feat: support funnel chart

funnel.go

@@ -0,0 +1,141 @@
+// 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 (
+	"fmt"
+	"sort"
+
+	"github.com/dustin/go-humanize"
+	"github.com/golang/freetype/truetype"
+	"github.com/wcharczuk/go-chart/v2"
+)
+
+type funnelChartOption struct {
+	Theme      string
+	Font       *truetype.Font
+	SeriesList SeriesList
+}
+
+func funnelChartRender(opt funnelChartOption, result *basicRenderResult) error {
+	d, err := NewDraw(DrawOption{
+		Parent: result.d,
+	}, PaddingOption(chart.Box{
+		Top: result.titleBox.Height(),
+	}))
+	if err != nil {
+		return err
+	}
+	seriesList := make([]Series, len(opt.SeriesList))
+	copy(seriesList, opt.SeriesList)
+	sort.Slice(seriesList, func(i, j int) bool {
+		// 大的数据在前
+		return seriesList[i].Data[0].Value > seriesList[j].Data[0].Value
+	})
+	max := float64(100)
+	min := float64(0)
+	for _, item := range seriesList {
+		if item.Max != nil {
+			max = *item.Max
+		}
+		if item.Min != nil {
+			min = *item.Min
+		}
+	}
+
+	theme := NewTheme(opt.Theme)
+	gap := 2
+	height := d.Box.Height()
+	width := d.Box.Width()
+	count := len(seriesList)
+
+	h := (height - gap*(count-1)) / count
+
+	y := 0
+	widthList := make([]int, len(seriesList))
+	textList := make([]string, len(seriesList))
+	for index, item := range seriesList {
+		value := item.Data[0].Value
+		percent := (item.Data[0].Value - min) / (max - min)
+		w := int(percent * float64(width))
+		widthList[index] = w
+		p := humanize.CommafWithDigits(value, 2) + "%"
+		textList[index] = fmt.Sprintf("%s(%s)", item.Name, p)
+	}
+
+	for index, w := range widthList {
+		series := seriesList[index]
+		nextWidth := 0
+		if index+1 < len(widthList) {
+			nextWidth = widthList[index+1]
+		}
+		topStartX := (width - w) >> 1
+		topEndX := topStartX + w
+		bottomStartX := (width - nextWidth) >> 1
+		bottomEndX := bottomStartX + nextWidth
+		points := []Point{
+			{
+				X: topStartX,
+				Y: y,
+			},
+			{
+				X: topEndX,
+				Y: y,
+			},
+			{
+				X: bottomEndX,
+				Y: y + h,
+			},
+			{
+				X: bottomStartX,
+				Y: y + h,
+			},
+			{
+				X: topStartX,
+				Y: y,
+			},
+		}
+		color := theme.GetSeriesColor(series.index)
+		d.fill(points, chart.Style{
+			FillColor: color,
+		})
+
+		// 文本
+		text := textList[index]
+		r := d.Render
+		textStyle := chart.Style{
+			FontColor: theme.GetTextColor(),
+			FontSize:  labelFontSize,
+			Font:      opt.Font,
+		}
+		textStyle.GetTextOptions().WriteToRenderer(r)
+		textBox := r.MeasureText(text)
+		textX := width>>1 - textBox.Width()>>1
+		textY := y + h>>1
+		d.text(text, textX, textY)
+
+		y += (h + gap)
+	}
+
+	return nil
+}