127 lines
3.2 KiB
Go
127 lines
3.2 KiB
Go
// MIT License
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// Copyright (c) 2022 Tree Xie
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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package charts
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import (
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"github.com/wcharczuk/go-chart/v2"
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)
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type LegendOption struct {
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Theme *Theme
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Style chart.Style
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Data []string
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Left string
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Right string
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Align string
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}
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type legend struct {
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d *Draw
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opt *LegendOption
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}
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func NewLegend(d *Draw, opt LegendOption) *legend {
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return &legend{
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d: d,
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opt: &opt,
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}
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}
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func (l *legend) Render() (chart.Box, error) {
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d := l.d
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opt := l.opt
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if len(opt.Data) == 0 {
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return chart.BoxZero, nil
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}
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theme := opt.Theme
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padding := opt.Style.Padding
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legendDraw, err := NewDraw(DrawOption{
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Parent: d,
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}, PaddingOption(padding))
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if err != nil {
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return chart.BoxZero, err
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}
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r := legendDraw.Render
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opt.Style.GetTextOptions().WriteToRenderer(r)
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x := 0
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y := 0
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legendWidth := 30
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legendDotHeight := 5
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textPadding := 5
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legendMargin := 10
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widthCount := 0
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// 文本宽度
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for _, text := range opt.Data {
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b := r.MeasureText(text)
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widthCount += b.Width()
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}
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// 加上标记
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widthCount += legendWidth * len(opt.Data)
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// 文本的padding
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widthCount += 2 * textPadding * len(opt.Data)
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// margin的宽度
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widthCount += legendMargin * (len(opt.Data) - 1)
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// TODO 支持更多的定位方式
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// 居中
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x = (legendDraw.Box.Width() - widthCount) >> 1
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for index, text := range opt.Data {
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if index != 0 {
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x += legendMargin
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}
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style := chart.Style{
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StrokeColor: theme.GetSeriesColor(index),
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FillColor: theme.GetSeriesColor(index),
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StrokeWidth: 3,
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}
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textBox := r.MeasureText(text)
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renderText := func() {
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x += textPadding
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legendDraw.text(text, x, y+legendDotHeight-2)
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x += textBox.Width()
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x += textPadding
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}
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if opt.Align == PositionRight {
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renderText()
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}
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style.GetFillAndStrokeOptions().WriteDrawingOptionsToRenderer(r)
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legendDraw.moveTo(x, y)
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legendDraw.lineTo(x+legendWidth, y)
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r.Stroke()
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legendDraw.circle(float64(legendDotHeight), x+legendWidth>>1, y)
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r.FillStroke()
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x += legendWidth
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if opt.Align != PositionRight {
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renderText()
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}
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}
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legendBox := padding.Clone()
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legendBox.Right = legendBox.Left + x
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legendBox.Bottom = legendBox.Top + 2*legendDotHeight
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return legendBox, nil
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}
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