skia2/gm/blurquickreject.cpp

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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm.h"
#include "SkBlurMask.h"
#include "SkBlurMaskFilter.h"
#include "SkCanvas.h"
// This GM tests out the quick reject bounds of the blur mask filter. It draws
// four blurred rects around a central clip. The blurred rect geometry outset
// by the blur radius does not overlap the clip rect so, if the blur clipping
// just uses the radius, they will be clipped out (and the result will differ
// from the result if quick reject were disabled. If the blur clipping uses
// the correct 3 sigma bound then the images with and without quick rejecting
// will be the same.
class BlurQuickRejectGM : public skiagm::GM {
public:
BlurQuickRejectGM() {}
protected:
SkString onShortName() override {
return SkString("blurquickreject");
}
SkISize onISize() override {
return SkISize::Make(kWidth, kHeight);
}
void onDraw(SkCanvas* canvas) override {
static const SkScalar kBlurRadius = SkIntToScalar(20);
static const SkScalar kBoxSize = SkIntToScalar(100);
SkRect clipRect = SkRect::MakeXYWH(0, 0, kBoxSize, kBoxSize);
SkRect blurRects[] = {
{ -kBoxSize - (kBlurRadius+1), 0, -(kBlurRadius+1), kBoxSize },
{ 0, -kBoxSize - (kBlurRadius+1), kBoxSize, -(kBlurRadius+1) },
{ kBoxSize+kBlurRadius+1, 0, 2*kBoxSize+kBlurRadius+1, kBoxSize },
{ 0, kBoxSize+kBlurRadius+1, kBoxSize, 2*kBoxSize+kBlurRadius+1 }
};
SkColor colors[] = {
SK_ColorRED,
SK_ColorGREEN,
SK_ColorBLUE,
SK_ColorYELLOW,
};
SkASSERT(SK_ARRAY_COUNT(colors) == SK_ARRAY_COUNT(blurRects));
SkPaint hairlinePaint;
hairlinePaint.setStyle(SkPaint::kStroke_Style);
hairlinePaint.setColor(SK_ColorWHITE);
hairlinePaint.setStrokeWidth(0);
SkPaint blurPaint;
blurPaint.setFilterQuality(kLow_SkFilterQuality);
SkMaskFilter* mf = SkBlurMaskFilter::Create(kNormal_SkBlurStyle,
SkBlurMask::ConvertRadiusToSigma(kBlurRadius));
blurPaint.setMaskFilter(mf)->unref();
canvas->clear(SK_ColorBLACK);
canvas->save();
canvas->translate(kBoxSize, kBoxSize);
canvas->drawRect(clipRect, hairlinePaint);
canvas->clipRect(clipRect);
for (size_t i = 0; i < SK_ARRAY_COUNT(blurRects); ++i) {
blurPaint.setColor(colors[i]);
canvas->drawRect(blurRects[i], blurPaint);
canvas->drawRect(blurRects[i], hairlinePaint);
}
canvas->restore();
}
private:
static const int kWidth = 300;
static const int kHeight = 300;
typedef GM INHERITED;
};
DEF_GM( return new BlurQuickRejectGM(); )