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