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      1 /*
      2  * Copyright 2011 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "SkBitmapDevice.h"
      9 #include "SkCanvas.h"
     10 #include "SkConfig8888.h"
     11 #include "Test.h"
     12 #include "sk_tool_utils.h"
     13 
     14 #if SK_SUPPORT_GPU
     15 #include "GrContext.h"
     16 #include "SkGpuDevice.h"
     17 #endif
     18 
     19 static uint32_t pack_unpremul_rgba(SkColor c) {
     20     uint32_t packed;
     21     uint8_t* byte = reinterpret_cast<uint8_t*>(&packed);
     22     byte[0] = SkColorGetR(c);
     23     byte[1] = SkColorGetG(c);
     24     byte[2] = SkColorGetB(c);
     25     byte[3] = SkColorGetA(c);
     26     return packed;
     27 }
     28 
     29 static uint32_t pack_unpremul_bgra(SkColor c) {
     30     uint32_t packed;
     31     uint8_t* byte = reinterpret_cast<uint8_t*>(&packed);
     32     byte[0] = SkColorGetB(c);
     33     byte[1] = SkColorGetG(c);
     34     byte[2] = SkColorGetR(c);
     35     byte[3] = SkColorGetA(c);
     36     return packed;
     37 }
     38 
     39 typedef uint32_t (*PackUnpremulProc)(SkColor);
     40 
     41 const struct {
     42     SkColorType         fColorType;
     43     PackUnpremulProc    fPackProc;
     44 } gUnpremul[] = {
     45     { kRGBA_8888_SkColorType, pack_unpremul_rgba },
     46     { kBGRA_8888_SkColorType, pack_unpremul_bgra },
     47 };
     48 
     49 static void fillCanvas(SkCanvas* canvas, SkColorType colorType, PackUnpremulProc proc) {
     50     // Don't strictly need a bitmap, but its a handy way to allocate the pixels
     51     SkBitmap bmp;
     52     bmp.allocN32Pixels(256, 256);
     53 
     54     for (int a = 0; a < 256; ++a) {
     55         uint32_t* pixels = bmp.getAddr32(0, a);
     56         for (int r = 0; r < 256; ++r) {
     57             pixels[r] = proc(SkColorSetARGB(a, r, 0, 0));
     58         }
     59     }
     60 
     61     const SkImageInfo info = SkImageInfo::Make(bmp.width(), bmp.height(),
     62                                                colorType, kUnpremul_SkAlphaType);
     63     canvas->writePixels(info, bmp.getPixels(), bmp.rowBytes(), 0, 0);
     64 }
     65 
     66 static void test_premul_alpha_roundtrip(skiatest::Reporter* reporter, SkBaseDevice* device) {
     67     SkCanvas canvas(device);
     68     for (size_t upmaIdx = 0; upmaIdx < SK_ARRAY_COUNT(gUnpremul); ++upmaIdx) {
     69         fillCanvas(&canvas, gUnpremul[upmaIdx].fColorType, gUnpremul[upmaIdx].fPackProc);
     70 
     71         const SkImageInfo info = SkImageInfo::Make(256, 256, gUnpremul[upmaIdx].fColorType,
     72                                                    kUnpremul_SkAlphaType);
     73         SkBitmap readBmp1;
     74         readBmp1.allocPixels(info);
     75         SkBitmap readBmp2;
     76         readBmp2.allocPixels(info);
     77 
     78         readBmp1.eraseColor(0);
     79         readBmp2.eraseColor(0);
     80 
     81         canvas.readPixels(&readBmp1, 0, 0);
     82         sk_tool_utils::write_pixels(&canvas, readBmp1, 0, 0, gUnpremul[upmaIdx].fColorType,
     83                                     kUnpremul_SkAlphaType);
     84         canvas.readPixels(&readBmp2, 0, 0);
     85 
     86         bool success = true;
     87         for (int y = 0; y < 256 && success; ++y) {
     88             const uint32_t* pixels1 = readBmp1.getAddr32(0, y);
     89             const uint32_t* pixels2 = readBmp2.getAddr32(0, y);
     90             for (int x = 0; x < 256 && success; ++x) {
     91                 // We see sporadic failures here. May help to see where it goes wrong.
     92                 if (pixels1[x] != pixels2[x]) {
     93                     SkDebugf("%x != %x, x = %d, y = %d\n", pixels1[x], pixels2[x], x, y);
     94                 }
     95                 REPORTER_ASSERT(reporter, success = pixels1[x] == pixels2[x]);
     96             }
     97         }
     98     }
     99 }
    100 
    101 DEF_TEST(PremulAlphaRoundTrip, reporter) {
    102     const SkImageInfo info = SkImageInfo::MakeN32Premul(256, 256);
    103     SkSurfaceProps props(SkSurfaceProps::kLegacyFontHost_InitType);
    104     SkAutoTUnref<SkBaseDevice> device(SkBitmapDevice::Create(info, props));
    105     test_premul_alpha_roundtrip(reporter, device);
    106 }
    107 #if SK_SUPPORT_GPU
    108 DEF_GPUTEST_FOR_RENDERING_CONTEXTS(PremulAlphaRoundTrip_Gpu, reporter, context) {
    109     const SkImageInfo info = SkImageInfo::MakeN32Premul(256, 256);
    110     SkSurfaceProps props(SkSurfaceProps::kLegacyFontHost_InitType);
    111     SkAutoTUnref<SkBaseDevice> device(
    112         SkGpuDevice::Create(context, SkBudgeted::kNo, info, 0, &props,
    113                             SkGpuDevice::kUninit_InitContents));
    114     test_premul_alpha_roundtrip(reporter, device);
    115 }
    116 #endif
    117 
    118