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/*
* 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 "SkGradientShader.h"
#include "SkSurface.h"
#include "gm.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];
SkAutoTUnref<SkShader> shader(SkGradientShader::CreateLinear(
pts, shaderColors, NULL, 2, SkShader::kClamp_TileMode));
SkRect r = SkRect::MakeXYWH(0, i * kRowHeight, width, kRowHeight);
SkPaint p;
p.setShader(shader);
canvas->drawRect(r, p);
}
}
// http://crrev.com/834303005
static 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 SkShader::CreateBitmapShader(bm, SkShader::kRepeat_TileMode,
SkShader::kRepeat_TileMode);
}
// 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))->unref();
canvas->drawPaint(paint);
}
/**
* This GM verifies that a transparent bitmap drawn over a
* checkerboard pattern looks correct.
*/
DEF_SIMPLE_GM(transparency_check, canvas, 1912, 1080) {
checkerboard(canvas, 0xFF999999, 0xFF666666, 8);
{
SkAutoCanvasRestore autoCanvasRestore(canvas, true);
SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(256, 9));
make_transparency(surface->getCanvas(), 256.0f, 9.0f);
canvas->scale(7.5f, 120.0f);
surface->draw(canvas, 0, 0, NULL);
}
}
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