feat: support line chart render function

charts.go

@@ -25,3 +25,26 @@ package charts
 type Renderer interface {
 	Render() (Box, error)
 }
+
+type defaultRenderOption struct {
+	Theme   ColorPalette
+	Padding Box
+}
+
+func defaultRender(p *Painter, opt defaultRenderOption) *Painter {
+	p.SetBackground(p.Width(), p.Height(), opt.Theme.GetBackgroundColor())
+	if !opt.Padding.IsZero() {
+		p = p.Child(PainterPaddingOption(opt.Padding))
+	}
+	return p
+}
+
+func doRender(renderers ...Renderer) error {
+	for _, r := range renderers {
+		_, err := r.Render()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}