gm/blurredclippedcircle.cpp

   1 /*
   2  * Copyright 2015 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 "SkBlurMaskFilter.h"
  10 #include "SkColorFilter.h"
  11 #include "SkPaint.h"
  12 #include "SkRRect.h"
  13
  14 namespace skiagm {
  15
  16 // This GM reproduces the precision artifacts seen in crbug.com/560651.
  17 // It draws a largish blurred circle with its center clipped out.
  18 class BlurredClippedCircleGM : public GM {
  19 public:
  20     BlurredClippedCircleGM() {
  21         this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
  22     }
  23
  24 protected:
  25
  26     SkString onShortName() override {
  27         return SkString("blurredclippedcircle");
  28     }
  29
  30     SkISize onISize() override {
  31         return SkISize::Make(kWidth, kHeight);
  32     }
  33
  34     void onDraw(SkCanvas* canvas) override {
  35         SkPaint whitePaint;
  36         whitePaint.setColor(SK_ColorWHITE);
  37         whitePaint.setBlendMode(SkBlendMode::kSrc);
  38         whitePaint.setAntiAlias(true);
  39
  40         // This scale exercises precision limits in the circle blur effect (crbug.com/560651)
  41         constexpr float kScale = 2.0f;
  42         canvas->scale(kScale, kScale);
  43
  44         canvas->save();
  45             SkRect clipRect1 = SkRect::MakeLTRB(0, 0,
  46                                                 SkIntToScalar(kWidth), SkIntToScalar(kHeight));
  47
  48             canvas->clipRect(clipRect1);
  49
  50             canvas->save();
  51
  52                 canvas->clipRect(clipRect1);
  53                 canvas->drawRect(clipRect1, whitePaint);
  54
  55                 canvas->save();
  56
  57                     SkRect clipRect2 = SkRect::MakeLTRB(8, 8, 288, 288);
  58                     SkRRect clipRRect = SkRRect::MakeOval(clipRect2);
  59                     canvas->clipRRect(clipRRect, SkCanvas::kDifference_Op, true);
  60
  61                     SkRect r = SkRect::MakeLTRB(4, 4, 292, 292);
  62                     SkRRect rr = SkRRect::MakeOval(r);
  63
  64                     SkPaint paint;
  65
  66                     paint.setMaskFilter(SkBlurMaskFilter::Make(
  67                                             kNormal_SkBlurStyle,
  68                                             1.366025f,
  69                                             SkBlurMaskFilter::kHighQuality_BlurFlag));
  70                     paint.setColorFilter(SkColorFilter::MakeModeFilter(
  71                                              SK_ColorRED,
  72                                              SkBlendMode::kSrcIn));
  73                     paint.setAntiAlias(true);
  74
  75                     canvas->drawRRect(rr, paint);
  76
  77                 canvas->restore();
  78             canvas->restore();
  79         canvas->restore();
  80     }
  81
  82 private:
  83     static constexpr int kWidth = 1164;
  84     static constexpr int kHeight = 802;
  85
  86     typedef GM INHERITED;
  87 };
  88
  89 //////////////////////////////////////////////////////////////////////////////
  90
  91 DEF_GM(return new BlurredClippedCircleGM;)
  92 }