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
19static 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
29static 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
39typedef uint32_t (*PackUnpremulProc)(SkColor);
40
41const 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
49static 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
66static 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
101DEF_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
108DEF_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