| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "SkCanvas.h" |
| #include "SkGradientShader.h" |
| #include "gm.h" |
| |
| // This GM reproduces what I think are overflow bugs in the CPU implementations of a |
| // couple xfermodes. I've marked non-obvious keys to reproducing the bug // Essential! |
| DEF_SIMPLE_GM(buggy_blend_modes, canvas, 800, 200) { |
| const auto tiling = SkShader::kClamp_TileMode; |
| const auto flags = SkGradientShader::kInterpolateColorsInPremul_Flag; // Essential! |
| |
| SkAutoTUnref<SkShader> cyanH, magentaV; |
| { |
| SkPoint pts[] = { {0,0}, {200, 0} }; |
| SkColor colors[] = { 0x00000000, 0xFF00FFFF }; |
| cyanH.reset( |
| SkGradientShader::CreateLinear(pts, colors, nullptr, 2, tiling, flags, nullptr)); |
| } |
| { |
| SkPoint pts[] = { {0,0}, {0, 200} }; |
| SkColor colors[] = { 0x00000000, 0xFFFF00FF }; |
| magentaV.reset( |
| SkGradientShader::CreateLinear(pts, colors, nullptr, 2, tiling, flags, nullptr)); |
| } |
| |
| SkXfermode::Mode modes[] = { |
| SkXfermode::kDarken_Mode, // Looks ok? |
| SkXfermode::kHardLight_Mode, // Definitely wrong. |
| SkXfermode::kLighten_Mode, // Definitely wrong. |
| SkXfermode::kOverlay_Mode, // Same code as kHardLight_Mode. |
| }; |
| |
| canvas->clear(SK_ColorWHITE); |
| for (auto mode : modes) { |
| canvas->saveLayer(nullptr, nullptr); // Essential! |
| SkPaint h, v; |
| h.setShader(cyanH); |
| v.setShader(magentaV); |
| v.setXfermodeMode(mode); |
| canvas->drawRect(SkRect::MakeWH(200,200), h); |
| canvas->drawRect(SkRect::MakeWH(200,200), v); |
| canvas->restore(); |
| |
| canvas->translate(200, 0); |
| } |
| } |