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 "SkClipOpPriv.h"
  11 #include "SkColorFilter.h"
  12 #include "SkPaint.h"
  13 #include "SkRRect.h"
  14
  15 namespace skiagm {
  16
  17 // This GM reproduces the precision artifacts seen in crbug.com/560651.
  18 // It draws a largish blurred circle with its center clipped out.
  19 class BlurredClippedCircleGM : public GM {
  20 public:
  21     BlurredClippedCircleGM() {
  22         this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
  23     }
  24
  25 protected:
  26
  27     SkString onShortName() override {
  28         return SkString("blurredclippedcircle");
  29     }
  30
  31     SkISize onISize() override {
  32         return SkISize::Make(kWidth, kHeight);
  33     }
  34
  35     void onDraw(SkCanvas* canvas) override {
  36         SkPaint whitePaint;
  37         whitePaint.setColor(SK_ColorWHITE);
  38         whitePaint.setBlendMode(SkBlendMode::kSrc);
  39         whitePaint.setAntiAlias(true);
  40
  41         // This scale exercises precision limits in the circle blur effect (crbug.com/560651)
  42         constexpr float kScale = 2.0f;
  43         canvas->scale(kScale, kScale);
  44
  45         canvas->save();
  46             SkRect clipRect1 = SkRect::MakeLTRB(0, 0,
  47                                                 SkIntToScalar(kWidth), SkIntToScalar(kHeight));
  48
  49             canvas->clipRect(clipRect1);
  50
  51             canvas->save();
  52
  53                 canvas->clipRect(clipRect1);
  54                 canvas->drawRect(clipRect1, whitePaint);
  55
  56                 canvas->save();
  57
  58                     SkRect clipRect2 = SkRect::MakeLTRB(8, 8, 288, 288);
  59                     SkRRect clipRRect = SkRRect::MakeOval(clipRect2);
  60                     canvas->clipRRect(clipRRect, kDifference_SkClipOp, true);
  61
  62                     SkRect r = SkRect::MakeLTRB(4, 4, 292, 292);
  63                     SkRRect rr = SkRRect::MakeOval(r);
  64
  65                     SkPaint paint;
  66
  67                     paint.setMaskFilter(SkBlurMaskFilter::Make(
  68                                             kNormal_SkBlurStyle,
  69                                             1.366025f,
  70                                             SkBlurMaskFilter::kHighQuality_BlurFlag));
  71                     paint.setColorFilter(SkColorFilter::MakeModeFilter(
  72                                              SK_ColorRED,
  73                                              SkBlendMode::kSrcIn));
  74                     paint.setAntiAlias(true);
  75
  76                     canvas->drawRRect(rr, paint);
  77
  78                 canvas->restore();
  79             canvas->restore();
  80         canvas->restore();
  81     }
  82
  83 private:
  84     static constexpr int kWidth = 1164;
  85     static constexpr int kHeight = 802;
  86
  87     typedef GM INHERITED;
  88 };
  89
  90 //////////////////////////////////////////////////////////////////////////////
  91
  92 DEF_GM(return new BlurredClippedCircleGM;)
  93 }