WIP texture drawing

canvas/canvas.go

@@ -79,9 +79,12 @@ type pen struct {
 func (this *pen) Rectangle (bounds image.Rectangle) {
 	bounds = bounds.Canon()
 	if this.weight == 0 {
-		if this.fill.A > 0 {
+		if this.fill.A > 0 && !this.textureObscures() {
 			this.fillRectangle(this.fill, bounds)
 		}
+		if this.texture != nil {
+			this.textureRectangle(bounds)
+		}
 	} else {
 		if this.stroke.A > 0 {
 			this.strokeRectangle(this.stroke, bounds)
@@ -115,6 +118,10 @@ func (this *pen) Stroke  (stroke color.Color)     { this.stroke  = convertColor(
 func (this *pen) Fill    (fill color.Color)       { this.fill    = convertColor(fill)     }
 func (this *pen) Texture (texture canvas.Texture) { this.texture = AssertTexture(texture) }
 
+func (this *pen) textureObscures () bool {
+	return this.texture != nil && this.texture.Opaque()
+}
+
 func convertColor (c color.Color) xgraphics.BGRA {
 	r, g, b, a := c.RGBA()
 	return xgraphics.BGRA {

canvas/draw.go

@@ -4,6 +4,46 @@ import "sort"
 import "image"
 import "github.com/jezek/xgbutil/xgraphics"
 
+func (this *pen) textureRectangle (bounds image.Rectangle) {
+	if this.texture.Opaque() {
+		this.textureRectangleOpaque(bounds)
+	} else {
+		this.textureRectangleTransparent(bounds)
+	}
+}
+
+func (this *pen) textureRectangleOpaque (bounds image.Rectangle) {
+	
+	dstBounds := bounds.Intersect(this.image.Bounds())
+	srcBounds := this.texture.rect
+	
+	offset    := dstBounds.Min.Sub(bounds.Min)
+	
+
+	dstStep := this.image.Stride - bounds.Dx() * 4
+	srcStep := this.texture.stride - srcBounds.Dx() * 4
+}
+
+func (this *pen) textureRectangleTransparent (bounds image.Rectangle) {
+	bounds = bounds.Intersect(this.image.Bounds())
+	var pos image.Point
+
+	for pos.Y = bounds.Min.Y; pos.Y < bounds.Max.Y; pos.Y ++ {
+	for pos.X = bounds.Min.X; pos.X < bounds.Max.X; pos.X ++ {
+		index := this.image.PixOffset(pos.X, pos.Y)
+		pixel := xgraphics.BlendBGRA(xgraphics.BGRA {
+			B: this.image.Pix[index + 0],
+			G: this.image.Pix[index + 1],
+			R: this.image.Pix[index + 2],
+			A: this.image.Pix[index + 3],
+		}, c)
+		this.image.Pix[index + 0] = pixel.B
+		this.image.Pix[index + 1] = pixel.G
+		this.image.Pix[index + 2] = pixel.R
+		this.image.Pix[index + 3] = pixel.A
+	}}
+}
+
 func (this *pen) fillRectangle (c xgraphics.BGRA, bounds image.Rectangle) {
 	if c.A == 255 {
 		this.fillRectangleOpaque(c, bounds)
@@ -227,3 +267,11 @@ func (this *pen) polyLine (c xgraphics.BGRA, points ...image.Point) {
 		prevPoint = point
 	}
 }
+
+func wrap (n, min, max int) int {
+	max -= min
+	n   -= min
+	n   %= max
+	if n < 0 { n += max }
+	return n + min
+}

canvas/texture.go

@@ -17,7 +17,7 @@ func NewTextureFrom (source image.Image) *Texture {
 	bounds := source.Bounds()
 	texture := &Texture {
 		pix:    make([]uint8, bounds.Dx() * bounds.Dy() * 4),
-		stride: bounds.Dx(),
+		stride: bounds.Dx() * 4,
 		rect:   bounds.Sub(bounds.Min),
 	}
 
@@ -59,6 +59,8 @@ func (this *Texture) Clip (bounds image.Rectangle) canvas.Texture {
 	return &clipped
 }
 
+func (this *Texture) pixOffset
+
 // AssertTexture checks if a given canvas.Texture is a texture from this package.
 func AssertTexture (unknown canvas.Texture) *Texture {
 	if tx, ok := unknown.(*Texture); ok {