feat: support between ticks

axis.go

@@ -42,10 +42,18 @@ type (
 
 const axisStrokeWidth = 1
 
-func GetXAxisAndValues(xAxis XAxis, theme string) (chart.XAxis, []float64) {
-	xValues := make([]float64, len(xAxis.Data))
-	ticks := make([]chart.Tick, len(xAxis.Data))
-	for index, key := range xAxis.Data {
+func GetXAxisAndValues(xAxis XAxis, tickPosition chart.TickPosition, theme string) (chart.XAxis, []float64) {
+	data := xAxis.Data
+	// 如果居中，则需要多添加一个值
+	if tickPosition == chart.TickPositionBetweenTicks {
+		data = append([]string{
+			"",
+		}, data...)
+	}
+
+	xValues := make([]float64, len(data))
+	ticks := make([]chart.Tick, len(data))
+	for index, key := range data {
 		f := float64(index)
 		xValues[index] = f
 		ticks[index] = chart.Tick{
@@ -60,7 +68,8 @@ func GetXAxisAndValues(xAxis XAxis, theme string) (chart.XAxis, []float64) {
 		}, xValues
 	}
 	return chart.XAxis{
-		Ticks: ticks,
+		Ticks:        ticks,
+		TickPosition: tickPosition,
 		Style: chart.Style{
 			FontColor:   AxisColorLight,
 			StrokeColor: AxisColorLight,

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)
 	}

base_series.go

@@ -37,8 +37,9 @@ var (
 
 // BaseSeries represents a line on a chart.
 type BaseSeries struct {
-	Name  string
-	Style chart.Style
+	Name         string
+	Style        chart.Style
+	TickPosition chart.TickPosition
 
 	YAxis chart.YAxisType
 
@@ -61,16 +62,26 @@ func (cs BaseSeries) GetStyle() chart.Style {
 
 // Len returns the number of elements in the series.
 func (cs BaseSeries) Len() int {
-	return len(cs.XValues)
+	offset := 0
+	if cs.TickPosition == chart.TickPositionBetweenTicks {
+		offset = -1
+	}
+	return len(cs.XValues) + offset
 }
 
 // GetValues gets the x,y values at a given index.
 func (cs BaseSeries) GetValues(index int) (float64, float64) {
+	if cs.TickPosition == chart.TickPositionBetweenTicks {
+		index++
+	}
 	return cs.XValues[index], cs.YValues[index]
 }
 
 // GetFirstValues gets the first x,y values.
 func (cs BaseSeries) GetFirstValues() (float64, float64) {
+	if cs.TickPosition == chart.TickPositionBetweenTicks {
+		return cs.XValues[1], cs.YValues[1]
+	}
 	return cs.XValues[0], cs.YValues[0]
 }
 

charts.go

@@ -69,7 +69,10 @@ func ToSVG(c *chart.Chart) ([]byte, error) {
 	return render(c, chart.SVG)
 }
 func New(opt Option) *chart.Chart {
-	xAxis, xValues := GetXAxisAndValues(opt.XAxis, opt.Theme)
+	tickPosition := chart.TickPositionBetweenTicks
+	// tickPosition = chart.TickPositionUnset
+
+	xAxis, xValues := GetXAxisAndValues(opt.XAxis, tickPosition, opt.Theme)
 
 	legendSize := len(opt.Legend.Data)
 	for index, item := range opt.Series {
@@ -87,7 +90,7 @@ func New(opt Option) *chart.Chart {
 		Height: opt.Height,
 		XAxis:  xAxis,
 		YAxis:  GetYAxis(opt.Theme),
-		Series: GetSeries(opt.Series, opt.Theme),
+		Series: GetSeries(opt.Series, tickPosition, opt.Theme),
 	}
 	// 设置secondary的样式
 	c.YAxisSecondary.Style = c.YAxis.Style

line_series.go

@@ -0,0 +1,40 @@
+// MIT License
+
+// Copyright (c) 2021 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"
+)
+
+type LineSeries struct {
+	BaseSeries
+}
+
+func (bs LineSeries) Render(r chart.Renderer, canvasBox chart.Box, xrange, yrange chart.Range, defaults chart.Style) {
+	style := bs.Style.InheritFrom(defaults)
+	// 如果是居中，画线时重新调整
+	if bs.TickPosition == chart.TickPositionBetweenTicks {
+		xrange = wrapRange(xrange, bs.TickPosition)
+	}
+	chart.Draw.LineSeries(r, canvasBox, xrange, yrange, style, bs)
+}

range.go

@@ -0,0 +1,52 @@
+// MIT License
+
+// Copyright (c) 2021 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"
+)
+
+type Range struct {
+	TickPosition chart.TickPosition
+	chart.ContinuousRange
+}
+
+func wrapRange(r chart.Range, tickPosition chart.TickPosition) chart.Range {
+	xr, ok := r.(*chart.ContinuousRange)
+	if !ok {
+		return r
+	}
+	return &Range{
+		TickPosition:    tickPosition,
+		ContinuousRange: *xr,
+	}
+}
+
+// Translate maps a given value into the ContinuousRange space.
+func (r Range) Translate(value float64) int {
+	v := r.ContinuousRange.Translate(value)
+	if r.TickPosition == chart.TickPositionBetweenTicks {
+		v -= int(float64(r.Domain) / (r.GetDelta() * 2))
+	}
+	return v
+}

series.go

@@ -49,8 +49,15 @@ func getSeriesColor(theme string, index int) drawing.Color {
 	return SeriesColorsLight[index%len(SeriesColorsLight)]
 }
 
-func GetSeries(series []Series, theme string) []chart.Series {
+func GetSeries(series []Series, tickPosition chart.TickPosition, theme string) []chart.Series {
 	arr := make([]chart.Series, len(series))
+	barCount := 0
+	barIndex := 0
+	for _, item := range series {
+		if item.Type == SeriesBar {
+			barCount++
+		}
+	}
 	for index, item := range series {
 		style := chart.Style{
 			StrokeWidth: lineStrokeWidth,
@@ -58,23 +65,28 @@ func GetSeries(series []Series, theme string) []chart.Series {
 			DotColor:    getSeriesColor(theme, index),
 			DotWidth:    dotWith,
 		}
+		item.Data = append([]float64{
+			0.0,
+		}, item.Data...)
+		baseSeries := BaseSeries{
+			Name:         item.Name,
+			XValues:      item.XValues,
+			Style:        style,
+			YValues:      item.Data,
+			TickPosition: tickPosition,
+		}
 		// TODO 判断类型
 		switch item.Type {
 		case SeriesBar:
 			arr[index] = BarSeries{
-				BaseSeries: BaseSeries{
-					Name:    item.Name,
-					XValues: item.XValues,
-					Style:   style,
-					YValues: item.Data,
-				},
+				Count:      barCount,
+				Index:      barIndex,
+				BaseSeries: baseSeries,
 			}
+			barIndex++
 		default:
-			arr[index] = chart.ContinuousSeries{
-				Name:    item.Name,
-				XValues: item.XValues,
-				Style:   style,
-				YValues: item.Data,
+			arr[index] = LineSeries{
+				BaseSeries: baseSeries,
 			}
 		}
 	}