made stroke and fill style code more generic

canvas.go

@@ -35,18 +35,11 @@ type pathPoint struct {
 
 type drawState struct {
 	transform lm.Mat3x3
-	fill      struct {
+	fill      drawStyle
-		color          glColor
+	stroke    drawStyle
-		radialGradient *RadialGradient
-		linearGradient *LinearGradient
-		image          *Image
-	}
-	stroke struct {
-		color     glColor
-		lineWidth float32
-	}
 	font      *Font
 	fontSize  float32
+	lineWidth float32
 	lineJoin  lineJoin
 	lineEnd   lineEnd
 
@@ -66,6 +59,13 @@ type drawState struct {
 	*/
 }
 
+type drawStyle struct {
+	color          glColor
+	radialGradient *RadialGradient
+	linearGradient *LinearGradient
+	image          *Image
+}
+
 type lineJoin uint8
 type lineEnd uint8
 
@@ -88,7 +88,7 @@ func New(x, y, w, h int) *Canvas {
 		fw: float32(w), fh: float32(h),
 		stateStack: make([]drawState, 0, 20),
 	}
-	cv.state.stroke.lineWidth = 1
+	cv.state.lineWidth = 1
 	cv.state.transform = lm.Mat3x3Identity()
 	return cv
 }
@@ -325,33 +325,40 @@ func glError() error {
 	return nil
 }
 
-// SetFillStyle sets the color or gradient for any fill calls
+// SetFillStyle sets the color, gradient, or image for any fill calls
 func (cv *Canvas) SetFillStyle(value ...interface{}) {
-	cv.state.fill.color = glColor{}
+	cv.state.fill = parseStyle(value...)
-	cv.state.fill.linearGradient = nil
+}
-	cv.state.fill.radialGradient = nil
+
-	cv.state.fill.image = nil
+// SetStrokeStyle sets the color, gradient, or image for any line drawing calls
+func (cv *Canvas) SetStrokeStyle(value ...interface{}) {
+	cv.state.stroke = parseStyle(value...)
+}
+
+func parseStyle(value ...interface{}) drawStyle {
+	var style drawStyle
 	if len(value) == 1 {
 		switch v := value[0].(type) {
 		case *LinearGradient:
-			cv.state.fill.linearGradient = v
+			style.linearGradient = v
-			return
+			return style
 		case *RadialGradient:
-			cv.state.fill.radialGradient = v
+			style.radialGradient = v
-			return
+			return style
 		case *Image:
-			cv.state.fill.image = v
+			style.image = v
-			return
+			return style
 		}
 	}
 	c, ok := parseColor(value...)
 	if ok {
-		cv.state.fill.color = c
+		style.color = c
 	}
+	return style
 }
 
-func (cv *Canvas) useFillShader() (vertexLoc uint32) {
+func (cv *Canvas) useShader(style *drawStyle) (vertexLoc uint32) {
-	if lg := cv.state.fill.linearGradient; lg != nil {
+	if lg := style.linearGradient; lg != nil {
 		lg.load()
 		gli.ActiveTexture(gl_TEXTURE0)
 		gli.BindTexture(gl_TEXTURE_1D, lg.tex)
@@ -368,7 +375,7 @@ func (cv *Canvas) useFillShader() (vertexLoc uint32) {
 		gli.Uniform1i(lgr.gradient, 0)
 		return lgr.vertex
 	}
-	if rg := cv.state.fill.radialGradient; rg != nil {
+	if rg := style.radialGradient; rg != nil {
 		rg.load()
 		gli.ActiveTexture(gl_TEXTURE0)
 		gli.BindTexture(gl_TEXTURE_1D, rg.tex)
@@ -388,7 +395,7 @@ func (cv *Canvas) useFillShader() (vertexLoc uint32) {
 		gli.Uniform1i(rgr.gradient, 0)
 		return rgr.vertex
 	}
-	if img := cv.state.fill.image; img != nil {
+	if img := style.image; img != nil {
 		gli.UseProgram(ipr.id)
 		gli.ActiveTexture(gl_TEXTURE0)
 		gli.BindTexture(gl_TEXTURE_2D, img.tex)
@@ -405,17 +412,9 @@ func (cv *Canvas) useFillShader() (vertexLoc uint32) {
 	return sr.vertex
 }
 
-// SetStrokeColor sets the color for any line drawing calls
-func (cv *Canvas) SetStrokeColor(value ...interface{}) {
-	c, ok := parseColor(value...)
-	if ok {
-		cv.state.stroke.color = c
-	}
-}
-
 // SetLineWidth sets the line width for any line drawing calls
 func (cv *Canvas) SetLineWidth(width float32) {
-	cv.state.stroke.lineWidth = width
+	cv.state.lineWidth = width
 }
 
 // SetFont sets the font and font size
@@ -507,7 +506,7 @@ func (cv *Canvas) FillRect(x, y, w, h float32) {
 	data := [8]float32{p0[0], p0[1], p1[0], p1[1], p2[0], p2[1], p3[0], p3[1]}
 	gli.BufferData(gl_ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl_STREAM_DRAW)
 
-	vertex := cv.useFillShader()
+	vertex := cv.useShader(&cv.state.fill)
 	gli.VertexAttribPointer(vertex, 2, gl_FLOAT, false, 0, nil)
 	gli.EnableVertexAttribArray(vertex)
 	gli.DrawArrays(gl_TRIANGLE_FAN, 0, 4)

paths.go

@@ -181,8 +181,8 @@ func (cv *Canvas) Stroke() {
 		p1 := p.tf
 
 		v0 := p1.Sub(p0).Norm()
-		v1 := lm.Vec2{v0[1], -v0[0]}.MulF(cv.state.stroke.lineWidth * 0.5)
+		v1 := lm.Vec2{v0[1], -v0[0]}.MulF(cv.state.lineWidth * 0.5)
-		v0 = v0.MulF(cv.state.stroke.lineWidth * 0.5)
+		v0 = v0.MulF(cv.state.lineWidth * 0.5)
 
 		lp0 := p0.Add(v1)
 		lp1 := p1.Add(v1)
@@ -197,7 +197,7 @@ func (cv *Canvas) Stroke() {
 				lp0 = lp0.Sub(v0)
 				lp2 = lp2.Sub(v0)
 			case Round:
-				tris = cv.addCircleTris(p0, cv.state.stroke.lineWidth*0.5, tris)
+				tris = cv.addCircleTris(p0, cv.state.lineWidth*0.5, tris)
 			}
 		}
 
@@ -209,7 +209,7 @@ func (cv *Canvas) Stroke() {
 				lp1 = lp1.Add(v0)
 				lp3 = lp3.Add(v0)
 			case Round:
-				tris = cv.addCircleTris(p1, cv.state.stroke.lineWidth*0.5, tris)
+				tris = cv.addCircleTris(p1, cv.state.lineWidth*0.5, tris)
 			}
 		}
 
@@ -257,7 +257,7 @@ func (cv *Canvas) Stroke() {
 
 func (cv *Canvas) lineJoint(p pathPoint, p0, p1, p2, l0p0, l0p1, l0p2, l0p3 lm.Vec2, tris []float32) []float32 {
 	v2 := p1.Sub(p2).Norm()
-	v3 := lm.Vec2{v2[1], -v2[0]}.MulF(cv.state.stroke.lineWidth * 0.5)
+	v3 := lm.Vec2{v2[1], -v2[0]}.MulF(cv.state.lineWidth * 0.5)
 
 	switch cv.state.lineJoin {
 	case Miter:
@@ -282,7 +282,7 @@ func (cv *Canvas) lineJoint(p pathPoint, p0, p1, p2, l0p0, l0p1, l0p2, l0p3 lm.V
 			p1[0], p1[1], l0p1[0], l0p1[1], l1p1[0], l1p1[1],
 			p1[0], p1[1], l1p3[0], l1p3[1], l0p3[0], l0p3[1])
 	case Round:
-		tris = cv.addCircleTris(p1, cv.state.stroke.lineWidth*0.5, tris)
+		tris = cv.addCircleTris(p1, cv.state.lineWidth*0.5, tris)
 	}
 
 	return tris