feat: add bar series render

bar_series.go

@@ -0,0 +1,59 @@
+// MIT License
+
+// Copyright (c) 2021 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 BarSeries struct {
+	BaseSeries
+}
+
+func (bs BarSeries) Render(r chart.Renderer, canvasBox chart.Box, xrange, yrange chart.Range, defaults chart.Style) {
+	if bs.Len() == 0 {
+		return
+	}
+	style := bs.Style.InheritFrom(defaults)
+	style.FillColor = style.StrokeColor
+	if !style.ShouldDrawStroke() {
+		return
+	}
+
+	cb := canvasBox.Bottom
+	cl := canvasBox.Left
+
+	for i := 0; i < bs.Len(); i++ {
+		vx, vy := bs.GetValues(i)
+
+		x := cl + xrange.Translate(vx)
+		y := cb - yrange.Translate(vy)
+
+		chart.Draw.Box(r, chart.Box{
+			Left: x,
+			Top:  y,
+			// TODO 计算宽度
+			Right:  x + 10,
+			Bottom: canvasBox.Bottom - 1,
+		}, style)
+	}
+
+}