image: basic test for the 16-bits-per-color-channel types.

R=r
CC=golang-dev
https://golang.org/cl/4635059

src/pkg/image/image_test.go

@@ -8,6 +8,12 @@ import (
 	"testing"
 )
 
+type image interface {
+	Image
+	Set(int, int, Color)
+	SubImage(Rectangle) Image
+}
+
 func cmp(t *testing.T, cm ColorModel, c0, c1 Color) bool {
 	r0, g0, b0, a0 := cm.Convert(c0).RGBA()
 	r1, g1, b1, a1 := cm.Convert(c1).RGBA()
@@ -15,12 +21,7 @@ func cmp(t *testing.T, cm ColorModel, c0, c1 Color) bool {
 }
 
 func TestImage(t *testing.T) {
-	type buffered interface {
-		Image
-		Set(int, int, Color)
-		SubImage(Rectangle) Image
-	}
-	testImage := []Image{
+	testImage := []image{
 		NewRGBA(10, 10),
 		NewRGBA64(10, 10),
 		NewNRGBA(10, 10),
@@ -35,36 +36,66 @@ func TestImage(t *testing.T) {
 		}),
 	}
 	for _, m := range testImage {
-		b := m.(buffered)
-		if !Rect(0, 0, 10, 10).Eq(b.Bounds()) {
-			t.Errorf("%T: want bounds %v, got %v", b, Rect(0, 0, 10, 10), b.Bounds())
+		if !Rect(0, 0, 10, 10).Eq(m.Bounds()) {
+			t.Errorf("%T: want bounds %v, got %v", m, Rect(0, 0, 10, 10), m.Bounds())
+			continue
+		}
+		if !cmp(t, m.ColorModel(), Transparent, m.At(6, 3)) {
+			t.Errorf("%T: at (6, 3), want a zero color, got %v", m, m.At(6, 3))
 			continue
 		}
-		if !cmp(t, b.ColorModel(), Transparent, b.At(6, 3)) {
-			t.Errorf("%T: at (6, 3), want a zero color, got %v", b, b.At(6, 3))
+		m.Set(6, 3, Opaque)
+		if !cmp(t, m.ColorModel(), Opaque, m.At(6, 3)) {
+			t.Errorf("%T: at (6, 3), want a non-zero color, got %v", m, m.At(6, 3))
 			continue
 		}
-		b.Set(6, 3, Opaque)
-		if !cmp(t, b.ColorModel(), Opaque, b.At(6, 3)) {
-			t.Errorf("%T: at (6, 3), want a non-zero color, got %v", b, b.At(6, 3))
+		m = m.SubImage(Rect(3, 2, 9, 8)).(image)
+		if !Rect(3, 2, 9, 8).Eq(m.Bounds()) {
+			t.Errorf("%T: sub-image want bounds %v, got %v", m, Rect(3, 2, 9, 8), m.Bounds())
 			continue
 		}
-		b = b.SubImage(Rect(3, 2, 9, 8)).(buffered)
-		if !Rect(3, 2, 9, 8).Eq(b.Bounds()) {
-			t.Errorf("%T: sub-image want bounds %v, got %v", b, Rect(3, 2, 9, 8), b.Bounds())
+		if !cmp(t, m.ColorModel(), Opaque, m.At(6, 3)) {
+			t.Errorf("%T: sub-image at (6, 3), want a non-zero color, got %v", m, m.At(6, 3))
 			continue
 		}
-		if !cmp(t, b.ColorModel(), Opaque, b.At(6, 3)) {
-			t.Errorf("%T: sub-image at (6, 3), want a non-zero color, got %v", b, b.At(6, 3))
+		if !cmp(t, m.ColorModel(), Transparent, m.At(3, 3)) {
+			t.Errorf("%T: sub-image at (3, 3), want a zero color, got %v", m, m.At(3, 3))
 			continue
 		}
-		if !cmp(t, b.ColorModel(), Transparent, b.At(3, 3)) {
-			t.Errorf("%T: sub-image at (3, 3), want a zero color, got %v", b, b.At(3, 3))
+		m.Set(3, 3, Opaque)
+		if !cmp(t, m.ColorModel(), Opaque, m.At(3, 3)) {
+			t.Errorf("%T: sub-image at (3, 3), want a non-zero color, got %v", m, m.At(3, 3))
+			continue
+		}
+	}
+}
+
+func Test16BitsPerColorChannel(t *testing.T) {
+	testColorModel := []ColorModel{
+		RGBA64ColorModel,
+		NRGBA64ColorModel,
+		Alpha16ColorModel,
+		Gray16ColorModel,
+	}
+	for _, cm := range testColorModel {
+		c := cm.Convert(RGBA64Color{0x1234, 0x1234, 0x1234, 0x1234}) // Premultiplied alpha.
+		r, _, _, _ := c.RGBA()
+		if r != 0x1234 {
+			t.Errorf("%T: want red value 0x%04x got 0x%04x", c, 0x1234, r)
 			continue
 		}
-		b.Set(3, 3, Opaque)
-		if !cmp(t, b.ColorModel(), Opaque, b.At(3, 3)) {
-			t.Errorf("%T: sub-image at (3, 3), want a non-zero color, got %v", b, b.At(3, 3))
+	}
+	testImage := []image{
+		NewRGBA64(10, 10),
+		NewNRGBA64(10, 10),
+		NewAlpha16(10, 10),
+		NewGray16(10, 10),
+	}
+	for _, m := range testImage {
+		m.Set(1, 2, NRGBA64Color{0xffff, 0xffff, 0xffff, 0x1357}) // Non-premultiplied alpha.
+		r, _, _, _ := m.At(1, 2).RGBA()
+		if r != 0x1357 {
+			t.Errorf("%T: want red value 0x%04x got 0x%04x", m, 0x1357, r)
 			continue
 		}
 	}