internal/graphicsdriver: replace Region with image.Rectangle (#2791)

Closes #2790

image.go

@@ -176,17 +176,6 @@ func (i *Image) adjustedBounds() image.Rectangle {
 	return image.Rect(x, y, x+b.Dx(), y+b.Dy())
 }
 
-func (i *Image) adjustedRegion() graphicsdriver.Region {
-	b := i.Bounds()
-	x, y := i.adjustPosition(b.Min.X, b.Min.Y)
-	return graphicsdriver.Region{
-		X:      float32(x),
-		Y:      float32(y),
-		Width:  float32(b.Dx()),
-		Height: float32(b.Dy()),
-	}
-}
-
 // DrawImage draws the given image on the image i.
 //
 // DrawImage accepts the options. For details, see the document of
@@ -272,7 +261,7 @@ func (i *Image) DrawImage(img *Image, options *DrawImageOptions) {
 		})
 	}
 
-	i.image.DrawTriangles(srcs, vs, is, blend, i.adjustedRegion(), [graphics.ShaderImageCount]graphicsdriver.Region{img.adjustedRegion()}, shader.shader, i.tmpUniforms, false, canSkipMipmap(geoM, filter), false)
+	i.image.DrawTriangles(srcs, vs, is, blend, i.adjustedBounds(), [graphics.ShaderImageCount]image.Rectangle{img.adjustedBounds()}, shader.shader, i.tmpUniforms, false, canSkipMipmap(geoM, filter), false)
 }
 
 // Vertex represents a vertex passed to DrawTriangles.
@@ -517,7 +506,7 @@ func (i *Image) DrawTriangles(vertices []Vertex, indices []uint16, img *Image, o
 		})
 	}
 
-	i.image.DrawTriangles(srcs, vs, is, blend, i.adjustedRegion(), [graphics.ShaderImageCount]graphicsdriver.Region{img.adjustedRegion()}, shader.shader, i.tmpUniforms, options.FillRule == EvenOdd, filter != builtinshader.FilterLinear, options.AntiAlias)
+	i.image.DrawTriangles(srcs, vs, is, blend, i.adjustedBounds(), [graphics.ShaderImageCount]image.Rectangle{img.adjustedBounds()}, shader.shader, i.tmpUniforms, options.FillRule == EvenOdd, filter != builtinshader.FilterLinear, options.AntiAlias)
 }
 
 // DrawTrianglesShaderOptions represents options for DrawTrianglesShader.
@@ -667,18 +656,18 @@ func (i *Image) DrawTrianglesShader(vertices []Vertex, indices []uint16, shader
 		imgs[i] = img.image
 	}
 
-	var srcRegions [graphics.ShaderImageCount]graphicsdriver.Region
+	var srcRegions [graphics.ShaderImageCount]image.Rectangle
 	for i, img := range options.Images {
 		if img == nil {
 			continue
 		}
-		srcRegions[i] = img.adjustedRegion()
+		srcRegions[i] = img.adjustedBounds()
 	}
 
 	i.tmpUniforms = i.tmpUniforms[:0]
 	i.tmpUniforms = shader.appendUniforms(i.tmpUniforms, options.Uniforms)
 
-	i.image.DrawTriangles(imgs, vs, is, blend, i.adjustedRegion(), srcRegions, shader.shader, i.tmpUniforms, options.FillRule == EvenOdd, true, options.AntiAlias)
+	i.image.DrawTriangles(imgs, vs, is, blend, i.adjustedBounds(), srcRegions, shader.shader, i.tmpUniforms, options.FillRule == EvenOdd, true, options.AntiAlias)
 }
 
 // DrawRectShaderOptions represents options for DrawRectShader.
@@ -773,20 +762,17 @@ func (i *Image) DrawRectShader(width, height int, shader *Shader, options *DrawR
 		imgs[i] = img.image
 	}
 
-	var srcRegions [graphics.ShaderImageCount]graphicsdriver.Region
+	var srcRegions [graphics.ShaderImageCount]image.Rectangle
 	for i, img := range options.Images {
 		if img == nil {
 			if shader.unit == shaderir.Pixels && i == 0 {
 				// Give the source size as pixels only when the unit is pixels so that users can get the source size via imageSrc0Size (#2166).
 				// With the texel mode, the imageSrc0Origin and imageSrc0Size values should be in texels so the source position in pixels would not match.
-				srcRegions[i] = graphicsdriver.Region{
-					Width:  float32(width),
-					Height: float32(height),
-				}
+				srcRegions[i] = image.Rect(0, 0, width, height)
 			}
 			continue
 		}
-		srcRegions[i] = img.adjustedRegion()
+		srcRegions[i] = img.adjustedBounds()
 	}
 
 	geoM := options.GeoM
@@ -797,14 +783,17 @@ func (i *Image) DrawRectShader(width, height int, shader *Shader, options *DrawR
 	cr, cg, cb, ca := options.ColorScale.elements()
 	vs := i.ensureTmpVertices(4 * graphics.VertexFloatCount)
 
-	// Do not use srcRegions[0].Width and srcRegions[0].Height as these might be empty.
-	graphics.QuadVertices(vs, srcRegions[0].X, srcRegions[0].Y, srcRegions[0].X+float32(width), srcRegions[0].Y+float32(height), a, b, c, d, tx, ty, cr, cg, cb, ca)
+	// Do not use srcRegions[0].Dx() and srcRegions[0].Dy() as these might be empty.
+	graphics.QuadVertices(vs,
+		float32(srcRegions[0].Min.X), float32(srcRegions[0].Min.Y),
+		float32(srcRegions[0].Min.X+width), float32(srcRegions[0].Min.Y+height),
+		a, b, c, d, tx, ty, cr, cg, cb, ca)
 	is := graphics.QuadIndices()
 
 	i.tmpUniforms = i.tmpUniforms[:0]
 	i.tmpUniforms = shader.appendUniforms(i.tmpUniforms, options.Uniforms)
 
-	i.image.DrawTriangles(imgs, vs, is, blend, i.adjustedRegion(), srcRegions, shader.shader, i.tmpUniforms, false, true, false)
+	i.image.DrawTriangles(imgs, vs, is, blend, i.adjustedBounds(), srcRegions, shader.shader, i.tmpUniforms, false, true, false)
 }
 
 // SubImage returns an image representing the portion of the image p visible through r.

internal/atlas/image.go

@@ -275,14 +275,9 @@ func (i *Image) ensureIsolatedFromSource(backends []*backend) {
 	vs := make([]float32, 4*graphics.VertexFloatCount)
 	graphics.QuadVertices(vs, 0, 0, w, h, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
+	dr := image.Rect(0, 0, i.width, i.height)
 
-	newI.drawTriangles([graphics.ShaderImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, NearestFilterShader, nil, false, true)
+	newI.drawTriangles([graphics.ShaderImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, NearestFilterShader, nil, false, true)
 	newI.moveTo(i)
 }
 
@@ -311,13 +306,8 @@ func (i *Image) putOnSourceBackend(graphicsDriver graphicsdriver.Graphics) {
 	vs := make([]float32, 4*graphics.VertexFloatCount)
 	graphics.QuadVertices(vs, 0, 0, w, h, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	newI.drawTriangles([graphics.ShaderImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, NearestFilterShader, nil, false, true)
+	dr := image.Rect(0, 0, i.width, i.height)
+	newI.drawTriangles([graphics.ShaderImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, NearestFilterShader, nil, false, true)
 
 	newI.moveTo(i)
 	i.usedAsSourceCount = 0
@@ -349,13 +339,13 @@ func (i *Image) regionWithPadding() image.Rectangle {
 //	5: Color G
 //	6: Color B
 //	7: Color Y
-func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool) {
+func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool) {
 	backendsM.Lock()
 	defer backendsM.Unlock()
 	i.drawTriangles(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, evenOdd, false)
 }
 
-func (i *Image) drawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool, keepOnAtlas bool) {
+func (i *Image) drawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool, keepOnAtlas bool) {
 	if i.disposed {
 		panic("atlas: the drawing target image must not be disposed (DrawTriangles)")
 	}
@@ -388,11 +378,10 @@ func (i *Image) drawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices [
 	}
 
 	r := i.regionWithPadding()
-	dx, dy := float32(r.Min.X), float32(r.Min.Y)
 	// TODO: Check if dstRegion does not to violate the region.
+	dstRegion = dstRegion.Add(r.Min)
 
-	dstRegion.X += dx
-	dstRegion.Y += dy
+	dx, dy := float32(r.Min.X), float32(r.Min.Y)
 
 	var oxf, oyf float32
 	if srcs[0] != nil {
@@ -428,13 +417,12 @@ func (i *Image) drawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices [
 
 		// A source region can be deliberately empty when this is not needed in order to avoid unexpected
 		// performance issue (#1293).
-		if srcRegions[i].Width == 0 || srcRegions[i].Height == 0 {
+		if srcRegions[i].Empty() {
 			continue
 		}
 
 		r := src.regionWithPadding()
-		srcRegions[i].X += float32(r.Min.X)
-		srcRegions[i].Y += float32(r.Min.Y)
+		srcRegions[i] = srcRegions[i].Add(r.Min)
 	}
 
 	var imgs [graphics.ShaderImageCount]*restorable.Image

internal/atlas/image_test.go

@@ -102,26 +102,16 @@ func TestEnsureIsolatedFromSourceBackend(t *testing.T) {
 	// img4.ensureIsolatedFromSource() should be called.
 	vs := quadVertices(size/2, size/2, size/4, size/4, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  size,
-		Height: size,
-	}
-	img4.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, size, size)
+	img4.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 	if got, want := img4.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
 
 	// img5 is not allocated now, but is allocated at DrawTriangles.
 	vs = quadVertices(0, 0, size/2, size/2, 1)
-	dr = graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  size / 2,
-		Height: size / 2,
-	}
-	img3.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img5}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	dr = image.Rect(0, 0, size/2, size/2)
+	img3.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img5}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 	if got, want := img3.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -151,7 +141,7 @@ func TestEnsureIsolatedFromSourceBackend(t *testing.T) {
 	// Check further drawing doesn't cause panic.
 	// This bug was fixed by 03dcd948.
 	vs = quadVertices(0, 0, size/2, size/2, 1)
-	img4.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	img4.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 }
 
 func TestReputOnSourceBackend(t *testing.T) {
@@ -191,16 +181,11 @@ func TestReputOnSourceBackend(t *testing.T) {
 
 	// Use img1 as a render target.
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  size,
-		Height: size,
-	}
+	dr := image.Rect(0, 0, size, size)
 	// Render onto img1. The count should not matter.
 	for i := 0; i < 5; i++ {
 		vs := quadVertices(size, size, 0, 0, 1)
-		img1.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		img1.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -212,7 +197,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	for i := 0; i < atlas.BaseCountToPutOnSourceBackend*2; i++ {
 		atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 		vs := quadVertices(size, size, 0, 0, 1)
-		img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -220,7 +205,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	// Finally, img1 is on a source backend.
 	atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 	vs := quadVertices(size, size, 0, 0, 1)
-	img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 	if got, want := img1.IsOnSourceBackendForTesting(), true; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -245,7 +230,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	}
 
 	vs = quadVertices(size, size, 0, 0, 1)
-	img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 	if got, want := img1.IsOnSourceBackendForTesting(), true; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -271,7 +256,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	// Use img1 as a render target again. The count should not matter.
 	for i := 0; i < 5; i++ {
 		vs := quadVertices(size, size, 0, 0, 1)
-		img1.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		img1.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -283,7 +268,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 		atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 		img1.WritePixels(make([]byte, 4*size*size), image.Rect(0, 0, size, size))
 		vs := quadVertices(size, size, 0, 0, 1)
-		img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -292,7 +277,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 
 	// img1 is not on an atlas due to WritePixels.
 	vs = quadVertices(size, size, 0, 0, 1)
-	img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 	if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -301,7 +286,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	for i := 0; i < atlas.BaseCountToPutOnSourceBackend*2; i++ {
 		atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 		vs := quadVertices(size, size, 0, 0, 1)
-		img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		img0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		if got, want := img3.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -395,13 +380,8 @@ func TestWritePixelsAfterDrawTriangles(t *testing.T) {
 
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 	dst.WritePixels(pix, image.Rect(0, 0, w, h))
 
 	pix = make([]byte, 4*w*h)
@@ -443,13 +423,8 @@ func TestSmallImages(t *testing.T) {
 
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 
 	pix = make([]byte, 4*w*h)
 	if err := dst.ReadPixels(ui.GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
@@ -491,13 +466,8 @@ func TestLongImages(t *testing.T) {
 	const scale = 120
 	vs := quadVertices(w, h, 0, 0, scale)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  dstW,
-		Height: dstH,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, dstW, dstH)
+	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 
 	pix = make([]byte, 4*dstW*dstH)
 	if err := dst.ReadPixels(ui.GraphicsDriverForTesting(), pix, image.Rect(0, 0, dstW, dstH)); err != nil {
@@ -608,13 +578,8 @@ func TestDisposedAndReputOnSourceBackend(t *testing.T) {
 	// Use src as a render target so that src is not on an atlas.
 	vs := quadVertices(size, size, 0, 0, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  size,
-		Height: size,
-	}
-	src.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, size, size)
+	src.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 	if got, want := src.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -623,7 +588,7 @@ func TestDisposedAndReputOnSourceBackend(t *testing.T) {
 	for i := 0; i < atlas.BaseCountToPutOnSourceBackend/2; i++ {
 		atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 		vs := quadVertices(size, size, 0, 0, 1)
-		dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		if got, want := src.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -653,19 +618,14 @@ func TestImageIsNotReputOnSourceBackendWithoutUsingAsSource(t *testing.T) {
 	// Use src as a render target so that src is not on an atlas.
 	vs := quadVertices(size, size, 0, 0, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  size,
-		Height: size,
-	}
+	dr := image.Rect(0, 0, size, size)
 
 	// Use src2 as a rendering target, and make src2 on a destination backend.
 	//
 	// Call DrawTriangles multiple times.
 	// The number of DrawTriangles doesn't matter as long as these are called in one frame.
 	for i := 0; i < 2; i++ {
-		src2.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		src2.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 	}
 	if got, want := src2.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
@@ -684,7 +644,7 @@ func TestImageIsNotReputOnSourceBackendWithoutUsingAsSource(t *testing.T) {
 	for i := 0; i < atlas.BaseCountToPutOnSourceBackend; i++ {
 		atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 		vs := quadVertices(size, size, 0, 0, 1)
-		dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		if got, want := src2.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -802,23 +762,18 @@ func TestDestinationCountOverflow(t *testing.T) {
 
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
+	dr := image.Rect(0, 0, w, h)
 
 	// Use dst0 as a destination for a while.
 	for i := 0; i < 31; i++ {
-		dst0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		dst0.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 	}
 
 	// Use dst0 as a source for a while.
 	// As dst0 is used as a destination too many times (31 is a maximum), dst0's backend should never be a source backend.
 	for i := 0; i < 100; i++ {
-		dst1.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{dst0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		dst1.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{dst0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 		if dst0.IsOnSourceBackendForTesting() {
 			t.Errorf("dst0 cannot be on a source backend: %d", i)
@@ -842,14 +797,9 @@ func TestIteratingImagesToPutOnSourceBackend(t *testing.T) {
 	// Use srcs as detinations once.
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
+	dr := image.Rect(0, 0, w, h)
 	for _, img := range srcs {
-		img.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+		img.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 	}
 	atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 
@@ -857,7 +807,7 @@ func TestIteratingImagesToPutOnSourceBackend(t *testing.T) {
 	// Check iterating the registered image works correctly.
 	for i := 0; i < 100; i++ {
 		for _, src := range srcs {
-			dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+			dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 		}
 		atlas.PutImagesOnSourceBackendForTesting(ui.GraphicsDriverForTesting())
 	}

internal/atlas/shader_test.go

@@ -33,20 +33,15 @@ func TestShaderFillTwice(t *testing.T) {
 
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
+	dr := image.Rect(0, 0, w, h)
 	g := ui.GraphicsDriverForTesting()
 	s0 := atlas.NewShader(etesting.ShaderProgramFill(0xff, 0xff, 0xff, 0xff))
-	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, s0, nil, false)
+	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, s0, nil, false)
 
 	// Vertices must be recreated (#1755)
 	vs = quadVertices(w, h, 0, 0, 1)
 	s1 := atlas.NewShader(etesting.ShaderProgramFill(0x80, 0x80, 0x80, 0xff))
-	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, s1, nil, false)
+	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, s1, nil, false)
 
 	pix := make([]byte, 4*w*h)
 	if err := dst.ReadPixels(g, pix, image.Rect(0, 0, w, h)); err != nil {
@@ -68,17 +63,12 @@ func TestImageDrawTwice(t *testing.T) {
 
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 
 	// Vertices must be recreated (#1755)
 	vs = quadVertices(w, h, 0, 0, 1)
-	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, atlas.NearestFilterShader, nil, false)
+	dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
 
 	pix := make([]byte, 4*w*h)
 	if err := dst.ReadPixels(ui.GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {

internal/buffered/image.go

@@ -149,7 +149,7 @@ func (i *Image) writePixelsImpl(pix []byte, region image.Rectangle) {
 // DrawTriangles draws the src image with the given vertices.
 //
 // Copying vertices and indices is the caller's responsibility.
-func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool) {
+func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool) {
 	for _, src := range srcs {
 		if i == src {
 			panic("buffered: Image.DrawTriangles: source images must be different from the receiver")
@@ -172,7 +172,7 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices [
 	i.drawTrianglesImpl(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, evenOdd)
 }
 
-func (i *Image) drawTrianglesImpl(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool) {
+func (i *Image) drawTrianglesImpl(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool) {
 	var imgs [graphics.ShaderImageCount]*atlas.Image
 	for i, img := range srcs {
 		if img == nil {

internal/graphicscommand/command.go

@@ -16,6 +16,7 @@ package graphicscommand
 
 import (
 	"fmt"
+	"image"
 	"math"
 	"strings"
 	"sync/atomic"
@@ -111,7 +112,7 @@ func mustUseDifferentVertexBuffer(nextNumVertexFloats int) bool {
 }
 
 // EnqueueDrawTrianglesCommand enqueues a drawing-image command.
-func (q *commandQueue) EnqueueDrawTrianglesCommand(dst *Image, srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool) {
+func (q *commandQueue) EnqueueDrawTrianglesCommand(dst *Image, srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool) {
 	if len(vertices) > graphics.MaxVertexFloatsCount {
 		panic(fmt.Sprintf("graphicscommand: len(vertices) must equal to or less than %d but was %d", graphics.MaxVertexFloatsCount, len(vertices)))
 	}
@@ -662,7 +663,23 @@ func roundUpPower2(x int) int {
 	return p2
 }
 
-func (q *commandQueue) prependPreservedUniforms(uniforms []uint32, shader *Shader, dst *Image, srcs [graphics.ShaderImageCount]*Image, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region) []uint32 {
+type rectangleF32 struct {
+	x      float32
+	y      float32
+	width  float32
+	height float32
+}
+
+func imageRectangleToRectangleF32(r image.Rectangle) rectangleF32 {
+	return rectangleF32{
+		x:      float32(r.Min.X),
+		y:      float32(r.Min.Y),
+		width:  float32(r.Dx()),
+		height: float32(r.Dy()),
+	}
+}
+
+func (q *commandQueue) prependPreservedUniforms(uniforms []uint32, shader *Shader, dst *Image, srcs [graphics.ShaderImageCount]*Image, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle) []uint32 {
 	origUniforms := uniforms
 	uniforms = q.uint32sBuffer.alloc(len(origUniforms) + graphics.PreservedUniformUint32Count)
 	copy(uniforms[graphics.PreservedUniformUint32Count:], origUniforms)
@@ -706,53 +723,58 @@ func (q *commandQueue) prependPreservedUniforms(uniforms []uint32, shader *Shade
 		uniforms[9] = 0
 	}
 
+	dr := imageRectangleToRectangleF32(dstRegion)
 	if shader.unit() == shaderir.Texels {
-		dstRegion.X /= float32(dw)
-		dstRegion.Y /= float32(dh)
-		dstRegion.Width /= float32(dw)
-		dstRegion.Height /= float32(dh)
+		dr.x /= float32(dw)
+		dr.y /= float32(dh)
+		dr.width /= float32(dw)
+		dr.height /= float32(dh)
 	}
 
 	// Set the destination region origin.
-	uniforms[10] = math.Float32bits(dstRegion.X)
-	uniforms[11] = math.Float32bits(dstRegion.Y)
+	uniforms[10] = math.Float32bits(dr.x)
+	uniforms[11] = math.Float32bits(dr.y)
 
 	// Set the destination region size.
-	uniforms[12] = math.Float32bits(dstRegion.Width)
-	uniforms[13] = math.Float32bits(dstRegion.Height)
+	uniforms[12] = math.Float32bits(dr.width)
+	uniforms[13] = math.Float32bits(dr.height)
 
+	var srs [graphics.ShaderImageCount]rectangleF32
+	for i, r := range srcRegions {
+		srs[i] = imageRectangleToRectangleF32(r)
+	}
 	if shader.unit() == shaderir.Texels {
 		for i, src := range srcs {
 			if src == nil {
 				continue
 			}
 			w, h := src.InternalSize()
-			srcRegions[i].X /= float32(w)
-			srcRegions[i].Y /= float32(h)
-			srcRegions[i].Width /= float32(w)
-			srcRegions[i].Height /= float32(h)
+			srs[i].x /= float32(w)
+			srs[i].y /= float32(h)
+			srs[i].width /= float32(w)
+			srs[i].height /= float32(h)
 		}
 	}
 
 	// Set the source region origins.
-	uniforms[14] = math.Float32bits(srcRegions[0].X)
-	uniforms[15] = math.Float32bits(srcRegions[0].Y)
-	uniforms[16] = math.Float32bits(srcRegions[1].X)
-	uniforms[17] = math.Float32bits(srcRegions[1].Y)
-	uniforms[18] = math.Float32bits(srcRegions[2].X)
-	uniforms[19] = math.Float32bits(srcRegions[2].Y)
-	uniforms[20] = math.Float32bits(srcRegions[3].X)
-	uniforms[21] = math.Float32bits(srcRegions[3].Y)
+	uniforms[14] = math.Float32bits(srs[0].x)
+	uniforms[15] = math.Float32bits(srs[0].y)
+	uniforms[16] = math.Float32bits(srs[1].x)
+	uniforms[17] = math.Float32bits(srs[1].y)
+	uniforms[18] = math.Float32bits(srs[2].x)
+	uniforms[19] = math.Float32bits(srs[2].y)
+	uniforms[20] = math.Float32bits(srs[3].x)
+	uniforms[21] = math.Float32bits(srs[3].y)
 
 	// Set the source region sizes.
-	uniforms[22] = math.Float32bits(srcRegions[0].Width)
-	uniforms[23] = math.Float32bits(srcRegions[0].Height)
-	uniforms[24] = math.Float32bits(srcRegions[1].Width)
-	uniforms[25] = math.Float32bits(srcRegions[1].Height)
-	uniforms[26] = math.Float32bits(srcRegions[2].Width)
-	uniforms[27] = math.Float32bits(srcRegions[2].Height)
-	uniforms[28] = math.Float32bits(srcRegions[3].Width)
-	uniforms[29] = math.Float32bits(srcRegions[3].Height)
+	uniforms[22] = math.Float32bits(srs[0].width)
+	uniforms[23] = math.Float32bits(srs[0].height)
+	uniforms[24] = math.Float32bits(srs[1].width)
+	uniforms[25] = math.Float32bits(srs[1].height)
+	uniforms[26] = math.Float32bits(srs[2].width)
+	uniforms[27] = math.Float32bits(srs[2].height)
+	uniforms[28] = math.Float32bits(srs[3].width)
+	uniforms[29] = math.Float32bits(srs[3].height)
 
 	// Set the projection matrix.
 	uniforms[30] = math.Float32bits(2 / float32(dw))

internal/graphicscommand/image.go

@@ -147,7 +147,7 @@ func (i *Image) InternalSize() (int, int) {
 //
 // If the source image is not specified, i.e., src is nil and there is no image in the uniform variables, the
 // elements for the source image are not used.
-func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool) {
+func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool) {
 	for _, src := range srcs {
 		if src == nil {
 			continue

internal/graphicscommand/image_test.go

@@ -58,13 +58,8 @@ func TestClear(t *testing.T) {
 
 	vs := quadVertices(w/2, h/2)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{src}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, nearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{src}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderImageCount]image.Rectangle{}, nearestFilterShader, nil, false)
 
 	pix := make([]byte, 4*w*h)
 	if err := dst.ReadPixels(ui.GraphicsDriverForTesting(), []graphicsdriver.PixelsArgs{
@@ -94,14 +89,9 @@ func TestWritePixelsPartAfterDrawTriangles(t *testing.T) {
 	dst := graphicscommand.NewImage(w, h, false)
 	vs := quadVertices(w/2, h/2)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{clr}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, nearestFilterShader, nil, false)
-	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, nearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{clr}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderImageCount]image.Rectangle{}, nearestFilterShader, nil, false)
+	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, nearestFilterShader, nil, false)
 	dst.WritePixels(make([]byte, 4), image.Rect(0, 0, 1, 1))
 
 	// TODO: Check the result.
@@ -113,17 +103,12 @@ func TestShader(t *testing.T) {
 	dst := graphicscommand.NewImage(w, h, false)
 	vs := quadVertices(w, h)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{clr}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, nearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{clr}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderImageCount]image.Rectangle{}, nearestFilterShader, nil, false)
 
 	g := ui.GraphicsDriverForTesting()
 	s := graphicscommand.NewShader(etesting.ShaderProgramFill(0xff, 0, 0, 0xff))
-	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, s, nil, false)
+	dst.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, s, nil, false)
 
 	pix := make([]byte, 4*w*h)
 	if err := dst.ReadPixels(g, []graphicsdriver.PixelsArgs{

internal/graphicsdriver/directx/graphics11_windows.go

@@ -578,10 +578,10 @@ func (g *graphics11) DrawTriangles(dstID graphicsdriver.ImageID, srcIDs [graphic
 	for _, dstRegion := range dstRegions {
 		g.deviceContext.RSSetScissorRects([]_D3D11_RECT{
 			{
-				left:   int32(dstRegion.Region.X),
-				top:    int32(dstRegion.Region.Y),
-				right:  int32(dstRegion.Region.X + dstRegion.Region.Width),
-				bottom: int32(dstRegion.Region.Y + dstRegion.Region.Height),
+				left:   int32(dstRegion.Region.Min.X),
+				top:    int32(dstRegion.Region.Min.Y),
+				right:  int32(dstRegion.Region.Max.X),
+				bottom: int32(dstRegion.Region.Max.Y),
 			},
 		})
 

internal/graphicsdriver/directx/pipeline12_windows.go

@@ -296,10 +296,10 @@ func (p *pipelineStates) drawTriangles(device *_ID3D12Device, commandList *_ID3D
 	for _, dstRegion := range dstRegions {
 		commandList.RSSetScissorRects([]_D3D12_RECT{
 			{
-				left:   int32(dstRegion.Region.X),
-				top:    int32(dstRegion.Region.Y),
-				right:  int32(dstRegion.Region.X + dstRegion.Region.Width),
-				bottom: int32(dstRegion.Region.Y + dstRegion.Region.Height),
+				left:   int32(dstRegion.Region.Min.X),
+				top:    int32(dstRegion.Region.Min.Y),
+				right:  int32(dstRegion.Region.Max.X),
+				bottom: int32(dstRegion.Region.Max.Y),
 			},
 		})
 		if evenOdd {

internal/graphicsdriver/graphics.go

@@ -21,15 +21,8 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
 )
 
-type Region struct {
-	X      float32
-	Y      float32
-	Width  float32
-	Height float32
-}
-
 type DstRegion struct {
-	Region     Region
+	Region     image.Rectangle
 	IndexCount int
 }
 

internal/graphicsdriver/metal/graphics_darwin.go

@@ -561,10 +561,10 @@ func (g *Graphics) draw(dst *Image, dstRegions []graphicsdriver.DstRegion, srcs
 
 	for _, dstRegion := range dstRegions {
 		g.rce.SetScissorRect(mtl.ScissorRect{
-			X:      int(dstRegion.Region.X),
-			Y:      int(dstRegion.Region.Y),
-			Width:  int(dstRegion.Region.Width),
-			Height: int(dstRegion.Region.Height),
+			X:      dstRegion.Region.Min.X,
+			Y:      dstRegion.Region.Min.Y,
+			Width:  dstRegion.Region.Dx(),
+			Height: dstRegion.Region.Dy(),
 		})
 
 		if evenOdd {

internal/graphicsdriver/opengl/graphics.go

@@ -251,10 +251,10 @@ func (g *Graphics) DrawTriangles(dstID graphicsdriver.ImageID, srcIDs [graphics.
 
 	for _, dstRegion := range dstRegions {
 		g.context.ctx.Scissor(
-			int32(dstRegion.Region.X),
-			int32(dstRegion.Region.Y),
-			int32(dstRegion.Region.Width),
-			int32(dstRegion.Region.Height),
+			int32(dstRegion.Region.Min.X),
+			int32(dstRegion.Region.Min.Y),
+			int32(dstRegion.Region.Dx()),
+			int32(dstRegion.Region.Dy()),
 		)
 		if evenOdd {
 			g.context.ctx.Clear(gl.STENCIL_BUFFER_BIT)

internal/mipmap/mipmap.go

@@ -66,7 +66,7 @@ func (m *Mipmap) ReadPixels(graphicsDriver graphicsdriver.Graphics, pixels []byt
 	return m.orig.ReadPixels(graphicsDriver, pixels, region)
 }
 
-func (m *Mipmap) DrawTriangles(srcs [graphics.ShaderImageCount]*Mipmap, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool, canSkipMipmap bool) {
+func (m *Mipmap) DrawTriangles(srcs [graphics.ShaderImageCount]*Mipmap, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool, canSkipMipmap bool) {
 	if len(indices) == 0 {
 		return
 	}
@@ -187,13 +187,8 @@ func (m *Mipmap) level(level int) *buffered.Image {
 
 	s := buffered.NewImage(w2, h2, m.imageType)
 
-	dstRegion := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  float32(w2),
-		Height: float32(h2),
-	}
-	s.DrawTriangles([graphics.ShaderImageCount]*buffered.Image{src}, vs, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderImageCount]graphicsdriver.Region{}, shader.shader, nil, false)
+	dstRegion := image.Rect(0, 0, w2, h2)
+	s.DrawTriangles([graphics.ShaderImageCount]*buffered.Image{src}, vs, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderImageCount]image.Rectangle{}, shader.shader, nil, false)
 	m.setImg(level, s)
 
 	return m.imgs[level]

internal/restorable/image.go

@@ -17,7 +17,6 @@ package restorable
 import (
 	"fmt"
 	"image"
-	"math"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicscommand"
@@ -77,8 +76,8 @@ type drawTrianglesHistoryItem struct {
 	vertices   []float32
 	indices    []uint16
 	blend      graphicsdriver.Blend
-	dstRegion  graphicsdriver.Region
-	srcRegions [graphics.ShaderImageCount]graphicsdriver.Region
+	dstRegion  image.Rectangle
+	srcRegions [graphics.ShaderImageCount]image.Rectangle
 	shader     *Shader
 	uniforms   []uint32
 	evenOdd    bool
@@ -180,13 +179,8 @@ func (i *Image) Extend(width, height int) *Image {
 	sw, sh := i.image.InternalSize()
 	vs := quadVertices(0, 0, float32(sw), float32(sh), 0, 0, float32(sw), float32(sh), 1, 1, 1, 1)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  float32(sw),
-		Height: float32(sh),
-	}
-	newImg.DrawTriangles(srcs, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, sw, sh)
+	newImg.DrawTriangles(srcs, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, NearestFilterShader, nil, false)
 	i.Dispose()
 
 	return newImg
@@ -205,13 +199,7 @@ func quadVertices(dx0, dy0, dx1, dy1, sx0, sy0, sx1, sy1, cr, cg, cb, ca float32
 func clearImage(i *graphicscommand.Image, region image.Rectangle) {
 	vs := quadVertices(float32(region.Min.X), float32(region.Min.Y), float32(region.Max.X), float32(region.Max.Y), 0, 0, 0, 0, 0, 0, 0, 0)
 	is := graphics.QuadIndices()
-	dstRegion := graphicsdriver.Region{
-		X:      float32(region.Min.X),
-		Y:      float32(region.Min.Y),
-		Width:  float32(region.Dx()),
-		Height: float32(region.Dy()),
-	}
-	i.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{}, vs, is, graphicsdriver.BlendClear, dstRegion, [graphics.ShaderImageCount]graphicsdriver.Region{}, clearShader.shader, nil, false)
+	i.DrawTriangles([graphics.ShaderImageCount]*graphicscommand.Image{}, vs, is, graphicsdriver.BlendClear, region, [graphics.ShaderImageCount]image.Rectangle{}, clearShader.shader, nil, false)
 }
 
 // BasePixelsForTesting returns the image's basePixels for testing.
@@ -333,7 +321,7 @@ func (i *Image) WritePixels(pixels []byte, region image.Rectangle) {
 //	5: Color G
 //	6: Color B
 //	7: Color Y
-func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool) {
+func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool) {
 	if len(vertices) == 0 {
 		return
 	}
@@ -353,7 +341,7 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices [
 
 	// Even if the image is already stale, call makeStale to extend the stale region.
 	if srcstale || !needsRestoring() || !i.needsRestoring() || i.stale {
-		i.makeStale(regionToRectangle(dstRegion))
+		i.makeStale(dstRegion)
 	} else {
 		i.appendDrawTrianglesHistory(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, evenOdd)
 	}
@@ -369,7 +357,7 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices [
 }
 
 // appendDrawTrianglesHistory appends a draw-image history item to the image.
-func (i *Image) appendDrawTrianglesHistory(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool) {
+func (i *Image) appendDrawTrianglesHistory(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool) {
 	if i.stale || !i.needsRestoring() {
 		panic("restorable: an image must not be stale or need restoring at appendDrawTrianglesHistory")
 	}
@@ -380,7 +368,7 @@ func (i *Image) appendDrawTrianglesHistory(srcs [graphics.ShaderImageCount]*Imag
 	// TODO: Would it be possible to merge draw image history items?
 	const maxDrawTrianglesHistoryCount = 1024
 	if len(i.drawTrianglesHistory)+1 > maxDrawTrianglesHistoryCount {
-		i.makeStale(regionToRectangle(dstRegion))
+		i.makeStale(dstRegion)
 		return
 	}
 	// All images must be resolved and not stale each after frame.
@@ -704,22 +692,13 @@ func (i *Image) InternalSize() (int, int) {
 
 func (i *Image) appendRegionsForDrawTriangles(regions *[]image.Rectangle) {
 	for _, d := range i.drawTrianglesHistory {
-		r := regionToRectangle(d.dstRegion)
-		if r.Empty() {
+		if d.dstRegion.Empty() {
 			continue
 		}
-		appendRegionRemovingDuplicates(regions, r)
+		appendRegionRemovingDuplicates(regions, d.dstRegion)
 	}
 }
 
-func regionToRectangle(region graphicsdriver.Region) image.Rectangle {
-	return image.Rect(
-		int(math.Floor(float64(region.X))),
-		int(math.Floor(float64(region.Y))),
-		int(math.Ceil(float64(region.X+region.Width))),
-		int(math.Ceil(float64(region.Y+region.Height))))
-}
-
 // appendRegionRemovingDuplicates adds a region to a given list of regions,
 // but removes any duplicate between the newly added region and any existing regions.
 //

internal/restorable/images_test.go

@@ -133,13 +133,8 @@ func TestRestoreChain(t *testing.T) {
 	for i := 0; i < num-1; i++ {
 		vs := quadVertices(1, 1, 0, 0)
 		is := graphics.QuadIndices()
-		dr := graphicsdriver.Region{
-			X:      0,
-			Y:      0,
-			Width:  1,
-			Height: 1,
-		}
-		imgs[i+1].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[i]}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+		dr := image.Rect(0, 0, 1, 1)
+		imgs[i+1].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[i]}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	}
 	if err := restorable.ResolveStaleImages(ui.GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
@@ -181,16 +176,11 @@ func TestRestoreChain2(t *testing.T) {
 	imgs[8].WritePixels([]byte{clr8.R, clr8.G, clr8.B, clr8.A}, image.Rect(0, 0, w, h))
 
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	imgs[8].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[7]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
-	imgs[9].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[8]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	imgs[8].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[7]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
+	imgs[9].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[8]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	for i := 0; i < 7; i++ {
-		imgs[i+1].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[i]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+		imgs[i+1].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[i]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	}
 
 	if err := restorable.ResolveStaleImages(ui.GraphicsDriverForTesting()); err != nil {
@@ -230,16 +220,11 @@ func TestRestoreOverrideSource(t *testing.T) {
 	clr1 := color.RGBA{B: 0x01, A: 0xff}
 	img1.WritePixels([]byte{clr0.R, clr0.G, clr0.B, clr0.A}, image.Rect(0, 0, w, h))
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	img2.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
-	img3.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img2}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	img2.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
+	img3.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img2}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	img0.WritePixels([]byte{clr1.R, clr1.G, clr1.B, clr1.A}, image.Rect(0, 0, w, h))
-	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	if err := restorable.ResolveStaleImages(ui.GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
 	}
@@ -317,30 +302,25 @@ func TestRestoreComplexGraph(t *testing.T) {
 		img0.Dispose()
 	}()
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
+	dr := image.Rect(0, 0, w, h)
 	vs := quadVertices(w, h, 0, 0)
-	img3.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img3.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	vs = quadVertices(w, h, 1, 0)
-	img3.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img3.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	vs = quadVertices(w, h, 1, 0)
-	img4.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img4.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	vs = quadVertices(w, h, 2, 0)
-	img4.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img2}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img4.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img2}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	vs = quadVertices(w, h, 0, 0)
-	img5.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img5.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	vs = quadVertices(w, h, 0, 0)
-	img6.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img6.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	vs = quadVertices(w, h, 1, 0)
-	img6.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img4}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img6.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img4}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	vs = quadVertices(w, h, 0, 0)
-	img7.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img2}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img7.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img2}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	vs = quadVertices(w, h, 2, 0)
-	img7.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	img7.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	if err := restorable.ResolveStaleImages(ui.GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
 	}
@@ -432,14 +412,9 @@ func TestRestoreRecursive(t *testing.T) {
 		img0.Dispose()
 	}()
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, quadVertices(w, h, 1, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
-	img0.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, quadVertices(w, h, 1, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, quadVertices(w, h, 1, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
+	img0.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, quadVertices(w, h, 1, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	if err := restorable.ResolveStaleImages(ui.GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
 	}
@@ -536,13 +511,8 @@ func TestDrawTrianglesAndWritePixels(t *testing.T) {
 
 	vs := quadVertices(1, 1, 0, 0)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  2,
-		Height: 1,
-	}
-	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, 2, 1)
+	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	img1.WritePixels([]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, image.Rect(0, 0, 2, 1))
 
 	if err := restorable.ResolveStaleImages(ui.GraphicsDriverForTesting()); err != nil {
@@ -579,14 +549,9 @@ func TestDispose(t *testing.T) {
 	defer img2.Dispose()
 
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  1,
-		Height: 1,
-	}
-	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img2}, quadVertices(1, 1, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
-	img0.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, quadVertices(1, 1, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, 1, 1)
+	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img2}, quadVertices(1, 1, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
+	img0.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img1}, quadVertices(1, 1, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	img1.Dispose()
 
 	if err := restorable.ResolveStaleImages(ui.GraphicsDriverForTesting()); err != nil {
@@ -694,13 +659,8 @@ func TestWritePixelsOnly(t *testing.T) {
 
 	vs := quadVertices(1, 1, 0, 0)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  1,
-		Height: 1,
-	}
-	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, 1, 1)
+	img1.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	img0.WritePixels([]byte{5, 6, 7, 8}, image.Rect(0, 0, 1, 1))
 
 	// BasePixelsForTesting is available without GPU accessing.
@@ -753,13 +713,8 @@ func TestReadPixelsFromVolatileImage(t *testing.T) {
 	src.WritePixels(pix, image.Rect(0, 0, w, h))
 	vs := quadVertices(1, 1, 0, 0)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 
 	// Read the pixels. If the implementation is correct, dst tries to read its pixels from GPU due to being
 	// stale.
@@ -782,13 +737,8 @@ func TestAllowWritePixelsAfterDrawTriangles(t *testing.T) {
 
 	vs := quadVertices(w, h, 0, 0)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	dst.WritePixels(make([]byte, 4*w*h), image.Rect(0, 0, w, h))
 	// WritePixels for a whole image doesn't panic.
 }
@@ -806,13 +756,8 @@ func TestAllowWritePixelsForPartAfterDrawTriangles(t *testing.T) {
 
 	vs := quadVertices(w, h, 0, 0)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	dst.WritePixels(make([]byte, 4*2*2), image.Rect(0, 0, 2, 2))
 	// WritePixels for a part of image doesn't panic.
 
@@ -905,13 +850,8 @@ func TestDrawTrianglesAndExtend(t *testing.T) {
 	orig := restorable.NewImage(w, h, restorable.ImageTypeRegular)
 	vs := quadVertices(w, h, 0, 0)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	orig.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	orig.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	extended := orig.Extend(w*2, h*2) // After this, orig is already disposed.
 
 	result := make([]byte, 4*(w*2)*(h*2))
@@ -960,13 +900,8 @@ func TestMutateSlices(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0)
 	is := make([]uint16, len(graphics.QuadIndices()))
 	copy(is, graphics.QuadIndices())
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 	for i := range vs {
 		vs[i] = 0
 	}
@@ -1157,13 +1092,8 @@ func TestDrawTrianglesAndReadPixels(t *testing.T) {
 
 	vs := quadVertices(w, h, 0, 0)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  w,
-		Height: h,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 
 	pix := make([]byte, 4*w*h)
 	if err := dst.ReadPixels(ui.GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
@@ -1186,13 +1116,8 @@ func TestWritePixelsAndDrawTriangles(t *testing.T) {
 	// Call DrawTriangles at a different region second.
 	vs := quadVertices(1, 1, 1, 0)
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      1,
-		Y:      0,
-		Width:  1,
-		Height: 1,
-	}
-	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(1, 0, 2, 1)
+	dst.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 
 	// Get the pixels.
 	pix := make([]byte, 4*2*1)

internal/restorable/shader_test.go

@@ -45,13 +45,8 @@ func clearImage(img *restorable.Image, w, h int) {
 		dx1, dy1, sx1, sy1, 0, 0, 0, 0,
 	}
 	is := graphics.QuadIndices()
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  float32(w),
-		Height: float32(h),
-	}
-	img.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{emptyImage}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, restorable.NearestFilterShader, nil, false)
+	dr := image.Rect(0, 0, w, h)
+	img.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{emptyImage}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, false)
 }
 
 func TestShader(t *testing.T) {
@@ -59,13 +54,8 @@ func TestShader(t *testing.T) {
 	defer img.Dispose()
 
 	s := restorable.NewShader(etesting.ShaderProgramFill(0xff, 0, 0, 0xff))
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  1,
-		Height: 1,
-	}
-	img.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, s, nil, false)
+	dr := image.Rect(0, 0, 1, 1)
+	img.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, s, nil, false)
 
 	if err := restorable.ResolveStaleImages(ui.GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
@@ -94,13 +84,8 @@ func TestShaderChain(t *testing.T) {
 
 	s := restorable.NewShader(etesting.ShaderProgramImages(1))
 	for i := 0; i < num-1; i++ {
-		dr := graphicsdriver.Region{
-			X:      0,
-			Y:      0,
-			Width:  1,
-			Height: 1,
-		}
-		imgs[i+1].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[i]}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, s, nil, false)
+		dr := image.Rect(0, 0, 1, 1)
+		imgs[i+1].DrawTriangles([graphics.ShaderImageCount]*restorable.Image{imgs[i]}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, s, nil, false)
 	}
 
 	if err := restorable.ResolveStaleImages(ui.GraphicsDriverForTesting()); err != nil {
@@ -131,13 +116,8 @@ func TestShaderMultipleSources(t *testing.T) {
 	dst := restorable.NewImage(1, 1, restorable.ImageTypeRegular)
 
 	s := restorable.NewShader(etesting.ShaderProgramImages(3))
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  1,
-		Height: 1,
-	}
-	dst.DrawTriangles(srcs, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, s, nil, false)
+	dr := image.Rect(0, 0, 1, 1)
+	dst.DrawTriangles(srcs, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, s, nil, false)
 
 	// Clear one of the sources after DrawTriangles. dst should not be affected.
 	clearImage(srcs[0], 1, 1)
@@ -168,31 +148,11 @@ func TestShaderMultipleSourcesOnOneTexture(t *testing.T) {
 	dst := restorable.NewImage(1, 1, restorable.ImageTypeRegular)
 
 	s := restorable.NewShader(etesting.ShaderProgramImages(3))
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  1,
-		Height: 1,
-	}
-	srcRegions := [graphics.ShaderImageCount]graphicsdriver.Region{
-		{
-			X:      0,
-			Y:      0,
-			Width:  1,
-			Height: 1,
-		},
-		{
-			X:      1,
-			Y:      0,
-			Width:  1,
-			Height: 1,
-		},
-		{
-			X:      2,
-			Y:      0,
-			Width:  1,
-			Height: 1,
-		},
+	dr := image.Rect(0, 0, 1, 1)
+	srcRegions := [graphics.ShaderImageCount]image.Rectangle{
+		image.Rect(0, 0, 1, 1),
+		image.Rect(1, 0, 2, 1),
+		image.Rect(2, 0, 3, 1),
 	}
 	dst.DrawTriangles(srcs, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, srcRegions, s, nil, false)
 
@@ -218,13 +178,8 @@ func TestShaderDispose(t *testing.T) {
 	defer img.Dispose()
 
 	s := restorable.NewShader(etesting.ShaderProgramFill(0xff, 0, 0, 0xff))
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  1,
-		Height: 1,
-	}
-	img.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, s, nil, false)
+	dr := image.Rect(0, 0, 1, 1)
+	img.DrawTriangles([graphics.ShaderImageCount]*restorable.Image{}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, s, nil, false)
 
 	// Dispose the shader. This should invalidate all the images using this shader i.e., all the images become
 	// stale.

internal/ui/image.go

@@ -76,7 +76,7 @@ func (i *Image) MarkDisposed() {
 	i.modifyCallback = nil
 }
 
-func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool, canSkipMipmap bool, antialias bool) {
+func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool, canSkipMipmap bool, antialias bool) {
 	if i.modifyCallback != nil {
 		i.modifyCallback()
 	}
@@ -245,13 +245,8 @@ func (i *Image) flushDotsBufferIfNeeded() {
 	i.dotsBuffer = nil
 
 	srcs := [graphics.ShaderImageCount]*mipmap.Mipmap{whiteImage.mipmap}
-	dr := graphicsdriver.Region{
-		X:      0,
-		Y:      0,
-		Width:  float32(i.width),
-		Height: float32(i.height),
-	}
-	i.mipmap.DrawTriangles(srcs, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]graphicsdriver.Region{}, NearestFilterShader.shader, nil, false, true)
+	dr := image.Rect(0, 0, i.width, i.height)
+	i.mipmap.DrawTriangles(srcs, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, NearestFilterShader.shader, nil, false, true)
 }
 
 func (i *Image) flushBigOffscreenBufferIfNeeded() {
@@ -282,13 +277,6 @@ func (i *Image) clear() {
 }
 
 func (i *Image) Fill(r, g, b, a float32, region image.Rectangle) {
-	dstRegion := graphicsdriver.Region{
-		X:      float32(region.Min.X),
-		Y:      float32(region.Min.Y),
-		Width:  float32(region.Dx()),
-		Height: float32(region.Dy()),
-	}
-
 	if len(i.tmpVerticesForFill) < 4*graphics.VertexFloatCount {
 		i.tmpVerticesForFill = make([]float32, 4*graphics.VertexFloatCount)
 	}
@@ -302,7 +290,7 @@ func (i *Image) Fill(r, g, b, a float32, region image.Rectangle) {
 
 	srcs := [graphics.ShaderImageCount]*Image{whiteImage}
 
-	i.DrawTriangles(srcs, i.tmpVerticesForFill, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderImageCount]graphicsdriver.Region{}, NearestFilterShader, nil, false, true, false)
+	i.DrawTriangles(srcs, i.tmpVerticesForFill, is, graphicsdriver.BlendCopy, region, [graphics.ShaderImageCount]image.Rectangle{}, NearestFilterShader, nil, false, true, false)
 }
 
 type bigOffscreenImage struct {
@@ -310,7 +298,7 @@ type bigOffscreenImage struct {
 	imageType atlas.ImageType
 
 	image  *Image
-	region graphicsdriver.Region
+	region image.Rectangle
 
 	blend graphicsdriver.Blend
 	dirty bool
@@ -334,7 +322,7 @@ func (i *bigOffscreenImage) markDisposed() {
 	i.dirty = false
 }
 
-func (i *bigOffscreenImage) drawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion graphicsdriver.Region, srcRegions [graphics.ShaderImageCount]graphicsdriver.Region, shader *Shader, uniforms []uint32, evenOdd bool, canSkipMipmap bool, antialias bool) {
+func (i *bigOffscreenImage) drawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool, canSkipMipmap bool, antialias bool) {
 	if i.blend != blend {
 		i.flush()
 	}
@@ -347,12 +335,12 @@ func (i *bigOffscreenImage) drawTriangles(srcs [graphics.ShaderImageCount]*Image
 		i.region = r
 	}
 
-	if i.region.Width == 0 || i.region.Height == 0 {
+	if i.region.Empty() {
 		return
 	}
 
 	if i.image == nil {
-		i.image = NewImage(int(i.region.Width)*bigOffscreenScale, int(i.region.Height)*bigOffscreenScale, i.imageType)
+		i.image = NewImage(i.region.Dx()*bigOffscreenScale, i.region.Dy()*bigOffscreenScale, i.imageType)
 	}
 
 	// Copy the current rendering result to get the correct blending result.
@@ -364,40 +352,26 @@ func (i *bigOffscreenImage) drawTriangles(srcs [graphics.ShaderImageCount]*Image
 		// i.tmpVerticesForCopying can be resused as this is sent to DrawTriangles immediately.
 		graphics.QuadVertices(
 			i.tmpVerticesForCopying,
-			i.region.X, i.region.Y, i.region.X+i.region.Width, i.region.Y+i.region.Height,
+			float32(i.region.Min.X), float32(i.region.Min.Y), float32(i.region.Max.X), float32(i.region.Max.Y),
 			bigOffscreenScale, 0, 0, bigOffscreenScale, 0, 0,
 			1, 1, 1, 1)
 		is := graphics.QuadIndices()
-		dstRegion := graphicsdriver.Region{
-			X:      0,
-			Y:      0,
-			Width:  i.region.Width * bigOffscreenScale,
-			Height: i.region.Height * bigOffscreenScale,
-		}
-		i.image.DrawTriangles(srcs, i.tmpVerticesForCopying, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderImageCount]graphicsdriver.Region{}, NearestFilterShader, nil, false, true, false)
+		dstRegion := image.Rect(0, 0, i.region.Dx()*bigOffscreenScale, i.region.Dy()*bigOffscreenScale)
+		i.image.DrawTriangles(srcs, i.tmpVerticesForCopying, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderImageCount]image.Rectangle{}, NearestFilterShader, nil, false, true, false)
 	}
 
 	for idx := 0; idx < len(vertices); idx += graphics.VertexFloatCount {
-		vertices[idx] = (vertices[idx] - i.region.X) * bigOffscreenScale
-		vertices[idx+1] = (vertices[idx+1] - i.region.Y) * bigOffscreenScale
+		vertices[idx] = (vertices[idx] - float32(i.region.Min.X)) * bigOffscreenScale
+		vertices[idx+1] = (vertices[idx+1] - float32(i.region.Min.Y)) * bigOffscreenScale
 	}
 
-	// Compute corners in dst coordinate space.
-	x0 := dstRegion.X
-	y0 := dstRegion.Y
-	x1 := dstRegion.X + dstRegion.Width
-	y1 := dstRegion.Y + dstRegion.Height
 	// Translate to i.region coordinate space, and clamp against region size.
-	x0 = max(x0-i.region.X, 0)
-	y0 = max(y0-i.region.Y, 0)
-	x1 = min(x1-i.region.X, i.region.Width)
-	y1 = min(y1-i.region.Y, i.region.Height)
-	dstRegion = graphicsdriver.Region{
-		X:      x0 * bigOffscreenScale,
-		Y:      y0 * bigOffscreenScale,
-		Width:  (x1 - x0) * bigOffscreenScale,
-		Height: (y1 - y0) * bigOffscreenScale,
-	}
+	dstRegion = dstRegion.Sub(i.region.Min)
+	dstRegion = dstRegion.Intersect(image.Rect(0, 0, i.region.Dx(), i.region.Dy()))
+	dstRegion.Min.X *= bigOffscreenScale
+	dstRegion.Min.Y *= bigOffscreenScale
+	dstRegion.Max.X *= bigOffscreenScale
+	dstRegion.Max.Y *= bigOffscreenScale
 
 	i.image.DrawTriangles(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, evenOdd, canSkipMipmap, false)
 	i.dirty = true
@@ -422,8 +396,8 @@ func (i *bigOffscreenImage) flush() {
 	// i.tmpVerticesForFlushing can be reused as this is sent to DrawTriangles in this function.
 	graphics.QuadVertices(
 		i.tmpVerticesForFlushing,
-		0, 0, i.region.Width*bigOffscreenScale, i.region.Height*bigOffscreenScale,
-		1.0/bigOffscreenScale, 0, 0, 1.0/bigOffscreenScale, i.region.X, i.region.Y,
+		0, 0, float32(i.region.Dx()*bigOffscreenScale), float32(i.region.Dy()*bigOffscreenScale),
+		1.0/bigOffscreenScale, 0, 0, 1.0/bigOffscreenScale, float32(i.region.Min.X), float32(i.region.Min.Y),
 		1, 1, 1, 1)
 	is := graphics.QuadIndices()
 	dstRegion := i.region
@@ -431,13 +405,13 @@ func (i *bigOffscreenImage) flush() {
 	if i.blend != graphicsdriver.BlendSourceOver {
 		blend = graphicsdriver.BlendCopy
 	}
-	i.orig.DrawTriangles(srcs, i.tmpVerticesForFlushing, is, blend, dstRegion, [graphics.ShaderImageCount]graphicsdriver.Region{}, LinearFilterShader, nil, false, true, false)
+	i.orig.DrawTriangles(srcs, i.tmpVerticesForFlushing, is, blend, dstRegion, [graphics.ShaderImageCount]image.Rectangle{}, LinearFilterShader, nil, false, true, false)
 
 	i.image.clear()
 	i.dirty = false
 }
 
-func (i *bigOffscreenImage) requiredRegion(vertices []float32) graphicsdriver.Region {
+func (i *bigOffscreenImage) requiredRegion(vertices []float32) image.Rectangle {
 	minX := float32(i.orig.width)
 	minY := float32(i.orig.height)
 	maxX := float32(0)
@@ -460,35 +434,19 @@ func (i *bigOffscreenImage) requiredRegion(vertices []float32) graphicsdriver.Re
 	}
 
 	// Adjust the granularity of the rectangle.
-	minX = float32(roundDown16(int(minX)))
-	minY = float32(roundDown16(int(minY)))
-	maxX = float32(roundUp16(int(maxX)))
-	maxY = float32(roundUp16(int(maxY)))
+	r := image.Rect(
+		roundDown16(int(minX)),
+		roundDown16(int(minY)),
+		roundUp16(int(maxX)),
+		roundUp16(int(maxY)))
+	r = r.Intersect(image.Rect(0, 0, i.orig.width, i.orig.height))
 
-	if minX < 0 {
-		minX = 0
-	}
-	if minY < 0 {
-		minY = 0
-	}
-	if maxX > float32(i.orig.width) {
-		maxX = float32(i.orig.width)
-	}
-	if maxY > float32(i.orig.height) {
-		maxY = float32(i.orig.height)
-	}
-
-	r := graphicsdriver.Region{
-		X:      minX,
-		Y:      minY,
-		Width:  maxX - minX,
-		Height: maxY - minY,
-	}
-	if r.Width < 0 || r.Height < 0 {
+	// TODO: Is this check required?
+	if r.Dx() < 0 || r.Dy() < 0 {
 		return i.region
 	}
 
-	return union(r, i.region)
+	return r.Union(i.region)
 }
 
 func floor(x float32) float32 {
@@ -506,37 +464,3 @@ func roundDown16(x int) int {
 func roundUp16(x int) int {
 	return ((x - 1) & ^(0xf)) + 0x10
 }
-
-func min(x, y float32) float32 {
-	if x < y {
-		return x
-	}
-	return y
-}
-
-func max(x, y float32) float32 {
-	if x > y {
-		return x
-	}
-	return y
-}
-
-func union(r0, r1 graphicsdriver.Region) graphicsdriver.Region {
-	if r0.Width == 0 || r0.Height == 0 {
-		return r1
-	}
-	if r1.Width == 0 || r1.Height == 0 {
-		return r0
-	}
-
-	x0 := min(r0.X, r1.X)
-	y0 := min(r0.Y, r1.Y)
-	x1 := max(r0.X+r0.Width, r1.X+r1.Width)
-	y1 := max(r0.Y+r0.Height, r1.Y+r1.Height)
-	return graphicsdriver.Region{
-		X:      x0,
-		Y:      y0,
-		Width:  x1 - x0,
-		Height: y1 - y0,
-	}
-}