feat: support line chart render function

line_chart.go

@@ -0,0 +1,134 @@
+// 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"
+)
+
+type lineChart struct {
+	p   *Painter
+	opt *LineChartOption
+}
+
+func NewLineChart(p *Painter, opt LineChartOption) *lineChart {
+	if opt.Theme == nil {
+		opt.Theme = NewTheme("")
+	}
+	return &lineChart{
+		p:   p,
+		opt: &opt,
+	}
+}
+
+type LineChartOption struct {
+	Theme ColorPalette
+	// The data series list
+	SeriesList SeriesList
+	// The x axis option
+	XAxis XAxisOption
+	// The padding of line chart
+	Padding Box
+	// The y axis option
+	YAxis YAxisOption
+}
+
+func (l *lineChart) Render() (Box, error) {
+	p := l.p
+	opt := l.opt
+	p = defaultRender(p, defaultRenderOption{
+		Theme:   opt.Theme,
+		Padding: opt.Padding,
+	})
+
+	seriesList := opt.SeriesList
+	seriesList.init()
+	// 过滤前先计算最大最小值
+	max, min := seriesList.GetMaxMin()
+
+	seriesList = seriesList.Filter(ChartTypeLine)
+
+	// Y轴
+	yr := NewRange(AxisRangeOption{
+		Min: min,
+		Max: max,
+		// 高度需要减去x轴的高度
+		Size:        p.Height() - defaultXAxisHeight,
+		DivideCount: defaultAxisDivideCount,
+	})
+	if opt.YAxis.Theme == nil {
+		opt.YAxis.Theme = opt.Theme
+	}
+	opt.YAxis.Data = yr.Values()
+	reverseStringSlice(opt.YAxis.Data)
+	yAxis := NewLeftYAxis(p, opt.YAxis)
+	yAxisBox, err := yAxis.Render()
+	if err != nil {
+		return chart.BoxZero, err
+	}
+	seriesPainter := p.Child(PainterPaddingOption(Box{
+		Bottom: defaultXAxisHeight,
+		Left:   yAxisBox.Width(),
+	}))
+
+	if opt.XAxis.Theme == nil {
+		opt.XAxis.Theme = opt.Theme
+	}
+	xAxis := NewBottomXAxis(p.Child(PainterPaddingOption(Box{
+		Left: yAxisBox.Width(),
+	})), opt.XAxis)
+
+	xDivideValues := autoDivide(seriesPainter.Width(), len(opt.XAxis.Data))
+	xValues := make([]int, len(xDivideValues)-1)
+	for i := 0; i < len(xDivideValues)-1; i++ {
+		xValues[i] = (xDivideValues[i] + xDivideValues[i+1]) >> 1
+	}
+	for index, series := range seriesList {
+		seriesColor := opt.Theme.GetSeriesColor(index)
+		seriesPainter.SetDrawingStyle(Style{
+			StrokeColor: seriesColor,
+			StrokeWidth: 2,
+			FillColor:   seriesColor,
+		})
+		points := make([]Point, 0)
+		for i, item := range series.Data {
+			h := yr.getRestHeight(item.Value)
+			p := Point{
+				X: xValues[i],
+				Y: h,
+			}
+			points = append(points, p)
+		}
+		seriesPainter.LineStroke(points)
+		seriesPainter.Dots(points)
+	}
+
+	err = doRender(
+		xAxis,
+	)
+	if err != nil {
+		return chart.BoxZero, err
+	}
+
+	return p.box, nil
+}