Add animated text samples
BUG=skia:
Change-Id: I0b0a00a0d5c5790a1fc963458bc90c968830afd8
Reviewed-on: https://skia-review.googlesource.com/8361
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Mike Reed <reed@google.com>
diff --git a/samplecode/SamplePathText.cpp b/samplecode/SamplePathText.cpp
new file mode 100644
index 0000000..26ffb9a
--- /dev/null
+++ b/samplecode/SamplePathText.cpp
@@ -0,0 +1,407 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SampleCode.h"
+#include "SkAnimTimer.h"
+#include "SkCanvas.h"
+#include "SkGlyphCache.h"
+#include "SkPaint.h"
+#include "SkPath.h"
+#include "SkRandom.h"
+#include "SkTaskGroup.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// Static text from paths.
+class PathText : public SampleView {
+public:
+ constexpr static int kNumPaths = 1500;
+ virtual const char* getName() const { return "PathText"; }
+
+ PathText() : fRand(25) {
+ SkPaint defaultPaint;
+ SkAutoGlyphCache agc(defaultPaint, nullptr, &SkMatrix::I());
+ SkGlyphCache* cache = agc.getCache();
+ SkPath glyphPaths[52];
+ for (int i = 0; i < 52; ++i) {
+ // I and l are rects on OS X ...
+ char c = "aQCDEFGH7JKLMNOPBRZTUVWXYSAbcdefghijk1mnopqrstuvwxyz"[i];
+ SkGlyphID id = cache->unicharToGlyph(c);
+ cache->getScalerContext()->getPath(SkPackedGlyphID(id), &glyphPaths[i]);
+ }
+
+ for (int i = 0; i < kNumPaths; ++i) {
+ const SkPath& p = glyphPaths[i % 52];
+ fGlyphs[i].init(fRand, p);
+ }
+ }
+
+ virtual void reset() {
+ for (Glyph& glyph : fGlyphs) {
+ glyph.reset(fRand, this->width(), this->height());
+ }
+ }
+
+ void onOnceBeforeDraw() final { this->INHERITED::onOnceBeforeDraw(); this->reset(); }
+ void onSizeChange() final { this->INHERITED::onSizeChange(); this->reset(); }
+
+ bool onQuery(SkEvent* evt) final {
+ if (SampleCode::TitleQ(*evt)) {
+ SampleCode::TitleR(evt, this->getName());
+ return true;
+ }
+ return this->INHERITED::onQuery(evt);
+ }
+
+ void onDrawContent(SkCanvas* canvas) override {
+ for (Glyph& glyph : fGlyphs) {
+ SkAutoCanvasRestore acr(canvas, true);
+ canvas->translate(glyph.fPosition.x(), glyph.fPosition.y());
+ canvas->scale(glyph.fZoom, glyph.fZoom);
+ canvas->rotate(glyph.fSpin);
+ canvas->translate(-glyph.fMidpt.x(), -glyph.fMidpt.y());
+ canvas->drawPath(glyph.fPath, glyph.fPaint);
+ }
+ }
+
+protected:
+ struct Glyph {
+ void init(SkRandom& rand, const SkPath& path);
+ void reset(SkRandom& rand, int w, int h);
+
+ SkPath fPath;
+ SkPaint fPaint;
+ SkPoint fPosition;
+ SkScalar fZoom;
+ SkScalar fSpin;
+ SkPoint fMidpt;
+ };
+
+ Glyph fGlyphs[kNumPaths];
+ SkRandom fRand;
+
+ typedef SampleView INHERITED;
+};
+
+void PathText::Glyph::init(SkRandom& rand, const SkPath& path) {
+ fPath = path;
+ fPaint.setAntiAlias(true);
+ fPaint.setColor(rand.nextU() | 0x80808080);
+}
+
+void PathText::Glyph::reset(SkRandom& rand, int w, int h) {
+ int screensize = SkTMax(w, h);
+ const SkRect& bounds = fPath.getBounds();
+ SkScalar t;
+
+ fPosition = {rand.nextF() * w, rand.nextF() * h};
+ t = pow(rand.nextF(), 100);
+ fZoom = ((1 - t) * screensize / 50 + t * screensize / 3) /
+ SkTMax(bounds.width(), bounds.height());
+ fSpin = rand.nextF() * 360;
+ fMidpt = {bounds.centerX(), bounds.centerY()};
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// Text from paths with animated transformation matrices.
+class MovingPathText : public PathText {
+public:
+ const char* getName() const override { return "MovingPathText"; }
+
+ MovingPathText()
+ : fFrontMatrices(kNumPaths)
+ , fBackMatrices(kNumPaths) {
+ }
+
+ ~MovingPathText() {
+ fBackgroundAnimationTask.wait();
+ }
+
+ void reset() override {
+ const SkScalar screensize = static_cast<SkScalar>(SkTMax(this->width(), this->height()));
+ this->INHERITED::reset();
+
+ for (auto& v : fVelocities) {
+ for (SkScalar* d : {&v.fDx, &v.fDy}) {
+ SkScalar t = pow(fRand.nextF(), 3);
+ *d = ((1 - t) / 60 + t / 10) * (fRand.nextBool() ? screensize : -screensize);
+ }
+
+ SkScalar t = pow(fRand.nextF(), 25);
+ v.fDSpin = ((1 - t) * 360 / 7.5 + t * 360 / 1.5) * (fRand.nextBool() ? 1 : -1);
+ }
+
+ // Get valid front data.
+ fBackgroundAnimationTask.wait();
+ this->runAnimationTask(0, 0, this->width(), this->height());
+ memcpy(fFrontMatrices, fBackMatrices, kNumPaths * sizeof(SkMatrix));
+ fLastTick = 0;
+ }
+
+ bool onAnimate(const SkAnimTimer& timer) final {
+ fBackgroundAnimationTask.wait();
+ this->swapAnimationBuffers();
+
+ const double tsec = timer.secs();
+ const double dt = fLastTick ? (timer.secs() - fLastTick) : 0;
+ fBackgroundAnimationTask.add(std::bind(&MovingPathText::runAnimationTask, this, tsec,
+ dt, this->width(), this->height()));
+ fLastTick = timer.secs();
+ return true;
+ }
+
+ /**
+ * Called on a background thread. Here we can only modify fBackMatrices.
+ */
+ virtual void runAnimationTask(double t, double dt, int w, int h) {
+ for (int idx = 0; idx < kNumPaths; ++idx) {
+ Velocity* v = &fVelocities[idx];
+ Glyph* glyph = &fGlyphs[idx];
+ SkMatrix* backMatrix = &fBackMatrices[idx];
+
+ glyph->fPosition.fX += v->fDx * dt;
+ if (glyph->fPosition.x() < 0) {
+ glyph->fPosition.fX -= 2 * glyph->fPosition.x();
+ v->fDx = -v->fDx;
+ } else if (glyph->fPosition.x() > w) {
+ glyph->fPosition.fX -= 2 * (glyph->fPosition.x() - w);
+ v->fDx = -v->fDx;
+ }
+
+ glyph->fPosition.fY += v->fDy * dt;
+ if (glyph->fPosition.y() < 0) {
+ glyph->fPosition.fY -= 2 * glyph->fPosition.y();
+ v->fDy = -v->fDy;
+ } else if (glyph->fPosition.y() > h) {
+ glyph->fPosition.fY -= 2 * (glyph->fPosition.y() - h);
+ v->fDy = -v->fDy;
+ }
+
+ glyph->fSpin += v->fDSpin * dt;
+
+ backMatrix->setTranslate(glyph->fPosition.x(), glyph->fPosition.y());
+ backMatrix->preScale(glyph->fZoom, glyph->fZoom);
+ backMatrix->preRotate(glyph->fSpin);
+ backMatrix->preTranslate(-glyph->fMidpt.x(), -glyph->fMidpt.y());
+ }
+ }
+
+ virtual void swapAnimationBuffers() {
+ std::swap(fFrontMatrices, fBackMatrices);
+ }
+
+ void onDrawContent(SkCanvas* canvas) override {
+ for (int i = 0; i < kNumPaths; ++i) {
+ SkAutoCanvasRestore acr(canvas, true);
+ canvas->concat(fFrontMatrices[i]);
+ canvas->drawPath(fGlyphs[i].fPath, fGlyphs[i].fPaint);
+ }
+ }
+
+protected:
+ struct Velocity {
+ SkScalar fDx, fDy;
+ SkScalar fDSpin;
+ };
+
+ Velocity fVelocities[kNumPaths];
+ SkAutoTMalloc<SkMatrix> fFrontMatrices;
+ SkAutoTMalloc<SkMatrix> fBackMatrices;
+ SkTaskGroup fBackgroundAnimationTask;
+ double fLastTick;
+
+ typedef PathText INHERITED;
+};
+
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// Text from paths with animated control points.
+class WavyPathText : public MovingPathText {
+public:
+ const char* getName() const override { return "WavyPathText"; }
+
+ WavyPathText()
+ : fFrontPaths(kNumPaths)
+ , fBackPaths(kNumPaths) {}
+
+ ~WavyPathText() {
+ fBackgroundAnimationTask.wait();
+ }
+
+ void reset() override {
+ fWaves.reset(fRand, this->width(), this->height());
+ this->INHERITED::reset();
+ std::copy(fBackPaths.get(), fBackPaths.get() + kNumPaths, fFrontPaths.get());
+ }
+
+ /**
+ * Called on a background thread. Here we can only modify fBackPaths.
+ */
+ void runAnimationTask(double t, double dt, int w, int h) override {
+ const float tsec = static_cast<float>(t);
+ this->INHERITED::runAnimationTask(t, 0.5 * dt, w, h);
+
+ for (int i = 0; i < kNumPaths; ++i) {
+ const Glyph& glyph = fGlyphs[i];
+ const SkMatrix& backMatrix = fBackMatrices[i];
+
+ const Sk2f matrix[3] = {
+ Sk2f(backMatrix.getScaleX(), backMatrix.getSkewY()),
+ Sk2f(backMatrix.getSkewX(), backMatrix.getScaleY()),
+ Sk2f(backMatrix.getTranslateX(), backMatrix.getTranslateY())
+ };
+
+ SkPath* backpath = &fBackPaths[i];
+ backpath->reset();
+ backpath->setFillType(SkPath::kEvenOdd_FillType);
+
+ SkPath::RawIter iter(glyph.fPath);
+ SkPath::Verb verb;
+ SkPoint pts[4];
+
+ while ((verb = iter.next(pts)) != SkPath::kDone_Verb) {
+ switch (verb) {
+ case SkPath::kMove_Verb: {
+ SkPoint pt = fWaves.apply(tsec, matrix, pts[0]);
+ backpath->moveTo(pt.x(), pt.y());
+ break;
+ }
+ case SkPath::kLine_Verb: {
+ SkPoint endpt = fWaves.apply(tsec, matrix, pts[1]);
+ backpath->lineTo(endpt.x(), endpt.y());
+ break;
+ }
+ case SkPath::kQuad_Verb: {
+ SkPoint controlPt = fWaves.apply(tsec, matrix, pts[1]);
+ SkPoint endpt = fWaves.apply(tsec, matrix, pts[2]);
+ backpath->quadTo(controlPt.x(), controlPt.y(), endpt.x(), endpt.y());
+ break;
+ }
+ case SkPath::kClose_Verb: {
+ backpath->close();
+ break;
+ }
+ case SkPath::kCubic_Verb:
+ case SkPath::kConic_Verb:
+ case SkPath::kDone_Verb:
+ SkFAIL("Unexpected path verb");
+ break;
+ }
+ }
+ }
+ }
+
+ void swapAnimationBuffers() override {
+ this->INHERITED::swapAnimationBuffers();
+ fFrontPaths.swap(fBackPaths);
+ }
+
+ void onDrawContent(SkCanvas* canvas) override {
+ for (int i = 0; i < kNumPaths; ++i) {
+ canvas->drawPath(fFrontPaths[i], fGlyphs[i].fPaint);
+ }
+ }
+
+private:
+ /**
+ * Describes 4 stacked sine waves that can offset a point as a function of wall time.
+ */
+ class Waves {
+ public:
+ void reset(SkRandom& rand, int w, int h);
+ SkPoint apply(float tsec, const Sk2f matrix[3], const SkPoint& pt) const;
+
+ private:
+ constexpr static double kAverageAngle = SK_ScalarPI / 8.0;
+ constexpr static double kMaxOffsetAngle = SK_ScalarPI / 3.0;
+
+ float fAmplitudes[4];
+ float fFrequencies[4];
+ float fDirsX[4];
+ float fDirsY[4];
+ float fSpeeds[4];
+ float fOffsets[4];
+ };
+
+ SkAutoTArray<SkPath> fFrontPaths;
+ SkAutoTArray<SkPath> fBackPaths;
+ Waves fWaves;
+
+ typedef MovingPathText INHERITED;
+};
+
+void WavyPathText::Waves::reset(SkRandom& rand, int w, int h) {
+ const double pixelsPerMeter = 0.06 * SkTMax(w, h);
+ const double medianWavelength = 8 * pixelsPerMeter;
+ const double medianWaveAmplitude = 0.05 * 4 * pixelsPerMeter;
+ const double gravity = 9.8 * pixelsPerMeter;
+
+ for (int i = 0; i < 4; ++i) {
+ const double offsetAngle = (rand.nextF() * 2 - 1) * kMaxOffsetAngle;
+ const double intensity = pow(2, rand.nextF() * 2 - 1);
+ const double wavelength = intensity * medianWavelength;
+
+ fAmplitudes[i] = intensity * medianWaveAmplitude;
+ fFrequencies[i] = 2 * SK_ScalarPI / wavelength;
+ fDirsX[i] = cosf(kAverageAngle + offsetAngle);
+ fDirsY[i] = sinf(kAverageAngle + offsetAngle);
+ fSpeeds[i] = -sqrt(gravity * 2 * SK_ScalarPI / wavelength);
+ fOffsets[i] = rand.nextF() * 2 * SK_ScalarPI;
+ }
+}
+
+SkPoint WavyPathText::Waves::apply(float tsec, const Sk2f matrix[3], const SkPoint& pt) const {
+ constexpr static int kTableSize = 4096;
+ static float sin2table[kTableSize];
+ static SkOnce initTable;
+ initTable([]() {
+ for (int i = 0; i <= kTableSize; ++i) {
+ const double sintheta = sin(i * (SK_ScalarPI / kTableSize));
+ sin2table[i] = static_cast<float>(sintheta * sintheta - 0.5);
+ }
+ });
+
+ const Sk4f amplitudes = Sk4f::Load(fAmplitudes);
+ const Sk4f frequencies = Sk4f::Load(fFrequencies);
+ const Sk4f dirsX = Sk4f::Load(fDirsX);
+ const Sk4f dirsY = Sk4f::Load(fDirsY);
+ const Sk4f speeds = Sk4f::Load(fSpeeds);
+ const Sk4f offsets = Sk4f::Load(fOffsets);
+
+ float devicePt[2];
+ (matrix[0] * pt.x() + matrix[1] * pt.y() + matrix[2]).store(devicePt);
+
+ const Sk4f t = (frequencies * (dirsX * devicePt[0] + dirsY * devicePt[1]) +
+ speeds * tsec +
+ offsets).abs() * (float(kTableSize) / float(SK_ScalarPI));
+
+ const Sk4i ipart = SkNx_cast<int>(t);
+ const Sk4f fpart = t - SkNx_cast<float>(ipart);
+
+ int32_t indices[4];
+ (ipart & (kTableSize-1)).store(indices);
+
+ const Sk4f left(sin2table[indices[0]], sin2table[indices[1]],
+ sin2table[indices[2]], sin2table[indices[3]]);
+ const Sk4f right(sin2table[indices[0] + 1], sin2table[indices[1] + 1],
+ sin2table[indices[2] + 1], sin2table[indices[3] + 1]);
+ const Sk4f height = amplitudes * (left * (1.f - fpart) + right * fpart);
+
+ Sk4f dy = height * dirsY;
+ Sk4f dx = height * dirsX;
+
+ float offsetY[4], offsetX[4];
+ (dy + SkNx_shuffle<2,3,0,1>(dy)).store(offsetY); // accumulate.
+ (dx + SkNx_shuffle<2,3,0,1>(dx)).store(offsetX);;
+
+ return {devicePt[0] + offsetY[0] + offsetY[1], devicePt[1] - offsetX[0] - offsetX[1]};
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+DEF_SAMPLE( return new WavyPathText; )
+DEF_SAMPLE( return new MovingPathText; )
+DEF_SAMPLE( return new PathText; )