adding donut type chart, like a pie chart with a blank circle on the center and little trick for label position (#111)

(some way of improvement)
This commit is contained in:
Alessandro 2019-02-19 19:52:03 +01:00 committed by Will Charczuk
parent 59451fbeb4
commit 9852fce5a1
5 changed files with 469 additions and 0 deletions

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package main
import (
"fmt"
"log"
"net/http"
"github.com/wcharczuk/go-chart"
)
func drawChart(res http.ResponseWriter, req *http.Request) {
pie := chart.DonutChart{
Width: 512,
Height: 512,
Values: []chart.Value{
{Value: 5, Label: "Blue"},
{Value: 5, Label: "Green"},
{Value: 4, Label: "Gray"},
{Value: 4, Label: "Orange"},
{Value: 3, Label: "Deep Blue"},
{Value: 3, Label: "test"},
},
}
res.Header().Set("Content-Type", "image/png")
err := pie.Render(chart.PNG, res)
if err != nil {
fmt.Printf("Error rendering pie chart: %v\n", err)
}
}
func drawChartRegression(res http.ResponseWriter, req *http.Request) {
pie := chart.DonutChart{
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))
}

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<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="512" height="512">\n<path d="M 0 0
L 512 0
L 512 512
L 0 512
L 0 0" style="stroke-width:0;stroke:rgba(255,255,255,1.0);fill:rgba(255,255,255,1.0)"/><path d="M 5 5
L 507 5
L 507 507
L 5 507
L 5 5" style="stroke-width:0;stroke:rgba(255,255,255,1.0);fill:rgba(255,255,255,1.0)"/><path d="M 256 256
L 438 256
A 182 182 225.00 1 1 127 127
L 256 256
Z" style="stroke-width:4;stroke:rgba(255,255,255,1.0);fill:rgba(106,195,203,1.0)"/><path d="M 256 256
L 127 127
A 182 182 90.00 0 1 385 127
L 256 256
Z" style="stroke-width:4;stroke:rgba(255,255,255,1.0);fill:rgba(42,190,137,1.0)"/><path d="M 256 256
L 385 127
A 182 182 45.00 0 1 438 256
L 256 256
Z" style="stroke-width:4;stroke:rgba(255,255,255,1.0);fill:rgba(110,128,139,1.0)"/><path d="M 256 256
L 321 256
A 65 65 359.00 1 1 321 255
L 256 256
Z" style="stroke-width:4;stroke:rgba(255,255,255,1.0);fill:rgba(255,255,255,1.0)"/><text x="159" y="461" style="stroke-width:0;stroke:none;fill:rgba(51,51,51,1.0);font-size:15.3px;font-family:'Roboto Medium',sans-serif">Blue</text><text x="241" y="48" style="stroke-width:0;stroke:none;fill:rgba(51,51,51,1.0);font-size:15.3px;font-family:'Roboto Medium',sans-serif">Two</text><text x="440" y="181" style="stroke-width:0;stroke:none;fill:rgba(51,51,51,1.0);font-size:15.3px;font-family:'Roboto Medium',sans-serif">One</text></svg>

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321
donut_chart.go Normal file
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package chart
import (
"errors"
"fmt"
"io"
"github.com/golang/freetype/truetype"
"github.com/wcharczuk/go-chart/util"
)
// DonutChart is a chart that draws sections of a circle based on percentages with an hole.
type DonutChart struct {
Title string
TitleStyle Style
ColorPalette ColorPalette
Width int
Height int
DPI float64
Background Style
Canvas Style
SliceStyle Style
Font *truetype.Font
defaultFont *truetype.Font
Values []Value
Elements []Renderable
}
// GetDPI returns the dpi for the chart.
func (pc DonutChart) GetDPI(defaults ...float64) float64 {
if pc.DPI == 0 {
if len(defaults) > 0 {
return defaults[0]
}
return DefaultDPI
}
return pc.DPI
}
// GetFont returns the text font.
func (pc DonutChart) GetFont() *truetype.Font {
if pc.Font == nil {
return pc.defaultFont
}
return pc.Font
}
// GetWidth returns the chart width or the default value.
func (pc DonutChart) GetWidth() int {
if pc.Width == 0 {
return DefaultChartWidth
}
return pc.Width
}
// GetHeight returns the chart height or the default value.
func (pc DonutChart) GetHeight() int {
if pc.Height == 0 {
return DefaultChartWidth
}
return pc.Height
}
// Render renders the chart with the given renderer to the given io.Writer.
func (pc DonutChart) Render(rp RendererProvider, w io.Writer) error {
if len(pc.Values) == 0 {
return errors.New("please provide at least one value")
}
r, err := rp(pc.GetWidth(), pc.GetHeight())
if err != nil {
return err
}
if pc.Font == nil {
defaultFont, err := GetDefaultFont()
if err != nil {
return err
}
pc.defaultFont = defaultFont
}
r.SetDPI(pc.GetDPI(DefaultDPI))
canvasBox := pc.getDefaultCanvasBox()
canvasBox = pc.getCircleAdjustedCanvasBox(canvasBox)
pc.drawBackground(r)
pc.drawCanvas(r, canvasBox)
finalValues, err := pc.finalizeValues(pc.Values)
if err != nil {
return err
}
pc.drawSlices(r, canvasBox, finalValues)
pc.drawTitle(r)
for _, a := range pc.Elements {
a(r, canvasBox, pc.styleDefaultsElements())
}
return r.Save(w)
}
func (pc DonutChart) drawBackground(r Renderer) {
Draw.Box(r, Box{
Right: pc.GetWidth(),
Bottom: pc.GetHeight(),
}, pc.getBackgroundStyle())
}
func (pc DonutChart) drawCanvas(r Renderer, canvasBox Box) {
Draw.Box(r, canvasBox, pc.getCanvasStyle())
}
func (pc DonutChart) drawTitle(r Renderer) {
if len(pc.Title) > 0 && pc.TitleStyle.Show {
Draw.TextWithin(r, pc.Title, pc.Box(), pc.styleDefaultsTitle())
}
}
func (pc DonutChart) drawSlices(r Renderer, canvasBox Box, values []Value) {
cx, cy := canvasBox.Center()
diameter := util.Math.MinInt(canvasBox.Width(), canvasBox.Height())
radius := float64(diameter >> 1) / 1.1
labelRadius := (radius * 2.83) / 3.0
// draw the donut slices
var rads, delta, delta2, total float64
var lx, ly int
if len(values) == 1 {
pc.styleDonutChartValue(0).WriteToRenderer(r)
r.MoveTo(cx, cy)
r.Circle(radius, cx, cy)
} else {
for index, v := range values {
v.Style.InheritFrom(pc.styleDonutChartValue(index)).WriteToRenderer(r)
r.MoveTo(cx, cy)
rads = util.Math.PercentToRadians(total)
delta = util.Math.PercentToRadians(v.Value)
r.ArcTo(cx, cy, (radius / 1.25), (radius / 1.25), rads, delta)
r.LineTo(cx, cy)
r.Close()
r.FillStroke()
total = total + v.Value
}
}
//making the donut hole
v := Value{Value: 100, Label: "center"}
styletemp := pc.SliceStyle.InheritFrom(Style{
StrokeColor: ColorWhite, StrokeWidth: 4.0, FillColor: ColorWhite, FontColor: ColorWhite, //Font: pc.GetFont(),//FontSize: pc.getScaledFontSize(),
})
v.Style.InheritFrom(styletemp).WriteToRenderer(r)
r.MoveTo(cx, cy)
r.ArcTo(cx, cy, (radius / 3.5), (radius / 3.5), util.Math.DegreesToRadians(0), util.Math.DegreesToRadians(359))
r.LineTo(cx, cy)
r.Close()
r.FillStroke()
// draw the labels
total = 0
for index, v := range values {
v.Style.InheritFrom(pc.styleDonutChartValue(index)).WriteToRenderer(r)
if len(v.Label) > 0 {
delta2 = util.Math.PercentToRadians(total + (v.Value / 2.0))
delta2 = util.Math.RadianAdd(delta2, _pi2)
lx, ly = util.Math.CirclePoint(cx, cy, labelRadius, delta2)
tb := r.MeasureText(v.Label)
lx = lx - (tb.Width() >> 1)
ly = ly + (tb.Height() >> 1)
r.Text(v.Label, lx, ly)
}
total = total + v.Value
}
}
func (pc DonutChart) finalizeValues(values []Value) ([]Value, error) {
finalValues := Values(values).Normalize()
if len(finalValues) == 0 {
return nil, fmt.Errorf("donut chart must contain at least (1) non-zero value")
}
return finalValues, nil
}
func (pc DonutChart) getDefaultCanvasBox() Box {
return pc.Box()
}
func (pc DonutChart) getCircleAdjustedCanvasBox(canvasBox Box) Box {
circleDiameter := util.Math.MinInt(canvasBox.Width(), canvasBox.Height())
square := Box{
Right: circleDiameter,
Bottom: circleDiameter,
}
return canvasBox.Fit(square)
}
func (pc DonutChart) getBackgroundStyle() Style {
return pc.Background.InheritFrom(pc.styleDefaultsBackground())
}
func (pc DonutChart) getCanvasStyle() Style {
return pc.Canvas.InheritFrom(pc.styleDefaultsCanvas())
}
func (pc DonutChart) styleDefaultsCanvas() Style {
return Style{
FillColor: pc.GetColorPalette().CanvasColor(),
StrokeColor: pc.GetColorPalette().CanvasStrokeColor(),
StrokeWidth: DefaultStrokeWidth,
}
}
func (pc DonutChart) styleDefaultsDonutChartValue() Style {
return Style{
StrokeColor: pc.GetColorPalette().TextColor(),
StrokeWidth: 4.0,
FillColor: pc.GetColorPalette().TextColor(),
}
}
func (pc DonutChart) styleDonutChartValue(index int) Style {
return pc.SliceStyle.InheritFrom(Style{
StrokeColor: ColorWhite,
StrokeWidth: 4.0,
FillColor: pc.GetColorPalette().GetSeriesColor(index),
FontSize: pc.getScaledFontSize(),
FontColor: pc.GetColorPalette().TextColor(),
Font: pc.GetFont(),
})
}
func (pc DonutChart) getScaledFontSize() float64 {
effectiveDimension := util.Math.MinInt(pc.GetWidth(), pc.GetHeight())
if effectiveDimension >= 2048 {
return 48.0
} else if effectiveDimension >= 1024 {
return 24.0
} else if effectiveDimension > 512 {
return 18.0
} else if effectiveDimension > 256 {
return 12.0
}
return 10.0
}
func (pc DonutChart) styleDefaultsBackground() Style {
return Style{
FillColor: pc.GetColorPalette().BackgroundColor(),
StrokeColor: pc.GetColorPalette().BackgroundStrokeColor(),
StrokeWidth: DefaultStrokeWidth,
}
}
func (pc DonutChart) styleDefaultsElements() Style {
return Style{
Font: pc.GetFont(),
}
}
func (pc DonutChart) styleDefaultsTitle() Style {
return pc.TitleStyle.InheritFrom(Style{
FontColor: pc.GetColorPalette().TextColor(),
Font: pc.GetFont(),
FontSize: pc.getTitleFontSize(),
TextHorizontalAlign: TextHorizontalAlignCenter,
TextVerticalAlign: TextVerticalAlignTop,
TextWrap: TextWrapWord,
})
}
func (pc DonutChart) getTitleFontSize() float64 {
effectiveDimension := util.Math.MinInt(pc.GetWidth(), pc.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
}
// GetColorPalette returns the color palette for the chart.
func (pc DonutChart) GetColorPalette() ColorPalette {
if pc.ColorPalette != nil {
return pc.ColorPalette
}
return AlternateColorPalette
}
// Box returns the chart bounds as a box.
func (pc DonutChart) Box() Box {
dpr := pc.Background.Padding.GetRight(DefaultBackgroundPadding.Right)
dpb := pc.Background.Padding.GetBottom(DefaultBackgroundPadding.Bottom)
return Box{
Top: pc.Background.Padding.GetTop(DefaultBackgroundPadding.Top),
Left: pc.Background.Padding.GetLeft(DefaultBackgroundPadding.Left),
Right: pc.GetWidth() - dpr,
Bottom: pc.GetHeight() - dpb,
}
}

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donut_chart_test.go Normal file
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package chart
import (
"bytes"
"testing"
assert "github.com/blend/go-sdk/assert"
)
func TestDonutChart(t *testing.T) {
assert := assert.New(t)
pie := DonutChart{
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 TestDonutChartDropsZeroValues(t *testing.T) {
assert := assert.New(t)
pie := DonutChart{
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 TestDonutChartAllZeroValues(t *testing.T) {
assert := assert.New(t)
pie := DonutChart{
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)
}