1 /*
2  * Copyright 2018 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 #include "samplecode/Sample.h"
8 #include "tools/ToolUtils.h"
9 
10 #include "include/core/SkCanvas.h"
11 #include "include/core/SkPath.h"
12 #include "include/core/SkRRect.h"
13 #include "include/core/SkTypeface.h"
14 #include "include/utils/SkRandom.h"
15 #include "tools/timer/TimeUtils.h"
16 
17 #include <cmath>
18 
19 // Implementation in C++ of Animated Emoji
20 // See https://t.d3fc.io/status/705212795936247808
21 // See https://crbug.com/848616
22 
23 class GlyphTransformView : public Sample {
24 public:
GlyphTransformView()25     GlyphTransformView() {}
26 
27 protected:
onOnceBeforeDraw()28     void onOnceBeforeDraw() override {
29         fEmojiFont.fTypeface = ToolUtils::emoji_typeface();
30         fEmojiFont.fText     = ToolUtils::emoji_sample_text();
31     }
32 
name()33     SkString name() override { return SkString("Glyph Transform"); }
34 
onDrawContent(SkCanvas * canvas)35     void onDrawContent(SkCanvas* canvas) override {
36         SkPaint paint;
37 
38         SkFont font(fEmojiFont.fTypeface);
39         const char* text = fEmojiFont.fText;
40 
41         double baseline = this->height() / 2;
42         canvas->drawLine(0, baseline, this->width(), baseline, paint);
43 
44         SkMatrix ctm;
45         ctm.setRotate(fRotate); // d3 rotate takes degrees
46         ctm.postScale(fScale * 4, fScale * 4);
47         ctm.postTranslate(fTranslate.fX  + this->width() * 0.8, fTranslate.fY + baseline);
48         canvas->concat(ctm);
49 
50         // d3 by default anchors text around the middle
51         SkRect bounds;
52         font.measureText(text, strlen(text), SkTextEncoding::kUTF8, &bounds);
53         canvas->drawSimpleText(text, strlen(text), SkTextEncoding::kUTF8, -bounds.centerX(), -bounds.centerY(),
54                                font, paint);
55     }
56 
onAnimate(double nanos)57     bool onAnimate(double nanos) override {
58         constexpr SkScalar maxt = 100000;
59         double t = TimeUtils::PingPong(1e-9 * nanos, 20, 0, 0, maxt); // d3 t is in milliseconds
60 
61         fTranslate.set(sin(t / 3000) - t * this->width() * 0.7 / maxt, sin(t / 999) / t);
62         fScale = 4.5 - std::sqrt(t) / 99;
63         fRotate = sin(t / 734);
64 
65         return true;
66     }
67 
68 private:
69     struct EmojiFont {
70         sk_sp<SkTypeface> fTypeface;
71         const char* fText;
72     } fEmojiFont;
73 
74     SkVector fTranslate;
75     SkScalar fScale;
76     SkScalar fRotate;
77 
78     typedef Sample INHERITED;
79 };
80 
81 //////////////////////////////////////////////////////////////////////////////
82 
83 DEF_SAMPLE( return new GlyphTransformView(); )
84