80 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			80 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C++
		
	
	
	
| /*
 | |
|  * 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 / SK_ARRAY_COUNT(kColors);
 | |
|     for (size_t i = 0; i < SK_ARRAY_COUNT(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);
 | |
|     }
 | |
| }
 |