feat: support horizontal bar chart

horizontal_bar_chart.go

@@ -0,0 +1,152 @@
+// 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 (
+	"github.com/golang/freetype/truetype"
+	"github.com/wcharczuk/go-chart/v2"
+)
+
+type horizontalBarChart struct {
+	p   *Painter
+	opt *HorizontalBarChartOption
+}
+
+type HorizontalBarChartOption struct {
+	Theme ColorPalette
+	// The font size
+	Font *truetype.Font
+	// The data series list
+	SeriesList SeriesList
+	// The x axis option
+	XAxis XAxisOption
+	// The padding of line chart
+	Padding Box
+	// The y axis option
+	YAxisOptions []YAxisOption
+	// The option of title
+	Title TitleOption
+	// The legend option
+	Legend LegendOption
+}
+
+func NewHorizontalBarChart(p *Painter, opt HorizontalBarChartOption) *horizontalBarChart {
+	if opt.Theme == nil {
+		opt.Theme = NewTheme("")
+	}
+	return &horizontalBarChart{
+		p:   p,
+		opt: &opt,
+	}
+}
+
+func (h *horizontalBarChart) render(result *defaultRenderResult, seriesList SeriesList) (Box, error) {
+	p := h.p
+	opt := h.opt
+	seriesPainter := result.seriesPainter
+	yRange := result.axisRanges[0]
+	y0, y1 := yRange.GetRange(0)
+	height := int(y1 - y0)
+	// 每一块之间的margin
+	margin := 10
+	// 每一个bar之间的margin
+	barMargin := 5
+	if height < 20 {
+		margin = 2
+		barMargin = 2
+	} else if height < 50 {
+		margin = 5
+		barMargin = 3
+	}
+	seriesCount := len(seriesList)
+	// 总的高度-两个margin-(总数-1)的barMargin
+	barHeight := (height - 2*margin - barMargin*(seriesCount-1)) / len(seriesList)
+
+	theme := opt.Theme
+
+	max, min := seriesList.GetMaxMin(0)
+	xRange := NewRange(AxisRangeOption{
+		Min:         min,
+		Max:         max,
+		DivideCount: defaultAxisDivideCount,
+		Size:        seriesPainter.Width(),
+	})
+
+	for i := range seriesList {
+		series := seriesList[i]
+		index := series.index
+		if index == 0 {
+			index = i
+		}
+		seriesColor := theme.GetSeriesColor(index)
+		divideValues := yRange.AutoDivide()
+		for j, item := range series.Data {
+			if j >= yRange.divideCount {
+				continue
+			}
+			// 显示位置切换
+			j = yRange.divideCount - j - 1
+			y := divideValues[j]
+			y += margin
+			if i != 0 {
+				y += i * (barHeight + barMargin)
+			}
+
+			w := int(xRange.getHeight(item.Value))
+			fillColor := seriesColor
+			if !item.Style.FillColor.IsZero() {
+				fillColor = item.Style.FillColor
+			}
+			right := w
+			seriesPainter.OverrideDrawingStyle(Style{
+				FillColor: fillColor,
+			}).Rect(chart.Box{
+				Top:    y,
+				Left:   0,
+				Right:  right,
+				Bottom: y + barHeight,
+			})
+		}
+	}
+	return p.box, nil
+}
+
+func (h *horizontalBarChart) Render() (Box, error) {
+	p := h.p
+	opt := h.opt
+	renderResult, err := defaultRender(p, defaultRenderOption{
+		Theme:        opt.Theme,
+		Padding:      opt.Padding,
+		SeriesList:   opt.SeriesList,
+		XAxis:        opt.XAxis,
+		YAxisOptions: opt.YAxisOptions,
+		TitleOption:  opt.Title,
+		LegendOption: opt.Legend,
+		axisReversed: true,
+	})
+	if err != nil {
+		return BoxZero, err
+	}
+	seriesList := opt.SeriesList.Filter(ChartTypeHorizontalBar)
+	return h.render(renderResult, seriesList)
+}