1 /*
2 * Copyright 2012 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/SkBitmap.h"
10 #include "include/core/SkCanvas.h"
11 #include "include/core/SkColor.h"
12 #include "include/core/SkFont.h"
13 #include "include/core/SkImage.h"
14 #include "include/core/SkImageFilter.h"
15 #include "include/core/SkImageInfo.h"
16 #include "include/core/SkPaint.h"
17 #include "include/core/SkPixelRef.h"
18 #include "include/core/SkRRect.h"
19 #include "include/core/SkRect.h"
20 #include "include/core/SkRefCnt.h"
21 #include "include/core/SkScalar.h"
22 #include "include/core/SkTypeface.h"
23 #include "include/effects/SkImageFilters.h"
24 #include "src/base/SkRandom.h"
25 #include "tools/ToolUtils.h"
26 #include "tools/fonts/FontToolUtils.h"
27 #include "tools/timer/TimeUtils.h"
28
29 #include <utility>
30
31 #define WIDTH 500
32 #define HEIGHT 500
33
draw_content(SkCanvas * canvas,float maxTextSize,int count)34 static void draw_content(SkCanvas* canvas, float maxTextSize, int count) {
35 const char* str = "The quick brown fox jumped over the lazy dog.";
36 SkRandom rand;
37 SkFont font = ToolUtils::DefaultPortableFont();
38 for (int i = 0; i < count; ++i) {
39 int x = rand.nextULessThan(WIDTH);
40 int y = rand.nextULessThan(HEIGHT);
41 SkPaint paint;
42 paint.setColor(ToolUtils::color_to_565(rand.nextBits(24) | 0xFF000000));
43 font.setSize(rand.nextRangeScalar(0, maxTextSize));
44 canvas->drawString(str, SkIntToScalar(x), SkIntToScalar(y), font, paint);
45 }
46 }
47
DEF_SIMPLE_GM_BG(imagemagnifier,canvas,WIDTH,HEIGHT,SK_ColorBLACK)48 DEF_SIMPLE_GM_BG(imagemagnifier, canvas, WIDTH, HEIGHT, SK_ColorBLACK) {
49 SkPaint filterPaint;
50 filterPaint.setImageFilter(
51 SkImageFilters::Magnifier(SkRect::MakeWH(WIDTH, HEIGHT), 2.f, 100.f,
52 SkFilterMode::kLinear, nullptr));
53 canvas->saveLayer(nullptr, &filterPaint);
54 draw_content(canvas, 300.f, 25);
55 canvas->restore();
56 }
57
58 ////////////////////////////////////////////////////////////////////////////////
59 #define WIDTH_HEIGHT 256
60
make_img()61 static sk_sp<SkImage> make_img() {
62 SkBitmap bitmap;
63 bitmap.allocN32Pixels(WIDTH_HEIGHT, WIDTH_HEIGHT);
64 SkCanvas canvas(bitmap);
65
66 canvas.clear(0x0);
67
68 SkPaint paint;
69 paint.setColor(SK_ColorBLUE);
70
71 for (float pos = 0; pos < WIDTH_HEIGHT; pos += 16) {
72 canvas.drawLine(0, pos, SkIntToScalar(WIDTH_HEIGHT), pos, paint);
73 canvas.drawLine(pos, 0, pos, SkIntToScalar(WIDTH_HEIGHT), paint);
74 }
75
76 SkBitmap result;
77 result.setInfo(SkImageInfo::MakeS32(WIDTH_HEIGHT, WIDTH_HEIGHT, kPremul_SkAlphaType));
78 result.setPixelRef(sk_ref_sp(bitmap.pixelRef()), 0, 0);
79
80 return result.asImage();
81 }
82
DEF_SIMPLE_GM_BG(imagemagnifier_cropped,canvas,WIDTH_HEIGHT,WIDTH_HEIGHT,SK_ColorBLACK)83 DEF_SIMPLE_GM_BG(imagemagnifier_cropped, canvas, WIDTH_HEIGHT, WIDTH_HEIGHT, SK_ColorBLACK) {
84 sk_sp<SkImageFilter> imageSource(SkImageFilters::Image(make_img(), SkFilterMode::kNearest));
85
86 // Crop out a 16 pixel ring around the result
87 const SkIRect cropRect = SkIRect::MakeXYWH(16, 16, WIDTH_HEIGHT-32, WIDTH_HEIGHT-32);
88
89 SkPaint filterPaint;
90 filterPaint.setImageFilter(SkImageFilters::Magnifier(
91 SkRect::MakeWH(WIDTH_HEIGHT, WIDTH_HEIGHT),
92 WIDTH_HEIGHT / (WIDTH_HEIGHT - 96.f), 64.f, {},
93 std::move(imageSource), &cropRect));
94
95 canvas->saveLayer(nullptr, &filterPaint);
96 canvas->restore();
97 }
98
99 class ImageMagnifierBounds : public skiagm::GM {
100 public:
ImageMagnifierBounds()101 ImageMagnifierBounds() : fX(0.f), fY(0.f) {}
102
103 protected:
getName() const104 SkString getName() const override { return SkString("imagemagnifier_bounds"); }
getISize()105 SkISize getISize() override { return SkISize::Make(768, 512); }
106
onAnimate(double nanos)107 bool onAnimate(double nanos) override {
108 fX = TimeUtils::SineWave(nanos, 10.f, 0.f, -200.f, 200.f);
109 fY = TimeUtils::SineWave(nanos, 10.f, 3.f, -200.f, 200.f);
110 return true;
111 }
112
onDraw(SkCanvas * canvas)113 void onDraw(SkCanvas* canvas) override {
114 this->drawRow(canvas, 16.f); // fish eye distortion
115 canvas->translate(0.f, 256.f);
116 this->drawRow(canvas, 0.f); // no distortion, just zoom
117 }
118
119 private:
120
drawRow(SkCanvas * canvas,float inset)121 void drawRow(SkCanvas* canvas, float inset) {
122 // Draw the magnifier two ways: backdrop filtered and then through a saveLayer with a
123 // regular filter. Lastly draw the un-filtered input. Relevant bounds are displayed on
124 // top of the rendering:
125 // - black = the lens bounding box
126 // - red = the clipped inset lens bounds
127 // - blue = the source of the undistorted magnified content
128 auto drawBorder = [canvas](SkRect rect, SkColor color,
129 float width, float borderInset = 0.f) {
130 SkPaint paint;
131 paint.setStyle(SkPaint::kStroke_Style);
132 paint.setStrokeWidth(width);
133 paint.setColor(color);
134 paint.setAntiAlias(true);
135
136 // This draws the original rect (unrounded) when borderInset = 0
137 rect.inset(borderInset, borderInset);
138 canvas->drawRRect(SkRRect::MakeRectXY(rect, borderInset, borderInset), paint);
139 };
140
141 // Logically there is a 'widgetBounds' that is the region of pixels to
142 // be filled with magnified content. Pixels inside widgetBounds are
143 // scaled up by a factor of 'zoomAmount', with a non linear distortion
144 // applied to pixels up to 'inset' inside 'widgetBounds'. The specific
145 // linearly scaled region is termed the 'srcRect' and is adjusted
146 // dynamically if parts of 'widgetBounds' are offscreen.
147 SkRect widgetBounds = {16.f, 24.f, 220.f, 248.f};
148 widgetBounds.offset(fX, fY); // animating helps highlight magnifier behavior
149
150 constexpr float kZoomAmount = 2.5f;
151
152 // The available content for backdrops, which clips the widgetBounds as it animates.
153 constexpr SkRect kOutBounds = {0.f, 0.f, 256.f, 256.f};
154
155 // The filter responds to any crop (explicit or from missing backdrop content). Compute
156 // the corresponding clipped bounds and source bounds for visualization purposes.
157 SkPoint zoomCenter = widgetBounds.center();
158 SkRect clippedWidget = widgetBounds;
159 SkAssertResult(clippedWidget.intersect(kOutBounds));
160 zoomCenter = {SkTPin(zoomCenter.fX, clippedWidget.fLeft, clippedWidget.fRight),
161 SkTPin(zoomCenter.fY, clippedWidget.fTop, clippedWidget.fBottom)};
162 zoomCenter = zoomCenter * (1.f - 1.f / kZoomAmount);
163 SkRect srcRect = {clippedWidget.fLeft / kZoomAmount + zoomCenter.fX,
164 clippedWidget.fTop / kZoomAmount + zoomCenter.fY,
165 clippedWidget.fRight / kZoomAmount + zoomCenter.fX,
166 clippedWidget.fBottom / kZoomAmount + zoomCenter.fY};
167
168 // Internally, the magnifier filter performs equivalent calculations but responds to the
169 // canvas matrix and available input automatically.
170 sk_sp<SkImageFilter> magnifier =
171 SkImageFilters::Magnifier(widgetBounds, kZoomAmount, inset,
172 SkFilterMode::kLinear, nullptr, kOutBounds);
173
174 // Draw once as a backdrop filter
175 canvas->save();
176 canvas->clipRect(kOutBounds);
177 draw_content(canvas, 32.f, 350);
178 canvas->saveLayer({nullptr, nullptr, magnifier.get(), 0});
179 canvas->restore();
180
181 drawBorder(widgetBounds, SK_ColorBLACK, 2.f);
182 if (inset > 0.f) {
183 drawBorder(clippedWidget, SK_ColorRED, 2.f, inset);
184 }
185 canvas->restore();
186
187 // Draw once as a regular filter
188 canvas->save();
189 canvas->translate(256.f, 0.f);
190 canvas->clipRect(kOutBounds);
191
192 SkPaint paint;
193 paint.setImageFilter(magnifier);
194 canvas->saveLayer(nullptr, &paint);
195 draw_content(canvas, 32.f, 350);
196 canvas->restore();
197
198 drawBorder(widgetBounds, SK_ColorBLACK, 2.f);
199 if (inset > 0.f) {
200 drawBorder(clippedWidget, SK_ColorRED, 2.f, inset);
201 }
202 canvas->restore();
203
204 // Draw once unfiltered
205 canvas->save();
206 canvas->translate(512.f, 0.f);
207 canvas->clipRect(kOutBounds);
208 draw_content(canvas, 32.f, 350);
209
210 drawBorder(widgetBounds, SK_ColorBLACK, 2.f);
211 drawBorder(srcRect, SK_ColorBLUE, 2.f, inset / kZoomAmount);
212 canvas->restore();
213 }
214
215 private:
216 SkScalar fX;
217 SkScalar fY;
218 };
219
220 DEF_GM(return new ImageMagnifierBounds(); )
221