1 /* 2 * Copyright 2024 Google LLC 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 "gm/gm.h" 9 #include "include/core/SkBlendMode.h" 10 #include "include/core/SkCanvas.h" 11 #include "include/core/SkColor.h" 12 #include "include/core/SkPaint.h" 13 #include "include/core/SkRect.h" 14 15 DEF_SIMPLE_GM(luminosity_overflow, canvas, 256, 256) { 16 // As reported in b/359049360: 17 // The luminosity blend mode includes a division that can behave badly (black results) when 18 // drawing low-alpha content over bright backgrounds. This GM reproduced the effect on several 19 // GPUs. Proper rendering should be various near-white colors, with no black boxes. 20 constexpr int kRGBs[] = {243, 247, 251, 255}; 21 canvas->save(); 22 for (int r : kRGBs) { 23 for (int g : kRGBs) { 24 for (int b : kRGBs) { 25 SkPaint p; 26 p.setColor(SkColorSetARGB(255, r, g, b)); 27 canvas->drawRect(SkRect::MakeWH(4, 256), p); 28 canvas->translate(4, 0); 29 } 30 } 31 } 32 canvas->restore(); 33 34 for (int a = 1; a <= 16; ++a) { 35 SkPaint p; 36 p.setColor(SkColorSetARGB(a, 255, 255, 255)); 37 p.setBlendMode(SkBlendMode::kLuminosity); 38 canvas->drawRect(SkRect::MakeWH(256, 16), p); 39 canvas->translate(0, 16); 40 } 41 } 42