feat: support line chart draw function

line.go

@@ -0,0 +1,105 @@
+// MIT License
+
+// Copyright (c) 2022 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"
+	"github.com/wcharczuk/go-chart/v2/drawing"
+)
+
+type LineStyle struct {
+	ClassName       string
+	StrokeDashArray []float64
+	StrokeColor     drawing.Color
+	StrokeWidth     float64
+	FillColor       drawing.Color
+	DotWidth        float64
+	DotColor        drawing.Color
+	DotFillColor    drawing.Color
+}
+
+func (ls *LineStyle) Style() chart.Style {
+	return chart.Style{
+		ClassName:       ls.ClassName,
+		StrokeDashArray: ls.StrokeDashArray,
+		StrokeColor:     ls.StrokeColor,
+		StrokeWidth:     ls.StrokeWidth,
+		FillColor:       ls.FillColor,
+		DotWidth:        ls.DotWidth,
+		DotColor:        ls.DotColor,
+	}
+}
+
+func (d *Draw) lineFill(points []Point, style LineStyle) {
+	s := style.Style()
+	if !(s.ShouldDrawStroke() && s.ShouldDrawFill()) {
+		return
+	}
+	r := d.Render
+	var x, y int
+	s.GetFillOptions().WriteDrawingOptionsToRenderer(r)
+	for index, point := range points {
+		x = point.X
+		y = point.Y
+		if index == 0 {
+			d.moveTo(x, y)
+		} else {
+			d.lineTo(x, y)
+		}
+	}
+	height := d.Box.Height()
+	d.lineTo(x, height)
+	x0 := points[0].X
+	y0 := points[0].Y
+	d.lineTo(x0, height)
+	d.lineTo(x0, y0)
+	r.Fill()
+}
+
+func (d *Draw) lineDot(points []Point, style LineStyle) {
+	s := style.Style()
+	if !s.ShouldDrawDot() {
+		return
+	}
+	r := d.Render
+	dotWith := s.GetDotWidth()
+
+	s.GetDotOptions().WriteDrawingOptionsToRenderer(r)
+	for _, point := range points {
+		if !style.DotFillColor.IsZero() {
+			r.SetFillColor(style.DotFillColor)
+		}
+		r.SetStrokeColor(s.DotColor)
+		d.circle(dotWith, point.X, point.Y)
+		r.FillStroke()
+	}
+}
+
+func (d *Draw) Line(points []Point, style LineStyle) {
+	if len(points) == 0 {
+		return
+	}
+	d.lineFill(points, style)
+	d.lineStroke(points, style)
+	d.lineDot(points, style)
+}