1 /*
2  * Copyright 2017 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/SkCanvas.h"
10 #include "include/core/SkColor.h"
11 #include "include/core/SkImageFilter.h"
12 #include "include/core/SkPaint.h"
13 #include "include/core/SkRect.h"
14 #include "include/core/SkScalar.h"
15 #include "include/effects/SkImageFilters.h"
16 
17 #include <initializer_list>
18 
19 // For all sigma, the black box should be centered in the red outline. For small sigma,
20 // the rectangle is not blurred, but still must be centered properly.
21 
22 DEF_SIMPLE_GM(check_small_sigma_offset, canvas, 200, 1200) {
23 
24     for (auto sigma : {0.0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.2}) {
25         // border calculation from SkBlurImageFilter
26         int border = SkScalarCeilToInt(sigma * 3);
27 
28         SkRect r = SkRect::MakeXYWH(50, 50, 100, 50);
29         SkRect b = r.makeOutset(border + 1, border + 1);
30         b.inset(0.5f, 0.5f);
31         SkPaint p;
32         p.setColor(SK_ColorRED);
33         p.setStyle(SkPaint::Style::kStroke_Style);
34 
35         canvas->drawRect(b, p);
36 
37         p.reset();
38         p.setColor(SK_ColorBLACK);
39         p.setImageFilter(SkImageFilters::Blur(sigma, sigma, nullptr));
40         canvas->drawRect(r, p);
41 
42         canvas->translate(0, 100);
43     }
44 }
45