go-chart/stacked_bar_chart.go

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package chart
import (
"errors"
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"fmt"
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"io"
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"math"
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"github.com/golang/freetype/truetype"
)
// StackedBar is a bar within a StackedBarChart.
type StackedBar struct {
Name string
Width int
Values []Value
}
// GetWidth returns the width of the bar.
func (sb StackedBar) GetWidth() int {
if sb.Width == 0 {
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return 50
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}
return sb.Width
}
// StackedBarChart is a chart that draws sections of a bar based on percentages.
type StackedBarChart struct {
Title string
TitleStyle Style
Width int
Height int
DPI float64
Background Style
Canvas Style
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XAxis Style
YAxis Style
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BarSpacing int
Font *truetype.Font
defaultFont *truetype.Font
Bars []StackedBar
Elements []Renderable
}
// GetDPI returns the dpi for the chart.
func (sbc StackedBarChart) GetDPI(defaults ...float64) float64 {
if sbc.DPI == 0 {
if len(defaults) > 0 {
return defaults[0]
}
return DefaultDPI
}
return sbc.DPI
}
// GetFont returns the text font.
func (sbc StackedBarChart) GetFont() *truetype.Font {
if sbc.Font == nil {
return sbc.defaultFont
}
return sbc.Font
}
// GetWidth returns the chart width or the default value.
func (sbc StackedBarChart) GetWidth() int {
if sbc.Width == 0 {
return DefaultChartWidth
}
return sbc.Width
}
// GetHeight returns the chart height or the default value.
func (sbc StackedBarChart) GetHeight() int {
if sbc.Height == 0 {
return DefaultChartWidth
}
return sbc.Height
}
// GetBarSpacing returns the spacing between bars.
func (sbc StackedBarChart) GetBarSpacing() int {
if sbc.BarSpacing == 0 {
return 100
}
return sbc.BarSpacing
}
// Render renders the chart with the given renderer to the given io.Writer.
func (sbc StackedBarChart) Render(rp RendererProvider, w io.Writer) error {
if len(sbc.Bars) == 0 {
return errors.New("Please provide at least one bar.")
}
r, err := rp(sbc.GetWidth(), sbc.GetHeight())
if err != nil {
return err
}
if sbc.Font == nil {
defaultFont, err := GetDefaultFont()
if err != nil {
return err
}
sbc.defaultFont = defaultFont
}
r.SetDPI(sbc.GetDPI(DefaultDPI))
canvasBox := sbc.getAdjustedCanvasBox(sbc.getDefaultCanvasBox())
sbc.drawBars(r, canvasBox)
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sbc.drawXAxis(r, canvasBox)
sbc.drawYAxis(r, canvasBox)
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sbc.drawTitle(r)
for _, a := range sbc.Elements {
a(r, canvasBox, sbc.styleDefaultsElements())
}
return r.Save(w)
}
func (sbc StackedBarChart) drawBars(r Renderer, canvasBox Box) {
xoffset := canvasBox.Left
for _, bar := range sbc.Bars {
sbc.drawBar(r, canvasBox, xoffset, bar)
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xoffset += (sbc.GetBarSpacing() + bar.GetWidth())
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}
}
func (sbc StackedBarChart) drawBar(r Renderer, canvasBox Box, xoffset int, bar StackedBar) int {
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barSpacing2 := sbc.GetBarSpacing() >> 1
bxl := xoffset + barSpacing2
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bxr := bxl + bar.GetWidth()
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normalizedBarComponents := Values(bar.Values).Normalize()
yoffset := canvasBox.Top
for index, bv := range normalizedBarComponents {
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barHeight := int(math.Ceil(bv.Value * float64(canvasBox.Height())))
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barBox := Box{
Top: yoffset,
Left: bxl,
Right: bxr,
Bottom: Math.MinInt(yoffset+barHeight, canvasBox.Bottom-DefaultStrokeWidth),
}
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Draw.Box(r, barBox, bv.Style.InheritFrom(sbc.styleDefaultsStackedBarValue(index)))
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yoffset += barHeight
}
return bxr
}
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func (sbc StackedBarChart) drawXAxis(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()
cursor := canvasBox.Left
for _, bar := range sbc.Bars {
barLabelBox := Box{
Top: canvasBox.Bottom + DefaultXAxisMargin,
Left: cursor,
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Right: cursor + bar.GetWidth() + sbc.GetBarSpacing(),
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Bottom: sbc.GetHeight(),
}
if len(bar.Name) > 0 {
Draw.TextWithin(r, bar.Name, barLabelBox, axisStyle)
}
axisStyle.WriteToRenderer(r)
r.MoveTo(barLabelBox.Right, canvasBox.Bottom)
r.LineTo(barLabelBox.Right, canvasBox.Bottom+DefaultVerticalTickHeight)
r.Stroke()
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cursor += bar.GetWidth() + sbc.GetBarSpacing()
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}
}
}
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func (sbc StackedBarChart) drawYAxis(r Renderer, canvasBox Box) {
if sbc.YAxis.Show {
axisStyle := sbc.YAxis.InheritFrom(sbc.styleDefaultsAxes())
axisStyle.WriteToRenderer(r)
r.MoveTo(canvasBox.Right, canvasBox.Top)
r.LineTo(canvasBox.Right, canvasBox.Bottom)
r.Stroke()
r.MoveTo(canvasBox.Right, canvasBox.Bottom)
r.LineTo(canvasBox.Right+DefaultHorizontalTickWidth, canvasBox.Bottom)
r.Stroke()
ticks := Sequence.Float64(1.0, 0.0, 0.2)
for _, t := range ticks {
axisStyle.GetStrokeOptions().WriteToRenderer(r)
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ty := canvasBox.Bottom - int(t*float64(canvasBox.Height()))
r.MoveTo(canvasBox.Right, ty)
r.LineTo(canvasBox.Right+DefaultHorizontalTickWidth, ty)
r.Stroke()
axisStyle.GetTextOptions().WriteToRenderer(r)
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text := fmt.Sprintf("%0.0f%%", t*100)
tb := r.MeasureText(text)
Draw.Text(r, text, canvasBox.Right+DefaultYAxisMargin+5, ty+(tb.Height()>>1), axisStyle)
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}
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}
}
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func (sbc StackedBarChart) drawTitle(r Renderer) {
if len(sbc.Title) > 0 && sbc.TitleStyle.Show {
Draw.TextWithin(r, sbc.Title, sbc.Box(), sbc.styleDefaultsTitle())
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}
}
func (sbc StackedBarChart) getDefaultCanvasBox() Box {
return sbc.Box()
}
func (sbc StackedBarChart) getAdjustedCanvasBox(canvasBox Box) Box {
var totalWidth int
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for _, bar := range sbc.Bars {
totalWidth += bar.GetWidth() + sbc.GetBarSpacing()
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}
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return Box{
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Top: canvasBox.Top,
Left: canvasBox.Left,
Right: canvasBox.Left + totalWidth,
Bottom: canvasBox.Bottom,
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}
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}
// Box returns the chart bounds as a box.
func (sbc StackedBarChart) Box() Box {
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dpr := sbc.Background.Padding.GetRight(10)
dpb := sbc.Background.Padding.GetBottom(50)
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return Box{
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Top: 20,
Left: 20,
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Right: sbc.GetWidth() - dpr,
Bottom: sbc.GetHeight() - dpb,
}
}
func (sbc StackedBarChart) styleDefaultsStackedBarValue(index int) Style {
return Style{
StrokeColor: GetAlternateColor(index),
StrokeWidth: 3.0,
FillColor: GetAlternateColor(index),
}
}
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func (sbc StackedBarChart) styleDefaultsTitle() Style {
return sbc.TitleStyle.InheritFrom(Style{
FontColor: DefaultTextColor,
Font: sbc.GetFont(),
FontSize: sbc.getTitleFontSize(),
TextHorizontalAlign: TextHorizontalAlignCenter,
TextVerticalAlign: TextVerticalAlignTop,
TextWrap: TextWrapWord,
})
}
func (sbc StackedBarChart) getTitleFontSize() float64 {
effectiveDimension := Math.MinInt(sbc.GetWidth(), sbc.GetHeight())
if effectiveDimension >= 2048 {
return 48
} else if effectiveDimension >= 1024 {
return 24
} else if effectiveDimension >= 512 {
return 18
} else if effectiveDimension >= 256 {
return 12
}
return 10
}
func (sbc StackedBarChart) styleDefaultsAxes() Style {
return Style{
StrokeColor: DefaultAxisColor,
Font: sbc.GetFont(),
FontSize: DefaultAxisFontSize,
FontColor: DefaultAxisColor,
TextHorizontalAlign: TextHorizontalAlignCenter,
TextVerticalAlign: TextVerticalAlignTop,
TextWrap: TextWrapWord,
}
}
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func (sbc StackedBarChart) styleDefaultsElements() Style {
return Style{
Font: sbc.GetFont(),
}
}