feat: support mark line and mark point render

mark_line.go

@@ -0,0 +1,118 @@
+// 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/golang/freetype/truetype"
+	"github.com/wcharczuk/go-chart/v2"
+)
+
+func NewMarkLine(markLineTypes ...string) SeriesMarkLine {
+	data := make([]SeriesMarkData, len(markLineTypes))
+	for index, t := range markLineTypes {
+		data[index] = SeriesMarkData{
+			Type: t,
+		}
+	}
+	return SeriesMarkLine{
+		Data: data,
+	}
+}
+
+type markLinePainter struct {
+	p       *Painter
+	options []markLineRenderOption
+}
+
+func (m *markLinePainter) Add(opt markLineRenderOption) {
+	m.options = append(m.options, opt)
+}
+
+func NewMarkLinePainter(p *Painter) *markLinePainter {
+	return &markLinePainter{
+		p:       p,
+		options: make([]markLineRenderOption, 0),
+	}
+}
+
+type markLineRenderOption struct {
+	FillColor   Color
+	FontColor   Color
+	StrokeColor Color
+	Font        *truetype.Font
+	Series      Series
+	Range       axisRange
+}
+
+func (m *markLinePainter) Render() (Box, error) {
+	painter := m.p
+	for _, opt := range m.options {
+		s := opt.Series
+		if len(s.MarkLine.Data) == 0 {
+			continue
+		}
+		summary := s.Summary()
+		for _, markLine := range s.MarkLine.Data {
+			// 由于mark line会修改style，因此每次重新设置
+			painter.OverrideDrawingStyle(Style{
+				FillColor:   opt.FillColor,
+				StrokeColor: opt.StrokeColor,
+				StrokeWidth: 1,
+				StrokeDashArray: []float64{
+					4,
+					2,
+				},
+			}).OverrideTextStyle(Style{
+				Font:      opt.Font,
+				FontColor: opt.FontColor,
+				FontSize:  labelFontSize,
+			})
+			value := float64(0)
+			switch markLine.Type {
+			case SeriesMarkDataTypeMax:
+				value = summary.MaxValue
+			case SeriesMarkDataTypeMin:
+				value = summary.MinValue
+			default:
+				value = summary.AverageValue
+			}
+			y := opt.Range.getRestHeight(value)
+			width := painter.Width()
+			text := commafWithDigits(value)
+			textBox := painter.MeasureText(text)
+			painter.MarkLine(0, y, width-2)
+			painter.Text(text, width, y+textBox.Height()>>1-2)
+		}
+	}
+	return chart.BoxZero, nil
+}
+
+func markLineRender(opt markLineRenderOption) {
+	// d := opt.Draw
+	// s := opt.Series
+	// if len(s.MarkLine.Data) == 0 {
+	// 	return
+	// }
+	// r := d.Render
+
+}