GPU device preserves pixel values across read/write/read of unpremul pixel values

Review URL: http://codereview.appspot.com/5695047/



git-svn-id: http://skia.googlecode.com/svn/trunk@3237 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 106 insertions, 0 deletions

diff --git a/tests/PremulAlphaRoundTripTest.cpp b/tests/PremulAlphaRoundTripTest.cpp
new file mode 100644
index 0000000000..c4ec6ab90a
--- /dev/null
+++ b/tests/PremulAlphaRoundTripTest.cpp
@@ -0,0 +1,106 @@
+
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Test.h"
+#include "SkCanvas.h"
+#include "SkConfig8888.h"
+#include "SkGpuDevice.h"
+
+
+namespace {
+
+void fillCanvas(SkCanvas* canvas, SkCanvas::Config8888 unpremulConfig) {
+    SkBitmap bmp;
+    bmp.setConfig(SkBitmap::kARGB_8888_Config, 256, 256);
+    bmp.allocPixels();
+    SkAutoLockPixels alp(bmp);
+    uint32_t* pixels = reinterpret_cast<uint32_t*>(bmp.getPixels());
+
+    for (int a = 0; a < 256; ++a) {
+        for (int r = 0; r < 256; ++r) {
+            pixels[a * 256 + r] = SkPackConfig8888(unpremulConfig, a, r, 0, 0);
+        }
+    }
+    canvas->writePixels(bmp, 0, 0, unpremulConfig);
+}
+
+static const SkCanvas::Config8888 gUnpremulConfigs[] = {
+    SkCanvas::kNative_Unpremul_Config8888,
+/**
+ * There is a bug in Ganesh (http://code.google.com/p/skia/issues/detail?id=438)
+ * that causes the readback of pixels from BGRA canvas to an RGBA bitmap to
+ * fail. This should be removed as soon as the issue above is resolved.
+ */
+#if !defined(SK_BUILD_FOR_ANDROID)
+    SkCanvas::kBGRA_Unpremul_Config8888,
+#endif
+    SkCanvas::kRGBA_Unpremul_Config8888,
+};
+
+void PremulAlphaRoundTripTest(skiatest::Reporter* reporter,
+                              GrContext* context) {
+    SkCanvas canvas;
+    for (int dtype = 0; dtype < 2; ++dtype) {
+        if (0 == dtype) {
+            canvas.setDevice(new SkDevice(SkBitmap::kARGB_8888_Config,
+                                          256,
+                                          256,
+                                          false))->unref();
+        } else {
+#if SK_SCALAR_IS_FIXED
+            // GPU device known not to work in the fixed pt build.
+            continue;
+#endif
+            canvas.setDevice(new SkGpuDevice(context,
+                                             SkBitmap::kARGB_8888_Config,
+                                             256,
+                                             256))->unref();
+        }
+
+        SkBitmap readBmp1;
+        readBmp1.setConfig(SkBitmap::kARGB_8888_Config, 256, 256);
+        readBmp1.allocPixels();
+        SkBitmap readBmp2;
+        readBmp2.setConfig(SkBitmap::kARGB_8888_Config, 256, 256);
+        readBmp2.allocPixels();
+
+        for (size_t upmaIdx = 0;
+             upmaIdx < SK_ARRAY_COUNT(gUnpremulConfigs);
+             ++upmaIdx) {
+            fillCanvas(&canvas, gUnpremulConfigs[upmaIdx]);
+            {
+                SkAutoLockPixels alp1(readBmp1);
+                SkAutoLockPixels alp2(readBmp2);
+                sk_bzero(readBmp1.getPixels(), readBmp1.getSafeSize());
+                sk_bzero(readBmp2.getPixels(), readBmp2.getSafeSize());
+            }
+
+            canvas.readPixels(&readBmp1, 0, 0, gUnpremulConfigs[upmaIdx]);
+            canvas.writePixels(readBmp1, 0, 0, gUnpremulConfigs[upmaIdx]);
+            canvas.readPixels(&readBmp2, 0, 0, gUnpremulConfigs[upmaIdx]);
+
+            SkAutoLockPixels alp1(readBmp1);
+            SkAutoLockPixels alp2(readBmp2);
+            uint32_t* pixels1 =
+                reinterpret_cast<uint32_t*>(readBmp1.getPixels());
+            uint32_t* pixels2 =
+                reinterpret_cast<uint32_t*>(readBmp2.getPixels());
+            for (int y = 0; y < 256; ++y) {
+                for (int x = 0; x < 256; ++x) {
+                    int i = y * 256 + x;
+                    REPORTER_ASSERT(reporter, pixels1[i] == pixels2[i]);
+                }
+            }
+        }
+    }
+}
+}
+
+#include "TestClassDef.h"
+DEFINE_GPUTESTCLASS("PremulAlphaRoundTripTest", PremulAlphaRoundTripTestClass, PremulAlphaRoundTripTest)
+