feat: support label for series, #1

label.go

@@ -0,0 +1,77 @@
+// 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/dustin/go-humanize"
+	"github.com/wcharczuk/go-chart/v2"
+)
+
+type LabelRenderer struct {
+	Options SeriesLabel
+	Offset  chart.Box
+}
+type LabelValue struct {
+	Left int
+	Top  int
+	Text string
+}
+
+func (l LabelRenderer) Render(r chart.Renderer, canvasBox chart.Box, xrange, yrange chart.Range, style chart.Style, vs chart.ValuesProvider) {
+	if !l.Options.Show {
+		return
+	}
+	r.SetFontColor(style.FontColor)
+	r.SetFontSize(style.FontSize)
+	r.SetFont(style.Font)
+	offsetX := l.Options.Offset.Left + l.Offset.Left
+	offsetY := l.Options.Offset.Top + l.Offset.Top
+	for i := 0; i < vs.Len(); i++ {
+		vx, vy := vs.GetValues(i)
+		x := canvasBox.Left + xrange.Translate(vx) + offsetX
+		y := canvasBox.Bottom - yrange.Translate(vy) + offsetY
+
+		text := humanize.CommafWithDigits(vy, 2)
+		// 往左移一半距离
+		x -= r.MeasureText(text).Width() >> 1
+		r.Text(text, x, y)
+	}
+}
+
+func (l LabelRenderer) CustomizeRender(r chart.Renderer, style chart.Style, values []LabelValue) {
+	if !l.Options.Show {
+		return
+	}
+	r.SetFont(style.Font)
+	r.SetFontColor(style.FontColor)
+	r.SetFontSize(style.FontSize)
+	offsetX := l.Options.Offset.Left + l.Offset.Left
+	offsetY := l.Options.Offset.Top + l.Offset.Top
+	for _, value := range values {
+		x := value.Left + offsetX
+		y := value.Top + offsetY
+		text := value.Text
+		x -= r.MeasureText(text).Width() >> 1
+		r.Text(text, x, y)
+	}
+}