feat: support bar chart

bar_chart.go

@@ -0,0 +1,84 @@
+// 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/wcharczuk/go-chart/v2"
+)
+
+func BarChartRender(opt ChartOption) (*Draw, error) {
+	result, err := chartBasicRender(&opt)
+	if err != nil {
+		return nil, err
+	}
+	d := result.d
+
+	bd, err := NewDraw(DrawOption{
+		Parent: d,
+	}, PaddingOption(chart.Box{
+		Top:  result.titleBox.Height(),
+		Left: YAxisWidth,
+	}))
+	if err != nil {
+		return nil, err
+	}
+	yRange := result.yRange
+	xRange := result.xRange
+	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
+
+	seriesCount := len(opt.SeriesList)
+	// 总的宽度-两个margin-(总数-1)的barMargin
+	barWidth := (width - 2*margin - barMargin*(seriesCount-1)) / len(opt.SeriesList)
+
+	barMaxHeight := yRange.Size
+	theme := NewTheme(opt.Theme)
+
+	for i, series := range opt.SeriesList {
+		for j, item := range series.Data {
+			x0, _ := xRange.GetRange(j)
+			x := int(x0)
+			x += margin
+			if i != 0 {
+				x += i * (barWidth + barMargin)
+			}
+
+			h := int(yRange.getHeight(item.Value))
+
+			bd.Bar(chart.Box{
+				Top:    barMaxHeight - h,
+				Left:   x,
+				Right:  x + barWidth,
+				Bottom: barMaxHeight - 1,
+			}, BarStyle{
+				FillColor: theme.GetSeriesColor(i),
+			})
+		}
+	}
+
+	return d, nil
+}