128 lines
3.0 KiB
Go
128 lines
3.0 KiB
Go
// Copyright 2010 The draw2d Authors. All rights reserved.
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// created: 06/12/2010 by Laurent Le Goff
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package draw2dbase
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import (
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"github.com/llgcode/draw2d"
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)
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// Liner receive segment definition
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type Liner interface {
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// LineTo Draw a line from the current position to the point (x, y)
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LineTo(x, y float64)
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}
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// Flattener receive segment definition
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type Flattener interface {
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// MoveTo Start a New line from the point (x, y)
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MoveTo(x, y float64)
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// LineTo Draw a line from the current position to the point (x, y)
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LineTo(x, y float64)
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// LineJoin add the most recent starting point to close the path to create a polygon
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LineJoin()
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// Close add the most recent starting point to close the path to create a polygon
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Close()
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// End mark the current line as finished so we can draw caps
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End()
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}
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// Flatten convert curves into straight segments keeping join segments info
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func Flatten(path *draw2d.Path, flattener Flattener, scale float64) {
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// First Point
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var startX, startY float64 = 0, 0
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// Current Point
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var x, y float64 = 0, 0
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i := 0
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for _, cmp := range path.Components {
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switch cmp {
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case draw2d.MoveToCmp:
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x, y = path.Points[i], path.Points[i+1]
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startX, startY = x, y
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if i != 0 {
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flattener.End()
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}
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flattener.MoveTo(x, y)
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i += 2
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case draw2d.LineToCmp:
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x, y = path.Points[i], path.Points[i+1]
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flattener.LineTo(x, y)
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flattener.LineJoin()
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i += 2
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case draw2d.QuadCurveToCmp:
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TraceQuad(flattener, path.Points[i-2:], 0.5)
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x, y = path.Points[i+2], path.Points[i+3]
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flattener.LineTo(x, y)
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i += 4
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case draw2d.CubicCurveToCmp:
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TraceCubic(flattener, path.Points[i-2:], 0.5)
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x, y = path.Points[i+4], path.Points[i+5]
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flattener.LineTo(x, y)
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i += 6
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case draw2d.ArcToCmp:
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x, y = TraceArc(flattener, path.Points[i], path.Points[i+1], path.Points[i+2], path.Points[i+3], path.Points[i+4], path.Points[i+5], scale)
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flattener.LineTo(x, y)
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i += 6
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case draw2d.CloseCmp:
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flattener.LineTo(startX, startY)
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flattener.Close()
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}
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}
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flattener.End()
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}
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// Transformer apply the Matrix transformation tr
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type Transformer struct {
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Tr draw2d.Matrix
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Flattener Flattener
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}
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func (t Transformer) MoveTo(x, y float64) {
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u := x*t.Tr[0] + y*t.Tr[2] + t.Tr[4]
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v := x*t.Tr[1] + y*t.Tr[3] + t.Tr[5]
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t.Flattener.MoveTo(u, v)
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}
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func (t Transformer) LineTo(x, y float64) {
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u := x*t.Tr[0] + y*t.Tr[2] + t.Tr[4]
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v := x*t.Tr[1] + y*t.Tr[3] + t.Tr[5]
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t.Flattener.LineTo(u, v)
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}
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func (t Transformer) LineJoin() {
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t.Flattener.LineJoin()
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}
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func (t Transformer) Close() {
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t.Flattener.Close()
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}
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func (t Transformer) End() {
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t.Flattener.End()
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}
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type SegmentedPath struct {
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Points []float64
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}
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func (p *SegmentedPath) MoveTo(x, y float64) {
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p.Points = append(p.Points, x, y)
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// TODO need to mark this point as moveto
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}
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func (p *SegmentedPath) LineTo(x, y float64) {
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p.Points = append(p.Points, x, y)
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}
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func (p *SegmentedPath) LineJoin() {
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// TODO need to mark the current point as linejoin
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}
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func (p *SegmentedPath) Close() {
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// TODO Close
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}
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func (p *SegmentedPath) End() {
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// Nothing to do
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}
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