| /* |
| * 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 "gm/gm.h" |
| #include "include/core/SkBitmap.h" |
| #include "include/core/SkCanvas.h" |
| #include "include/core/SkColor.h" |
| #include "include/core/SkPaint.h" |
| #include "include/core/SkPoint.h" |
| #include "include/core/SkRect.h" |
| #include "include/core/SkRefCnt.h" |
| #include "include/core/SkScalar.h" |
| #include "include/core/SkShader.h" |
| #include "include/core/SkSurface.h" |
| #include "include/core/SkTileMode.h" |
| #include "include/core/SkTypes.h" |
| #include "include/effects/SkGradientShader.h" |
| |
| static void make_transparency(SkCanvas* canvas, SkScalar width, SkScalar height) { |
| SkPoint pts[2]; |
| pts[0] = SkPoint::Make(0, 0); |
| pts[1] = SkPoint::Make(width, 0); |
| const SkColor kColors[] = { |
| SK_ColorBLACK, |
| SK_ColorGRAY, |
| SK_ColorWHITE, |
| SK_ColorRED, |
| SK_ColorYELLOW, |
| SK_ColorGREEN, |
| SK_ColorCYAN, |
| SK_ColorBLUE, |
| SK_ColorMAGENTA, |
| }; |
| const SkScalar kRowHeight = height / std::size(kColors); |
| for (size_t i = 0; i < std::size(kColors); ++i) { |
| SkColor shaderColors[2]; |
| shaderColors[0] = SK_AlphaTRANSPARENT; |
| shaderColors[1] = kColors[i]; |
| SkPaint p; |
| p.setShader(SkGradientShader::MakeLinear(pts, shaderColors, nullptr, 2, SkTileMode::kClamp)); |
| canvas->drawRect(SkRect::MakeXYWH(0, i * kRowHeight, width, kRowHeight), p); |
| } |
| } |
| |
| // http://crrev.com/834303005 |
| static sk_sp<SkShader> create_checkerboard_shader(SkColor c1, SkColor c2, int size) { |
| SkBitmap bm; |
| bm.allocN32Pixels(2 * size, 2 * size); |
| bm.eraseColor(c1); |
| bm.eraseArea(SkIRect::MakeLTRB(0, 0, size, size), c2); |
| bm.eraseArea(SkIRect::MakeLTRB(size, size, 2 * size, 2 * size), c2); |
| return bm.makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat, SkSamplingOptions()); |
| } |
| |
| // http://crrev.com/834303005 |
| static void checkerboard(SkCanvas* canvas, SkColor c1, SkColor c2, int size) { |
| SkPaint paint; |
| paint.setShader(create_checkerboard_shader(c1, c2, size)); |
| canvas->drawPaint(paint); |
| } |
| |
| /** |
| * This GM verifies that a transparent bitmap drawn over a |
| * checkerboard pattern looks correct. |
| */ |
| DEF_SIMPLE_GM(transparency_check, canvas, 1792, 1080) { |
| checkerboard(canvas, 0xFF999999, 0xFF666666, 8); |
| { |
| SkAutoCanvasRestore autoCanvasRestore(canvas, true); |
| auto surface(SkSurface::MakeRasterN32Premul(256, 9)); |
| make_transparency(surface->getCanvas(), 256.0f, 9.0f); |
| canvas->scale(7.0f, 120.0f); |
| surface->draw(canvas, 0, 0); |
| } |
| } |