automated snapshot

internal/graphics/graphics.go

@@ -31,15 +31,35 @@ type Style struct {
 	Stroke, Fill bool
 }
 
+func BeginDrawing() {
+	rl.BeginDrawing()
+}
+
+func EndDrawing() {
+	rl.EndDrawing()
+}
+
 func (g *Graphics) Center() Point {
 	return g.Bounds.Center()
 }
 
 func (g *Graphics) Begin() {
-	rl.BeginBlendMode(rl.BlendAlphaPremultiply)
 	g.PushMatrix()
-	g.Translate(g.Bounds.UL())
 	g.BeginClip(g.Bounds)
+	g.Translate(g.Bounds.UL())
+}
+
+func (g *Graphics) BeginPremultiplyBlend() {
+	rl.BeginBlendMode(rl.BlendAlphaPremultiply)
+}
+
+func (g *Graphics) EndPremultiplyBlend() {
+	rl.EndBlendMode()
+}
+
+func (g *Graphics) End() {
+	g.PopMatrix()
+	g.EndClip()
 }
 
 func (g *Graphics) Clear() {
@@ -50,12 +70,6 @@ func (g *Graphics) Background(c color.RGBA) {
 	rl.ClearBackground(c)
 }
 
-func (g *Graphics) End() {
-	g.EndBlend()
-	g.EndClip()
-	g.PopMatrix()
-}
-
 func (g *Graphics) Width() float32 {
 	return g.Bounds.Width
 }
@@ -133,13 +147,14 @@ func (g *Graphics) BeginTexture(t rl.RenderTexture2D) {
 	rl.BeginTextureMode(t)
 }
 
-
 func (g *Graphics) DrawTexture(t rl.Texture2D, p Point, c color.RGBA) {
 	rl.DrawTexture(t, int32(p.X), int32(p.Y), c)
 }
 
-
 func (g *Graphics) TransferTexture(t rl.Texture2D, src Rect, dst Rect, tint color.RGBA) {
+	// flip source since textures are upside down on GPU
+	//src.Y += src.Height
+	src.Height = -src.Height
 	rl.DrawTexturePro(t, src.ToRL(), dst.ToRL(), rl.Vector2{}, 0, tint)
 }
 
@@ -185,7 +200,16 @@ type Rect rl.Rectangle
 func (r *Rect) Center() Point {
 	return Point {
 		X: r.X + r.Width / 2,
-		Y: r.X + r.Height / 2,
+		Y: r.Y + r.Height / 2,
+	}
+}
+
+func (r *Rect) ContractByAbs(px float32) Rect {
+	return Rect {
+		X: r.X + px,
+		Y: r.Y + px,
+		Width: r.Width - 2*px,
+		Height: r.Height - 2*px,
 	}
 }