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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/gm.h"
9 #include "include/core/SkBlurTypes.h"
10 #include "include/core/SkCanvas.h"
11 #include "include/core/SkColor.h"
12 #include "include/core/SkMaskFilter.h"
13 #include "include/core/SkPaint.h"
14 #include "include/core/SkRect.h"
15 #include "include/core/SkScalar.h"
16 #include "include/core/SkSize.h"
17 #include "include/core/SkString.h"
18 #include "include/core/SkTypes.h"
19 #include "src/core/SkBlurMask.h"
20 
21 // This GM tests out the quick reject bounds of the blur mask filter. It draws
22 // four blurred rects around a central clip. The blurred rect geometry outset
23 // by the blur radius does not overlap the clip rect so, if the blur clipping
24 // just uses the radius, they will be clipped out (and the result will differ
25 // from the result if quick reject were disabled. If the blur clipping uses
26 // the correct 3 sigma bound then the images with and without quick rejecting
27 // will be the same.
28 class BlurQuickRejectGM : public skiagm::GM {
29 public:
BlurQuickRejectGM()30     BlurQuickRejectGM() {}
31 
32 protected:
onShortName()33     SkString onShortName() override {
34         return SkString("blurquickreject");
35     }
36 
onISize()37     SkISize onISize() override {
38         return SkISize::Make(kWidth, kHeight);
39     }
40 
onDraw(SkCanvas * canvas)41     void onDraw(SkCanvas* canvas) override {
42         constexpr SkScalar kBlurRadius = SkIntToScalar(20);
43         constexpr SkScalar kBoxSize = SkIntToScalar(100);
44 
45         SkRect clipRect = SkRect::MakeXYWH(0, 0, kBoxSize, kBoxSize);
46         SkRect blurRects[] = {
47             { -kBoxSize - (kBlurRadius+1), 0, -(kBlurRadius+1), kBoxSize },
48             { 0, -kBoxSize - (kBlurRadius+1), kBoxSize, -(kBlurRadius+1) },
49             { kBoxSize+kBlurRadius+1, 0, 2*kBoxSize+kBlurRadius+1, kBoxSize },
50             { 0, kBoxSize+kBlurRadius+1, kBoxSize, 2*kBoxSize+kBlurRadius+1 }
51         };
52         SkColor colors[] = {
53             SK_ColorRED,
54             SK_ColorGREEN,
55             SK_ColorBLUE,
56             SK_ColorYELLOW,
57         };
58         SkASSERT(SK_ARRAY_COUNT(colors) == SK_ARRAY_COUNT(blurRects));
59 
60         SkPaint hairlinePaint;
61         hairlinePaint.setStyle(SkPaint::kStroke_Style);
62         hairlinePaint.setColor(SK_ColorWHITE);
63         hairlinePaint.setStrokeWidth(0);
64 
65         SkPaint blurPaint;
66         blurPaint.setMaskFilter(SkMaskFilter::MakeBlur(kNormal_SkBlurStyle,
67                                                     SkBlurMask::ConvertRadiusToSigma(kBlurRadius)));
68 
69         canvas->clear(SK_ColorBLACK);
70         canvas->save();
71         canvas->translate(kBoxSize, kBoxSize);
72         canvas->drawRect(clipRect, hairlinePaint);
73         canvas->clipRect(clipRect);
74         for (size_t i = 0; i < SK_ARRAY_COUNT(blurRects); ++i) {
75             blurPaint.setColor(colors[i]);
76             canvas->drawRect(blurRects[i], blurPaint);
77             canvas->drawRect(blurRects[i], hairlinePaint);
78         }
79         canvas->restore();
80     }
81 
82 private:
83     inline static constexpr int kWidth = 300;
84     inline static constexpr int kHeight = 300;
85 
86     using INHERITED = GM;
87 };
88 
89 DEF_GM( return new BlurQuickRejectGM(); )
90