1 /*
2 * Copyright 2019 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/SkPictureRecorder.h"
14 #include "include/core/SkRect.h"
15 #include "include/core/SkRefCnt.h"
16 #include "include/core/SkScalar.h"
17 #include "include/core/SkShader.h"
18 #include "include/core/SkTypes.h"
19 #include "include/effects/SkGradientShader.h"
20 #include "include/effects/SkImageFilters.h"
21
22 #include <initializer_list>
23
24 // Make a noisy (with hard-edges) background, so we can see the effect of the blur
25 //
make_shader(SkScalar cx,SkScalar cy,SkScalar rad)26 static sk_sp<SkShader> make_shader(SkScalar cx, SkScalar cy, SkScalar rad) {
27 const SkColor colors[] = {
28 SK_ColorRED, SK_ColorRED, SK_ColorBLUE, SK_ColorBLUE, SK_ColorGREEN, SK_ColorGREEN,
29 SK_ColorRED, SK_ColorRED, SK_ColorBLUE, SK_ColorBLUE, SK_ColorGREEN, SK_ColorGREEN,
30 };
31 constexpr int count = SK_ARRAY_COUNT(colors);
32 SkScalar pos[count] = { 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6 };
33 for (int i = 0; i < count; ++i) {
34 pos[i] *= 1.0f/6;
35 }
36 return SkGradientShader::MakeSweep(cx, cy, colors, pos, count);
37 }
38
do_draw(SkCanvas * canvas,bool useClip,bool useHintRect)39 static void do_draw(SkCanvas* canvas, bool useClip, bool useHintRect) {
40 SkAutoCanvasRestore acr(canvas, true);
41 canvas->clipRect({0, 0, 256, 256});
42
43 const SkScalar cx = 128, cy = 128, rad = 100;
44 SkPaint p;
45 p.setShader(make_shader(cx, cy, rad));
46 p.setAntiAlias(true);
47 canvas->drawCircle(cx, cy, rad, p);
48
49 // now setup a saveLayer that will pull in the backdrop and blur it
50 //
51 const SkRect r = {cx-50, cy-50, cx+50, cy+50};
52 const SkRect* drawrptr = useHintRect ? &r : nullptr;
53 const SkScalar sigma = 10;
54 if (useClip) {
55 canvas->clipRect(r);
56 }
57 // Using kClamp because kDecal, the default, produces transparency near the edge of the canvas's
58 // device.
59 auto blur = SkImageFilters::Blur(sigma, sigma, SkTileMode::kClamp, nullptr);
60 auto rec = SkCanvas::SaveLayerRec(drawrptr, nullptr, blur.get(), 0);
61 canvas->saveLayer(rec);
62 // draw something inside, just to demonstrate that we don't blur the new contents,
63 // just the backdrop.
64 p.setColor(SK_ColorYELLOW);
65 p.setShader(nullptr);
66 canvas->drawCircle(cx, cy, 30, p);
67 canvas->restore();
68 }
69
70 /*
71 * Draws a 2x4 grid of sweep circles.
72 * - for a given row, each col should be identical (canvas, picture)
73 * - row:0 no-hint-rect no-clip-rect expect big blur (except inner circle)
74 * - row:1 no-hint-rect clip-rect expect small blur (except inner circle)
75 * - row:2 hint-rect no-clip-rect expect big blur (except inner circle)
76 * - row:3 hint-rect clip-rect expect small blur (except inner circle)
77 *
78 * The test is that backdrop effects should be independent of the hint-rect, but should
79 * respect the clip-rect.
80 */
81 DEF_SIMPLE_GM(backdrop_hintrect_clipping, canvas, 512, 1024) {
82 for (bool useHintRect : {false, true}) {
83 for (bool useClip : {false, true}) {
84 canvas->save();
85 do_draw(canvas, useClip, useHintRect);
86
87 SkPictureRecorder rec;
88 do_draw(rec.beginRecording(256, 256), useClip, useHintRect);
89 canvas->translate(256, 0);
90 canvas->drawPicture(rec.finishRecordingAsPicture());
91 canvas->restore();
92
93 canvas->translate(0, 256);
94 }
95 }
96 }
97