- add draw (android, gopher)

- resolve some point on matrix transformation

draw2d/src/pkg/draw2d/dasher.go

@@ -0,0 +1,72 @@
+package draw2d
+
+import(
+	"freetype-go.googlecode.com/hg/freetype/raster"	
+)
+
+type DashAdder struct {
+	adder          raster.Adder
+	x, y, distance float
+	dash           []float
+	currentDash    int
+	dashOffset     float
+}
+
+func traceDashPath(dash []float, dashOffset float, approximationScale float, adder raster.Adder, paths ...*Path) {
+	var dasher DashAdder
+	if dash != nil && len(dash) > 0 {
+		dasher.dash = dash
+	} else {
+		dasher.dash = nil
+	}
+	dasher.currentDash = 0
+	dasher.dashOffset = dashOffset
+	dasher.adder = adder
+	for _, path := range paths {
+		path.TraceLine(&dasher, approximationScale)
+	}
+}
+
+func (dasher *DashAdder) MoveTo(x, y float) {
+	dasher.adder.Start(floatToPoint(x, y))
+	dasher.x, dasher.y = x, y
+	dasher.distance = dasher.dashOffset
+	dasher.currentDash = 0
+}
+
+func (dasher *DashAdder) LineTo(x, y float) {
+	rest := dasher.dash[dasher.currentDash] - dasher.distance
+	for rest < 0 {
+		dasher.distance = dasher.distance - dasher.dash[dasher.currentDash]
+		dasher.currentDash = (dasher.currentDash + 1) % len(dasher.dash)
+		rest = dasher.dash[dasher.currentDash] - dasher.distance
+	}
+	d := distance(dasher.x, dasher.y, x, y)
+	for d >= rest {
+		k := rest / d
+		lx := dasher.x + k*(x-dasher.x)
+		ly := dasher.y + k*(y-dasher.y)
+		if dasher.currentDash%2 == 0 {
+			// line
+			dasher.adder.Add1(floatToPoint(lx, ly))
+		} else {
+			// gap
+			dasher.adder.Start(floatToPoint(lx, ly))
+		}
+		d = d - rest
+		dasher.x, dasher.y = lx, ly
+		dasher.currentDash = (dasher.currentDash + 1) % len(dasher.dash)
+		rest = dasher.dash[dasher.currentDash]
+	}
+	dasher.distance = d
+	if dasher.currentDash%2 == 0 {
+		dasher.adder.Add1(floatToPoint(x, y))
+	} else {
+		dasher.adder.Start(floatToPoint(x, y))
+	}
+	if dasher.distance >= dasher.dash[dasher.currentDash] {
+		dasher.distance = dasher.distance - dasher.dash[dasher.currentDash]
+		dasher.currentDash = (dasher.currentDash + 1) % len(dasher.dash)
+	}
+	dasher.x, dasher.y = x, y
+}

draw2d/src/pkg/draw2d/path_adder.go

@@ -0,0 +1,31 @@
+package draw2d
+
+
+import(
+	"freetype-go.googlecode.com/hg/freetype/raster"	
+)
+
+
+type PathAdder struct {
+	adder raster.Adder
+}
+
+
+func floatToPoint(x, y float) raster.Point {
+	return raster.Point{raster.Fix32(x * 256), raster.Fix32(y * 256)}
+}
+
+func tracePath(approximationScale float, adder raster.Adder, paths ...*Path) {
+	pathAdder := &PathAdder{adder}
+	for _, path := range paths {
+		path.TraceLine(pathAdder, approximationScale)
+	}
+}
+
+func (pathAdder *PathAdder) MoveTo(x, y float) {
+	pathAdder.adder.Start(floatToPoint(x, y))
+}
+
+func (pathAdder *PathAdder) LineTo(x, y float) {
+	pathAdder.adder.Add1(floatToPoint(x, y))
+}