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