diff options
Diffstat (limited to 'Godeps/_workspace/src/code.google.com/p/draw2d/draw2d/stroker.go')
-rw-r--r-- | Godeps/_workspace/src/code.google.com/p/draw2d/draw2d/stroker.go | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/code.google.com/p/draw2d/draw2d/stroker.go b/Godeps/_workspace/src/code.google.com/p/draw2d/draw2d/stroker.go new file mode 100644 index 000000000..9331187f6 --- /dev/null +++ b/Godeps/_workspace/src/code.google.com/p/draw2d/draw2d/stroker.go @@ -0,0 +1,135 @@ +// Copyright 2010 The draw2d Authors. All rights reserved. +// created: 13/12/2010 by Laurent Le Goff + +package draw2d + +type Cap int + +const ( + RoundCap Cap = iota + ButtCap + SquareCap +) + +type Join int + +const ( + BevelJoin Join = iota + RoundJoin + MiterJoin +) + +type LineStroker struct { + Next VertexConverter + HalfLineWidth float64 + Cap Cap + Join Join + vertices []float64 + rewind []float64 + x, y, nx, ny float64 + command VertexCommand +} + +func NewLineStroker(c Cap, j Join, converter VertexConverter) *LineStroker { + l := new(LineStroker) + l.Next = converter + l.HalfLineWidth = 0.5 + l.vertices = make([]float64, 0, 256) + l.rewind = make([]float64, 0, 256) + l.Cap = c + l.Join = j + l.command = VertexNoCommand + return l +} + +func (l *LineStroker) NextCommand(command VertexCommand) { + l.command = command + if command == VertexStopCommand { + l.Next.NextCommand(VertexStartCommand) + for i, j := 0, 1; j < len(l.vertices); i, j = i+2, j+2 { + l.Next.Vertex(l.vertices[i], l.vertices[j]) + l.Next.NextCommand(VertexNoCommand) + } + for i, j := len(l.rewind)-2, len(l.rewind)-1; j > 0; i, j = i-2, j-2 { + l.Next.NextCommand(VertexNoCommand) + l.Next.Vertex(l.rewind[i], l.rewind[j]) + } + if len(l.vertices) > 1 { + l.Next.NextCommand(VertexNoCommand) + l.Next.Vertex(l.vertices[0], l.vertices[1]) + } + l.Next.NextCommand(VertexStopCommand) + // reinit vertices + l.vertices = l.vertices[0:0] + l.rewind = l.rewind[0:0] + l.x, l.y, l.nx, l.ny = 0, 0, 0, 0 + } +} + +func (l *LineStroker) Vertex(x, y float64) { + switch l.command { + case VertexNoCommand: + l.line(l.x, l.y, x, y) + case VertexJoinCommand: + l.joinLine(l.x, l.y, l.nx, l.ny, x, y) + case VertexStartCommand: + l.x, l.y = x, y + case VertexCloseCommand: + l.line(l.x, l.y, x, y) + l.joinLine(l.x, l.y, l.nx, l.ny, x, y) + l.closePolygon() + } + l.command = VertexNoCommand +} + +func (l *LineStroker) appendVertex(vertices ...float64) { + s := len(vertices) / 2 + if len(l.vertices)+s >= cap(l.vertices) { + v := make([]float64, len(l.vertices), cap(l.vertices)+128) + copy(v, l.vertices) + l.vertices = v + v = make([]float64, len(l.rewind), cap(l.rewind)+128) + copy(v, l.rewind) + l.rewind = v + } + + copy(l.vertices[len(l.vertices):len(l.vertices)+s], vertices[:s]) + l.vertices = l.vertices[0 : len(l.vertices)+s] + copy(l.rewind[len(l.rewind):len(l.rewind)+s], vertices[s:]) + l.rewind = l.rewind[0 : len(l.rewind)+s] + +} + +func (l *LineStroker) closePolygon() { + if len(l.vertices) > 1 { + l.appendVertex(l.vertices[0], l.vertices[1], l.rewind[0], l.rewind[1]) + } +} + +func (l *LineStroker) line(x1, y1, x2, y2 float64) { + dx := (x2 - x1) + dy := (y2 - y1) + d := vectorDistance(dx, dy) + if d != 0 { + nx := dy * l.HalfLineWidth / d + ny := -(dx * l.HalfLineWidth / d) + l.appendVertex(x1+nx, y1+ny, x2+nx, y2+ny, x1-nx, y1-ny, x2-nx, y2-ny) + l.x, l.y, l.nx, l.ny = x2, y2, nx, ny + } +} + +func (l *LineStroker) joinLine(x1, y1, nx1, ny1, x2, y2 float64) { + dx := (x2 - x1) + dy := (y2 - y1) + d := vectorDistance(dx, dy) + + if d != 0 { + nx := dy * l.HalfLineWidth / d + ny := -(dx * l.HalfLineWidth / d) + /* l.join(x1, y1, x1 + nx, y1 - ny, nx, ny, x1 + ny2, y1 + nx2, nx2, ny2) + l.join(x1, y1, x1 - ny1, y1 - nx1, nx1, ny1, x1 - ny2, y1 - nx2, nx2, ny2)*/ + + l.appendVertex(x1+nx, y1+ny, x2+nx, y2+ny, x1-nx, y1-ny, x2-nx, y2-ny) + l.x, l.y, l.nx, l.ny = x2, y2, nx, ny + } +} |