slight tweak to legend (adds a new style) and example
This commit is contained in:
Will Charczuk
parent
00799114fa
commit
1edf6193b2
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@ -0,0 +1,111 @@
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package main
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import (
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"net/http"
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"github.com/wcharczuk/go-chart"
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)
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func drawChart(res http.ResponseWriter, req *http.Request) {
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/*
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In this example we add a `Renderable` or a custom component to the `Elements` array.
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In this specific case it is a pre-built renderable (`CreateLegend`) that draws a legend for the chart's series.
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If you like, you can use `CreateLegend` as a template for writing your own renderable, or even your own legend.
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*/
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graph := chart.Chart{
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XAxis: chart.XAxis{
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Style: chart.Style{Show: true},
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},
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YAxis: chart.YAxis{
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Style: chart.Style{Show: true},
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},
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Background: chart.Style{
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Padding: chart.Box{
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Top: 20,
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Left: 260,
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},
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},
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Series: []chart.Series{
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chart.ContinuousSeries{
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Name: "A test series",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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},
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chart.ContinuousSeries{
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Name: "Another test series",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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},
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chart.ContinuousSeries{
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Name: "Yet Another test series",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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},
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chart.ContinuousSeries{
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Name: "Even More series",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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},
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chart.ContinuousSeries{
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Name: "Foo Bar",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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},
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chart.ContinuousSeries{
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Name: "Bar Baz",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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},
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chart.ContinuousSeries{
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Name: "Free Yourself",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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},
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chart.ContinuousSeries{
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Name: "Wheres Ja?",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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},
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chart.ContinuousSeries{
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Name: "Fast and the Furious",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{5.0, 4.0, 3.0, 2.0, 1.0},
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},
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chart.ContinuousSeries{
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Name: "2 Fast 2 Furious",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{5.0, 4.0, 3.0, 2.0, 1.0},
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},
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chart.ContinuousSeries{
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Name: "They only get more fast and more furious",
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XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
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YValues: []float64{5.0, 4.0, 3.0, 2.0, 1.0},
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},
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},
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}
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//note we have to do this as a separate step because we need a reference to graph
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graph.Elements = []chart.Renderable{
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chart.LegendLeft(&graph),
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}
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res.Header().Set("Content-Type", "image/png")
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graph.Render(chart.PNG, res)
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}
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func main() {
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http.HandleFunc("/", drawChart)
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http.ListenAndServe(":8080", nil)
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}
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114
legend.go
114
legend.go
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@ -213,3 +213,117 @@ func LegendThin(c *Chart, userDefaults ...Style) Renderable {
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}
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}
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}
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// LegendLeft is a legend that is designed for longer series lists.
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func LegendLeft(c *Chart, userDefaults ...Style) Renderable {
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return func(r Renderer, cb Box, chartDefaults Style) {
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legendDefaults := Style{
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FillColor: drawing.ColorWhite,
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FontColor: DefaultTextColor,
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FontSize: 8.0,
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StrokeColor: DefaultAxisColor,
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StrokeWidth: DefaultAxisLineWidth,
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}
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var legendStyle Style
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if len(userDefaults) > 0 {
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legendStyle = userDefaults[0].InheritFrom(chartDefaults.InheritFrom(legendDefaults))
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} else {
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legendStyle = chartDefaults.InheritFrom(legendDefaults)
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}
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// DEFAULTS
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legendPadding := Box{
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Top: 5,
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Left: 5,
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Right: 5,
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Bottom: 5,
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}
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lineTextGap := 5
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lineLengthMinimum := 25
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var labels []string
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var lines []Style
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for index, s := range c.Series {
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if s.GetStyle().IsZero() || s.GetStyle().Show {
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if _, isAnnotationSeries := s.(AnnotationSeries); !isAnnotationSeries {
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labels = append(labels, s.GetName())
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lines = append(lines, s.GetStyle().InheritFrom(c.styleDefaultsSeries(index)))
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}
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}
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}
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legend := Box{
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Top: 5,
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Left: 5,
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// bottom and right will be sized by the legend content + relevant padding.
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}
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legendContent := Box{
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Top: legend.Top + legendPadding.Top,
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Left: legend.Left + legendPadding.Left,
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Right: legend.Left + legendPadding.Left,
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Bottom: legend.Top + legendPadding.Top,
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}
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legendStyle.GetTextOptions().WriteToRenderer(r)
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// measure
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labelCount := 0
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for x := 0; x < len(labels); x++ {
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if len(labels[x]) > 0 {
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tb := r.MeasureText(labels[x])
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if labelCount > 0 {
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legendContent.Bottom += DefaultMinimumTickVerticalSpacing
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}
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legendContent.Bottom += tb.Height()
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right := legendContent.Left + tb.Width() + lineTextGap + lineLengthMinimum
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legendContent.Right = Math.MaxInt(legendContent.Right, right)
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labelCount++
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}
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}
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legend = legend.Grow(legendContent)
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legend.Right = legendContent.Right + legendPadding.Right
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legend.Bottom = legendContent.Bottom + legendPadding.Bottom
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Draw.Box(r, legend, legendStyle)
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legendStyle.GetTextOptions().WriteToRenderer(r)
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ycursor := legendContent.Top
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tx := legendContent.Left
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legendCount := 0
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var label string
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for x := 0; x < len(labels); x++ {
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label = labels[x]
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if len(label) > 0 {
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if legendCount > 0 {
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ycursor += DefaultMinimumTickVerticalSpacing
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}
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tb := r.MeasureText(label)
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ty := ycursor + tb.Height()
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r.Text(label, tx, ty)
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th2 := tb.Height() >> 1
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lx := tx + tb.Width() + lineTextGap
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ly := ty - th2
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lx2 := legendContent.Right - legendPadding.Right
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r.SetStrokeColor(lines[x].GetStrokeColor())
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r.SetStrokeWidth(lines[x].GetStrokeWidth())
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r.SetStrokeDashArray(lines[x].GetStrokeDashArray())
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r.MoveTo(lx, ly)
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r.LineTo(lx2, ly)
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r.Stroke()
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ycursor += tb.Height()
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legendCount++
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}
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}
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}
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}
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