feat: support between ticks

bar_series.go

@@ -22,14 +22,26 @@
 
 package charts
 
-import "github.com/wcharczuk/go-chart/v2"
+import (
+	"github.com/wcharczuk/go-chart/v2"
+)
+
+const defaultBarMargin = 10
 
 type BarSeries struct {
 	BaseSeries
+	Count int
+	Index int
+	// 间隔
+	Margin int
+	// 偏移量
+	Offset int
+	// 宽度
+	BarWidth int
 }
 
 func (bs BarSeries) Render(r chart.Renderer, canvasBox chart.Box, xrange, yrange chart.Range, defaults chart.Style) {
-	if bs.Len() == 0 {
+	if bs.Len() == 0 || bs.Count <= 0 {
 		return
 	}
 	style := bs.Style.InheritFrom(defaults)
@@ -40,18 +52,25 @@ func (bs BarSeries) Render(r chart.Renderer, canvasBox chart.Box, xrange, yrange
 
 	cb := canvasBox.Bottom
 	cl := canvasBox.Left
+	margin := bs.Margin
+	if margin <= 0 {
+		margin = defaultBarMargin
+	}
+	barWidth := bs.BarWidth
+	if barWidth <= 0 {
+		barWidth = canvasBox.Width() / (bs.Len() * bs.Count)
+	}
 
 	for i := 0; i < bs.Len(); i++ {
 		vx, vy := bs.GetValues(i)
 
-		x := cl + xrange.Translate(vx)
+		x := cl + xrange.Translate(vx) + bs.Index*(margin+barWidth) + bs.Offset
 		y := cb - yrange.Translate(vy)
 
 		chart.Draw.Box(r, chart.Box{
-			Left: x,
-			Top:  y,
-			// TODO 计算宽度
-			Right:  x + 10,
+			Left:   x,
+			Top:    y,
+			Right:  x + barWidth,
 			Bottom: canvasBox.Bottom - 1,
 		}, style)
 	}