69b6cb7fc5
Use the ArcTo method to draw the single value case. Rename pc (piechart) to dc (donutchart)
329 lines
8 KiB
Go
329 lines
8 KiB
Go
package chart
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import (
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"errors"
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"fmt"
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"io"
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"github.com/golang/freetype/truetype"
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)
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// DonutChart is a chart that draws sections of a circle based on percentages with an hole.
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type DonutChart struct {
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Title string
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TitleStyle Style
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ColorPalette ColorPalette
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Width int
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Height int
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DPI float64
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Background Style
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Canvas Style
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SliceStyle Style
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Font *truetype.Font
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defaultFont *truetype.Font
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Values []Value
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Elements []Renderable
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}
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// GetDPI returns the dpi for the chart.
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func (dc DonutChart) GetDPI(defaults ...float64) float64 {
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if dc.DPI == 0 {
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if len(defaults) > 0 {
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return defaults[0]
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}
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return DefaultDPI
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}
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return dc.DPI
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}
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// GetFont returns the text font.
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func (dc DonutChart) GetFont() *truetype.Font {
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if dc.Font == nil {
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return dc.defaultFont
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}
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return dc.Font
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}
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// GetWidth returns the chart width or the default value.
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func (dc DonutChart) GetWidth() int {
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if dc.Width == 0 {
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return DefaultChartWidth
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}
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return dc.Width
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}
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// GetHeight returns the chart height or the default value.
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func (dc DonutChart) GetHeight() int {
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if dc.Height == 0 {
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return DefaultChartWidth
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}
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return dc.Height
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}
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// Render renders the chart with the given renderer to the given io.Writer.
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func (dc DonutChart) Render(rp RendererProvider, w io.Writer) error {
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if len(dc.Values) == 0 {
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return errors.New("please provide at least one value")
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}
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r, err := rp(dc.GetWidth(), dc.GetHeight())
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if err != nil {
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return err
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}
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if dc.Font == nil {
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defaultFont, err := GetDefaultFont()
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if err != nil {
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return err
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}
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dc.defaultFont = defaultFont
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}
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r.SetDPI(dc.GetDPI(DefaultDPI))
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canvasBox := dc.getDefaultCanvasBox()
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canvasBox = dc.getCircleAdjustedCanvasBox(canvasBox)
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dc.drawBackground(r)
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dc.drawCanvas(r, canvasBox)
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finalValues, err := dc.finalizeValues(dc.Values)
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if err != nil {
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return err
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}
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dc.drawSlices(r, canvasBox, finalValues)
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dc.drawTitle(r)
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for _, a := range dc.Elements {
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a(r, canvasBox, dc.styleDefaultsElements())
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}
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return r.Save(w)
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}
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func (dc DonutChart) drawBackground(r Renderer) {
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Draw.Box(r, Box{
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Right: dc.GetWidth(),
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Bottom: dc.GetHeight(),
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}, dc.getBackgroundStyle())
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}
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func (dc DonutChart) drawCanvas(r Renderer, canvasBox Box) {
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Draw.Box(r, canvasBox, dc.getCanvasStyle())
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}
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func (dc DonutChart) drawTitle(r Renderer) {
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if len(dc.Title) > 0 && !dc.TitleStyle.Hidden {
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Draw.TextWithin(r, dc.Title, dc.Box(), dc.styleDefaultsTitle())
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}
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}
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func (dc DonutChart) drawSlices(r Renderer, canvasBox Box, values []Value) {
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cx, cy := canvasBox.Center()
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diameter := MinInt(canvasBox.Width(), canvasBox.Height())
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radius := float64(diameter>>1) / 1.1
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labelRadius := (radius * 2.83) / 3.0
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// draw the donut slices
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var rads, delta, delta2, total float64
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var lx, ly int
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if len(values) == 1 {
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dc.styleDonutChartValueSingle(0).WriteToRenderer(r)
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r.MoveTo(cx, cy)
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r.ArcTo(cx, cy, (radius / 1.25), (radius / 1.25), DegreesToRadians(0), DegreesToRadians(359))
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r.LineTo(cx, cy)
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r.Close()
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r.FillStroke()
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} else {
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for index, v := range values {
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v.Style.InheritFrom(dc.styleDonutChartValue(index)).WriteToRenderer(r)
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r.MoveTo(cx, cy)
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rads = PercentToRadians(total)
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delta = PercentToRadians(v.Value)
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r.ArcTo(cx, cy, (radius / 1.25), (radius / 1.25), rads, delta)
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r.LineTo(cx, cy)
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r.Close()
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r.FillStroke()
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total = total + v.Value
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}
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}
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//making the donut hole
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v := Value{Value: 100, Label: "center"}
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styletemp := dc.SliceStyle.InheritFrom(Style{
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StrokeColor: ColorWhite, StrokeWidth: 4.0, FillColor: ColorWhite, FontColor: ColorWhite,
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})
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v.Style.InheritFrom(styletemp).WriteToRenderer(r)
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r.MoveTo(cx, cy)
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r.ArcTo(cx, cy, (radius / 3.5), (radius / 3.5), DegreesToRadians(0), DegreesToRadians(359))
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r.LineTo(cx, cy)
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r.Close()
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r.FillStroke()
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// draw the labels
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total = 0
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for index, v := range values {
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v.Style.InheritFrom(dc.styleDonutChartValue(index)).WriteToRenderer(r)
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if len(v.Label) > 0 {
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delta2 = PercentToRadians(total + (v.Value / 2.0))
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delta2 = RadianAdd(delta2, _pi2)
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lx, ly = CirclePoint(cx, cy, labelRadius, delta2)
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tb := r.MeasureText(v.Label)
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lx = lx - (tb.Width() >> 1)
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ly = ly + (tb.Height() >> 1)
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r.Text(v.Label, lx, ly)
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}
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total = total + v.Value
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}
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}
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func (dc DonutChart) finalizeValues(values []Value) ([]Value, error) {
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finalValues := Values(values).Normalize()
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if len(finalValues) == 0 {
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return nil, fmt.Errorf("donut chart must contain at least (1) non-zero value")
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}
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return finalValues, nil
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}
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func (dc DonutChart) getDefaultCanvasBox() Box {
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return dc.Box()
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}
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func (dc DonutChart) getCircleAdjustedCanvasBox(canvasBox Box) Box {
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circleDiameter := MinInt(canvasBox.Width(), canvasBox.Height())
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square := Box{
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Right: circleDiameter,
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Bottom: circleDiameter,
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}
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return canvasBox.Fit(square)
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}
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func (dc DonutChart) getBackgroundStyle() Style {
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return dc.Background.InheritFrom(dc.styleDefaultsBackground())
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}
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func (dc DonutChart) getCanvasStyle() Style {
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return dc.Canvas.InheritFrom(dc.styleDefaultsCanvas())
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}
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func (dc DonutChart) styleDefaultsCanvas() Style {
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return Style{
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FillColor: dc.GetColorPalette().CanvasColor(),
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StrokeColor: dc.GetColorPalette().CanvasStrokeColor(),
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StrokeWidth: DefaultStrokeWidth,
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}
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}
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func (dc DonutChart) styleDefaultsDonutChartValue() Style {
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return Style{
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StrokeColor: dc.GetColorPalette().TextColor(),
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StrokeWidth: 4.0,
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FillColor: dc.GetColorPalette().TextColor(),
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}
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}
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func (dc DonutChart) styleDonutChartValue(index int) Style {
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return dc.SliceStyle.InheritFrom(Style{
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StrokeColor: ColorWhite,
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StrokeWidth: 4.0,
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FillColor: dc.GetColorPalette().GetSeriesColor(index),
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FontSize: dc.getScaledFontSize(),
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FontColor: dc.GetColorPalette().TextColor(),
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Font: dc.GetFont(),
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})
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}
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func (dc DonutChart) styleDonutChartValueSingle(index int) Style {
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return dc.SliceStyle.InheritFrom(Style{
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StrokeColor: dc.GetColorPalette().GetSeriesColor(index),
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StrokeWidth: 4.0,
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FillColor: dc.GetColorPalette().GetSeriesColor(index),
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FontSize: dc.getScaledFontSize(),
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FontColor: dc.GetColorPalette().TextColor(),
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Font: dc.GetFont(),
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})
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}
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func (dc DonutChart) getScaledFontSize() float64 {
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effectiveDimension := MinInt(dc.GetWidth(), dc.GetHeight())
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if effectiveDimension >= 2048 {
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return 48.0
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} else if effectiveDimension >= 1024 {
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return 24.0
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} else if effectiveDimension > 512 {
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return 18.0
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} else if effectiveDimension > 256 {
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return 12.0
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}
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return 10.0
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}
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func (dc DonutChart) styleDefaultsBackground() Style {
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return Style{
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FillColor: dc.GetColorPalette().BackgroundColor(),
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StrokeColor: dc.GetColorPalette().BackgroundStrokeColor(),
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StrokeWidth: DefaultStrokeWidth,
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}
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}
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func (dc DonutChart) styleDefaultsElements() Style {
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return Style{
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Font: dc.GetFont(),
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}
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}
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func (dc DonutChart) styleDefaultsTitle() Style {
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return dc.TitleStyle.InheritFrom(Style{
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FontColor: dc.GetColorPalette().TextColor(),
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Font: dc.GetFont(),
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FontSize: dc.getTitleFontSize(),
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TextHorizontalAlign: TextHorizontalAlignCenter,
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TextVerticalAlign: TextVerticalAlignTop,
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TextWrap: TextWrapWord,
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})
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}
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func (dc DonutChart) getTitleFontSize() float64 {
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effectiveDimension := MinInt(dc.GetWidth(), dc.GetHeight())
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if effectiveDimension >= 2048 {
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return 48
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} else if effectiveDimension >= 1024 {
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return 24
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} else if effectiveDimension >= 512 {
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return 18
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} else if effectiveDimension >= 256 {
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return 12
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}
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return 10
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}
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// GetColorPalette returns the color palette for the chart.
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func (dc DonutChart) GetColorPalette() ColorPalette {
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if dc.ColorPalette != nil {
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return dc.ColorPalette
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}
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return AlternateColorPalette
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}
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// Box returns the chart bounds as a box.
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func (dc DonutChart) Box() Box {
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dpr := dc.Background.Padding.GetRight(DefaultBackgroundPadding.Right)
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dpb := dc.Background.Padding.GetBottom(DefaultBackgroundPadding.Bottom)
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return Box{
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Top: dc.Background.Padding.GetTop(DefaultBackgroundPadding.Top),
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Left: dc.Background.Padding.GetLeft(DefaultBackgroundPadding.Left),
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Right: dc.GetWidth() - dpr,
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Bottom: dc.GetHeight() - dpb,
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}
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}
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