linear_regression_series_test.go

@@ -0,0 +1,78 @@
+package chart
+
+import (
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/seq"
+)
+
+func TestLinearRegressionSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	mainSeries := ContinuousSeries{
+		Name:    "A test series",
+		XValues: seq.Range(1.0, 100.0),
+		YValues: seq.Range(1.0, 100.0),
+	}
+
+	linRegSeries := &LinearRegressionSeries{
+		InnerSeries: mainSeries,
+	}
+
+	lrx0, lry0 := linRegSeries.GetValues(0)
+	assert.InDelta(1.0, lrx0, 0.0000001)
+	assert.InDelta(1.0, lry0, 0.0000001)
+
+	lrxn, lryn := linRegSeries.GetLastValues()
+	assert.InDelta(100.0, lrxn, 0.0000001)
+	assert.InDelta(100.0, lryn, 0.0000001)
+}
+
+func TestLinearRegressionSeriesDesc(t *testing.T) {
+	assert := assert.New(t)
+
+	mainSeries := ContinuousSeries{
+		Name:    "A test series",
+		XValues: seq.Range(100.0, 1.0),
+		YValues: seq.Range(100.0, 1.0),
+	}
+
+	linRegSeries := &LinearRegressionSeries{
+		InnerSeries: mainSeries,
+	}
+
+	lrx0, lry0 := linRegSeries.GetValues(0)
+	assert.InDelta(100.0, lrx0, 0.0000001)
+	assert.InDelta(100.0, lry0, 0.0000001)
+
+	lrxn, lryn := linRegSeries.GetLastValues()
+	assert.InDelta(1.0, lrxn, 0.0000001)
+	assert.InDelta(1.0, lryn, 0.0000001)
+}
+
+func TestLinearRegressionSeriesWindowAndOffset(t *testing.T) {
+	assert := assert.New(t)
+
+	mainSeries := ContinuousSeries{
+		Name:    "A test series",
+		XValues: seq.Range(100.0, 1.0),
+		YValues: seq.Range(100.0, 1.0),
+	}
+
+	linRegSeries := &LinearRegressionSeries{
+		InnerSeries: mainSeries,
+		Offset:      10,
+		Limit:       10,
+	}
+
+	assert.Equal(10, linRegSeries.Len())
+
+	lrx0, lry0 := linRegSeries.GetValues(0)
+	assert.InDelta(90.0, lrx0, 0.0000001)
+	assert.InDelta(90.0, lry0, 0.0000001)
+
+	lrxn, lryn := linRegSeries.GetLastValues()
+	assert.InDelta(80.0, lrxn, 0.0000001)
+	assert.InDelta(80.0, lryn, 0.0000001)
+}

linear_series.go

@@ -1,119 +0,0 @@
-package chart
-
-import (
-	"fmt"
-)
-
-// Interface Assertions.
-var (
-	_ Series              = (*LinearSeries)(nil)
-	_ FirstValuesProvider = (*LinearSeries)(nil)
-	_ LastValuesProvider  = (*LinearSeries)(nil)
-)
-
-// LinearSeries is a series that plots a line in a given domain.
-type LinearSeries struct {
-	Name  string
-	Style Style
-	YAxis YAxisType
-
-	XValues     []float64
-	InnerSeries LinearCoefficientProvider
-
-	m     float64
-	b     float64
-	stdev float64
-	avg   float64
-}
-
-// GetName returns the name of the time series.
-func (ls LinearSeries) GetName() string {
-	return ls.Name
-}
-
-// GetStyle returns the line style.
-func (ls LinearSeries) GetStyle() Style {
-	return ls.Style
-}
-
-// GetYAxis returns which YAxis the series draws on.
-func (ls LinearSeries) GetYAxis() YAxisType {
-	return ls.YAxis
-}
-
-// Len returns the number of elements in the series.
-func (ls LinearSeries) Len() int {
-	return len(ls.XValues)
-}
-
-// GetEndIndex returns the effective limit end.
-func (ls LinearSeries) GetEndIndex() int {
-	return len(ls.XValues) - 1
-}
-
-// GetValues gets a value at a given index.
-func (ls *LinearSeries) GetValues(index int) (x, y float64) {
-	if ls.InnerSeries == nil || len(ls.XValues) == 0 {
-		return
-	}
-	if ls.IsZero() {
-		ls.computeCoefficients()
-	}
-	x = ls.XValues[index]
-	y = (ls.m * ls.normalize(x)) + ls.b
-	return
-}
-
-// GetFirstValues computes the first linear regression value.
-func (ls *LinearSeries) GetFirstValues() (x, y float64) {
-	if ls.InnerSeries == nil || len(ls.XValues) == 0 {
-		return
-	}
-	if ls.IsZero() {
-		ls.computeCoefficients()
-	}
-	x, y = ls.GetValues(0)
-	return
-}
-
-// GetLastValues computes the last linear regression value.
-func (ls *LinearSeries) GetLastValues() (x, y float64) {
-	if ls.InnerSeries == nil || len(ls.XValues) == 0 {
-		return
-	}
-	if ls.IsZero() {
-		ls.computeCoefficients()
-	}
-	x, y = ls.GetValues(ls.GetEndIndex())
-	return
-}
-
-// Render renders the series.
-func (ls *LinearSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
-	Draw.LineSeries(r, canvasBox, xrange, yrange, ls.Style.InheritFrom(defaults), ls)
-}
-
-// Validate validates the series.
-func (ls LinearSeries) Validate() error {
-	if ls.InnerSeries == nil {
-		return fmt.Errorf("linear regression series requires InnerSeries to be set")
-	}
-	return nil
-}
-
-// IsZero returns if the linear series has computed coefficients or not.
-func (ls LinearSeries) IsZero() bool {
-	return ls.m == 0 && ls.b == 0
-}
-
-// computeCoefficients computes the `m` and `b` terms in the linear formula given by `y = mx+b`.
-func (ls *LinearSeries) computeCoefficients() {
-	ls.m, ls.b, ls.stdev, ls.avg = ls.InnerSeries.Coefficients()
-}
-
-func (ls *LinearSeries) normalize(xvalue float64) float64 {
-	if ls.avg > 0 && ls.stdev > 0 {
-		return (xvalue - ls.avg) / ls.stdev
-	}
-	return xvalue
-}

macd_series_test.go

@@ -0,0 +1,88 @@
+package chart
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/blendlabs/go-assert"
+)
+
+var (
+	macdExpected = []float64{
+		0,
+		0.06381766382,
+		0.1641441222,
+		0.2817201894,
+		0.4033023481,
+		0.3924673744,
+		0.2983093823,
+		0.1561821464,
+		-0.008916708129,
+		-0.05210332292,
+		-0.01649503993,
+		0.06667130899,
+		0.1751344574,
+		0.1657328378,
+		0.08257097469,
+		-0.04265109369,
+		-0.1875741257,
+		-0.2091853882,
+		-0.1518975486,
+		-0.04781419838,
+		0.08025242841,
+		0.08881960494,
+		0.02183529775,
+		-0.08904155476,
+		-0.2214141128,
+		-0.2321805992,
+		-0.1656331722,
+		-0.05373789678,
+		0.08083727586,
+		0.09475354363,
+		0.03209767112,
+		-0.07534076818,
+		-0.2050442354,
+		-0.2138010557,
+		-0.1458045181,
+		-0.03293263556,
+		0.1022243734,
+		0.1163957964,
+		0.05372761902,
+		-0.05393941791,
+		-0.1840438454,
+		-0.1933365048,
+		-0.1259788988,
+		-0.01382225715,
+		0.1205656194,
+		0.1339326478,
+		0.07044017167,
+		-0.03805851969,
+		-0.1689918111,
+		-0.1791024416,
+	}
+)
+
+func TestMACDSeries(t *testing.T) {
+	assert := assert.New(t)
+
+	mockSeries := mockValuesProvider{
+		emaXValues,
+		emaYValues,
+	}
+	assert.Equal(50, mockSeries.Len())
+
+	mas := &MACDSeries{
+		InnerSeries: mockSeries,
+	}
+
+	var yvalues []float64
+	for x := 0; x < mas.Len(); x++ {
+		_, y := mas.GetValues(x)
+		yvalues = append(yvalues, y)
+	}
+
+	assert.NotEmpty(yvalues)
+	for index, vy := range yvalues {
+		assert.InDelta(vy, macdExpected[index], emaDelta, fmt.Sprintf("delta @ %d actual: %0.9f expected: %0.9f", index, vy, macdExpected[index]))
+	}
+}

market_hours_range.go

@@ -0,0 +1,194 @@
+package chart
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/wcharczuk/go-chart/seq"
+	"github.com/wcharczuk/go-chart/util"
+)
+
+// MarketHoursRange is a special type of range that compresses a time range into just the
+// market (i.e. NYSE operating hours and days) range.
+type MarketHoursRange struct {
+	Min time.Time
+	Max time.Time
+
+	MarketOpen  time.Time
+	MarketClose time.Time
+
+	HolidayProvider util.HolidayProvider
+
+	ValueFormatter ValueFormatter
+
+	Descending bool
+	Domain     int
+}
+
+// IsDescending returns if the range is descending.
+func (mhr MarketHoursRange) IsDescending() bool {
+	return mhr.Descending
+}
+
+// GetTimezone returns the timezone for the market hours range.
+func (mhr MarketHoursRange) GetTimezone() *time.Location {
+	return mhr.GetMarketOpen().Location()
+}
+
+// IsZero returns if the range is setup or not.
+func (mhr MarketHoursRange) IsZero() bool {
+	return mhr.Min.IsZero() && mhr.Max.IsZero()
+}
+
+// GetMin returns the min value.
+func (mhr MarketHoursRange) GetMin() float64 {
+	return util.Time.ToFloat64(mhr.Min)
+}
+
+// GetMax returns the max value.
+func (mhr MarketHoursRange) GetMax() float64 {
+	return util.Time.ToFloat64(mhr.GetEffectiveMax())
+}
+
+// GetEffectiveMax gets either the close on the max, or the max itself.
+func (mhr MarketHoursRange) GetEffectiveMax() time.Time {
+	maxClose := util.Date.On(mhr.MarketClose, mhr.Max)
+	if maxClose.After(mhr.Max) {
+		return maxClose
+	}
+	return mhr.Max
+}
+
+// SetMin sets the min value.
+func (mhr *MarketHoursRange) SetMin(min float64) {
+	mhr.Min = util.Time.FromFloat64(min)
+	mhr.Min = mhr.Min.In(mhr.GetTimezone())
+}
+
+// SetMax sets the max value.
+func (mhr *MarketHoursRange) SetMax(max float64) {
+	mhr.Max = util.Time.FromFloat64(max)
+	mhr.Max = mhr.Max.In(mhr.GetTimezone())
+}
+
+// GetDelta gets the delta.
+func (mhr MarketHoursRange) GetDelta() float64 {
+	min := mhr.GetMin()
+	max := mhr.GetMax()
+	return max - min
+}
+
+// GetDomain gets the domain.
+func (mhr MarketHoursRange) GetDomain() int {
+	return mhr.Domain
+}
+
+// SetDomain sets the domain.
+func (mhr *MarketHoursRange) SetDomain(domain int) {
+	mhr.Domain = domain
+}
+
+// GetHolidayProvider coalesces a userprovided holiday provider and the date.DefaultHolidayProvider.
+func (mhr MarketHoursRange) GetHolidayProvider() util.HolidayProvider {
+	if mhr.HolidayProvider == nil {
+		return util.Date.IsNYSEHoliday
+	}
+	return mhr.HolidayProvider
+}
+
+// GetMarketOpen returns the market open time.
+func (mhr MarketHoursRange) GetMarketOpen() time.Time {
+	if mhr.MarketOpen.IsZero() {
+		return util.NYSEOpen()
+	}
+	return mhr.MarketOpen
+}
+
+// GetMarketClose returns the market close time.
+func (mhr MarketHoursRange) GetMarketClose() time.Time {
+	if mhr.MarketClose.IsZero() {
+		return util.NYSEClose()
+	}
+	return mhr.MarketClose
+}
+
+// GetTicks returns the ticks for the range.
+// This is to override the default continous ticks that would be generated for the range.
+func (mhr *MarketHoursRange) GetTicks(r Renderer, defaults Style, vf ValueFormatter) []Tick {
+	times := seq.TimeUtil.MarketHours(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	timesWidth := mhr.measureTimes(r, defaults, vf, times)
+	if timesWidth <= mhr.Domain {
+		return mhr.makeTicks(vf, times)
+	}
+
+	times = seq.TimeUtil.MarketHourQuarters(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	timesWidth = mhr.measureTimes(r, defaults, vf, times)
+	if timesWidth <= mhr.Domain {
+		return mhr.makeTicks(vf, times)
+	}
+
+	times = seq.TimeUtil.MarketDayCloses(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	timesWidth = mhr.measureTimes(r, defaults, vf, times)
+	if timesWidth <= mhr.Domain {
+		return mhr.makeTicks(vf, times)
+	}
+
+	times = seq.TimeUtil.MarketDayAlternateCloses(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	timesWidth = mhr.measureTimes(r, defaults, vf, times)
+	if timesWidth <= mhr.Domain {
+		return mhr.makeTicks(vf, times)
+	}
+
+	times = seq.TimeUtil.MarketDayMondayCloses(mhr.Min, mhr.Max, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	timesWidth = mhr.measureTimes(r, defaults, vf, times)
+	if timesWidth <= mhr.Domain {
+		return mhr.makeTicks(vf, times)
+	}
+
+	return GenerateContinuousTicks(r, mhr, false, defaults, vf)
+}
+
+func (mhr *MarketHoursRange) measureTimes(r Renderer, defaults Style, vf ValueFormatter, times []time.Time) int {
+	defaults.GetTextOptions().WriteToRenderer(r)
+	var total int
+	for index, t := range times {
+		timeLabel := vf(t)
+
+		labelBox := r.MeasureText(timeLabel)
+		total += int(labelBox.Width())
+		if index > 0 {
+			total += DefaultMinimumTickHorizontalSpacing
+		}
+	}
+	return total
+}
+
+func (mhr *MarketHoursRange) makeTicks(vf ValueFormatter, times []time.Time) []Tick {
+	ticks := make([]Tick, len(times))
+	for index, t := range times {
+		ticks[index] = Tick{
+			Value: util.Time.ToFloat64(t),
+			Label: vf(t),
+		}
+	}
+	return ticks
+}
+
+func (mhr MarketHoursRange) String() string {
+	return fmt.Sprintf("MarketHoursRange [%s, %s] => %d", mhr.Min.Format(time.RFC3339), mhr.Max.Format(time.RFC3339), mhr.Domain)
+}
+
+// Translate maps a given value into the ContinuousRange space.
+func (mhr MarketHoursRange) Translate(value float64) int {
+	valueTime := util.Time.FromFloat64(value)
+	valueTimeEastern := valueTime.In(util.Date.Eastern())
+	totalSeconds := util.Date.CalculateMarketSecondsBetween(mhr.Min, mhr.GetEffectiveMax(), mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	valueDelta := util.Date.CalculateMarketSecondsBetween(mhr.Min, valueTimeEastern, mhr.GetMarketOpen(), mhr.GetMarketClose(), mhr.GetHolidayProvider())
+	translated := int((float64(valueDelta) / float64(totalSeconds)) * float64(mhr.Domain))
+
+	if mhr.IsDescending() {
+		return mhr.Domain - translated
+	}
+
+	return translated
+}

market_hours_range_test.go

@@ -0,0 +1,73 @@
+package chart
+
+import (
+	"testing"
+	"time"
+
+	assert "github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/util"
+)
+
+func TestMarketHoursRangeGetDelta(t *testing.T) {
+	assert := assert.New(t)
+
+	r := &MarketHoursRange{
+		Min:             time.Date(2016, 07, 19, 9, 30, 0, 0, util.Date.Eastern()),
+		Max:             time.Date(2016, 07, 22, 16, 00, 0, 0, util.Date.Eastern()),
+		MarketOpen:      util.NYSEOpen(),
+		MarketClose:     util.NYSEClose(),
+		HolidayProvider: util.Date.IsNYSEHoliday,
+	}
+
+	assert.NotZero(r.GetDelta())
+}
+
+func TestMarketHoursRangeTranslate(t *testing.T) {
+	assert := assert.New(t)
+
+	r := &MarketHoursRange{
+		Min:             time.Date(2016, 07, 18, 9, 30, 0, 0, util.Date.Eastern()),
+		Max:             time.Date(2016, 07, 22, 16, 00, 0, 0, util.Date.Eastern()),
+		MarketOpen:      util.NYSEOpen(),
+		MarketClose:     util.NYSEClose(),
+		HolidayProvider: util.Date.IsNYSEHoliday,
+		Domain:          1000,
+	}
+
+	weds := time.Date(2016, 07, 20, 9, 30, 0, 0, util.Date.Eastern())
+
+	assert.Equal(0, r.Translate(util.Time.ToFloat64(r.Min)))
+	assert.Equal(400, r.Translate(util.Time.ToFloat64(weds)))
+	assert.Equal(1000, r.Translate(util.Time.ToFloat64(r.Max)))
+}
+
+func TestMarketHoursRangeGetTicks(t *testing.T) {
+	assert := assert.New(t)
+
+	r, err := PNG(1024, 1024)
+	assert.Nil(err)
+
+	f, err := GetDefaultFont()
+	assert.Nil(err)
+
+	defaults := Style{
+		Font:      f,
+		FontSize:  10,
+		FontColor: ColorBlack,
+	}
+
+	ra := &MarketHoursRange{
+		Min:             util.Date.On(util.NYSEOpen(), util.Date.Date(2016, 07, 18, util.Date.Eastern())),
+		Max:             util.Date.On(util.NYSEClose(), util.Date.Date(2016, 07, 22, util.Date.Eastern())),
+		MarketOpen:      util.NYSEOpen(),
+		MarketClose:     util.NYSEClose(),
+		HolidayProvider: util.Date.IsNYSEHoliday,
+		Domain:          1024,
+	}
+
+	ticks := ra.GetTicks(r, defaults, TimeValueFormatter)
+	assert.NotEmpty(ticks)
+	assert.Len(ticks, 5)
+	assert.NotEqual(util.Time.ToFloat64(ra.Min), ticks[0].Value)
+	assert.NotEmpty(ticks[0].Label)
+}

matrix/matrix_test.go

@@ -0,0 +1,396 @@
+package matrix
+
+import (
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+func TestNew(t *testing.T) {
+	assert := assert.New(t)
+
+	m := New(10, 5)
+	rows, cols := m.Size()
+	assert.Equal(10, rows)
+	assert.Equal(5, cols)
+	assert.Zero(m.Get(0, 0))
+	assert.Zero(m.Get(9, 4))
+}
+
+func TestNewWithValues(t *testing.T) {
+	assert := assert.New(t)
+
+	m := New(5, 2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
+	rows, cols := m.Size()
+	assert.Equal(5, rows)
+	assert.Equal(2, cols)
+	assert.Equal(1, m.Get(0, 0))
+	assert.Equal(10, m.Get(4, 1))
+}
+
+func TestIdentitiy(t *testing.T) {
+	assert := assert.New(t)
+
+	id := Identity(5)
+	rows, cols := id.Size()
+	assert.Equal(5, rows)
+	assert.Equal(5, cols)
+	assert.Equal(1, id.Get(0, 0))
+	assert.Equal(1, id.Get(1, 1))
+	assert.Equal(1, id.Get(2, 2))
+	assert.Equal(1, id.Get(3, 3))
+	assert.Equal(1, id.Get(4, 4))
+	assert.Equal(0, id.Get(0, 1))
+	assert.Equal(0, id.Get(1, 0))
+	assert.Equal(0, id.Get(4, 0))
+	assert.Equal(0, id.Get(0, 4))
+}
+
+func TestNewFromArrays(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3, 4},
+		{5, 6, 7, 8},
+	})
+	assert.NotNil(m)
+
+	rows, cols := m.Size()
+	assert.Equal(2, rows)
+	assert.Equal(4, cols)
+}
+
+func TestOnes(t *testing.T) {
+	assert := assert.New(t)
+
+	ones := Ones(5, 10)
+	rows, cols := ones.Size()
+	assert.Equal(5, rows)
+	assert.Equal(10, cols)
+
+	for row := 0; row < rows; row++ {
+		for col := 0; col < cols; col++ {
+			assert.Equal(1, ones.Get(row, col))
+		}
+	}
+}
+
+func TestMatrixEpsilon(t *testing.T) {
+	assert := assert.New(t)
+
+	ones := Ones(2, 2)
+	ones = ones.WithEpsilon(0.001)
+	assert.Equal(0.001, ones.Epsilon())
+}
+
+func TestMatrixArrays(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+	})
+
+	assert.NotNil(m)
+
+	arrays := m.Arrays()
+
+	assert.Equal(arrays, [][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+	})
+}
+
+func TestMatrixIsSquare(t *testing.T) {
+	assert := assert.New(t)
+
+	assert.False(NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+	}).IsSquare())
+
+	assert.False(NewFromArrays([][]float64{
+		{1, 2},
+		{3, 4},
+		{5, 6},
+	}).IsSquare())
+
+	assert.True(NewFromArrays([][]float64{
+		{1, 2},
+		{3, 4},
+	}).IsSquare())
+}
+
+func TestMatrixIsSymmetric(t *testing.T) {
+	assert := assert.New(t)
+
+	assert.False(NewFromArrays([][]float64{
+		{1, 2, 3},
+		{2, 1, 2},
+	}).IsSymmetric())
+
+	assert.False(NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	}).IsSymmetric())
+
+	assert.True(NewFromArrays([][]float64{
+		{1, 2, 3},
+		{2, 1, 2},
+		{3, 2, 1},
+	}).IsSymmetric())
+
+}
+
+func TestMatrixGet(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	})
+
+	assert.Equal(1, m.Get(0, 0))
+	assert.Equal(2, m.Get(0, 1))
+	assert.Equal(3, m.Get(0, 2))
+	assert.Equal(4, m.Get(1, 0))
+	assert.Equal(5, m.Get(1, 1))
+	assert.Equal(6, m.Get(1, 2))
+	assert.Equal(7, m.Get(2, 0))
+	assert.Equal(8, m.Get(2, 1))
+	assert.Equal(9, m.Get(2, 2))
+}
+
+func TestMatrixSet(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	})
+
+	m.Set(1, 1, 99)
+	assert.Equal(99, m.Get(1, 1))
+}
+
+func TestMatrixCol(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	})
+
+	assert.Equal([]float64{1, 4, 7}, m.Col(0))
+	assert.Equal([]float64{2, 5, 8}, m.Col(1))
+	assert.Equal([]float64{3, 6, 9}, m.Col(2))
+}
+
+func TestMatrixRow(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	})
+
+	assert.Equal([]float64{1, 2, 3}, m.Row(0))
+	assert.Equal([]float64{4, 5, 6}, m.Row(1))
+	assert.Equal([]float64{7, 8, 9}, m.Row(2))
+}
+
+func TestMatrixSwapRows(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	})
+
+	m.SwapRows(0, 1)
+
+	assert.Equal([]float64{4, 5, 6}, m.Row(0))
+	assert.Equal([]float64{1, 2, 3}, m.Row(1))
+	assert.Equal([]float64{7, 8, 9}, m.Row(2))
+}
+
+func TestMatrixCopy(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	})
+
+	m2 := m.Copy()
+	assert.False(m == m2)
+	assert.True(m.Equals(m2))
+}
+
+func TestMatrixDiagonalVector(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 4, 7},
+		{4, 2, 8},
+		{7, 8, 3},
+	})
+
+	diag := m.DiagonalVector()
+	assert.Equal([]float64{1, 2, 3}, diag)
+}
+
+func TestMatrixDiagonalVectorLandscape(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 4, 7, 99},
+		{4, 2, 8, 99},
+	})
+
+	diag := m.DiagonalVector()
+	assert.Equal([]float64{1, 2}, diag)
+}
+
+func TestMatrixDiagonalVectorPortrait(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 4},
+		{4, 2},
+		{99, 99},
+	})
+
+	diag := m.DiagonalVector()
+	assert.Equal([]float64{1, 2}, diag)
+}
+
+func TestMatrixDiagonal(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 4, 7},
+		{4, 2, 8},
+		{7, 8, 3},
+	})
+
+	m2 := NewFromArrays([][]float64{
+		{1, 0, 0},
+		{0, 2, 0},
+		{0, 0, 3},
+	})
+
+	assert.True(m.Diagonal().Equals(m2))
+}
+
+func TestMatrixEquals(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 4, 7},
+		{4, 2, 8},
+		{7, 8, 3},
+	})
+
+	assert.False(m.Equals(nil))
+	var nilMatrix *Matrix
+	assert.True(nilMatrix.Equals(nil))
+	assert.False(m.Equals(New(1, 1)))
+	assert.False(m.Equals(New(3, 3)))
+	assert.True(m.Equals(New(3, 3, 1, 4, 7, 4, 2, 8, 7, 8, 3)))
+}
+
+func TestMatrixL(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	})
+
+	l := m.L()
+	assert.True(l.Equals(New(3, 3, 1, 2, 3, 0, 5, 6, 0, 0, 9)))
+}
+
+func TestMatrixU(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	})
+
+	u := m.U()
+	assert.True(u.Equals(New(3, 3, 0, 0, 0, 4, 0, 0, 7, 8, 0)))
+}
+
+func TestMatrixString(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+	})
+
+	assert.Equal("1 2 3 \n4 5 6 \n7 8 9 \n", m.String())
+}
+
+func TestMatrixLU(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 3, 5},
+		{2, 4, 7},
+		{1, 1, 0},
+	})
+
+	l, u, p := m.LU()
+	assert.NotNil(l)
+	assert.NotNil(u)
+	assert.NotNil(p)
+}
+
+func TestMatrixQR(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{12, -51, 4},
+		{6, 167, -68},
+		{-4, 24, -41},
+	})
+
+	q, r := m.QR()
+	assert.NotNil(q)
+	assert.NotNil(r)
+}
+
+func TestMatrixTranspose(t *testing.T) {
+	assert := assert.New(t)
+
+	m := NewFromArrays([][]float64{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9},
+		{10, 11, 12},
+	})
+
+	m2 := m.Transpose()
+
+	rows, cols := m2.Size()
+	assert.Equal(3, rows)
+	assert.Equal(4, cols)
+
+	assert.Equal(1, m2.Get(0, 0))
+	assert.Equal(10, m2.Get(0, 3))
+	assert.Equal(3, m2.Get(2, 0))
+}

matrix/regression_test.go

@@ -0,0 +1,22 @@
+package matrix
+
+import (
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+func TestPoly(t *testing.T) {
+	assert := assert.New(t)
+	var xGiven = []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
+	var yGiven = []float64{1, 6, 17, 34, 57, 86, 121, 162, 209, 262, 321}
+	var degree = 2
+
+	c, err := Poly(xGiven, yGiven, degree)
+	assert.Nil(err)
+	assert.Len(c, 3)
+
+	assert.InDelta(c[0], 0.999999999, DefaultEpsilon)
+	assert.InDelta(c[1], 2, DefaultEpsilon)
+	assert.InDelta(c[2], 3, DefaultEpsilon)
+}

pie_chart.go

@@ -6,12 +6,11 @@ import (
 	"io"
 	"math"
 
-	"git.fireandbrimst.one/aw/go-chart/util"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	"github.com/golang/freetype/truetype"
+	"github.com/wcharczuk/go-chart/util"
 )
 
 const (
-	_pi  = math.Pi
 	_pi2 = math.Pi / 2.0
 	_pi4 = math.Pi / 4.0
 )
@@ -138,26 +137,19 @@ func (pc PieChart) drawSlices(r Renderer, canvasBox Box, values []Value) {
 	// draw the pie slices
 	var rads, delta, delta2, total float64
 	var lx, ly int
+	for index, v := range values {
+		v.Style.InheritFrom(pc.stylePieChartValue(index)).WriteToRenderer(r)
 
-	if len(values) == 1 {
-		pc.stylePieChartValue(0).WriteToRenderer(r)
 		r.MoveTo(cx, cy)
-		r.Circle(radius, cx, cy)
-	} else {
-		for index, v := range values {
-			v.Style.InheritFrom(pc.stylePieChartValue(index)).WriteToRenderer(r)
+		rads = util.Math.PercentToRadians(total)
+		delta = util.Math.PercentToRadians(v.Value)
 
-			r.MoveTo(cx, cy)
-			rads = util.Math.PercentToRadians(total)
-			delta = util.Math.PercentToRadians(v.Value)
+		r.ArcTo(cx, cy, radius, radius, rads, delta)
 
-			r.ArcTo(cx, cy, radius, radius, rads, delta)
-
-			r.LineTo(cx, cy)
-			r.Close()
-			r.FillStroke()
-			total = total + v.Value
-		}
+		r.LineTo(cx, cy)
+		r.Close()
+		r.FillStroke()
+		total = total + v.Value
 	}
 
 	// draw the labels
@@ -170,15 +162,8 @@ func (pc PieChart) drawSlices(r Renderer, canvasBox Box, values []Value) {
 			lx, ly = util.Math.CirclePoint(cx, cy, labelRadius, delta2)
 
 			tb := r.MeasureText(v.Label)
-			lx = lx - (tb.Width() >> 1)
-			ly = ly + (tb.Height() >> 1)
-
-			if lx < 0 {
-				lx = 0
-			}
-			if ly < 0 {
-				lx = 0
-			}
+			lx = lx - (int(tb.Width()) >> 1)
+			ly = ly + (int(tb.Height()) >> 1)
 
 			r.Text(v.Label, lx, ly)
 		}

pie_chart_test.go

@@ -0,0 +1,69 @@
+package chart
+
+import (
+	"bytes"
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+)
+
+func TestPieChart(t *testing.T) {
+	assert := assert.New(t)
+
+	pie := PieChart{
+		Canvas: Style{
+			FillColor: ColorLightGray,
+		},
+		Values: []Value{
+			{Value: 10, Label: "Blue"},
+			{Value: 9, Label: "Green"},
+			{Value: 8, Label: "Gray"},
+			{Value: 7, Label: "Orange"},
+			{Value: 6, Label: "HEANG"},
+			{Value: 5, Label: "??"},
+			{Value: 2, Label: "!!"},
+		},
+	}
+
+	b := bytes.NewBuffer([]byte{})
+	pie.Render(PNG, b)
+	assert.NotZero(b.Len())
+}
+
+func TestPieChartDropsZeroValues(t *testing.T) {
+	assert := assert.New(t)
+
+	pie := PieChart{
+		Canvas: Style{
+			FillColor: ColorLightGray,
+		},
+		Values: []Value{
+			{Value: 5, Label: "Blue"},
+			{Value: 5, Label: "Green"},
+			{Value: 0, Label: "Gray"},
+		},
+	}
+
+	b := bytes.NewBuffer([]byte{})
+	err := pie.Render(PNG, b)
+	assert.Nil(err)
+}
+
+func TestPieChartAllZeroValues(t *testing.T) {
+	assert := assert.New(t)
+
+	pie := PieChart{
+		Canvas: Style{
+			FillColor: ColorLightGray,
+		},
+		Values: []Value{
+			{Value: 0, Label: "Blue"},
+			{Value: 0, Label: "Green"},
+			{Value: 0, Label: "Gray"},
+		},
+	}
+
+	b := bytes.NewBuffer([]byte{})
+	err := pie.Render(PNG, b)
+	assert.NotNil(err)
+}

polynomial_regression_series.go

@@ -4,15 +4,8 @@ import (
 	"fmt"
 	"math"
 
-	"git.fireandbrimst.one/aw/go-chart/matrix"
-	util "git.fireandbrimst.one/aw/go-chart/util"
-)
-
-// Interface Assertions.
-var (
-	_ Series              = (*PolynomialRegressionSeries)(nil)
-	_ FirstValuesProvider = (*PolynomialRegressionSeries)(nil)
-	_ LastValuesProvider  = (*PolynomialRegressionSeries)(nil)
+	"github.com/wcharczuk/go-chart/matrix"
+	util "github.com/wcharczuk/go-chart/util"
 )
 
 // PolynomialRegressionSeries implements a polynomial regression over a given
@@ -108,23 +101,6 @@ func (prs *PolynomialRegressionSeries) GetValues(index int) (x, y float64) {
 	return
 }
 
-// GetFirstValues computes the first poly regression value.
-func (prs *PolynomialRegressionSeries) GetFirstValues() (x, y float64) {
-	if prs.InnerSeries == nil || prs.InnerSeries.Len() == 0 {
-		return
-	}
-	if prs.coeffs == nil {
-		coeffs, err := prs.computeCoefficients()
-		if err != nil {
-			panic(err)
-		}
-		prs.coeffs = coeffs
-	}
-	x, y = prs.InnerSeries.GetValues(0)
-	y = prs.apply(x)
-	return
-}
-
 // GetLastValues computes the last poly regression value.
 func (prs *PolynomialRegressionSeries) GetLastValues() (x, y float64) {
 	if prs.InnerSeries == nil || prs.InnerSeries.Len() == 0 {

polynomial_regression_test.go

@@ -0,0 +1,35 @@
+package chart
+
+import (
+	"testing"
+
+	assert "github.com/blendlabs/go-assert"
+	"github.com/wcharczuk/go-chart/matrix"
+)
+
+func TestPolynomialRegression(t *testing.T) {
+	assert := assert.New(t)
+
+	var xv []float64
+	var yv []float64
+
+	for i := 0; i < 100; i++ {
+		xv = append(xv, float64(i))
+		yv = append(yv, float64(i*i))
+	}
+
+	values := ContinuousSeries{
+		XValues: xv,
+		YValues: yv,
+	}
+
+	poly := &PolynomialRegressionSeries{
+		InnerSeries: values,
+		Degree:      2,
+	}
+
+	for i := 0; i < 100; i++ {
+		_, y := poly.GetValues(i)
+		assert.InDelta(float64(i*i), y, matrix.DefaultEpsilon)
+	}
+}

raster_renderer.go

@@ -6,9 +6,9 @@ import (
 	"io"
 	"math"
 
-	"git.fireandbrimst.one/aw/go-chart/drawing"
-	"git.fireandbrimst.one/aw/go-chart/util"
-	"git.fireandbrimst.one/aw/golang-freetype/truetype"
+	util "github.com/blendlabs/go-util"
+	"github.com/golang/freetype/truetype"
+	"github.com/wcharczuk/go-chart/drawing"
 )
 
 // PNG returns a new png/raster renderer.
@@ -49,10 +49,6 @@ func (rr *rasterRenderer) SetDPI(dpi float64) {
 	rr.gc.SetDPI(dpi)
 }
 
-// SetClassName implements the interface method. However, PNGs have no classes.
-func (vr *rasterRenderer) SetClassName(_ string) {
-}
-
 // SetStrokeColor implements the interface method.
 func (rr *rasterRenderer) SetStrokeColor(c drawing.Color) {
 	rr.s.StrokeColor = c
@@ -159,13 +155,13 @@ func (rr *rasterRenderer) Text(body string, x, y int) {
 }
 
 // MeasureText returns the height and width in pixels of a string.
-func (rr *rasterRenderer) MeasureText(body string) Box {
+func (rr *rasterRenderer) MeasureText(body string) Box2d {
 	rr.gc.SetFont(rr.s.Font)
 	rr.gc.SetFontSize(rr.s.FontSize)
 	rr.gc.SetFillColor(rr.s.FontColor)
 	l, t, r, b, err := rr.gc.GetStringBounds(body)
 	if err != nil {
-		return Box{}
+		return Box2d{}
 	}
 	if l < 0 {
 		r = r - l // equivalent to r+(-1*l)
@@ -193,10 +189,10 @@ func (rr *rasterRenderer) MeasureText(body string) Box {
 		Bottom: int(math.Ceil(b)),
 	}
 	if rr.rotateRadians == nil {
-		return textBox
+		return textBox.Corners()
 	}
 
-	return textBox.Corners().Rotate(util.Math.RadiansToDegrees(*rr.rotateRadians)).Box()
+	return textBox.Corners().Rotate(util.Math.RadiansToDegrees(*rr.rotateRadians))
 }
 
 // SetTextRotation sets a text rotation.