refactor: adjust theme of chart

chart.go

@@ -59,7 +59,8 @@ type ChartOption struct {
 	BackgroundColor drawing.Color
 }
 
-func (o *ChartOption) FillDefault(t *Theme) {
+func (o *ChartOption) FillDefault(theme string) {
+	t := NewTheme(theme)
 	f, _ := chart.GetDefaultFont()
 	if o.BackgroundColor.IsZero() {
 		o.BackgroundColor = t.GetBackgroundColor()
@@ -91,6 +92,9 @@ func (o *ChartOption) FillDefault(t *Theme) {
 	if o.Legend.Style.FontColor.IsZero() {
 		o.Legend.Style.FontColor = t.GetTextColor()
 	}
+	if o.XAxis.Theme == "" {
+		o.XAxis.Theme = theme
+	}
 }
 
 func (o *ChartOption) getWidth() int {
@@ -139,3 +143,60 @@ func (r Range) Values() []string {
 	}
 	return values
 }
+
+type basicRenderResult struct {
+	xRange   *Range
+	yRange   *Range
+	d        *Draw
+	titleBox chart.Box
+}
+
+func chartBasicRender(opt *ChartOption) (*basicRenderResult, error) {
+	d, err := NewDraw(
+		DrawOption{
+			Parent: opt.Parent,
+			Width:  opt.getWidth(),
+			Height: opt.getHeight(),
+		},
+		PaddingOption(opt.Padding),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	opt.FillDefault(opt.Theme)
+	if opt.Parent == nil {
+		d.setBackground(opt.getWidth(), opt.getHeight(), opt.BackgroundColor)
+	}
+
+	// 标题
+	titleBox, err := drawTitle(d, &opt.Title)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = NewLegend(d, opt.Legend).Render()
+	if err != nil {
+		return nil, err
+	}
+
+	// xAxis
+	xAxisHeight, xRange, err := drawXAxis(d, &opt.XAxis)
+	if err != nil {
+		return nil, err
+	}
+
+	// 暂时仅支持单一yaxis
+	yRange, err := drawYAxis(d, opt, xAxisHeight, chart.Box{
+		Top: titleBox.Height(),
+	})
+	if err != nil {
+		return nil, err
+	}
+	return &basicRenderResult{
+		xRange:   xRange,
+		yRange:   yRange,
+		d:        d,
+		titleBox: titleBox,
+	}, nil
+}

line_chart.go

@@ -32,60 +32,25 @@ type LineChartOption struct {
 }
 
 func NewLineChart(opt LineChartOption) (*Draw, error) {
-	d, err := NewDraw(
-		DrawOption{
-			Parent: opt.Parent,
-			Width:  opt.getWidth(),
-			Height: opt.getHeight(),
-		},
-		PaddingOption(opt.Padding),
-	)
+	result, err := chartBasicRender(&opt.ChartOption)
 	if err != nil {
 		return nil, err
 	}
 
-	theme := Theme{
-		mode: opt.Theme,
-	}
-	opt.FillDefault(&theme)
-	if opt.Parent == nil {
-		d.setBackground(opt.getWidth(), opt.getHeight(), opt.BackgroundColor)
-	}
-
-	// 标题
-	titleBox, err := drawTitle(d, &opt.Title)
-	if err != nil {
-		return nil, err
-	}
-
-	_, err = NewLegend(d, opt.Legend).Render()
-	if err != nil {
-		return nil, err
-	}
-
-	// xAxis
-	xAxisHeight, xRange, err := drawXAxis(d, &opt.XAxis, &theme)
-	if err != nil {
-		return nil, err
-	}
-
-	// 暂时仅支持单一yaxis
-	yRange, err := drawYAxis(d, &opt.ChartOption, &theme, xAxisHeight, chart.Box{
-		Top: titleBox.Height(),
-	})
-	if err != nil {
-		return nil, err
-	}
+	d := result.d
+	theme := NewTheme(opt.Theme)
 
 	sd, err := NewDraw(DrawOption{
 		Parent: d,
 	}, PaddingOption(chart.Box{
-		Top:  titleBox.Height(),
+		Top:  result.titleBox.Height(),
 		Left: YAxisWidth,
 	}))
 	if err != nil {
 		return nil, err
 	}
+	yRange := result.yRange
+	xRange := result.xRange
 	for i, series := range opt.SeriesList {
 		points := make([]Point, 0)
 		for j, item := range series.Data {

theme.go

@@ -31,6 +31,12 @@ type Theme struct {
 	mode string
 }
 
+func NewTheme(mode string) *Theme {
+	return &Theme{
+		mode: mode,
+	}
+}
+
 func (t *Theme) IsDark() bool {
 	return t.mode == ThemeDark
 }

xaxis.go

@@ -27,11 +27,12 @@ import "github.com/wcharczuk/go-chart/v2"
 type XAxisOption struct {
 	BoundaryGap *bool
 	Data        []string
+	Theme       string
 	// TODO split number
 }
 
 // drawXAxis draws x axis, and returns the height, range of if.
-func drawXAxis(p *Draw, opt *XAxisOption, theme *Theme) (int, *Range, error) {
+func drawXAxis(p *Draw, opt *XAxisOption) (int, *Range, error) {
 	dXAxis, err := NewDraw(
 		DrawOption{
 			Parent: p,
@@ -43,6 +44,7 @@ func drawXAxis(p *Draw, opt *XAxisOption, theme *Theme) (int, *Range, error) {
 	if err != nil {
 		return 0, nil, err
 	}
+	theme := NewTheme(opt.Theme)
 	data := NewAxisDataListFromStringList(opt.Data)
 	style := AxisStyle{
 		BoundaryGap: opt.BoundaryGap,

yaxis.go

@@ -28,7 +28,8 @@ import (
 
 const YAxisWidth = 40
 
-func drawYAxis(p *Draw, opt *ChartOption, theme *Theme, xAxisHeight int, padding chart.Box) (*Range, error) {
+func drawYAxis(p *Draw, opt *ChartOption, xAxisHeight int, padding chart.Box) (*Range, error) {
+	theme := NewTheme(opt.Theme)
 	yRange := opt.getYRange(0)
 	data := NewAxisDataListFromStringList(yRange.Values())
 	style := AxisStyle{