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Diffstat (limited to 'vendor/github.com/llgcode/draw2d/draw2dbase/stroker.go')
-rw-r--r--vendor/github.com/llgcode/draw2d/draw2dbase/stroker.go90
1 files changed, 90 insertions, 0 deletions
diff --git a/vendor/github.com/llgcode/draw2d/draw2dbase/stroker.go b/vendor/github.com/llgcode/draw2d/draw2dbase/stroker.go
new file mode 100644
index 0000000..640b228
--- /dev/null
+++ b/vendor/github.com/llgcode/draw2d/draw2dbase/stroker.go
@@ -0,0 +1,90 @@
+// Copyright 2010 The draw2d Authors. All rights reserved.
+// created: 13/12/2010 by Laurent Le Goff
+
+package draw2dbase
+
+import (
+ "math"
+
+ "github.com/llgcode/draw2d"
+)
+
+type LineStroker struct {
+ Flattener Flattener
+ HalfLineWidth float64
+ Cap draw2d.LineCap
+ Join draw2d.LineJoin
+ vertices []float64
+ rewind []float64
+ x, y, nx, ny float64
+}
+
+func NewLineStroker(c draw2d.LineCap, j draw2d.LineJoin, flattener Flattener) *LineStroker {
+ l := new(LineStroker)
+ l.Flattener = flattener
+ l.HalfLineWidth = 0.5
+ l.Cap = c
+ l.Join = j
+ return l
+}
+
+func (l *LineStroker) MoveTo(x, y float64) {
+ l.x, l.y = x, y
+}
+
+func (l *LineStroker) LineTo(x, y float64) {
+ l.line(l.x, l.y, x, y)
+}
+
+func (l *LineStroker) LineJoin() {
+
+}
+
+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) Close() {
+ if len(l.vertices) > 1 {
+ l.appendVertex(l.vertices[0], l.vertices[1], l.rewind[0], l.rewind[1])
+ }
+}
+
+func (l *LineStroker) End() {
+ if len(l.vertices) > 1 {
+ l.Flattener.MoveTo(l.vertices[0], l.vertices[1])
+ for i, j := 2, 3; j < len(l.vertices); i, j = i+2, j+2 {
+ l.Flattener.LineTo(l.vertices[i], l.vertices[j])
+ }
+ }
+ for i, j := len(l.rewind)-2, len(l.rewind)-1; j > 0; i, j = i-2, j-2 {
+ l.Flattener.LineTo(l.rewind[i], l.rewind[j])
+ }
+ if len(l.vertices) > 1 {
+ l.Flattener.LineTo(l.vertices[0], l.vertices[1])
+ }
+ l.Flattener.End()
+ // 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) appendVertex(vertices ...float64) {
+ s := len(vertices) / 2
+ l.vertices = append(l.vertices, vertices[:s]...)
+ l.rewind = append(l.rewind, vertices[s:]...)
+}
+
+func vectorDistance(dx, dy float64) float64 {
+ return float64(math.Sqrt(dx*dx + dy*dy))
+}