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