feat: pie chart render function

bar_chart.go

@@ -27,10 +27,9 @@ import (
 )
 
 func barChartRender(opt ChartOption, result *basicRenderResult) (*Draw, error) {
-	d := result.d
 
-	bd, err := NewDraw(DrawOption{
-		Parent: d,
+	d, err := NewDraw(DrawOption{
+		Parent: result.d,
 	}, PaddingOption(chart.Box{
 		Top:  result.titleBox.Height(),
 		Left: YAxisWidth,
@@ -65,7 +64,7 @@ func barChartRender(opt ChartOption, result *basicRenderResult) (*Draw, error) {
 
 			h := int(yRange.getHeight(item.Value))
 
-			bd.Bar(chart.Box{
+			d.Bar(chart.Box{
 				Top:    barMaxHeight - h,
 				Left:   x,
 				Right:  x + barWidth,
@@ -76,5 +75,5 @@ func barChartRender(opt ChartOption, result *basicRenderResult) (*Draw, error) {
 		}
 	}
 
-	return d, nil
+	return result.d, nil
 }

chart.go

@@ -23,6 +23,7 @@
 package charts
 
 import (
+	"errors"
 	"math"
 
 	"github.com/dustin/go-humanize"
@@ -168,21 +169,37 @@ type basicRenderResult struct {
 }
 
 func ChartRender(opt ChartOption) (*Draw, error) {
-	result, err := chartBasicRender(&opt)
-	if err != nil {
-		return nil, err
+	if len(opt.SeriesList) == 0 {
+		return nil, errors.New("series can not be nil")
 	}
+
 	lineSeries := make([]Series, 0)
 	barSeries := make([]Series, 0)
+	isPieChart := false
 	for index, item := range opt.SeriesList {
 		item.index = index
 		switch item.Type {
+		case ChartTypePie:
+			isPieChart = true
 		case ChartTypeBar:
 			barSeries = append(barSeries, item)
 		default:
 			lineSeries = append(lineSeries, item)
 		}
 	}
+	// 如果指定了pie，则以pie的形式处理，不支持多类型图表
+	// pie不需要axis
+	if isPieChart {
+		opt.XAxis.Hidden = true
+		opt.YAxis.Hidden = true
+	}
+	result, err := chartBasicRender(&opt)
+	if err != nil {
+		return nil, err
+	}
+	if isPieChart {
+		return pieChartRender(opt, result)
+	}
 	if len(barSeries) != 0 {
 		o := opt
 		o.SeriesList = barSeries
@@ -231,19 +248,27 @@ func chartBasicRender(opt *ChartOption) (*basicRenderResult, error) {
 		return nil, err
 	}
 
+	xAxisHeight := 0
+	var xRange *Range
+
+	if !opt.XAxis.Hidden {
 		// xAxis
-	xAxisHeight, xRange, err := drawXAxis(d, &opt.XAxis)
+		xAxisHeight, xRange, err = drawXAxis(d, &opt.XAxis)
 		if err != nil {
 			return nil, err
 		}
+	}
 
 	// 暂时仅支持单一yaxis
-	yRange, err := drawYAxis(d, opt, xAxisHeight, chart.Box{
+	var yRange *Range
+	if !opt.YAxis.Hidden {
+		yRange, err = drawYAxis(d, opt, xAxisHeight, chart.Box{
 			Top: titleBox.Height(),
 		})
 		if err != nil {
 			return nil, err
 		}
+	}
 	return &basicRenderResult{
 		xRange:   xRange,
 		yRange:   yRange,

draw.go

@@ -138,6 +138,10 @@ func (d *Draw) moveTo(x, y int) {
 	d.Render.MoveTo(x+d.Box.Left, y+d.Box.Top)
 }
 
+func (d *Draw) arcTo(cx, cy int, rx, ry, startAngle, delta float64) {
+	d.Render.ArcTo(cx+d.Box.Left, cy+d.Box.Top, rx, ry, startAngle, delta)
+}
+
 func (d *Draw) lineTo(x, y int) {
 	d.Render.LineTo(x+d.Box.Left, y+d.Box.Top)
 }

line_chart.go

@@ -29,11 +29,10 @@ import (
 
 func lineChartRender(opt ChartOption, result *basicRenderResult) (*Draw, error) {
 
-	d := result.d
 	theme := NewTheme(opt.Theme)
 
-	sd, err := NewDraw(DrawOption{
-		Parent: d,
+	d, err := NewDraw(DrawOption{
+		Parent: result.d,
 	}, PaddingOption(chart.Box{
 		Top:  result.titleBox.Height(),
 		Left: YAxisWidth,
@@ -60,7 +59,7 @@ func lineChartRender(opt ChartOption, result *basicRenderResult) (*Draw, error)
 			if theme.IsDark() {
 				dotFillColor = seriesColor
 			}
-			sd.Line(points, LineStyle{
+			d.Line(points, LineStyle{
 				StrokeColor:  seriesColor,
 				StrokeWidth:  2,
 				DotColor:     seriesColor,
@@ -70,5 +69,5 @@ func lineChartRender(opt ChartOption, result *basicRenderResult) (*Draw, error)
 		}
 	}
 
-	return d, nil
+	return result.d, nil
 }

pie_chart.go

@@ -0,0 +1,111 @@
+// MIT License
+
+// Copyright (c) 2022 Tree Xie
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+package charts
+
+import (
+	"math"
+
+	"github.com/wcharczuk/go-chart/v2"
+)
+
+const defaultRadiusPercent = 0.4
+
+func getPieStyle(theme *Theme, index int) chart.Style {
+	seriesColor := theme.GetSeriesColor(index)
+	return chart.Style{
+		StrokeColor: seriesColor,
+		StrokeWidth: 1,
+		FillColor:   seriesColor,
+	}
+
+}
+
+func pieChartRender(opt ChartOption, result *basicRenderResult) (*Draw, error) {
+	d, err := NewDraw(DrawOption{
+		Parent: result.d,
+	}, PaddingOption(chart.Box{
+		Top: result.titleBox.Height(),
+	}))
+	if err != nil {
+		return nil, err
+	}
+
+	values := make([]float64, len(opt.SeriesList))
+	total := float64(0)
+	for index, series := range opt.SeriesList {
+		value := float64(0)
+		for _, item := range series.Data {
+			value += item.Value
+		}
+		values[index] = value
+		total += value
+	}
+	r := d.Render
+	theme := NewTheme(opt.Theme)
+
+	box := d.Box
+	cx := box.Width() >> 1
+	cy := box.Height() >> 1
+
+	diameter := chart.MinInt(box.Width(), box.Height())
+	radius := float64(diameter) * defaultRadiusPercent
+	labelRadius := radius + 20
+
+	if len(values) == 1 {
+		getPieStyle(theme, 0).WriteToRenderer(r)
+		d.moveTo(cx, cy)
+		d.circle(radius, cx, cy)
+	} else {
+		currentValue := float64(0)
+		for index, v := range values {
+			getPieStyle(theme, index).WriteToRenderer(r)
+			d.moveTo(cx, cy)
+			start := chart.PercentToRadians(currentValue/total) - math.Pi/2
+			currentValue += v
+			delta := chart.PercentToRadians(v / total)
+			d.arcTo(cx, cy, radius, radius, start, delta)
+			d.lineTo(cx, cy)
+			r.Close()
+			r.FillStroke()
+
+			// label的角度为饼块中间
+			angle := start + delta/2
+			startx := cx + int(radius*math.Cos(angle))
+			starty := cy + int(radius*math.Sin(angle))
+
+			endx := cx + int(labelRadius*math.Cos(angle))
+			endy := cy + int(labelRadius*math.Sin(angle))
+			d.moveTo(startx, starty)
+			d.lineTo(endx, endy)
+			offset := 30
+			if endx < cx {
+				offset *= -1
+			}
+			d.moveTo(endx, endy)
+			d.lineTo(endx+offset, endy)
+			r.Stroke()
+			// TODO label show
+		}
+	}
+	return result.d, nil
+}

xaxis.go

@@ -28,6 +28,7 @@ type XAxisOption struct {
 	BoundaryGap *bool
 	Data        []string
 	Theme       string
+	Hidden      bool
 	// TODO split number
 }
 

yaxis.go

@@ -29,6 +29,7 @@ import (
 type YAxisOption struct {
 	Min    *float64
 	Max    *float64
+	Hidden bool
 }
 
 const YAxisWidth = 40