feat: support title render function

yaxis.go

@@ -0,0 +1,62 @@
+// 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"
+)
+
+const YAxisWidth = 40
+
+func drawYAxis(d *Draw, opt *ChartOption, theme *Theme, xAxisHeight int, padding chart.Box) (*Range, error) {
+	yRange := opt.getYRange(0)
+	data := NewAxisDataListFromStringList(yRange.Values())
+	style := AxisStyle{
+		Position:       PositionLeft,
+		BoundaryGap:    FalseFlag(),
+		FontColor:      theme.GetAxisStrokeColor(),
+		TickShow:       FalseFlag(),
+		StrokeWidth:    1,
+		SplitLineColor: theme.GetAxisSplitLineColor(),
+		SplitLineShow:  true,
+	}
+	width := d.measureAxis(data, style)
+
+	padding.Left += (YAxisWidth - width)
+
+	dYAxis, err := NewDraw(
+		DrawOption{
+			Parent: d,
+			Width:  d.Box.Width(),
+			// 减去x轴的高
+			Height: d.Box.Height() - xAxisHeight,
+		},
+		PaddingOption(padding),
+	)
+	if err != nil {
+		return nil, err
+	}
+	dYAxis.Axis(data, style)
+	yRange.Size = dYAxis.Box.Height()
+	return &yRange, nil
+}