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      1 /*
      2  * Copyright 2013 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "gm.h"
      9 #include "SkBlurMask.h"
     10 #include "SkBlurMaskFilter.h"
     11 #include "SkCanvas.h"
     12 
     13 // This GM tests out the quick reject bounds of the blur mask filter. It draws
     14 // four blurred rects around a central clip. The blurred rect geometry outset
     15 // by the blur radius does not overlap the clip rect so, if the blur clipping
     16 // just uses the radius, they will be clipped out (and the result will differ
     17 // from the result if quick reject were disabled. If the blur clipping uses
     18 // the correct 3 sigma bound then the images with and without quick rejecting
     19 // will be the same.
     20 class BlurQuickRejectGM : public skiagm::GM {
     21 public:
     22     BlurQuickRejectGM() {}
     23 
     24 protected:
     25     virtual SkString onShortName() SK_OVERRIDE {
     26         return SkString("blurquickreject");
     27     }
     28 
     29     virtual SkISize onISize() SK_OVERRIDE {
     30         return SkISize::Make(kWidth, kHeight);
     31     }
     32 
     33     virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
     34         static const SkScalar kBlurRadius = SkIntToScalar(20);
     35         static const SkScalar kBoxSize = SkIntToScalar(100);
     36 
     37         SkRect clipRect = SkRect::MakeXYWH(0, 0, kBoxSize, kBoxSize);
     38         SkRect blurRects[] = {
     39             { -kBoxSize - (kBlurRadius+1), 0, -(kBlurRadius+1), kBoxSize },
     40             { 0, -kBoxSize - (kBlurRadius+1), kBoxSize, -(kBlurRadius+1) },
     41             { kBoxSize+kBlurRadius+1, 0, 2*kBoxSize+kBlurRadius+1, kBoxSize },
     42             { 0, kBoxSize+kBlurRadius+1, kBoxSize, 2*kBoxSize+kBlurRadius+1 }
     43         };
     44         SkColor colors[] = {
     45             SK_ColorRED,
     46             SK_ColorGREEN,
     47             SK_ColorBLUE,
     48             SK_ColorYELLOW,
     49         };
     50         SkASSERT(SK_ARRAY_COUNT(colors) == SK_ARRAY_COUNT(blurRects));
     51 
     52         SkPaint hairlinePaint;
     53         hairlinePaint.setStyle(SkPaint::kStroke_Style);
     54         hairlinePaint.setColor(SK_ColorWHITE);
     55         hairlinePaint.setStrokeWidth(0);
     56 
     57         SkPaint blurPaint;
     58         blurPaint.setFilterLevel(SkPaint::kLow_FilterLevel);
     59         SkMaskFilter* mf = SkBlurMaskFilter::Create(kNormal_SkBlurStyle,
     60                                                     SkBlurMask::ConvertRadiusToSigma(kBlurRadius));
     61         blurPaint.setMaskFilter(mf)->unref();
     62 
     63         canvas->clear(SK_ColorBLACK);
     64         canvas->save();
     65         canvas->translate(kBoxSize, kBoxSize);
     66         canvas->drawRect(clipRect, hairlinePaint);
     67         canvas->clipRect(clipRect);
     68         for (size_t i = 0; i < SK_ARRAY_COUNT(blurRects); ++i) {
     69             blurPaint.setColor(colors[i]);
     70             canvas->drawRect(blurRects[i], blurPaint);
     71             canvas->drawRect(blurRects[i], hairlinePaint);
     72         }
     73         canvas->restore();
     74     }
     75 
     76 private:
     77     static const int kWidth = 300;
     78     static const int kHeight = 300;
     79 
     80     typedef GM INHERITED;
     81 };
     82 
     83 DEF_GM( return new BlurQuickRejectGM(); )
     84