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- /*
- * Copyright 2008 The Android Open Source Project
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #include "include/utils/SkInterpolator.h"
- #include "include/core/SkMath.h"
- #include "include/private/SkFixed.h"
- #include "include/private/SkMalloc.h"
- #include "include/private/SkTo.h"
- #include "src/core/SkTSearch.h"
- SkInterpolatorBase::SkInterpolatorBase() {
- fStorage = nullptr;
- fTimes = nullptr;
- SkDEBUGCODE(fTimesArray = nullptr;)
- }
- SkInterpolatorBase::~SkInterpolatorBase() {
- if (fStorage) {
- sk_free(fStorage);
- }
- }
- void SkInterpolatorBase::reset(int elemCount, int frameCount) {
- fFlags = 0;
- fElemCount = SkToU8(elemCount);
- fFrameCount = SkToS16(frameCount);
- fRepeat = SK_Scalar1;
- if (fStorage) {
- sk_free(fStorage);
- fStorage = nullptr;
- fTimes = nullptr;
- SkDEBUGCODE(fTimesArray = nullptr);
- }
- }
- /* Each value[] run is formated as:
- <time (in msec)>
- <blend>
- <data[fElemCount]>
- Totaling fElemCount+2 entries per keyframe
- */
- bool SkInterpolatorBase::getDuration(SkMSec* startTime, SkMSec* endTime) const {
- if (fFrameCount == 0) {
- return false;
- }
- if (startTime) {
- *startTime = fTimes[0].fTime;
- }
- if (endTime) {
- *endTime = fTimes[fFrameCount - 1].fTime;
- }
- return true;
- }
- SkScalar SkInterpolatorBase::ComputeRelativeT(SkMSec time, SkMSec prevTime,
- SkMSec nextTime, const SkScalar blend[4]) {
- SkASSERT(time > prevTime && time < nextTime);
- SkScalar t = (SkScalar)(time - prevTime) / (SkScalar)(nextTime - prevTime);
- return blend ?
- SkUnitCubicInterp(t, blend[0], blend[1], blend[2], blend[3]) : t;
- }
- SkInterpolatorBase::Result SkInterpolatorBase::timeToT(SkMSec time, SkScalar* T,
- int* indexPtr, bool* exactPtr) const {
- SkASSERT(fFrameCount > 0);
- Result result = kNormal_Result;
- if (fRepeat != SK_Scalar1) {
- SkMSec startTime = 0, endTime = 0; // initialize to avoid warning
- this->getDuration(&startTime, &endTime);
- SkMSec totalTime = endTime - startTime;
- SkMSec offsetTime = time - startTime;
- endTime = SkScalarFloorToInt(fRepeat * totalTime);
- if (offsetTime >= endTime) {
- SkScalar fraction = SkScalarFraction(fRepeat);
- offsetTime = fraction == 0 && fRepeat > 0 ? totalTime :
- (SkMSec) SkScalarFloorToInt(fraction * totalTime);
- result = kFreezeEnd_Result;
- } else {
- int mirror = fFlags & kMirror;
- offsetTime = offsetTime % (totalTime << mirror);
- if (offsetTime > totalTime) { // can only be true if fMirror is true
- offsetTime = (totalTime << 1) - offsetTime;
- }
- }
- time = offsetTime + startTime;
- }
- int index = SkTSearch<SkMSec>(&fTimes[0].fTime, fFrameCount, time,
- sizeof(SkTimeCode));
- bool exact = true;
- if (index < 0) {
- index = ~index;
- if (index == 0) {
- result = kFreezeStart_Result;
- } else if (index == fFrameCount) {
- if (fFlags & kReset) {
- index = 0;
- } else {
- index -= 1;
- }
- result = kFreezeEnd_Result;
- } else {
- exact = false;
- }
- }
- SkASSERT(index < fFrameCount);
- const SkTimeCode* nextTime = &fTimes[index];
- SkMSec nextT = nextTime[0].fTime;
- if (exact) {
- *T = 0;
- } else {
- SkMSec prevT = nextTime[-1].fTime;
- *T = ComputeRelativeT(time, prevT, nextT, nextTime[-1].fBlend);
- }
- *indexPtr = index;
- *exactPtr = exact;
- return result;
- }
- SkInterpolator::SkInterpolator() {
- INHERITED::reset(0, 0);
- fValues = nullptr;
- SkDEBUGCODE(fScalarsArray = nullptr;)
- }
- SkInterpolator::SkInterpolator(int elemCount, int frameCount) {
- SkASSERT(elemCount > 0);
- this->reset(elemCount, frameCount);
- }
- void SkInterpolator::reset(int elemCount, int frameCount) {
- INHERITED::reset(elemCount, frameCount);
- fStorage = sk_malloc_throw((sizeof(SkScalar) * elemCount +
- sizeof(SkTimeCode)) * frameCount);
- fTimes = (SkTimeCode*) fStorage;
- fValues = (SkScalar*) ((char*) fStorage + sizeof(SkTimeCode) * frameCount);
- #ifdef SK_DEBUG
- fTimesArray = (SkTimeCode(*)[10]) fTimes;
- fScalarsArray = (SkScalar(*)[10]) fValues;
- #endif
- }
- #define SK_Fixed1Third (SK_Fixed1/3)
- #define SK_Fixed2Third (SK_Fixed1*2/3)
- static const SkScalar gIdentityBlend[4] = {
- 0.33333333f, 0.33333333f, 0.66666667f, 0.66666667f
- };
- bool SkInterpolator::setKeyFrame(int index, SkMSec time,
- const SkScalar values[], const SkScalar blend[4]) {
- SkASSERT(values != nullptr);
- if (blend == nullptr) {
- blend = gIdentityBlend;
- }
- bool success = ~index == SkTSearch<SkMSec>(&fTimes->fTime, index, time,
- sizeof(SkTimeCode));
- SkASSERT(success);
- if (success) {
- SkTimeCode* timeCode = &fTimes[index];
- timeCode->fTime = time;
- memcpy(timeCode->fBlend, blend, sizeof(timeCode->fBlend));
- SkScalar* dst = &fValues[fElemCount * index];
- memcpy(dst, values, fElemCount * sizeof(SkScalar));
- }
- return success;
- }
- SkInterpolator::Result SkInterpolator::timeToValues(SkMSec time,
- SkScalar values[]) const {
- SkScalar T;
- int index;
- bool exact;
- Result result = timeToT(time, &T, &index, &exact);
- if (values) {
- const SkScalar* nextSrc = &fValues[index * fElemCount];
- if (exact) {
- memcpy(values, nextSrc, fElemCount * sizeof(SkScalar));
- } else {
- SkASSERT(index > 0);
- const SkScalar* prevSrc = nextSrc - fElemCount;
- for (int i = fElemCount - 1; i >= 0; --i) {
- values[i] = SkScalarInterp(prevSrc[i], nextSrc[i], T);
- }
- }
- }
- return result;
- }
- ///////////////////////////////////////////////////////////////////////////////
- typedef int Dot14;
- #define Dot14_ONE (1 << 14)
- #define Dot14_HALF (1 << 13)
- #define Dot14ToFloat(x) ((x) / 16384.f)
- static inline Dot14 Dot14Mul(Dot14 a, Dot14 b) {
- return (a * b + Dot14_HALF) >> 14;
- }
- static inline Dot14 eval_cubic(Dot14 t, Dot14 A, Dot14 B, Dot14 C) {
- return Dot14Mul(Dot14Mul(Dot14Mul(C, t) + B, t) + A, t);
- }
- static inline Dot14 pin_and_convert(SkScalar x) {
- if (x <= 0) {
- return 0;
- }
- if (x >= SK_Scalar1) {
- return Dot14_ONE;
- }
- return SkScalarToFixed(x) >> 2;
- }
- SkScalar SkUnitCubicInterp(SkScalar value, SkScalar bx, SkScalar by,
- SkScalar cx, SkScalar cy) {
- // pin to the unit-square, and convert to 2.14
- Dot14 x = pin_and_convert(value);
- if (x == 0) return 0;
- if (x == Dot14_ONE) return SK_Scalar1;
- Dot14 b = pin_and_convert(bx);
- Dot14 c = pin_and_convert(cx);
- // Now compute our coefficients from the control points
- // t -> 3b
- // t^2 -> 3c - 6b
- // t^3 -> 3b - 3c + 1
- Dot14 A = 3*b;
- Dot14 B = 3*(c - 2*b);
- Dot14 C = 3*(b - c) + Dot14_ONE;
- // Now search for a t value given x
- Dot14 t = Dot14_HALF;
- Dot14 dt = Dot14_HALF;
- for (int i = 0; i < 13; i++) {
- dt >>= 1;
- Dot14 guess = eval_cubic(t, A, B, C);
- if (x < guess) {
- t -= dt;
- } else {
- t += dt;
- }
- }
- // Now we have t, so compute the coeff for Y and evaluate
- b = pin_and_convert(by);
- c = pin_and_convert(cy);
- A = 3*b;
- B = 3*(c - 2*b);
- C = 3*(b - c) + Dot14_ONE;
- return SkFixedToScalar(eval_cubic(t, A, B, C) << 2);
- }
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