DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (d8847129d134)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271

/*
 * 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 "SkInterpolator.h"
#include "SkMath.h"
#include "SkTSearch.h"

SkInterpolatorBase::SkInterpolatorBase() {
    fStorage    = NULL;
    fTimes      = NULL;
    SkDEBUGCODE(fTimesArray = NULL;)
}

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 = NULL;
        fTimes = NULL;
        SkDEBUGCODE(fTimesArray = NULL);
    }
}

/*  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 = SkScalarDiv((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, SkBool* 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 = NULL;
    SkDEBUGCODE(fScalarsArray = NULL;)
}

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 != NULL);

    if (blend == NULL) {
        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;
    SkBool 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);
}