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
+}

chart.go

@@ -51,6 +51,7 @@ type ChartOption struct {
 	Title           TitleOption
 	Legend          LegendOption
 	XAxis           XAxisOption
+	YAxis           YAxisOption
 	Width           int
 	Height          int
 	Parent          *Draw
@@ -128,8 +129,16 @@ func (o *ChartOption) getYRange(axisIndex int) Range {
 			}
 		}
 	}
+	min = min * 0.9
+	max = max * 1.1
+	if o.YAxis.Min != nil {
+		min = *o.YAxis.Min
+	}
+	if o.YAxis.Max != nil {
+		max = *o.YAxis.Max
+	}
 	// y轴分设置默认划分为6块
-	r := NewRange(min*0.9, max*1.1, 6)
+	r := NewRange(min, max, 6)
 	return r
 }
 

line_chart.go

@@ -27,12 +27,8 @@ import (
 	"github.com/wcharczuk/go-chart/v2/drawing"
 )
 
-type LineChartOption struct {
-	ChartOption
-}
-
-func NewLineChart(opt LineChartOption) (*Draw, error) {
-	result, err := chartBasicRender(&opt.ChartOption)
+func LineChartRender(opt ChartOption) (*Draw, error) {
+	result, err := chartBasicRender(&opt)
 	if err != nil {
 		return nil, err
 	}
@@ -54,7 +50,7 @@ func NewLineChart(opt LineChartOption) (*Draw, error) {
 	for i, series := range opt.SeriesList {
 		points := make([]Point, 0)
 		for j, item := range series.Data {
-			y := yRange.getHeight(item.Value)
+			y := yRange.getRestHeight(item.Value)
 			points = append(points, Point{
 				Y: y,
 				X: xRange.getWidth(float64(j)),

range.go

@@ -60,10 +60,20 @@ func NewRange(min, max float64, divideCount int) Range {
 }
 
 func (r *Range) getHeight(value float64) int {
+	v := (value - r.Min) / (r.Max - r.Min)
+	return int(v * float64(r.Size))
+}
+
+func (r *Range) getRestHeight(value float64) int {
 	v := 1 - (value-r.Min)/(r.Max-r.Min)
 	return int(v * float64(r.Size))
 }
 
+func (r *Range) GetRange(index int) (float64, float64) {
+	unit := float64(r.Size) / float64(r.divideCount)
+	return unit * float64(index), unit * float64(index+1)
+}
+
 func (r *Range) getWidth(value float64) int {
 	v := value / (r.Max - r.Min)
 	// 移至居中

yaxis.go

@@ -26,6 +26,11 @@ import (
 	"github.com/wcharczuk/go-chart/v2"
 )
 
+type YAxisOption struct {
+	Min *float64
+	Max *float64
+}
+
 const YAxisWidth = 40
 
 func drawYAxis(p *Draw, opt *ChartOption, xAxisHeight int, padding chart.Box) (*Range, error) {