feat: support bar chart render

bar_chart.go

@@ -0,0 +1,205 @@
+// 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 barChart struct {
+	p   *Painter
+	opt *BarChartOption
+}
+
+func NewBarChart(p *Painter, opt BarChartOption) *barChart {
+	if opt.Theme == nil {
+		opt.Theme = NewTheme("")
+	}
+	return &barChart{
+		p:   p,
+		opt: &opt,
+	}
+}
+
+type BarChartOption 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 (b *barChart) Render() (Box, error) {
+	p := b.p
+	opt := b.opt
+	seriesList := opt.SeriesList
+	seriesList.init()
+	renderResult, err := defaultRender(p, defaultRenderOption{
+		Theme:        opt.Theme,
+		Padding:      opt.Padding,
+		SeriesList:   seriesList,
+		XAxis:        opt.XAxis,
+		YAxisOptions: opt.YAxisOptions,
+		TitleOption:  opt.Title,
+		LegendOption: opt.Legend,
+	})
+	if err != nil {
+		return chart.BoxZero, err
+	}
+	seriesPainter := renderResult.seriesPainter
+	seriesList = seriesList.Filter(ChartTypeBar)
+
+	xRange := NewRange(AxisRangeOption{
+		DivideCount: len(opt.XAxis.Data),
+		Size:        seriesPainter.Width(),
+	})
+	x0, x1 := xRange.GetRange(0)
+	width := int(x1 - x0)
+	// 每一块之间的margin
+	margin := 10
+	// 每一个bar之间的margin
+	barMargin := 5
+	if width < 20 {
+		margin = 2
+		barMargin = 2
+	} else if width < 50 {
+		margin = 5
+		barMargin = 3
+	}
+	seriesCount := len(seriesList)
+	// 总的宽度-两个margin-(总数-1)的barMargin
+	barWidth := (width - 2*margin - barMargin*(seriesCount-1)) / len(seriesList)
+	barMaxHeight := seriesPainter.Height()
+	theme := opt.Theme
+	seriesNames := seriesList.Names()
+
+	markPointPainter := NewMarkPointPainter(seriesPainter)
+	markLinePainter := NewMarkLinePainter(seriesPainter)
+	rendererList := []Renderer{
+		markPointPainter,
+		markLinePainter,
+	}
+	for i := range seriesList {
+		series := seriesList[i]
+		yRange := renderResult.axisRanges[series.AxisIndex]
+		index := series.index
+		if index == 0 {
+			index = i
+		}
+		seriesColor := theme.GetSeriesColor(index)
+
+		divideValues := xRange.AutoDivide()
+		points := make([]Point, len(series.Data))
+		for j, item := range series.Data {
+			if j >= xRange.divideCount {
+				continue
+			}
+			x := divideValues[j]
+			x += margin
+			if i != 0 {
+				x += i * (barWidth + barMargin)
+			}
+
+			h := int(yRange.getHeight(item.Value))
+			fillColor := seriesColor
+			if !item.Style.FillColor.IsZero() {
+				fillColor = item.Style.FillColor
+			}
+			top := barMaxHeight - h
+
+			seriesPainter.OverrideDrawingStyle(Style{
+				FillColor: fillColor,
+			}).Rect(chart.Box{
+				Top:    top,
+				Left:   x,
+				Right:  x + barWidth,
+				Bottom: barMaxHeight - 1,
+			})
+			// 用于生成marker point
+			points[j] = Point{
+				// 居中的位置
+				X: x + barWidth>>1,
+				Y: top,
+			}
+			// 用于生成marker point
+			points[j] = Point{
+				// 居中的位置
+				X: x + barWidth>>1,
+				Y: top,
+			}
+			// 如果label不需要展示，则返回
+			if !series.Label.Show {
+				continue
+			}
+			distance := series.Label.Distance
+			if distance == 0 {
+				distance = 5
+			}
+			text := NewValueLabelFormater(seriesNames, series.Label.Formatter)(i, item.Value, -1)
+			labelStyle := Style{
+				FontColor: theme.GetTextColor(),
+				FontSize:  labelFontSize,
+				Font:      opt.Font,
+			}
+			if !series.Label.Color.IsZero() {
+				labelStyle.FontColor = series.Label.Color
+			}
+			seriesPainter.OverrideTextStyle(labelStyle)
+			textBox := seriesPainter.MeasureText(text)
+			seriesPainter.Text(text, x+(barWidth-textBox.Width())>>1, barMaxHeight-h-distance)
+		}
+
+		markPointPainter.Add(markPointRenderOption{
+			FillColor: seriesColor,
+			Font:      opt.Font,
+			Series:    series,
+			Points:    points,
+		})
+		markLinePainter.Add(markLineRenderOption{
+			FillColor:   seriesColor,
+			FontColor:   opt.Theme.GetTextColor(),
+			StrokeColor: seriesColor,
+			Font:        opt.Font,
+			Series:      series,
+			Range:       yRange,
+		})
+	}
+	// 最大、最小的mark point
+	err = doRender(rendererList...)
+	if err != nil {
+		return chart.BoxZero, err
+	}
+
+	return chart.BoxZero, nil
+}