92 lines
2.1 KiB
Go
92 lines
2.1 KiB
Go
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// Copyright 2015 The draw2d Authors. All rights reserved.
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// created: 16/12/2017 by Drahoslav Bednářpackage draw2dsvg
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package draw2dsvg
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import (
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"fmt"
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"github.com/llgcode/draw2d"
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"image/color"
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"math"
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"strings"
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)
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func toSvgRGBA(c color.Color) string {
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r, g, b, a := c.RGBA()
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return fmt.Sprintf("rgba(%v, %v, %v, %.3f)", r>>8, g>>8, b>>8, float64(a>>8)/255)
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}
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func toSvgLength(l float64) string {
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return fmt.Sprintf("%.4f", l)
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}
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func toSvgArray(nums []float64) string {
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arr := make([]string, len(nums))
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for i, num := range nums {
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arr[i] = fmt.Sprintf("%.4f", num)
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}
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return strings.Join(arr, ",")
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}
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func toSvgPathDesc(p *draw2d.Path) string {
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parts := make([]string, len(p.Components))
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ps := p.Points
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for i, cmp := range p.Components {
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switch cmp {
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case draw2d.MoveToCmp:
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parts[i] = fmt.Sprintf("M %.4f,%.4f", ps[0], ps[1])
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ps = ps[2:]
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case draw2d.LineToCmp:
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parts[i] = fmt.Sprintf("L %.4f,%.4f", ps[0], ps[1])
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ps = ps[2:]
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case draw2d.QuadCurveToCmp:
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parts[i] = fmt.Sprintf("Q %.4f,%.4f %.4f,%.4f", ps[0], ps[1], ps[2], ps[3])
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ps = ps[4:]
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case draw2d.CubicCurveToCmp:
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parts[i] = fmt.Sprintf("C %.4f,%.4f %.4f,%.4f %.4f,%.4f", ps[0], ps[1], ps[2], ps[3], ps[4], ps[5])
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ps = ps[6:]
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case draw2d.ArcToCmp:
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cx, cy := ps[0], ps[1] // center
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rx, ry := ps[2], ps[3] // radii
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fi := ps[4] + ps[5] // startAngle + angle
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// compute endpoint
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sinfi, cosfi := math.Sincos(fi)
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nom := math.Hypot(ry*cosfi, rx*sinfi)
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x := cx + (rx*ry*cosfi)/nom
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y := cy + (rx*ry*sinfi)/nom
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// compute large and sweep flags
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large := 0
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sweep := 0
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if math.Abs(ps[5]) > math.Pi {
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large = 1
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}
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if !math.Signbit(ps[5]) {
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sweep = 1
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}
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// dirty hack to ensure whole arc is drawn
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// if start point equals end point
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if sweep == 1 {
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x += 0.001 * sinfi
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y += 0.001 * -cosfi
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} else {
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x += 0.001 * sinfi
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y += 0.001 * cosfi
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}
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// rx ry x-axis-rotation large-arc-flag sweep-flag x y
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parts[i] = fmt.Sprintf("A %.4f %.4f %v %v %v %.4f %.4f",
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rx, ry,
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0,
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large, sweep,
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x, y,
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)
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ps = ps[6:]
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case draw2d.CloseCmp:
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parts[i] = "Z"
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}
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}
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return strings.Join(parts, " ")
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}
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