Add horizontal render option to stacked bar chart (#39)

_examples/horizontal_stacked_bar/main.go

@@ -0,0 +1,222 @@
+package main
+
+import (
+	"os"
+
+	"github.com/wcharczuk/go-chart"
+	"github.com/wcharczuk/go-chart/drawing"
+)
+
+func main() {
+	chart.DefaultBackgroundColor = chart.ColorTransparent
+	chart.DefaultCanvasColor = chart.ColorTransparent
+
+	barWidth := 80
+
+	var (
+		colorWhite          = drawing.Color{R: 241, G: 241, B: 241, A: 255}
+		colorMariner        = drawing.Color{R: 60, G: 100, B: 148, A: 255}
+		colorLightSteelBlue = drawing.Color{R: 182, G: 195, B: 220, A: 255}
+		colorPoloBlue       = drawing.Color{R: 126, G: 155, B: 200, A: 255}
+		colorSteelBlue      = drawing.Color{R: 73, G: 120, B: 177, A: 255}
+	)
+
+	stackedBarChart := chart.StackedBarChart{
+		Title:      "Quarterly Sales",
+		TitleStyle: chart.StyleShow(),
+		Background: chart.Style{
+			Padding: chart.Box{
+				Top: 75,
+			},
+		},
+		Width:        800,
+		Height:       600,
+		XAxis:        chart.StyleShow(),
+		YAxis:        chart.StyleShow(),
+		BarSpacing:   40,
+		IsHorizontal: true,
+		Bars: []chart.StackedBar{
+			{
+				Name:  "Q1",
+				Width: barWidth,
+				Values: []chart.Value{
+					{
+						Label: "32K",
+						Value: 32,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorMariner,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "46K",
+						Value: 46,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorLightSteelBlue,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "48K",
+						Value: 48,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorPoloBlue,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "42K",
+						Value: 42,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorSteelBlue,
+							FontColor:   colorWhite,
+						},
+					},
+				},
+			},
+			{
+				Name:  "Q2",
+				Width: barWidth,
+				Values: []chart.Value{
+					{
+						Label: "45K",
+						Value: 45,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorMariner,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "60K",
+						Value: 60,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorLightSteelBlue,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "62K",
+						Value: 62,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorPoloBlue,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "53K",
+						Value: 53,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorSteelBlue,
+							FontColor:   colorWhite,
+						},
+					},
+				},
+			},
+			{
+				Name:  "Q3",
+				Width: barWidth,
+				Values: []chart.Value{
+					{
+						Label: "54K",
+						Value: 54,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorMariner,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "58K",
+						Value: 58,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorLightSteelBlue,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "55K",
+						Value: 55,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorPoloBlue,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "47K",
+						Value: 47,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorSteelBlue,
+							FontColor:   colorWhite,
+						},
+					},
+				},
+			},
+			{
+				Name:  "Q4",
+				Width: barWidth,
+				Values: []chart.Value{
+					{
+						Label: "46K",
+						Value: 46,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorMariner,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "70K",
+						Value: 70,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorLightSteelBlue,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "74K",
+						Value: 74,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorPoloBlue,
+							FontColor:   colorWhite,
+						},
+					},
+					{
+						Label: "60K",
+						Value: 60,
+						Style: chart.Style{
+							StrokeWidth: .01,
+							FillColor:   colorSteelBlue,
+							FontColor:   colorWhite,
+						},
+					},
+				},
+			},
+		},
+	}
+
+	pngFile, err := os.Create("output.png")
+	if err != nil {
+		panic(err)
+	}
+
+	if err := stackedBarChart.Render(chart.PNG, pngFile); err != nil {
+		panic(err)
+	}
+
+	if err := pngFile.Close(); err != nil {
+		panic(err)
+	}
+}

draw.go

@@ -296,8 +296,10 @@ 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()
-	case TextVerticalAlignMiddle, TextVerticalAlignMiddleBaseline:
+	case TextVerticalAlignMiddle:
-		y = (y - linesBox.Height()) >> 1
+		y = y + (box.Height() >> 1) - (linesBox.Height() >> 1)
+	case TextVerticalAlignMiddleBaseline:
+		y = y + (box.Height() >> 1) - linesBox.Height()
 	}
 
 	var tx, ty int

stacked_bar_chart.go

@@ -46,6 +46,8 @@ type StackedBarChart struct {
 	Font        *truetype.Font
 	defaultFont *truetype.Font
 
+	IsHorizontal bool
+
 	Bars     []StackedBar
 	Elements []Renderable
 }
@@ -113,11 +115,20 @@ func (sbc StackedBarChart) Render(rp RendererProvider, w io.Writer) error {
 	}
 	r.SetDPI(sbc.GetDPI(DefaultDPI))
 
-	canvasBox := sbc.getAdjustedCanvasBox(r, sbc.getDefaultCanvasBox())
+	var canvasBox Box
-	sbc.drawCanvas(r, canvasBox)
+	if sbc.IsHorizontal {
-	sbc.drawBars(r, canvasBox)
+		canvasBox = sbc.getHorizontalAdjustedCanvasBox(r, sbc.getDefaultCanvasBox())
-	sbc.drawXAxis(r, canvasBox)
+		sbc.drawCanvas(r, canvasBox)
-	sbc.drawYAxis(r, canvasBox)
+		sbc.drawHorizontalBars(r, canvasBox)
+		sbc.drawHorizontalXAxis(r, canvasBox)
+		sbc.drawHorizontalYAxis(r, canvasBox)
+	} else {
+		canvasBox = sbc.getAdjustedCanvasBox(r, sbc.getDefaultCanvasBox())
+		sbc.drawCanvas(r, canvasBox)
+		sbc.drawBars(r, canvasBox)
+		sbc.drawXAxis(r, canvasBox)
+		sbc.drawYAxis(r, canvasBox)
+	}
 
 	sbc.drawTitle(r)
 	for _, a := range sbc.Elements {
@@ -139,6 +150,14 @@ func (sbc StackedBarChart) drawBars(r Renderer, canvasBox Box) {
 	}
 }
 
+func (sbc StackedBarChart) drawHorizontalBars(r Renderer, canvasBox Box) {
+	yOffset := canvasBox.Top
+	for _, bar := range sbc.Bars {
+		sbc.drawHorizontalBar(r, canvasBox, yOffset, bar)
+		yOffset += sbc.GetBarSpacing() + bar.GetWidth()
+	}
+}
+
 func (sbc StackedBarChart) drawBar(r Renderer, canvasBox Box, xoffset int, bar StackedBar) int {
 	barSpacing2 := sbc.GetBarSpacing() >> 1
 	bxl := xoffset + barSpacing2
@@ -188,6 +207,55 @@ func (sbc StackedBarChart) drawBar(r Renderer, canvasBox Box, xoffset int, bar S
 	return bxr
 }
 
+func (sbc StackedBarChart) drawHorizontalBar(r Renderer, canvasBox Box, yoffset int, bar StackedBar) {
+	halfBarSpacing := sbc.GetBarSpacing() >> 1
+
+	boxTop := yoffset + halfBarSpacing
+	boxBottom := boxTop + bar.GetWidth()
+
+	normalizedBarComponents := Values(bar.Values).Normalize()
+
+	xOffset := canvasBox.Right
+	for index, bv := range normalizedBarComponents {
+		barHeight := int(math.Ceil(bv.Value * float64(canvasBox.Width())))
+		barBox := Box{
+			Top:    boxTop,
+			Left:   util.Math.MinInt(xOffset-barHeight, canvasBox.Left+DefaultStrokeWidth),
+			Right:  xOffset,
+			Bottom: boxBottom,
+		}
+		Draw.Box(r, barBox, bv.Style.InheritFrom(sbc.styleDefaultsStackedBarValue(index)))
+		xOffset -= barHeight
+	}
+
+	// draw the labels
+	xOffset = canvasBox.Right
+	var lx, ly int
+	for index, bv := range normalizedBarComponents {
+		barHeight := int(math.Ceil(bv.Value * float64(canvasBox.Width())))
+
+		if len(bv.Label) > 0 {
+			lx = xOffset - (barHeight / 2)
+			ly = boxTop + ((boxBottom - boxTop) / 2)
+
+			bv.Style.InheritFrom(sbc.styleDefaultsStackedBarValue(index)).WriteToRenderer(r)
+			tb := r.MeasureText(bv.Label)
+			lx = lx - (tb.Width() >> 1)
+			ly = ly + (tb.Height() >> 1)
+
+			if lx < 0 {
+				lx = 0
+			}
+			if ly < 0 {
+				lx = 0
+			}
+
+			r.Text(bv.Label, lx, ly)
+		}
+		xOffset -= barHeight
+	}
+}
+
 func (sbc StackedBarChart) drawXAxis(r Renderer, canvasBox Box) {
 	if !sbc.XAxis.Hidden {
 		axisStyle := sbc.XAxis.InheritFrom(sbc.styleDefaultsAxes())
@@ -222,6 +290,37 @@ func (sbc StackedBarChart) drawXAxis(r Renderer, canvasBox Box) {
 	}
 }
 
+func (sbc StackedBarChart) drawHorizontalXAxis(r Renderer, canvasBox Box) {
+	if sbc.XAxis.Show {
+		axisStyle := sbc.XAxis.InheritFrom(sbc.styleDefaultsAxes())
+		axisStyle.WriteToRenderer(r)
+		r.MoveTo(canvasBox.Left, canvasBox.Bottom)
+		r.LineTo(canvasBox.Right, canvasBox.Bottom)
+		r.Stroke()
+
+		r.MoveTo(canvasBox.Left, canvasBox.Bottom)
+		r.LineTo(canvasBox.Left, canvasBox.Bottom+DefaultVerticalTickHeight)
+		r.Stroke()
+
+		ticks := seq.RangeWithStep(0.0, 1.0, 0.2)
+		for _, t := range ticks {
+			axisStyle.GetStrokeOptions().WriteToRenderer(r)
+			tx := canvasBox.Left + int(t*float64(canvasBox.Width()))
+			r.MoveTo(tx, canvasBox.Bottom)
+			r.LineTo(tx, canvasBox.Bottom+DefaultVerticalTickHeight)
+			r.Stroke()
+
+			axisStyle.GetTextOptions().WriteToRenderer(r)
+			text := fmt.Sprintf("%0.0f%%", t*100)
+
+			textBox := r.MeasureText(text)
+			textX := tx - (textBox.Width() >> 1)
+			textY := canvasBox.Bottom + DefaultXAxisMargin + 10
+			Draw.Text(r, text, textX, textY, axisStyle)
+		}
+	}
+}
+
 func (sbc StackedBarChart) drawYAxis(r Renderer, canvasBox Box) {
 	if !sbc.YAxis.Hidden {
 		axisStyle := sbc.YAxis.InheritFrom(sbc.styleDefaultsAxes())
@@ -248,7 +347,39 @@ func (sbc StackedBarChart) drawYAxis(r Renderer, canvasBox Box) {
 			tb := r.MeasureText(text)
 			Draw.Text(r, text, canvasBox.Right+DefaultYAxisMargin+5, ty+(tb.Height()>>1), axisStyle)
 		}
+	}
+}
 
+func (sbc StackedBarChart) drawHorizontalYAxis(r Renderer, canvasBox Box) {
+	if sbc.YAxis.Show {
+		axisStyle := sbc.YAxis.InheritFrom(sbc.styleDefaultsHorizontalAxes())
+		axisStyle.WriteToRenderer(r)
+
+		r.MoveTo(canvasBox.Left, canvasBox.Bottom)
+		r.LineTo(canvasBox.Left, canvasBox.Top)
+		r.Stroke()
+
+		r.MoveTo(canvasBox.Left, canvasBox.Bottom)
+		r.LineTo(canvasBox.Left-DefaultHorizontalTickWidth, canvasBox.Bottom)
+		r.Stroke()
+
+		cursor := canvasBox.Top
+		for _, bar := range sbc.Bars {
+			barLabelBox := Box{
+				Top:    cursor,
+				Left:   0,
+				Right:  canvasBox.Left + DefaultYAxisMargin,
+				Bottom: cursor + bar.GetWidth() + sbc.GetBarSpacing(),
+			}
+			if len(bar.Name) > 0 {
+				Draw.TextWithin(r, bar.Name, barLabelBox, axisStyle)
+			}
+			axisStyle.WriteToRenderer(r)
+			r.MoveTo(canvasBox.Left, barLabelBox.Bottom)
+			r.LineTo(canvasBox.Left-DefaultHorizontalTickWidth, barLabelBox.Bottom)
+			r.Stroke()
+			cursor += bar.GetWidth() + sbc.GetBarSpacing()
+		}
 	}
 }
 
@@ -338,6 +469,48 @@ func (sbc StackedBarChart) getAdjustedCanvasBox(r Renderer, canvasBox Box) Box {
 
 }
 
+func (sbc StackedBarChart) getHorizontalAdjustedCanvasBox(r Renderer, canvasBox Box) Box {
+	var totalHeight int
+	for _, bar := range sbc.Bars {
+		totalHeight += bar.GetWidth() + sbc.GetBarSpacing()
+	}
+
+	if sbc.YAxis.Show {
+		yAxisWidth := DefaultHorizontalTickWidth
+
+		axisStyle := sbc.YAxis.InheritFrom(sbc.styleDefaultsHorizontalAxes())
+		axisStyle.WriteToRenderer(r)
+
+		cursor := canvasBox.Top
+		for _, bar := range sbc.Bars {
+			if len(bar.Name) > 0 {
+				barLabelBox := Box{
+					Top:    cursor,
+					Left:   0,
+					Right:  canvasBox.Left + DefaultYAxisMargin,
+					Bottom: cursor + bar.GetWidth() + sbc.GetBarSpacing(),
+				}
+				lines := Text.WrapFit(r, bar.Name, barLabelBox.Width(), axisStyle)
+				linesBox := Text.MeasureLines(r, lines, axisStyle)
+
+				yAxisWidth = util.Math.MaxInt(linesBox.Height()+(2*DefaultXAxisMargin), yAxisWidth)
+			}
+		}
+		return Box{
+			Top:    canvasBox.Top,
+			Left:   canvasBox.Left + yAxisWidth,
+			Right:  canvasBox.Right,
+			Bottom: canvasBox.Top + totalHeight,
+		}
+	}
+	return Box{
+		Top:    canvasBox.Top,
+		Left:   canvasBox.Left,
+		Right:  canvasBox.Right,
+		Bottom: canvasBox.Top + totalHeight,
+	}
+}
+
 // Box returns the chart bounds as a box.
 func (sbc StackedBarChart) Box() Box {
 	dpr := sbc.Background.Padding.GetRight(10)
@@ -412,6 +585,19 @@ func (sbc StackedBarChart) styleDefaultsAxes() Style {
 		TextWrap:            TextWrapWord,
 	}
 }
+
+func (sbc StackedBarChart) styleDefaultsHorizontalAxes() Style {
+	return Style{
+		StrokeColor:         DefaultAxisColor,
+		Font:                sbc.GetFont(),
+		FontSize:            DefaultAxisFontSize,
+		FontColor:           DefaultAxisColor,
+		TextHorizontalAlign: TextHorizontalAlignCenter,
+		TextVerticalAlign:   TextVerticalAlignMiddle,
+		TextWrap:            TextWrapWord,
+	}
+}
+
 func (sbc StackedBarChart) styleDefaultsElements() Style {
 	return Style{
 		Font: sbc.GetFont(),

text.go

@@ -46,7 +46,7 @@ const (
 	TextVerticalAlignBottom TextVerticalAlign = 2
 	// TextVerticalAlignMiddle aligns the text so that there is an equal amount of space above and below the top and bottom of the ligatures.
 	TextVerticalAlignMiddle TextVerticalAlign = 3
-	// TextVerticalAlignMiddleBaseline aligns the text veritcally so that there is an equal number of pixels above and below the baseline of the string.
+	// TextVerticalAlignMiddleBaseline aligns the text vertically so that there is an equal number of pixels above and below the baseline of the string.
 	TextVerticalAlignMiddleBaseline TextVerticalAlign = 4
 	// TextVerticalAlignTop alignts the text so that the top of the ligatures are at y-pixel 0 in the container.
 	TextVerticalAlignTop TextVerticalAlign = 5