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