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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/SkFilterQuality.h"
13 #include "include/core/SkMaskFilter.h"
14 #include "include/core/SkPaint.h"
15 #include "include/core/SkRect.h"
16 #include "include/core/SkScalar.h"
17 #include "include/core/SkSize.h"
18 #include "include/core/SkString.h"
19 #include "include/core/SkTypes.h"
20 #include "src/core/SkBlurMask.h"
21 
22 // This GM tests out the quick reject bounds of the blur mask filter. It draws
23 // four blurred rects around a central clip. The blurred rect geometry outset
24 // by the blur radius does not overlap the clip rect so, if the blur clipping
25 // just uses the radius, they will be clipped out (and the result will differ
26 // from the result if quick reject were disabled. If the blur clipping uses
27 // the correct 3 sigma bound then the images with and without quick rejecting
28 // will be the same.
29 class BlurQuickRejectGM : public skiagm::GM {
30 public:
BlurQuickRejectGM()31     BlurQuickRejectGM() {}
32 
33 protected:
onShortName()34     SkString onShortName() override {
35         return SkString("blurquickreject");
36     }
37 
onISize()38     SkISize onISize() override {
39         return SkISize::Make(kWidth, kHeight);
40     }
41 
onDraw(SkCanvas * canvas)42     void onDraw(SkCanvas* canvas) override {
43         constexpr SkScalar kBlurRadius = SkIntToScalar(20);
44         constexpr SkScalar kBoxSize = SkIntToScalar(100);
45 
46         SkRect clipRect = SkRect::MakeXYWH(0, 0, kBoxSize, kBoxSize);
47         SkRect blurRects[] = {
48             { -kBoxSize - (kBlurRadius+1), 0, -(kBlurRadius+1), kBoxSize },
49             { 0, -kBoxSize - (kBlurRadius+1), kBoxSize, -(kBlurRadius+1) },
50             { kBoxSize+kBlurRadius+1, 0, 2*kBoxSize+kBlurRadius+1, kBoxSize },
51             { 0, kBoxSize+kBlurRadius+1, kBoxSize, 2*kBoxSize+kBlurRadius+1 }
52         };
53         SkColor colors[] = {
54             SK_ColorRED,
55             SK_ColorGREEN,
56             SK_ColorBLUE,
57             SK_ColorYELLOW,
58         };
59         SkASSERT(SK_ARRAY_COUNT(colors) == SK_ARRAY_COUNT(blurRects));
60 
61         SkPaint hairlinePaint;
62         hairlinePaint.setStyle(SkPaint::kStroke_Style);
63         hairlinePaint.setColor(SK_ColorWHITE);
64         hairlinePaint.setStrokeWidth(0);
65 
66         SkPaint blurPaint;
67         blurPaint.setMaskFilter(SkMaskFilter::MakeBlur(kNormal_SkBlurStyle,
68                                                     SkBlurMask::ConvertRadiusToSigma(kBlurRadius)));
69 
70         canvas->clear(SK_ColorBLACK);
71         canvas->save();
72         canvas->translate(kBoxSize, kBoxSize);
73         canvas->drawRect(clipRect, hairlinePaint);
74         canvas->clipRect(clipRect);
75         for (size_t i = 0; i < SK_ARRAY_COUNT(blurRects); ++i) {
76             blurPaint.setColor(colors[i]);
77             canvas->drawRect(blurRects[i], blurPaint);
78             canvas->drawRect(blurRects[i], hairlinePaint);
79         }
80         canvas->restore();
81     }
82 
83 private:
84     static constexpr int kWidth = 300;
85     static constexpr int kHeight = 300;
86 
87     using INHERITED = GM;
88 };
89 
90 DEF_GM( return new BlurQuickRejectGM(); )
91