exp/draw test.

R=rsc
CC=golang-dev
https://golang.org/cl/203062

diff --git a/src/pkg/Makefile b/src/pkg/Makefile
index 68e4a16d3a167f3bb107889858123e6c5c675e77..2a65d376986af36e3df00a23a14ec11a4fec2f54 100644 (file)
--- a/src/pkg/Makefile
+++ b/src/pkg/Makefile
@@ -121,7 +121,6 @@ DIRS=\
 
 NOTEST=\
        debug/proc\
-       exp/draw\
        go/ast\
        go/doc\
        go/token\

diff --git a/src/pkg/exp/draw/draw_test.go b/src/pkg/exp/draw/draw_test.go
new file mode 100644 (file)
index 0000000..61794da
--- /dev/null
+++ b/src/pkg/exp/draw/draw_test.go
@@ -0,0 +1,89 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package draw
+
+import (
+       "image"
+       "testing"
+)
+
+func eq(c0, c1 image.Color) bool {
+       r0, g0, b0, a0 := c0.RGBA()
+       r1, g1, b1, a1 := c1.RGBA()
+       return r0 == r1 && g0 == g1 && b0 == b1 && a0 == a1
+}
+
+func fillBlue(alpha int) image.Image {
+       return image.ColorImage{image.RGBAColor{0, 0, uint8(alpha), uint8(alpha)}}
+}
+
+func fillAlpha(alpha int) image.Image {
+       return image.ColorImage{image.AlphaColor{uint8(alpha)}}
+}
+
+func vgradGreen(alpha int) image.Image {
+       m := image.NewRGBA(16, 16)
+       for y := 0; y < 16; y++ {
+               for x := 0; x < 16; x++ {
+                       m.Set(x, y, image.RGBAColor{0, uint8(y * alpha / 15), 0, uint8(alpha)})
+               }
+       }
+       return m
+}
+
+func vgradAlpha(alpha int) image.Image {
+       m := image.NewAlpha(16, 16)
+       for y := 0; y < 16; y++ {
+               for x := 0; x < 16; x++ {
+                       m.Set(x, y, image.AlphaColor{uint8(y * alpha / 15)})
+               }
+       }
+       return m
+}
+
+func hgradRed(alpha int) Image {
+       m := image.NewRGBA(16, 16)
+       for y := 0; y < 16; y++ {
+               for x := 0; x < 16; x++ {
+                       m.Set(x, y, image.RGBAColor{uint8(x * alpha / 15), 0, 0, uint8(alpha)})
+               }
+       }
+       return m
+}
+
+type drawTest struct {
+       desc     string
+       src      image.Image
+       mask     image.Image
+       expected image.Color
+}
+
+var drawTests = []drawTest{
+       // Uniform mask (0% opaque) mask.
+       drawTest{"nop", vgradGreen(255), fillAlpha(0), image.RGBAColor{136, 0, 0, 255}},
+       // Uniform mask (100%, 75%, nil) and vertical-gradient source.
+       drawTest{"copy", vgradGreen(90), fillAlpha(255), image.RGBAColor{0, 48, 0, 90}},
+       drawTest{"copyAlpha", vgradGreen(90), fillAlpha(192), image.RGBAColor{100, 36, 0, 255}},
+       drawTest{"copyNil", vgradGreen(90), nil, image.RGBAColor{0, 48, 0, 90}},
+       // Uniform mask (100%, 75%, nil) and uniform source.
+       drawTest{"fill", fillBlue(90), fillAlpha(255), image.RGBAColor{0, 0, 90, 90}},
+       drawTest{"fillAlpha", fillBlue(90), fillAlpha(192), image.RGBAColor{100, 0, 68, 255}},
+       drawTest{"fillNil", fillBlue(90), nil, image.RGBAColor{0, 0, 90, 90}},
+       // Variable mask. In detail, at (x, y) == (8, 8):
+       // The destination pixel is {136, 0, 0, 255}.
+       // The source pixel is {0, 0, 255, 255}.
+       // The mask pixel's alpha is 102, or 40%.
+       drawTest{"generic", fillBlue(255), vgradAlpha(192), image.RGBAColor{81, 0, 102, 255}},
+}
+
+func TestDraw(t *testing.T) {
+       for _, test := range drawTests {
+               dst := hgradRed(255)
+               DrawMask(dst, Rect(0, 0, 16, 16), test.src, ZP, test.mask, ZP, SoverD)
+               if !eq(dst.At(8, 8), test.expected) {
+                       t.Errorf("draw %s: %v versus %v", test.desc, dst.At(8, 8), test.expected)
+               }
+       }
+}