75 lines
2.4 KiB
C++
75 lines
2.4 KiB
C++
/*
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* Copyright 2015 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "SkGradientShader.h"
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#include "SkSurface.h"
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#include "gm.h"
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static void make_transparency(SkCanvas* canvas,
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SkScalar width,
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SkScalar height) {
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SkPoint pts[2];
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pts[0] = SkPoint::Make(0, 0);
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pts[1] = SkPoint::Make(width, 0);
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const SkColor kColors[] = {
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SK_ColorBLACK,
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SK_ColorGRAY,
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SK_ColorWHITE,
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SK_ColorRED,
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SK_ColorYELLOW,
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SK_ColorGREEN,
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SK_ColorCYAN,
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SK_ColorBLUE,
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SK_ColorMAGENTA,
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};
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const SkScalar kRowHeight = height / SK_ARRAY_COUNT(kColors);
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for (size_t i = 0; i < SK_ARRAY_COUNT(kColors); ++i) {
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SkColor shaderColors[2];
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shaderColors[0] = SK_AlphaTRANSPARENT;
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shaderColors[1] = kColors[i];
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SkAutoTUnref<SkShader> shader(SkGradientShader::CreateLinear(
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pts, shaderColors, NULL, 2, SkShader::kClamp_TileMode));
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SkRect r = SkRect::MakeXYWH(0, i * kRowHeight, width, kRowHeight);
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SkPaint p;
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p.setShader(shader);
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canvas->drawRect(r, p);
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}
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}
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// http://crrev.com/834303005
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static SkShader* create_checkerboard_shader(SkColor c1, SkColor c2, int size) {
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SkBitmap bm;
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bm.allocN32Pixels(2 * size, 2 * size);
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bm.eraseColor(c1);
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bm.eraseArea(SkIRect::MakeLTRB(0, 0, size, size), c2);
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bm.eraseArea(SkIRect::MakeLTRB(size, size, 2 * size, 2 * size), c2);
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return SkShader::CreateBitmapShader(bm, SkShader::kRepeat_TileMode,
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SkShader::kRepeat_TileMode);
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}
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// http://crrev.com/834303005
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static void checkerboard(SkCanvas* canvas, SkColor c1, SkColor c2, int size) {
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SkPaint paint;
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paint.setShader(create_checkerboard_shader(c1, c2, size))->unref();
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canvas->drawPaint(paint);
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}
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/**
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* This GM verifies that a transparent bitmap drawn over a
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* checkerboard pattern looks correct.
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*/
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DEF_SIMPLE_GM(transparency_check, canvas, 1792, 1080) {
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checkerboard(canvas, 0xFF999999, 0xFF666666, 8);
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{
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SkAutoCanvasRestore autoCanvasRestore(canvas, true);
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SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(256, 9));
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make_transparency(surface->getCanvas(), 256.0f, 9.0f);
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canvas->scale(7.0f, 120.0f);
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surface->draw(canvas, 0, 0, NULL);
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}
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}
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