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 #include "src/core/SkCanvasPriv.h"
22 #include "src/core/SkMatrixPriv.h"
23
24 #include <initializer_list>
25
26 // Make a noisy (with hard-edges) background, so we can see the effect of the blur
27 //
make_shader(SkScalar cx,SkScalar cy,SkScalar rad)28 static sk_sp<SkShader> make_shader(SkScalar cx, SkScalar cy, SkScalar rad) {
29 const SkColor colors[] = {
30 SK_ColorRED, SK_ColorRED, SK_ColorBLUE, SK_ColorBLUE, SK_ColorGREEN, SK_ColorGREEN,
31 SK_ColorRED, SK_ColorRED, SK_ColorBLUE, SK_ColorBLUE, SK_ColorGREEN, SK_ColorGREEN,
32 };
33 constexpr int count = std::size(colors);
34 SkScalar pos[count] = { 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6 };
35 for (int i = 0; i < count; ++i) {
36 pos[i] *= 1.0f/6;
37 }
38 return SkGradientShader::MakeSweep(cx, cy, colors, pos, count);
39 }
40
do_draw(SkCanvas * canvas,bool useClip,bool useHintRect,SkScalar scaleFactor)41 static void do_draw(SkCanvas* canvas, bool useClip, bool useHintRect, SkScalar scaleFactor) {
42 SkAutoCanvasRestore acr(canvas, true);
43 canvas->clipRect({0, 0, 256, 256});
44
45 const SkScalar cx = 128, cy = 128, rad = 100;
46 SkPaint p;
47 p.setShader(make_shader(cx, cy, rad));
48 p.setAntiAlias(true);
49 canvas->drawCircle(cx, cy, rad, p);
50
51 // now setup a saveLayer that will pull in the backdrop and blur it
52 //
53 const SkRect r = {cx-50, cy-50, cx+50, cy+50};
54 const SkRect* drawrptr = useHintRect ? &r : nullptr;
55 const SkScalar sigma = 10;
56 if (useClip) {
57 canvas->clipRect(r);
58 }
59 // Using kClamp because kDecal, the default, produces transparency near the edge of the canvas's
60 // device.
61 SkRect blurCrop;
62 SkAssertResult(SkMatrixPriv::InverseMapRect(canvas->getLocalToDeviceAs3x3(),
63 &blurCrop,
64 SkRect::MakeWH(canvas->imageInfo().width(),
65 canvas->imageInfo().height())));
66 auto blur = SkImageFilters::Blur(sigma, sigma, SkTileMode::kClamp, nullptr, blurCrop);
67 auto rec = SkCanvasPriv::ScaledBackdropLayer(drawrptr, nullptr, blur.get(), scaleFactor, 0);
68 canvas->saveLayer(rec);
69 // draw something inside, just to demonstrate that we don't blur the new contents,
70 // just the backdrop.
71 p.setColor(SK_ColorYELLOW);
72 p.setShader(nullptr);
73 canvas->drawCircle(cx, cy, 30, p);
74 canvas->restore();
75 }
76
77 /*
78 * Draws a 2x4 grid of sweep circles.
79 * - for a given row, each col should be identical (canvas, picture)
80 * - row:0 no-hint-rect no-clip-rect expect big blur (except inner circle)
81 * - row:1 no-hint-rect clip-rect expect small blur (except inner circle)
82 * - row:2 hint-rect no-clip-rect expect big blur (except inner circle)
83 * - row:3 hint-rect clip-rect expect small blur (except inner circle)
84 *
85 * The test is that backdrop effects should be independent of the hint-rect, but should
86 * respect the clip-rect.
87 */
88 DEF_SIMPLE_GM(backdrop_hintrect_clipping, canvas, 512, 1024) {
89 for (bool useHintRect : {false, true}) {
90 for (bool useClip : {false, true}) {
91 canvas->save();
92 do_draw(canvas, useClip, useHintRect, 1.0f);
93
94 SkPictureRecorder rec;
95 do_draw(rec.beginRecording(256, 256), useClip, useHintRect, 1.0f);
96 canvas->translate(256, 0);
97 canvas->drawPicture(rec.finishRecordingAsPicture());
98 canvas->restore();
99
100 canvas->translate(0, 256);
101 }
102 }
103 }
104
105 /*
106 * Draws a 3x4 grid of sweep circles.
107 * - for a given row, each col should be identical except that the intermediate scale factor used
108 * to evaluate the backdrop follows (1.0, 0.25, 0.1). Rows follow same pattern as above.
109 *
110 * The test is that backdrop effects should be independent of the hint-rect, should respect the
111 * clip rect, and be logically consistent with the reduced intermediate scaling.
112 */
113 DEF_SIMPLE_GM(backdrop_scalefactor, canvas, 768, 1024) {
114 for (bool useHintRect : {false, true}) {
115 for (bool useClip : {false, true}) {
116 canvas->save();
117 do_draw(canvas, useClip, useHintRect, 1.0f);
118 canvas->translate(256, 0);
119 do_draw(canvas, useClip, useHintRect, 0.25f);
120 canvas->translate(256, 0);
121 do_draw(canvas, useClip, useHintRect, 0.1f);
122 canvas->restore();
123
124 canvas->translate(0, 256);
125 }
126 }
127 }
128