sanity check tests.

_examples/scatter/main.go

@@ -48,7 +48,33 @@ func drawChart(res http.ResponseWriter, req *http.Request) {
 
 }
 
+func unit(res http.ResponseWriter, req *http.Request) {
+	graph := chart.Chart{
+		Height: 50,
+		Width:  50,
+		Canvas: chart.Style{
+			Padding: chart.Box{IsSet: true},
+		},
+		Background: chart.Style{
+			Padding: chart.Box{IsSet: true},
+		},
+		Series: []chart.Series{
+			chart.ContinuousSeries{
+				XValues: chart.Sequence.Float64(0, 4, 1),
+				YValues: chart.Sequence.Float64(0, 4, 1),
+			},
+		},
+	}
+
+	res.Header().Set("Content-Type", "image/png")
+	err := graph.Render(chart.PNG, res)
+	if err != nil {
+		log.Println(err.Error())
+	}
+}
+
 func main() {
 	http.HandleFunc("/", drawChart)
+	http.HandleFunc("/unit", unit)
 	log.Fatal(http.ListenAndServe(":8080", nil))
 }

box.go

@@ -5,8 +5,25 @@ import (
 	"math"
 )
 
+var (
+	// BoxZero is a preset box that represents an intentional zero value.
+	BoxZero = Box{IsSet: true}
+)
+
+// NewBox returns a new (set) box.
+func NewBox(top, left, right, bottom int) Box {
+	return Box{
+		IsSet:  true,
+		Top:    top,
+		Left:   left,
+		Right:  right,
+		Bottom: bottom,
+	}
+}
+
 // Box represents the main 4 dimensions of a box.
 type Box struct {
+	IsSet  bool
 	Top    int
 	Left   int
 	Right  int
@@ -15,6 +32,9 @@ type Box struct {
 
 // IsZero returns if the box is set or not.
 func (b Box) IsZero() bool {
+	if b.IsSet {
+		return false
+	}
 	return b.Top == 0 && b.Left == 0 && b.Right == 0 && b.Bottom == 0
 }
 
@@ -25,7 +45,7 @@ func (b Box) String() string {
 
 // GetTop returns a coalesced value with a default.
 func (b Box) GetTop(defaults ...int) int {
-	if b.Top == 0 {
+	if !b.IsSet && b.Top == 0 {
 		if len(defaults) > 0 {
 			return defaults[0]
 		}
@@ -36,7 +56,7 @@ func (b Box) GetTop(defaults ...int) int {
 
 // GetLeft returns a coalesced value with a default.
 func (b Box) GetLeft(defaults ...int) int {
-	if b.Left == 0 {
+	if !b.IsSet && b.Left == 0 {
 		if len(defaults) > 0 {
 			return defaults[0]
 		}
@@ -47,7 +67,7 @@ func (b Box) GetLeft(defaults ...int) int {
 
 // GetRight returns a coalesced value with a default.
 func (b Box) GetRight(defaults ...int) int {
-	if b.Right == 0 {
+	if !b.IsSet && b.Right == 0 {
 		if len(defaults) > 0 {
 			return defaults[0]
 		}
@@ -58,7 +78,7 @@ func (b Box) GetRight(defaults ...int) int {
 
 // GetBottom returns a coalesced value with a default.
 func (b Box) GetBottom(defaults ...int) int {
-	if b.Bottom == 0 {
+	if !b.IsSet && b.Bottom == 0 {
 		if len(defaults) > 0 {
 			return defaults[0]
 		}
@@ -91,6 +111,7 @@ func (b Box) Aspect() float64 {
 // Clone returns a new copy of the box.
 func (b Box) Clone() Box {
 	return Box{
+		IsSet:  b.IsSet,
 		Top:    b.Top,
 		Left:   b.Left,
 		Right:  b.Right,

box_test.go

@@ -109,9 +109,9 @@ func TestBoxConstrain(t *testing.T) {
 func TestBoxOuterConstrain(t *testing.T) {
 	assert := assert.New(t)
 
-	box := Box{0, 0, 100, 100}
+	box := NewBox(0, 0, 100, 100)
-	canvas := Box{5, 5, 95, 95}
+	canvas := NewBox(5, 5, 95, 95)
-	taller := Box{-10, 5, 50, 50}
+	taller := NewBox(-10, 5, 50, 50)
 
 	c := canvas.OuterConstrain(box, taller)
 	assert.Equal(15, c.Top, c.String())
@@ -119,7 +119,7 @@ func TestBoxOuterConstrain(t *testing.T) {
 	assert.Equal(95, c.Right, c.String())
 	assert.Equal(95, c.Bottom, c.String())
 
-	wider := Box{5, 5, 110, 50}
+	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())

chart_test.go

@@ -2,6 +2,8 @@ package chart
 
 import (
 	"bytes"
+	"image"
+	"image/png"
 	"math"
 	"testing"
 	"time"
@@ -484,10 +486,22 @@ func TestChartCheckRangesWithRanges(t *testing.T) {
 	assert.Nil(c.checkRanges(xr, yr, yra))
 }
 
+func at(i image.Image, x, y int) drawing.Color {
+	return drawing.ColorFromAlphaMixedRGBA(i.At(x, y).RGBA())
+}
+
 func TestChartE2ELine(t *testing.T) {
 	assert := assert.New(t)
 
 	c := Chart{
+		Height: 50,
+		Width:  50,
+		Canvas: Style{
+			Padding: Box{IsSet: true},
+		},
+		Background: Style{
+			Padding: Box{IsSet: true},
+		},
 		Series: []Series{
 			ContinuousSeries{
 				XValues: Sequence.Float64(0, 4, 1),
@@ -502,5 +516,60 @@ func TestChartE2ELine(t *testing.T) {
 
 	// do color tests ...
 
+	i, err := png.Decode(buffer)
+	assert.Nil(err)
 
+	// test the bottom and top of the line
+	assert.Equal(drawing.ColorWhite, at(i, 0, 0))
+	assert.Equal(drawing.ColorWhite, at(i, 49, 49))
+
+	// test a line mid point
+	defaultSeriesColor := GetDefaultColor(0)
+	assert.Equal(defaultSeriesColor, at(i, 0, 49))
+	assert.Equal(defaultSeriesColor, at(i, 49, 0))
+	assert.Equal(drawing.ColorFromHex("bddbf6"), at(i, 24, 24))
+}
+
+func TestChartE2ELineWithFill(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Chart{
+		Height: 50,
+		Width:  50,
+		Canvas: Style{
+			Padding: Box{IsSet: true},
+		},
+		Background: Style{
+			Padding: Box{IsSet: true},
+		},
+		Series: []Series{
+			ContinuousSeries{
+				Style: Style{
+					Show:        true,
+					StrokeColor: drawing.ColorBlue,
+					FillColor:   drawing.ColorRed,
+				},
+				XValues: Sequence.Float64(0, 4, 1),
+				YValues: Sequence.Float64(0, 4, 1),
+			},
+		},
+	}
+
+	var buffer = &bytes.Buffer{}
+	err := c.Render(PNG, buffer)
+	assert.Nil(err)
+
+	// do color tests ...
+
+	i, err := png.Decode(buffer)
+	assert.Nil(err)
+
+	// test the bottom and top of the line
+	assert.Equal(drawing.ColorWhite, at(i, 0, 0))
+	assert.Equal(drawing.ColorRed, at(i, 49, 49))
+
+	// test a line mid point
+	defaultSeriesColor := drawing.ColorBlue
+	assert.Equal(defaultSeriesColor, at(i, 0, 49))
+	assert.Equal(defaultSeriesColor, at(i, 49, 0))
 }

drawing/color.go

@@ -104,6 +104,16 @@ func (c Color) Equals(other Color) bool {
 		c.A == other.A
 }
 
+// AverageWith averages two colors.
+func (c Color) AverageWith(other Color) Color {
+	return Color{
+		R: (c.R + other.R) >> 1,
+		G: (c.G + other.G) >> 1,
+		B: (c.B + other.B) >> 1,
+		A: c.A,
+	}
+}
+
 // String returns a css string representation of the color.
 func (c Color) String() string {
 	fa := float64(c.A) / float64(255)

drawing/image.go

@@ -1,23 +0,0 @@
-package drawing
-
-import "image"
-
-// Image is a helper wraper that allows (sane) access to pixel info.
-type Image struct {
-	Inner *image.RGBA
-}
-
-// Width returns the image's width in pixels.
-func (i Image) Width() int {
-	return i.Inner.Rect.Size().X
-}
-
-// Height returns the image's height in pixels.
-func (i Image) Height() int {
-	return i.Inner.Rect.Size().Y
-}
-
-// At returns a pixel color at a given x/y.
-func (i Image) At(x, y int) Color {
-	return ColorFromAlphaMixedRGBA(i.Inner.At(x, y).RGBA())
-}

xaxis_test.go

@@ -61,7 +61,7 @@ func TestXAxisMeasure(t *testing.T) {
 	assert.Nil(err)
 	ticks := []Tick{{Value: 1.0, Label: "1.0"}, {Value: 2.0, Label: "2.0"}, {Value: 3.0, Label: "3.0"}}
 	xa := XAxis{}
-	xab := xa.Measure(r, Box{0, 0, 100, 100}, &ContinuousRange{Min: 1.0, Max: 3.0, Domain: 100}, style, ticks)
+	xab := xa.Measure(r, NewBox(0, 0, 100, 100), &ContinuousRange{Min: 1.0, Max: 3.0, Domain: 100}, style, ticks)
 	assert.Equal(122, xab.Width())
 	assert.Equal(21, xab.Height())
 }

yaxis_test.go

@@ -61,7 +61,7 @@ func TestYAxisMeasure(t *testing.T) {
 	assert.Nil(err)
 	ticks := []Tick{{Value: 1.0, Label: "1.0"}, {Value: 2.0, Label: "2.0"}, {Value: 3.0, Label: "3.0"}}
 	ya := YAxis{}
-	yab := ya.Measure(r, Box{0, 0, 100, 100}, &ContinuousRange{Min: 1.0, Max: 3.0, Domain: 100}, style, ticks)
+	yab := ya.Measure(r, NewBox(0, 0, 100, 100), &ContinuousRange{Min: 1.0, Max: 3.0, Domain: 100}, style, ticks)
 	assert.Equal(32, yab.Width())
 	assert.Equal(110, yab.Height())
 }
@@ -79,7 +79,7 @@ func TestYAxisSecondaryMeasure(t *testing.T) {
 	assert.Nil(err)
 	ticks := []Tick{{Value: 1.0, Label: "1.0"}, {Value: 2.0, Label: "2.0"}, {Value: 3.0, Label: "3.0"}}
 	ya := YAxis{AxisType: YAxisSecondary}
-	yab := ya.Measure(r, Box{0, 0, 100, 100}, &ContinuousRange{Min: 1.0, Max: 3.0, Domain: 100}, style, ticks)
+	yab := ya.Measure(r, NewBox(0, 0, 100, 100), &ContinuousRange{Min: 1.0, Max: 3.0, Domain: 100}, style, ticks)
 	assert.Equal(32, yab.Width())
 	assert.Equal(110, yab.Height())
 }