feat: support pie, radar and funnel chart

pie_chart.go

@@ -0,0 +1,211 @@
+// 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 (
+	"errors"
+	"math"
+
+	"github.com/golang/freetype/truetype"
+	"github.com/wcharczuk/go-chart/v2"
+)
+
+type pieChart struct {
+	p   *Painter
+	opt *PieChartOption
+}
+
+type PieChartOption struct {
+	Theme ColorPalette
+	// The font size
+	Font *truetype.Font
+	// The data series list
+	SeriesList SeriesList
+	// The padding of line chart
+	Padding Box
+	// The option of title
+	Title TitleOption
+	// The legend option
+	Legend LegendOption
+	// background is filled
+	backgroundIsFilled bool
+}
+
+func NewPieChart(p *Painter, opt PieChartOption) *pieChart {
+	if opt.Theme == nil {
+		opt.Theme = NewTheme("")
+	}
+	return &pieChart{
+		p:   p,
+		opt: &opt,
+	}
+}
+
+func (p *pieChart) render(result *defaultRenderResult, seriesList SeriesList) (Box, error) {
+	opt := p.opt
+	values := make([]float64, len(seriesList))
+	total := float64(0)
+	radiusValue := ""
+	for index, series := range seriesList {
+		if len(series.Radius) != 0 {
+			radiusValue = series.Radius
+		}
+		value := float64(0)
+		for _, item := range series.Data {
+			value += item.Value
+		}
+		values[index] = value
+		total += value
+	}
+	if total <= 0 {
+		return BoxZero, errors.New("The sum value of pie chart should gt 0")
+	}
+	seriesPainter := result.seriesPainter
+	cx := seriesPainter.Width() >> 1
+	cy := seriesPainter.Height() >> 1
+
+	diameter := chart.MinInt(seriesPainter.Width(), seriesPainter.Height())
+	radius := getRadius(float64(diameter), radiusValue)
+
+	labelLineWidth := 15
+	if radius < 50 {
+		labelLineWidth = 10
+	}
+	labelRadius := radius + float64(labelLineWidth)
+	seriesNames := opt.Legend.Data
+	if len(seriesNames) == 0 {
+		seriesNames = seriesList.Names()
+	}
+	theme := opt.Theme
+	if len(values) == 1 {
+		seriesPainter.OverrideDrawingStyle(Style{
+			StrokeWidth: 1,
+			StrokeColor: theme.GetSeriesColor(0),
+			FillColor:   theme.GetSeriesColor(0),
+		})
+		seriesPainter.MoveTo(cx, cy).
+			Circle(radius, cx, cy)
+	} else {
+		currentValue := float64(0)
+		prevEndX := 0
+		prevEndY := 0
+		for index, v := range values {
+			seriesPainter.OverrideDrawingStyle(Style{
+				StrokeWidth: 1,
+				StrokeColor: theme.GetSeriesColor(index),
+				FillColor:   theme.GetSeriesColor(index),
+			})
+			seriesPainter.MoveTo(cx, cy)
+			start := chart.PercentToRadians(currentValue/total) - math.Pi/2
+			currentValue += v
+			percent := (v / total)
+			delta := chart.PercentToRadians(percent)
+			seriesPainter.ArcTo(cx, cy, radius, radius, start, delta).
+				LineTo(cx, cy).
+				Close().
+				FillStroke()
+
+			series := seriesList[index]
+			// 是否显示label
+			showLabel := series.Label.Show
+			if !showLabel {
+				continue
+			}
+
+			// 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))
+			// 计算是否有重叠，如果有则调整y坐标位置
+			if index != 0 &&
+				math.Abs(float64(endx-prevEndX)) < labelFontSize &&
+				math.Abs(float64(endy-prevEndY)) < labelFontSize {
+				endy -= (labelFontSize << 1)
+			}
+			prevEndX = endx
+			prevEndY = endy
+
+			seriesPainter.MoveTo(startx, starty)
+			seriesPainter.LineTo(endx, endy)
+			offset := labelLineWidth
+			if endx < cx {
+				offset *= -1
+			}
+			seriesPainter.MoveTo(endx, endy)
+			endx += offset
+			seriesPainter.LineTo(endx, endy)
+			seriesPainter.Stroke()
+
+			textStyle := Style{
+				FontColor: theme.GetTextColor(),
+				FontSize:  labelFontSize,
+				Font:      opt.Font,
+			}
+			if !series.Label.Color.IsZero() {
+				textStyle.FontColor = series.Label.Color
+			}
+			seriesPainter.OverrideTextStyle(textStyle)
+			text := NewPieLabelFormatter(seriesNames, series.Label.Formatter)(index, v, percent)
+			textBox := seriesPainter.MeasureText(text)
+			textMargin := 3
+			x := endx + textMargin
+			y := endy + textBox.Height()>>1 - 1
+			if offset < 0 {
+				textWidth := textBox.Width()
+				x = endx - textWidth - textMargin
+			}
+			seriesPainter.Text(text, x, y)
+		}
+	}
+
+	return p.p.box, nil
+}
+
+func (p *pieChart) Render() (Box, error) {
+	opt := p.opt
+
+	renderResult, err := defaultRender(p.p, defaultRenderOption{
+		Theme:      opt.Theme,
+		Padding:    opt.Padding,
+		SeriesList: opt.SeriesList,
+		XAxis: XAxisOption{
+			Show: FalseFlag(),
+		},
+		YAxisOptions: []YAxisOption{
+			{
+				Show: FalseFlag(),
+			},
+		},
+		TitleOption:        opt.Title,
+		LegendOption:       opt.Legend,
+		backgroundIsFilled: opt.backgroundIsFilled,
+	})
+	if err != nil {
+		return BoxZero, err
+	}
+	seriesList := opt.SeriesList.Filter(ChartTypePie)
+	return p.render(renderResult, seriesList)
+}