refactor: auto count the split number for x axis

axis.go

@@ -23,15 +23,18 @@
 package charts
 
 import (
+	"math"
+
 	"github.com/golang/freetype/truetype"
 	"github.com/wcharczuk/go-chart/v2"
 	"github.com/wcharczuk/go-chart/v2/drawing"
 )
 
-type AxisStyle struct {
+type AxisOption struct {
 	BoundaryGap    *bool
 	Show           *bool
 	Position       string
+	SplitNumber    int
 	ClassName      string
 	StrokeColor    drawing.Color
 	StrokeWidth    float64
@@ -48,10 +51,10 @@ type AxisStyle struct {
 type axis struct {
 	d     *Draw
 	data  *AxisDataList
-	style *AxisStyle
+	style *AxisOption
 }
 
-func NewAxis(d *Draw, data AxisDataList, style AxisStyle) *axis {
+func NewAxis(d *Draw, data AxisDataList, style AxisOption) *axis {
 	return &axis{
 		d:     d,
 		data:  &data,
@@ -60,15 +63,15 @@ func NewAxis(d *Draw, data AxisDataList, style AxisStyle) *axis {
 
 }
 
-func (as *AxisStyle) GetLabelMargin() int {
+func (as *AxisOption) GetLabelMargin() int {
 	return getDefaultInt(as.LabelMargin, 8)
 }
 
-func (as *AxisStyle) GetTickLength() int {
+func (as *AxisOption) GetTickLength() int {
 	return getDefaultInt(as.TickLength, 5)
 }
 
-func (as *AxisStyle) Style(f *truetype.Font) chart.Style {
+func (as *AxisOption) Style(f *truetype.Font) chart.Style {
 	s := chart.Style{
 		ClassName:   as.ClassName,
 		StrokeColor: as.StrokeColor,
@@ -99,10 +102,12 @@ func (l AxisDataList) TextList() []string {
 	return textList
 }
 
-type axisOption struct {
+type axisRenderOption struct {
 	textMaxWith   int
 	textMaxHeight int
 	boundaryGap   bool
+	unitCount     int
+	modValue      int
 }
 
 func NewAxisDataListFromStringList(textList []string) AxisDataList {
@@ -115,7 +120,7 @@ func NewAxisDataListFromStringList(textList []string) AxisDataList {
 	return list
 }
 
-func (a *axis) axisLabel(opt *axisOption) {
+func (a *axis) axisLabel(opt *axisRenderOption) {
 	style := a.style
 	data := *a.data
 	d := a.d
@@ -131,11 +136,14 @@ func (a *axis) axisLabel(opt *axisOption) {
 	height := d.Box.Height()
 	textList := data.TextList()
 	count := len(textList)
+
 	boundaryGap := opt.boundaryGap
 	if !boundaryGap {
 		count--
 	}
 
+	unitCount := opt.unitCount
+	modValue := opt.modValue
 	labelMargin := style.GetLabelMargin()
 
 	// 轴线
@@ -176,6 +184,9 @@ func (a *axis) axisLabel(opt *axisOption) {
 		}
 		values := autoDivide(width, count)
 		for index, text := range data.TextList() {
+			if unitCount != 0 && index%unitCount != modValue {
+				continue
+			}
 			x := values[index]
 			leftOffset := 0
 			b := r.MeasureText(text)
@@ -191,7 +202,7 @@ func (a *axis) axisLabel(opt *axisOption) {
 	}
 }
 
-func (a *axis) axisLine(opt *axisOption) {
+func (a *axis) axisLine(opt *axisRenderOption) {
 	d := a.d
 	r := d.Render
 	style := a.style
@@ -239,7 +250,7 @@ func (a *axis) axisLine(opt *axisOption) {
 	r.FillStroke()
 }
 
-func (a *axis) axisTick(opt *axisOption) {
+func (a *axis) axisTick(opt *axisRenderOption) {
 	d := a.d
 	r := d.Render
 
@@ -259,6 +270,7 @@ func (a *axis) axisTick(opt *axisOption) {
 	if isFalse(style.TickShow) {
 		tickShow = false
 	}
+	unitCount := opt.unitCount
 
 	tickLengthValue := style.GetTickLength()
 	labelHeight := labelMargin + opt.textMaxHeight
@@ -308,7 +320,10 @@ func (a *axis) axisTick(opt *axisOption) {
 			y0 = labelHeight
 		}
 		if tickShow {
-			for _, v := range values {
+			for index, v := range values {
+				if index%unitCount != 0 {
+					continue
+				}
 				x := v
 				y := y0
 				d.moveTo(x, y-tickLengthValue)
@@ -326,7 +341,10 @@ func (a *axis) axisTick(opt *axisOption) {
 				splitLineHeight = height - labelHeight
 			}
 
-			for _, v := range values {
+			for index, v := range values {
+				if index%unitCount != 0 {
+					continue
+				}
 				x := v
 				y := y0
 
@@ -368,7 +386,7 @@ func (a *axis) Render() {
 		return
 	}
 	textMaxWidth, textMaxHeight := a.axisMeasureTextMaxWidthHeight()
-	opt := &axisOption{
+	opt := &axisRenderOption{
 		textMaxWith:   textMaxWidth,
 		textMaxHeight: textMaxHeight,
 		boundaryGap:   true,
@@ -377,6 +395,38 @@ func (a *axis) Render() {
 		opt.boundaryGap = false
 	}
 
+	unitCount := chart.MaxInt(style.SplitNumber, 1)
+	width := a.d.Box.Width()
+	textList := a.data.TextList()
+	count := len(textList)
+
+	position := style.Position
+	switch position {
+	case PositionLeft:
+		fallthrough
+	case PositionRight:
+	default:
+		maxCount := width / (opt.textMaxWith + 10)
+		// 可以显示所有
+		if maxCount >= count {
+			unitCount = 1
+		} else if maxCount < count/unitCount {
+			unitCount = int(math.Ceil(float64(count) / float64(maxCount)))
+		}
+	}
+
+	boundaryGap := opt.boundaryGap
+	modValue := 0
+	if boundaryGap && unitCount > 1 {
+		// 如果是居中，unit count需要设置为奇数
+		if unitCount%2 == 0 {
+			unitCount++
+		}
+		modValue = unitCount / 2
+	}
+	opt.modValue = modValue
+	opt.unitCount = unitCount
+
 	// 坐标轴线
 	a.axisLine(opt)
 	a.axisTick(opt)

axis_test.go

@@ -31,10 +31,10 @@ import (
 	"github.com/wcharczuk/go-chart/v2/drawing"
 )
 
-func TestAxisStyle(t *testing.T) {
+func TestAxisOption(t *testing.T) {
 	assert := assert.New(t)
 
-	as := AxisStyle{}
+	as := AxisOption{}
 
 	assert.Equal(8, as.GetLabelMargin())
 	as.LabelMargin = 10
@@ -64,7 +64,7 @@ func TestAxisDataList(t *testing.T) {
 func TestAxis(t *testing.T) {
 	assert := assert.New(t)
 
-	data := NewAxisDataListFromStringList([]string{
+	axisData := NewAxisDataListFromStringList([]string{
 		"Mon",
 		"Tue",
 		"Wed",
@@ -73,8 +73,8 @@ func TestAxis(t *testing.T) {
 		"Sat",
 		"Sun",
 	})
-	getDefaultStyle := func() AxisStyle {
+	getDefaultOption := func() AxisOption {
-		return AxisStyle{
+		return AxisOption{
 			StrokeColor:    drawing.ColorBlack,
 			StrokeWidth:    1,
 			FontColor:      drawing.ColorBlack,
@@ -85,14 +85,15 @@ func TestAxis(t *testing.T) {
 		}
 	}
 	tests := []struct {
-		newStyle func() AxisStyle
+		newOption func() AxisOption
-		result   string
+		newData   func() AxisDataList
+		result    string
 	}{
 		// 文本按起始位置展示
 		// axis位于bottom
 		{
-			newStyle: func() AxisStyle {
+			newOption: func() AxisOption {
-				opt := getDefaultStyle()
+				opt := getDefaultOption()
 				opt.BoundaryGap = FalseFlag()
 				return opt
 			},
@@ -101,8 +102,8 @@ func TestAxis(t *testing.T) {
 		// 文本居中展示
 		// axis位于bottom
 		{
-			newStyle: func() AxisStyle {
+			newOption: func() AxisOption {
-				opt := getDefaultStyle()
+				opt := getDefaultOption()
 				return opt
 			},
 			result: "<svg xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\" width=\"400\" height=\"300\">\\n<path  d=\"M 5 270\nL 395 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 5 270\nL 5 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 61 270\nL 61 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 117 270\nL 117 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 173 270\nL 173 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 229 270\nL 229 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 285 270\nL 285 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 340 270\nL 340 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 395 270\nL 395 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 5 5\nL 5 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 61 5\nL 61 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 117 5\nL 117 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 173 5\nL 173 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 229 5\nL 229 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 285 5\nL 285 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 340 5\nL 340 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 395 5\nL 395 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><text x=\"20\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Mon</text><text x=\"78\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Tue</text><text x=\"132\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Wed</text><text x=\"190\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Thu</text><text x=\"249\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Fri</text><text x=\"303\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Sat</text><text x=\"356\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Sun</text></svg>",
@@ -110,8 +111,8 @@ func TestAxis(t *testing.T) {
 		// 文本按起始位置展示
 		// axis位于top
 		{
-			newStyle: func() AxisStyle {
+			newOption: func() AxisOption {
-				opt := getDefaultStyle()
+				opt := getDefaultOption()
 				opt.Position = PositionTop
 				opt.BoundaryGap = FalseFlag()
 				return opt
@@ -121,8 +122,8 @@ func TestAxis(t *testing.T) {
 		// 文本居中展示
 		// axis位于top
 		{
-			newStyle: func() AxisStyle {
+			newOption: func() AxisOption {
-				opt := getDefaultStyle()
+				opt := getDefaultOption()
 				opt.Position = PositionTop
 				return opt
 			},
@@ -131,8 +132,8 @@ func TestAxis(t *testing.T) {
 		// 文本按起始位置展示
 		// axis位于left
 		{
-			newStyle: func() AxisStyle {
+			newOption: func() AxisOption {
-				opt := getDefaultStyle()
+				opt := getDefaultOption()
 				opt.Position = PositionLeft
 				opt.BoundaryGap = FalseFlag()
 				return opt
@@ -142,8 +143,8 @@ func TestAxis(t *testing.T) {
 		// 文本居中展示
 		// axis位于left
 		{
-			newStyle: func() AxisStyle {
+			newOption: func() AxisOption {
-				opt := getDefaultStyle()
+				opt := getDefaultOption()
 				opt.Position = PositionLeft
 				return opt
 			},
@@ -152,8 +153,8 @@ func TestAxis(t *testing.T) {
 		// 文本按起始位置展示
 		// axis位于right
 		{
-			newStyle: func() AxisStyle {
+			newOption: func() AxisOption {
-				opt := getDefaultStyle()
+				opt := getDefaultOption()
 				opt.Position = PositionRight
 				opt.BoundaryGap = FalseFlag()
 				return opt
@@ -163,13 +164,47 @@ func TestAxis(t *testing.T) {
 		// 文本居中展示
 		// axis位于right
 		{
-			newStyle: func() AxisStyle {
+			newOption: func() AxisOption {
-				opt := getDefaultStyle()
+				opt := getDefaultOption()
 				opt.Position = PositionRight
 				return opt
 			},
 			result: "<svg xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\" width=\"400\" height=\"300\">\\n<path  d=\"M 361 5\nL 361 295\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 361 5\nL 366 5\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 361 47\nL 366 47\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 361 89\nL 366 89\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 361 131\nL 366 131\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 361 172\nL 366 172\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 361 213\nL 366 213\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 361 254\nL 366 254\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 361 295\nL 366 295\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 5 5\nL 360 5\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 5 47\nL 360 47\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 5 89\nL 360 89\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 5 131\nL 360 131\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 5 172\nL 360 172\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 5 213\nL 360 213\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 5 254\nL 360 254\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><text x=\"369\" y=\"280\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Mon</text><text x=\"369\" y=\"239\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Tue</text><text x=\"369\" y=\"198\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Wed</text><text x=\"369\" y=\"157\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Thu</text><text x=\"369\" y=\"115\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Fri</text><text x=\"369\" y=\"73\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Sat</text><text x=\"369\" y=\"31\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">Sun</text></svg>",
 		},
+		// text较多，仅展示部分
+		{
+			newOption: func() AxisOption {
+				opt := getDefaultOption()
+				opt.Position = PositionBottom
+				return opt
+			},
+			newData: func() AxisDataList {
+				return NewAxisDataListFromStringList([]string{
+					"01-01",
+					"01-02",
+					"01-03",
+					"01-04",
+					"01-05",
+					"01-06",
+					"01-07",
+					"01-08",
+					"01-09",
+					"01-10",
+					"01-11",
+					"01-12",
+					"01-13",
+					"01-14",
+					"01-15",
+					"01-16",
+					"01-17",
+					"01-18",
+					"01-19",
+					"01-20",
+					"01-21",
+				})
+			},
+			result: "<svg xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\" width=\"400\" height=\"300\">\\n<path  d=\"M 5 270\nL 395 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 5 270\nL 5 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 62 270\nL 62 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 119 270\nL 119 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 176 270\nL 176 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 233 270\nL 233 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 287 270\nL 287 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 341 270\nL 341 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 395 270\nL 395 275\" style=\"stroke-width:1;stroke:rgba(0,0,0,1.0);fill:none\"/><path  d=\"M 5 5\nL 5 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 62 5\nL 62 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 119 5\nL 119 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 176 5\nL 176 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 233 5\nL 233 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 287 5\nL 287 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 341 5\nL 341 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><path  d=\"M 395 5\nL 395 270\" style=\"stroke-width:1;stroke:rgba(0,0,0,0.2);fill:none\"/><text x=\"16\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">01-02</text><text x=\"73\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">01-05</text><text x=\"130\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">01-08</text><text x=\"187\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">01-11</text><text x=\"243\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">01-14</text><text x=\"297\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">01-17</text><text x=\"351\" y=\"287\" style=\"stroke-width:0;stroke:none;fill:rgba(0,0,0,1.0);font-size:12.8px;font-family:'Roboto Medium',sans-serif\">01-20</text></svg>",
+		},
 	}
 	for _, tt := range tests {
 		d, err := NewDraw(DrawOption{
@@ -182,7 +217,11 @@ func TestAxis(t *testing.T) {
 			Bottom: 5,
 		}))
 		assert.Nil(err)
-		style := tt.newStyle()
+		style := tt.newOption()
+		data := axisData
+		if tt.newData != nil {
+			data = tt.newData()
+		}
 		NewAxis(d, data, style).Render()
 
 		result, err := d.Bytes()
@@ -204,14 +243,14 @@ func TestMeasureAxis(t *testing.T) {
 		"Sun",
 	})
 	f, _ := chart.GetDefaultFont()
-	width := NewAxis(d, data, AxisStyle{
+	width := NewAxis(d, data, AxisOption{
 		FontSize: 12,
 		Font:     f,
 		Position: PositionLeft,
 	}).measureAxis()
 	assert.Equal(44, width)
 
-	height := NewAxis(d, data, AxisStyle{
+	height := NewAxis(d, data, AxisOption{
 		FontSize: 12,
 		Font:     f,
 		Position: PositionTop,

util.go

@@ -62,15 +62,6 @@ func autoDivide(max, size int) []int {
 	values[size] = max
 	return values
 }
-func maxInt(values ...int) int {
-	result := 0
-	for _, v := range values {
-		if v > result {
-			result = v
-		}
-	}
-	return result
-}
 
 // measureTextMaxWidthHeight returns maxWidth and maxHeight of text list
 func measureTextMaxWidthHeight(textList []string, r chart.Renderer) (int, int) {
@@ -78,8 +69,8 @@ func measureTextMaxWidthHeight(textList []string, r chart.Renderer) (int, int) {
 	maxHeight := 0
 	for _, text := range textList {
 		box := r.MeasureText(text)
-		maxWidth = maxInt(maxWidth, box.Width())
+		maxWidth = chart.MaxInt(maxWidth, box.Width())
-		maxHeight = maxInt(maxHeight, box.Height())
+		maxHeight = chart.MaxInt(maxHeight, box.Height())
 	}
 	return maxWidth, maxHeight
 }

util_test.go

@@ -51,12 +51,6 @@ func TestAutoDivide(t *testing.T) {
 	}, autoDivide(600, 7))
 }
 
-func TestMaxInt(t *testing.T) {
-	assert := assert.New(t)
-
-	assert.Equal(5, maxInt(1, 3, 5, 2))
-}
-
 func TestMeasureTextMaxWidthHeight(t *testing.T) {
 	assert := assert.New(t)
 	r, err := chart.SVG(400, 300)

xaxis.go

@@ -29,6 +29,7 @@ type XAxisOption struct {
 	Data        []string
 	Theme       string
 	Hidden      bool
+	SplitNumber int
 	// TODO split number
 }
 
@@ -47,11 +48,12 @@ func drawXAxis(p *Draw, opt *XAxisOption) (int, *Range, error) {
 	}
 	theme := NewTheme(opt.Theme)
 	data := NewAxisDataListFromStringList(opt.Data)
-	style := AxisStyle{
+	style := AxisOption{
 		BoundaryGap: opt.BoundaryGap,
 		StrokeColor: theme.GetAxisStrokeColor(),
 		FontColor:   theme.GetAxisStrokeColor(),
 		StrokeWidth: 1,
+		SplitNumber: opt.SplitNumber,
 	}
 
 	boundary := true

yaxis.go

@@ -38,7 +38,7 @@ func drawYAxis(p *Draw, opt *ChartOption, xAxisHeight int, padding chart.Box) (*
 	theme := NewTheme(opt.Theme)
 	yRange := opt.getYRange(0)
 	data := NewAxisDataListFromStringList(yRange.Values())
-	style := AxisStyle{
+	style := AxisOption{
 		Position:       PositionLeft,
 		BoundaryGap:    FalseFlag(),
 		FontColor:      theme.GetAxisStrokeColor(),