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      1 /*
      2  * Copyright 2006 The Android Open Source Project
      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 
      8 #include "SkGradientShaderPriv.h"
      9 #include "SkLinearGradient.h"
     10 #include "SkRadialGradient.h"
     11 #include "SkTwoPointRadialGradient.h"
     12 #include "SkTwoPointConicalGradient.h"
     13 #include "SkSweepGradient.h"
     14 
     15 SkGradientShaderBase::SkGradientShaderBase(const Descriptor& desc) {
     16     SkASSERT(desc.fCount > 1);
     17 
     18     fCacheAlpha = 256;  // init to a value that paint.getAlpha() can't return
     19 
     20     fMapper = desc.fMapper;
     21     SkSafeRef(fMapper);
     22     fGradFlags = SkToU8(desc.fFlags);
     23 
     24     SkASSERT((unsigned)desc.fTileMode < SkShader::kTileModeCount);
     25     SkASSERT(SkShader::kTileModeCount == SK_ARRAY_COUNT(gTileProcs));
     26     fTileMode = desc.fTileMode;
     27     fTileProc = gTileProcs[desc.fTileMode];
     28 
     29     fCache16 = fCache16Storage = NULL;
     30     fCache32 = NULL;
     31     fCache32PixelRef = NULL;
     32 
     33     /*  Note: we let the caller skip the first and/or last position.
     34         i.e. pos[0] = 0.3, pos[1] = 0.7
     35         In these cases, we insert dummy entries to ensure that the final data
     36         will be bracketed by [0, 1].
     37         i.e. our_pos[0] = 0, our_pos[1] = 0.3, our_pos[2] = 0.7, our_pos[3] = 1
     38 
     39         Thus colorCount (the caller's value, and fColorCount (our value) may
     40         differ by up to 2. In the above example:
     41             colorCount = 2
     42             fColorCount = 4
     43      */
     44     fColorCount = desc.fCount;
     45     // check if we need to add in dummy start and/or end position/colors
     46     bool dummyFirst = false;
     47     bool dummyLast = false;
     48     if (desc.fPos) {
     49         dummyFirst = desc.fPos[0] != 0;
     50         dummyLast = desc.fPos[desc.fCount - 1] != SK_Scalar1;
     51         fColorCount += dummyFirst + dummyLast;
     52     }
     53 
     54     if (fColorCount > kColorStorageCount) {
     55         size_t size = sizeof(SkColor) + sizeof(Rec);
     56         fOrigColors = reinterpret_cast<SkColor*>(
     57                                         sk_malloc_throw(size * fColorCount));
     58     }
     59     else {
     60         fOrigColors = fStorage;
     61     }
     62 
     63     // Now copy over the colors, adding the dummies as needed
     64     {
     65         SkColor* origColors = fOrigColors;
     66         if (dummyFirst) {
     67             *origColors++ = desc.fColors[0];
     68         }
     69         memcpy(origColors, desc.fColors, desc.fCount * sizeof(SkColor));
     70         if (dummyLast) {
     71             origColors += desc.fCount;
     72             *origColors = desc.fColors[desc.fCount - 1];
     73         }
     74     }
     75 
     76     fRecs = (Rec*)(fOrigColors + fColorCount);
     77     if (fColorCount > 2) {
     78         Rec* recs = fRecs;
     79         recs->fPos = 0;
     80         //  recs->fScale = 0; // unused;
     81         recs += 1;
     82         if (desc.fPos) {
     83             /*  We need to convert the user's array of relative positions into
     84                 fixed-point positions and scale factors. We need these results
     85                 to be strictly monotonic (no two values equal or out of order).
     86                 Hence this complex loop that just jams a zero for the scale
     87                 value if it sees a segment out of order, and it assures that
     88                 we start at 0 and end at 1.0
     89             */
     90             SkFixed prev = 0;
     91             int startIndex = dummyFirst ? 0 : 1;
     92             int count = desc.fCount + dummyLast;
     93             for (int i = startIndex; i < count; i++) {
     94                 // force the last value to be 1.0
     95                 SkFixed curr;
     96                 if (i == desc.fCount) {  // we're really at the dummyLast
     97                     curr = SK_Fixed1;
     98                 } else {
     99                     curr = SkScalarToFixed(desc.fPos[i]);
    100                 }
    101                 // pin curr withing range
    102                 if (curr < 0) {
    103                     curr = 0;
    104                 } else if (curr > SK_Fixed1) {
    105                     curr = SK_Fixed1;
    106                 }
    107                 recs->fPos = curr;
    108                 if (curr > prev) {
    109                     recs->fScale = (1 << 24) / (curr - prev);
    110                 } else {
    111                     recs->fScale = 0; // ignore this segment
    112                 }
    113                 // get ready for the next value
    114                 prev = curr;
    115                 recs += 1;
    116             }
    117         } else {    // assume even distribution
    118             SkFixed dp = SK_Fixed1 / (desc.fCount - 1);
    119             SkFixed p = dp;
    120             SkFixed scale = (desc.fCount - 1) << 8;  // (1 << 24) / dp
    121             for (int i = 1; i < desc.fCount; i++) {
    122                 recs->fPos   = p;
    123                 recs->fScale = scale;
    124                 recs += 1;
    125                 p += dp;
    126             }
    127         }
    128     }
    129     this->initCommon();
    130 }
    131 
    132 static uint32_t pack_mode_flags(SkShader::TileMode mode, uint32_t flags) {
    133     SkASSERT(0 == (flags >> 28));
    134     SkASSERT(0 == ((uint32_t)mode >> 4));
    135     return (flags << 4) | mode;
    136 }
    137 
    138 static SkShader::TileMode unpack_mode(uint32_t packed) {
    139     return (SkShader::TileMode)(packed & 0xF);
    140 }
    141 
    142 static uint32_t unpack_flags(uint32_t packed) {
    143     return packed >> 4;
    144 }
    145 
    146 SkGradientShaderBase::SkGradientShaderBase(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
    147     fCacheAlpha = 256;
    148 
    149     fMapper = buffer.readUnitMapper();
    150 
    151     fCache16 = fCache16Storage = NULL;
    152     fCache32 = NULL;
    153     fCache32PixelRef = NULL;
    154 
    155     int colorCount = fColorCount = buffer.getArrayCount();
    156     if (colorCount > kColorStorageCount) {
    157         size_t size = sizeof(SkColor) + sizeof(SkPMColor) + sizeof(Rec);
    158         fOrigColors = (SkColor*)sk_malloc_throw(size * colorCount);
    159     } else {
    160         fOrigColors = fStorage;
    161     }
    162     buffer.readColorArray(fOrigColors, colorCount);
    163 
    164     {
    165         uint32_t packed = buffer.readUInt();
    166         fGradFlags = SkToU8(unpack_flags(packed));
    167         fTileMode = unpack_mode(packed);
    168     }
    169     fTileProc = gTileProcs[fTileMode];
    170     fRecs = (Rec*)(fOrigColors + colorCount);
    171     if (colorCount > 2) {
    172         Rec* recs = fRecs;
    173         recs[0].fPos = 0;
    174         for (int i = 1; i < colorCount; i++) {
    175             recs[i].fPos = buffer.readInt();
    176             recs[i].fScale = buffer.readUInt();
    177         }
    178     }
    179     buffer.readMatrix(&fPtsToUnit);
    180     this->initCommon();
    181 }
    182 
    183 SkGradientShaderBase::~SkGradientShaderBase() {
    184     if (fCache16Storage) {
    185         sk_free(fCache16Storage);
    186     }
    187     SkSafeUnref(fCache32PixelRef);
    188     if (fOrigColors != fStorage) {
    189         sk_free(fOrigColors);
    190     }
    191     SkSafeUnref(fMapper);
    192 }
    193 
    194 void SkGradientShaderBase::initCommon() {
    195     fFlags = 0;
    196     unsigned colorAlpha = 0xFF;
    197     for (int i = 0; i < fColorCount; i++) {
    198         colorAlpha &= SkColorGetA(fOrigColors[i]);
    199     }
    200     fColorsAreOpaque = colorAlpha == 0xFF;
    201 }
    202 
    203 void SkGradientShaderBase::flatten(SkFlattenableWriteBuffer& buffer) const {
    204     this->INHERITED::flatten(buffer);
    205     buffer.writeFlattenable(fMapper);
    206     buffer.writeColorArray(fOrigColors, fColorCount);
    207     buffer.writeUInt(pack_mode_flags(fTileMode, fGradFlags));
    208     if (fColorCount > 2) {
    209         Rec* recs = fRecs;
    210         for (int i = 1; i < fColorCount; i++) {
    211             buffer.writeInt(recs[i].fPos);
    212             buffer.writeUInt(recs[i].fScale);
    213         }
    214     }
    215     buffer.writeMatrix(fPtsToUnit);
    216 }
    217 
    218 bool SkGradientShaderBase::isOpaque() const {
    219     return fColorsAreOpaque;
    220 }
    221 
    222 bool SkGradientShaderBase::setContext(const SkBitmap& device,
    223                                  const SkPaint& paint,
    224                                  const SkMatrix& matrix) {
    225     if (!this->INHERITED::setContext(device, paint, matrix)) {
    226         return false;
    227     }
    228 
    229     const SkMatrix& inverse = this->getTotalInverse();
    230 
    231     if (!fDstToIndex.setConcat(fPtsToUnit, inverse)) {
    232         // need to keep our set/end context calls balanced.
    233         this->INHERITED::endContext();
    234         return false;
    235     }
    236 
    237     fDstToIndexProc = fDstToIndex.getMapXYProc();
    238     fDstToIndexClass = (uint8_t)SkShader::ComputeMatrixClass(fDstToIndex);
    239 
    240     // now convert our colors in to PMColors
    241     unsigned paintAlpha = this->getPaintAlpha();
    242 
    243     fFlags = this->INHERITED::getFlags();
    244     if (fColorsAreOpaque && paintAlpha == 0xFF) {
    245         fFlags |= kOpaqueAlpha_Flag;
    246     }
    247     // we can do span16 as long as our individual colors are opaque,
    248     // regardless of the paint's alpha
    249     if (fColorsAreOpaque) {
    250         fFlags |= kHasSpan16_Flag;
    251     }
    252 
    253     this->setCacheAlpha(paintAlpha);
    254     return true;
    255 }
    256 
    257 void SkGradientShaderBase::setCacheAlpha(U8CPU alpha) const {
    258     // if the new alpha differs from the previous time we were called, inval our cache
    259     // this will trigger the cache to be rebuilt.
    260     // we don't care about the first time, since the cache ptrs will already be NULL
    261     if (fCacheAlpha != alpha) {
    262         fCache16 = NULL;            // inval the cache
    263         fCache32 = NULL;            // inval the cache
    264         fCacheAlpha = alpha;        // record the new alpha
    265         // inform our subclasses
    266         if (fCache32PixelRef) {
    267             fCache32PixelRef->notifyPixelsChanged();
    268         }
    269     }
    270 }
    271 
    272 #define Fixed_To_Dot8(x)        (((x) + 0x80) >> 8)
    273 
    274 /** We take the original colors, not our premultiplied PMColors, since we can
    275     build a 16bit table as long as the original colors are opaque, even if the
    276     paint specifies a non-opaque alpha.
    277 */
    278 void SkGradientShaderBase::Build16bitCache(uint16_t cache[], SkColor c0, SkColor c1,
    279                                       int count) {
    280     SkASSERT(count > 1);
    281     SkASSERT(SkColorGetA(c0) == 0xFF);
    282     SkASSERT(SkColorGetA(c1) == 0xFF);
    283 
    284     SkFixed r = SkColorGetR(c0);
    285     SkFixed g = SkColorGetG(c0);
    286     SkFixed b = SkColorGetB(c0);
    287 
    288     SkFixed dr = SkIntToFixed(SkColorGetR(c1) - r) / (count - 1);
    289     SkFixed dg = SkIntToFixed(SkColorGetG(c1) - g) / (count - 1);
    290     SkFixed db = SkIntToFixed(SkColorGetB(c1) - b) / (count - 1);
    291 
    292     r = SkIntToFixed(r) + 0x8000;
    293     g = SkIntToFixed(g) + 0x8000;
    294     b = SkIntToFixed(b) + 0x8000;
    295 
    296     do {
    297         unsigned rr = r >> 16;
    298         unsigned gg = g >> 16;
    299         unsigned bb = b >> 16;
    300         cache[0] = SkPackRGB16(SkR32ToR16(rr), SkG32ToG16(gg), SkB32ToB16(bb));
    301         cache[kCache16Count] = SkDitherPack888ToRGB16(rr, gg, bb);
    302         cache += 1;
    303         r += dr;
    304         g += dg;
    305         b += db;
    306     } while (--count != 0);
    307 }
    308 
    309 /*
    310  *  r,g,b used to be SkFixed, but on gcc (4.2.1 mac and 4.6.3 goobuntu) in
    311  *  release builds, we saw a compiler error where the 0xFF parameter in
    312  *  SkPackARGB32() was being totally ignored whenever it was called with
    313  *  a non-zero add (e.g. 0x8000).
    314  *
    315  *  We found two work-arounds:
    316  *      1. change r,g,b to unsigned (or just one of them)
    317  *      2. change SkPackARGB32 to + its (a << SK_A32_SHIFT) value instead
    318  *         of using |
    319  *
    320  *  We chose #1 just because it was more localized.
    321  *  See http://code.google.com/p/skia/issues/detail?id=1113
    322  *
    323  *  The type SkUFixed encapsulate this need for unsigned, but logically Fixed.
    324  */
    325 typedef uint32_t SkUFixed;
    326 
    327 void SkGradientShaderBase::Build32bitCache(SkPMColor cache[], SkColor c0, SkColor c1,
    328                                       int count, U8CPU paintAlpha, uint32_t gradFlags) {
    329     SkASSERT(count > 1);
    330 
    331     // need to apply paintAlpha to our two endpoints
    332     uint32_t a0 = SkMulDiv255Round(SkColorGetA(c0), paintAlpha);
    333     uint32_t a1 = SkMulDiv255Round(SkColorGetA(c1), paintAlpha);
    334 
    335 
    336     const bool interpInPremul = SkToBool(gradFlags &
    337                            SkGradientShader::kInterpolateColorsInPremul_Flag);
    338 
    339     uint32_t r0 = SkColorGetR(c0);
    340     uint32_t g0 = SkColorGetG(c0);
    341     uint32_t b0 = SkColorGetB(c0);
    342 
    343     uint32_t r1 = SkColorGetR(c1);
    344     uint32_t g1 = SkColorGetG(c1);
    345     uint32_t b1 = SkColorGetB(c1);
    346 
    347     if (interpInPremul) {
    348         r0 = SkMulDiv255Round(r0, a0);
    349         g0 = SkMulDiv255Round(g0, a0);
    350         b0 = SkMulDiv255Round(b0, a0);
    351 
    352         r1 = SkMulDiv255Round(r1, a1);
    353         g1 = SkMulDiv255Round(g1, a1);
    354         b1 = SkMulDiv255Round(b1, a1);
    355     }
    356 
    357     SkFixed da = SkIntToFixed(a1 - a0) / (count - 1);
    358     SkFixed dr = SkIntToFixed(r1 - r0) / (count - 1);
    359     SkFixed dg = SkIntToFixed(g1 - g0) / (count - 1);
    360     SkFixed db = SkIntToFixed(b1 - b0) / (count - 1);
    361 
    362     /*  We pre-add 1/8 to avoid having to add this to our [0] value each time
    363         in the loop. Without this, the bias for each would be
    364             0x2000  0xA000  0xE000  0x6000
    365         With this trick, we can add 0 for the first (no-op) and just adjust the
    366         others.
    367      */
    368     SkUFixed a = SkIntToFixed(a0) + 0x2000;
    369     SkUFixed r = SkIntToFixed(r0) + 0x2000;
    370     SkUFixed g = SkIntToFixed(g0) + 0x2000;
    371     SkUFixed b = SkIntToFixed(b0) + 0x2000;
    372 
    373     /*
    374      *  Our dither-cell (spatially) is
    375      *      0 2
    376      *      3 1
    377      *  Where
    378      *      [0] -> [-1/8 ... 1/8 ) values near 0
    379      *      [1] -> [ 1/8 ... 3/8 ) values near 1/4
    380      *      [2] -> [ 3/8 ... 5/8 ) values near 1/2
    381      *      [3] -> [ 5/8 ... 7/8 ) values near 3/4
    382      */
    383 
    384     if (0xFF == a0 && 0 == da) {
    385         do {
    386             cache[kCache32Count*0] = SkPackARGB32(0xFF, (r + 0     ) >> 16,
    387                                                         (g + 0     ) >> 16,
    388                                                         (b + 0     ) >> 16);
    389             cache[kCache32Count*1] = SkPackARGB32(0xFF, (r + 0x8000) >> 16,
    390                                                         (g + 0x8000) >> 16,
    391                                                         (b + 0x8000) >> 16);
    392             cache[kCache32Count*2] = SkPackARGB32(0xFF, (r + 0xC000) >> 16,
    393                                                         (g + 0xC000) >> 16,
    394                                                         (b + 0xC000) >> 16);
    395             cache[kCache32Count*3] = SkPackARGB32(0xFF, (r + 0x4000) >> 16,
    396                                                         (g + 0x4000) >> 16,
    397                                                         (b + 0x4000) >> 16);
    398             cache += 1;
    399             r += dr;
    400             g += dg;
    401             b += db;
    402         } while (--count != 0);
    403     } else if (interpInPremul) {
    404         do {
    405             cache[kCache32Count*0] = SkPackARGB32((a + 0     ) >> 16,
    406                                                   (r + 0     ) >> 16,
    407                                                   (g + 0     ) >> 16,
    408                                                   (b + 0     ) >> 16);
    409             cache[kCache32Count*1] = SkPackARGB32((a + 0x8000) >> 16,
    410                                                   (r + 0x8000) >> 16,
    411                                                   (g + 0x8000) >> 16,
    412                                                   (b + 0x8000) >> 16);
    413             cache[kCache32Count*2] = SkPackARGB32((a + 0xC000) >> 16,
    414                                                   (r + 0xC000) >> 16,
    415                                                   (g + 0xC000) >> 16,
    416                                                   (b + 0xC000) >> 16);
    417             cache[kCache32Count*3] = SkPackARGB32((a + 0x4000) >> 16,
    418                                                   (r + 0x4000) >> 16,
    419                                                   (g + 0x4000) >> 16,
    420                                                   (b + 0x4000) >> 16);
    421             cache += 1;
    422             a += da;
    423             r += dr;
    424             g += dg;
    425             b += db;
    426         } while (--count != 0);
    427     } else {    // interpolate in unpreml space
    428         do {
    429             cache[kCache32Count*0] = SkPremultiplyARGBInline((a + 0     ) >> 16,
    430                                                              (r + 0     ) >> 16,
    431                                                              (g + 0     ) >> 16,
    432                                                              (b + 0     ) >> 16);
    433             cache[kCache32Count*1] = SkPremultiplyARGBInline((a + 0x8000) >> 16,
    434                                                              (r + 0x8000) >> 16,
    435                                                              (g + 0x8000) >> 16,
    436                                                              (b + 0x8000) >> 16);
    437             cache[kCache32Count*2] = SkPremultiplyARGBInline((a + 0xC000) >> 16,
    438                                                              (r + 0xC000) >> 16,
    439                                                              (g + 0xC000) >> 16,
    440                                                              (b + 0xC000) >> 16);
    441             cache[kCache32Count*3] = SkPremultiplyARGBInline((a + 0x4000) >> 16,
    442                                                              (r + 0x4000) >> 16,
    443                                                              (g + 0x4000) >> 16,
    444                                                              (b + 0x4000) >> 16);
    445             cache += 1;
    446             a += da;
    447             r += dr;
    448             g += dg;
    449             b += db;
    450         } while (--count != 0);
    451     }
    452 }
    453 
    454 static inline int SkFixedToFFFF(SkFixed x) {
    455     SkASSERT((unsigned)x <= SK_Fixed1);
    456     return x - (x >> 16);
    457 }
    458 
    459 static inline U16CPU bitsTo16(unsigned x, const unsigned bits) {
    460     SkASSERT(x < (1U << bits));
    461     if (6 == bits) {
    462         return (x << 10) | (x << 4) | (x >> 2);
    463     }
    464     if (8 == bits) {
    465         return (x << 8) | x;
    466     }
    467     sk_throw();
    468     return 0;
    469 }
    470 
    471 const uint16_t* SkGradientShaderBase::getCache16() const {
    472     if (fCache16 == NULL) {
    473         // double the count for dither entries
    474         const int entryCount = kCache16Count * 2;
    475         const size_t allocSize = sizeof(uint16_t) * entryCount;
    476 
    477         if (fCache16Storage == NULL) { // set the storage and our working ptr
    478             fCache16Storage = (uint16_t*)sk_malloc_throw(allocSize);
    479         }
    480         fCache16 = fCache16Storage;
    481         if (fColorCount == 2) {
    482             Build16bitCache(fCache16, fOrigColors[0], fOrigColors[1],
    483                             kCache16Count);
    484         } else {
    485             Rec* rec = fRecs;
    486             int prevIndex = 0;
    487             for (int i = 1; i < fColorCount; i++) {
    488                 int nextIndex = SkFixedToFFFF(rec[i].fPos) >> kCache16Shift;
    489                 SkASSERT(nextIndex < kCache16Count);
    490 
    491                 if (nextIndex > prevIndex)
    492                     Build16bitCache(fCache16 + prevIndex, fOrigColors[i-1], fOrigColors[i], nextIndex - prevIndex + 1);
    493                 prevIndex = nextIndex;
    494             }
    495         }
    496 
    497         if (fMapper) {
    498             fCache16Storage = (uint16_t*)sk_malloc_throw(allocSize);
    499             uint16_t* linear = fCache16;         // just computed linear data
    500             uint16_t* mapped = fCache16Storage;  // storage for mapped data
    501             SkUnitMapper* map = fMapper;
    502             for (int i = 0; i < kCache16Count; i++) {
    503                 int index = map->mapUnit16(bitsTo16(i, kCache16Bits)) >> kCache16Shift;
    504                 mapped[i] = linear[index];
    505                 mapped[i + kCache16Count] = linear[index + kCache16Count];
    506             }
    507             sk_free(fCache16);
    508             fCache16 = fCache16Storage;
    509         }
    510     }
    511     return fCache16;
    512 }
    513 
    514 const SkPMColor* SkGradientShaderBase::getCache32() const {
    515     if (fCache32 == NULL) {
    516         SkImageInfo info;
    517         info.fWidth = kCache32Count;
    518         info.fHeight = 4;   // for our 4 dither rows
    519         info.fAlphaType = kPremul_SkAlphaType;
    520         info.fColorType = kPMColor_SkColorType;
    521 
    522         if (NULL == fCache32PixelRef) {
    523             fCache32PixelRef = SkMallocPixelRef::NewAllocate(info, 0, NULL);
    524         }
    525         fCache32 = (SkPMColor*)fCache32PixelRef->getAddr();
    526         if (fColorCount == 2) {
    527             Build32bitCache(fCache32, fOrigColors[0], fOrigColors[1],
    528                             kCache32Count, fCacheAlpha, fGradFlags);
    529         } else {
    530             Rec* rec = fRecs;
    531             int prevIndex = 0;
    532             for (int i = 1; i < fColorCount; i++) {
    533                 int nextIndex = SkFixedToFFFF(rec[i].fPos) >> kCache32Shift;
    534                 SkASSERT(nextIndex < kCache32Count);
    535 
    536                 if (nextIndex > prevIndex)
    537                     Build32bitCache(fCache32 + prevIndex, fOrigColors[i-1],
    538                                     fOrigColors[i], nextIndex - prevIndex + 1,
    539                                     fCacheAlpha, fGradFlags);
    540                 prevIndex = nextIndex;
    541             }
    542         }
    543 
    544         if (fMapper) {
    545             SkMallocPixelRef* newPR = SkMallocPixelRef::NewAllocate(info, 0, NULL);
    546             SkPMColor* linear = fCache32;           // just computed linear data
    547             SkPMColor* mapped = (SkPMColor*)newPR->getAddr();    // storage for mapped data
    548             SkUnitMapper* map = fMapper;
    549             for (int i = 0; i < kCache32Count; i++) {
    550                 int index = map->mapUnit16((i << 8) | i) >> 8;
    551                 mapped[i + kCache32Count*0] = linear[index + kCache32Count*0];
    552                 mapped[i + kCache32Count*1] = linear[index + kCache32Count*1];
    553                 mapped[i + kCache32Count*2] = linear[index + kCache32Count*2];
    554                 mapped[i + kCache32Count*3] = linear[index + kCache32Count*3];
    555             }
    556             fCache32PixelRef->unref();
    557             fCache32PixelRef = newPR;
    558             fCache32 = (SkPMColor*)newPR->getAddr();
    559         }
    560     }
    561     return fCache32;
    562 }
    563 
    564 /*
    565  *  Because our caller might rebuild the same (logically the same) gradient
    566  *  over and over, we'd like to return exactly the same "bitmap" if possible,
    567  *  allowing the client to utilize a cache of our bitmap (e.g. with a GPU).
    568  *  To do that, we maintain a private cache of built-bitmaps, based on our
    569  *  colors and positions. Note: we don't try to flatten the fMapper, so if one
    570  *  is present, we skip the cache for now.
    571  */
    572 void SkGradientShaderBase::getGradientTableBitmap(SkBitmap* bitmap) const {
    573     // our caller assumes no external alpha, so we ensure that our cache is
    574     // built with 0xFF
    575     this->setCacheAlpha(0xFF);
    576 
    577     // don't have a way to put the mapper into our cache-key yet
    578     if (fMapper) {
    579         // force our cahce32pixelref to be built
    580         (void)this->getCache32();
    581         bitmap->setConfig(SkBitmap::kARGB_8888_Config, kCache32Count, 1);
    582         bitmap->setPixelRef(fCache32PixelRef);
    583         return;
    584     }
    585 
    586     // build our key: [numColors + colors[] + {positions[]} + flags ]
    587     int count = 1 + fColorCount + 1;
    588     if (fColorCount > 2) {
    589         count += fColorCount - 1;    // fRecs[].fPos
    590     }
    591 
    592     SkAutoSTMalloc<16, int32_t> storage(count);
    593     int32_t* buffer = storage.get();
    594 
    595     *buffer++ = fColorCount;
    596     memcpy(buffer, fOrigColors, fColorCount * sizeof(SkColor));
    597     buffer += fColorCount;
    598     if (fColorCount > 2) {
    599         for (int i = 1; i < fColorCount; i++) {
    600             *buffer++ = fRecs[i].fPos;
    601         }
    602     }
    603     *buffer++ = fGradFlags;
    604     SkASSERT(buffer - storage.get() == count);
    605 
    606     ///////////////////////////////////
    607 
    608     SK_DECLARE_STATIC_MUTEX(gMutex);
    609     static SkBitmapCache* gCache;
    610     // each cache cost 1K of RAM, since each bitmap will be 1x256 at 32bpp
    611     static const int MAX_NUM_CACHED_GRADIENT_BITMAPS = 32;
    612     SkAutoMutexAcquire ama(gMutex);
    613 
    614     if (NULL == gCache) {
    615         gCache = SkNEW_ARGS(SkBitmapCache, (MAX_NUM_CACHED_GRADIENT_BITMAPS));
    616     }
    617     size_t size = count * sizeof(int32_t);
    618 
    619     if (!gCache->find(storage.get(), size, bitmap)) {
    620         // force our cahce32pixelref to be built
    621         (void)this->getCache32();
    622         bitmap->setConfig(SkBitmap::kARGB_8888_Config, kCache32Count, 1);
    623         bitmap->setPixelRef(fCache32PixelRef);
    624 
    625         gCache->add(storage.get(), size, *bitmap);
    626     }
    627 }
    628 
    629 void SkGradientShaderBase::commonAsAGradient(GradientInfo* info) const {
    630     if (info) {
    631         if (info->fColorCount >= fColorCount) {
    632             if (info->fColors) {
    633                 memcpy(info->fColors, fOrigColors, fColorCount * sizeof(SkColor));
    634             }
    635             if (info->fColorOffsets) {
    636                 if (fColorCount == 2) {
    637                     info->fColorOffsets[0] = 0;
    638                     info->fColorOffsets[1] = SK_Scalar1;
    639                 } else if (fColorCount > 2) {
    640                     for (int i = 0; i < fColorCount; ++i) {
    641                         info->fColorOffsets[i] = SkFixedToScalar(fRecs[i].fPos);
    642                     }
    643                 }
    644             }
    645         }
    646         info->fColorCount = fColorCount;
    647         info->fTileMode = fTileMode;
    648         info->fGradientFlags = fGradFlags;
    649     }
    650 }
    651 
    652 #ifdef SK_DEVELOPER
    653 void SkGradientShaderBase::toString(SkString* str) const {
    654 
    655     str->appendf("%d colors: ", fColorCount);
    656 
    657     for (int i = 0; i < fColorCount; ++i) {
    658         str->appendHex(fOrigColors[i]);
    659         if (i < fColorCount-1) {
    660             str->append(", ");
    661         }
    662     }
    663 
    664     if (fColorCount > 2) {
    665         str->append(" points: (");
    666         for (int i = 0; i < fColorCount; ++i) {
    667             str->appendScalar(SkFixedToScalar(fRecs[i].fPos));
    668             if (i < fColorCount-1) {
    669                 str->append(", ");
    670             }
    671         }
    672         str->append(")");
    673     }
    674 
    675     static const char* gTileModeName[SkShader::kTileModeCount] = {
    676         "clamp", "repeat", "mirror"
    677     };
    678 
    679     str->append(" ");
    680     str->append(gTileModeName[fTileMode]);
    681 
    682     // TODO: add "fMapper->toString(str);" when SkUnitMapper::toString is added
    683 
    684     this->INHERITED::toString(str);
    685 }
    686 #endif
    687 
    688 ///////////////////////////////////////////////////////////////////////////////
    689 ///////////////////////////////////////////////////////////////////////////////
    690 
    691 #include "SkEmptyShader.h"
    692 
    693 // assumes colors is SkColor* and pos is SkScalar*
    694 #define EXPAND_1_COLOR(count)               \
    695     SkColor tmp[2];                         \
    696     do {                                    \
    697         if (1 == count) {                   \
    698             tmp[0] = tmp[1] = colors[0];    \
    699             colors = tmp;                   \
    700             pos = NULL;                     \
    701             count = 2;                      \
    702         }                                   \
    703     } while (0)
    704 
    705 static void desc_init(SkGradientShaderBase::Descriptor* desc,
    706                       const SkColor colors[],
    707                       const SkScalar pos[], int colorCount,
    708                       SkShader::TileMode mode,
    709                       SkUnitMapper* mapper, uint32_t flags) {
    710     desc->fColors   = colors;
    711     desc->fPos      = pos;
    712     desc->fCount    = colorCount;
    713     desc->fTileMode = mode;
    714     desc->fMapper   = mapper;
    715     desc->fFlags    = flags;
    716 }
    717 
    718 SkShader* SkGradientShader::CreateLinear(const SkPoint pts[2],
    719                                          const SkColor colors[],
    720                                          const SkScalar pos[], int colorCount,
    721                                          SkShader::TileMode mode,
    722                                          SkUnitMapper* mapper,
    723                                          uint32_t flags) {
    724     if (NULL == pts || NULL == colors || colorCount < 1) {
    725         return NULL;
    726     }
    727     EXPAND_1_COLOR(colorCount);
    728 
    729     SkGradientShaderBase::Descriptor desc;
    730     desc_init(&desc, colors, pos, colorCount, mode, mapper, flags);
    731     return SkNEW_ARGS(SkLinearGradient, (pts, desc));
    732 }
    733 
    734 SkShader* SkGradientShader::CreateRadial(const SkPoint& center, SkScalar radius,
    735                                          const SkColor colors[],
    736                                          const SkScalar pos[], int colorCount,
    737                                          SkShader::TileMode mode,
    738                                          SkUnitMapper* mapper,
    739                                          uint32_t flags) {
    740     if (radius <= 0 || NULL == colors || colorCount < 1) {
    741         return NULL;
    742     }
    743     EXPAND_1_COLOR(colorCount);
    744 
    745     SkGradientShaderBase::Descriptor desc;
    746     desc_init(&desc, colors, pos, colorCount, mode, mapper, flags);
    747     return SkNEW_ARGS(SkRadialGradient, (center, radius, desc));
    748 }
    749 
    750 SkShader* SkGradientShader::CreateTwoPointRadial(const SkPoint& start,
    751                                                  SkScalar startRadius,
    752                                                  const SkPoint& end,
    753                                                  SkScalar endRadius,
    754                                                  const SkColor colors[],
    755                                                  const SkScalar pos[],
    756                                                  int colorCount,
    757                                                  SkShader::TileMode mode,
    758                                                  SkUnitMapper* mapper,
    759                                                  uint32_t flags) {
    760     if (startRadius < 0 || endRadius < 0 || NULL == colors || colorCount < 1) {
    761         return NULL;
    762     }
    763     EXPAND_1_COLOR(colorCount);
    764 
    765     SkGradientShaderBase::Descriptor desc;
    766     desc_init(&desc, colors, pos, colorCount, mode, mapper, flags);
    767     return SkNEW_ARGS(SkTwoPointRadialGradient,
    768                       (start, startRadius, end, endRadius, desc));
    769 }
    770 
    771 SkShader* SkGradientShader::CreateTwoPointConical(const SkPoint& start,
    772                                                   SkScalar startRadius,
    773                                                   const SkPoint& end,
    774                                                   SkScalar endRadius,
    775                                                   const SkColor colors[],
    776                                                   const SkScalar pos[],
    777                                                   int colorCount,
    778                                                   SkShader::TileMode mode,
    779                                                   SkUnitMapper* mapper,
    780                                                   uint32_t flags) {
    781     if (startRadius < 0 || endRadius < 0 || NULL == colors || colorCount < 1) {
    782         return NULL;
    783     }
    784     if (start == end && startRadius == endRadius) {
    785         return SkNEW(SkEmptyShader);
    786     }
    787     EXPAND_1_COLOR(colorCount);
    788 
    789     SkGradientShaderBase::Descriptor desc;
    790     desc_init(&desc, colors, pos, colorCount, mode, mapper, flags);
    791     return SkNEW_ARGS(SkTwoPointConicalGradient,
    792                       (start, startRadius, end, endRadius, desc));
    793 }
    794 
    795 SkShader* SkGradientShader::CreateSweep(SkScalar cx, SkScalar cy,
    796                                         const SkColor colors[],
    797                                         const SkScalar pos[],
    798                                         int colorCount, SkUnitMapper* mapper,
    799                                         uint32_t flags) {
    800     if (NULL == colors || colorCount < 1) {
    801         return NULL;
    802     }
    803     EXPAND_1_COLOR(colorCount);
    804 
    805     SkGradientShaderBase::Descriptor desc;
    806     desc_init(&desc, colors, pos, colorCount, SkShader::kClamp_TileMode, mapper, flags);
    807     return SkNEW_ARGS(SkSweepGradient, (cx, cy, desc));
    808 }
    809 
    810 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkGradientShader)
    811     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkLinearGradient)
    812     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkRadialGradient)
    813     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkSweepGradient)
    814     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkTwoPointRadialGradient)
    815     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkTwoPointConicalGradient)
    816 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END
    817 
    818 ///////////////////////////////////////////////////////////////////////////////
    819 
    820 #if SK_SUPPORT_GPU
    821 
    822 #include "effects/GrTextureStripAtlas.h"
    823 #include "GrTBackendEffectFactory.h"
    824 #include "SkGr.h"
    825 
    826 GrGLGradientEffect::GrGLGradientEffect(const GrBackendEffectFactory& factory)
    827     : INHERITED(factory)
    828     , fCachedYCoord(SK_ScalarMax) {
    829 }
    830 
    831 GrGLGradientEffect::~GrGLGradientEffect() { }
    832 
    833 void GrGLGradientEffect::emitUniforms(GrGLShaderBuilder* builder, EffectKey key) {
    834 
    835     if (GrGradientEffect::kTwo_ColorType == ColorTypeFromKey(key)) { // 2 Color case
    836         fColorStartUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
    837                                              kVec4f_GrSLType, "GradientStartColor");
    838         fColorEndUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
    839                                            kVec4f_GrSLType, "GradientEndColor");
    840 
    841     } else if (GrGradientEffect::kThree_ColorType == ColorTypeFromKey(key)){ // 3 Color Case
    842         fColorStartUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
    843                                              kVec4f_GrSLType, "GradientStartColor");
    844         fColorMidUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
    845                                            kVec4f_GrSLType, "GradientMidColor");
    846         fColorEndUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
    847                                              kVec4f_GrSLType, "GradientEndColor");
    848 
    849     } else { // if not a fast case
    850         fFSYUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
    851                                       kFloat_GrSLType, "GradientYCoordFS");
    852     }
    853 }
    854 
    855 static inline void set_color_uni(const GrGLUniformManager& uman,
    856                                  const GrGLUniformManager::UniformHandle uni,
    857                                  const SkColor* color) {
    858        uman.set4f(uni,
    859                   SkColorGetR(*color) / 255.f,
    860                   SkColorGetG(*color) / 255.f,
    861                   SkColorGetB(*color) / 255.f,
    862                   SkColorGetA(*color) / 255.f);
    863 }
    864 
    865 static inline void set_mul_color_uni(const GrGLUniformManager& uman,
    866                                      const GrGLUniformManager::UniformHandle uni,
    867                                      const SkColor* color){
    868        float a = SkColorGetA(*color) / 255.f;
    869        float aDiv255 = a / 255.f;
    870        uman.set4f(uni,
    871                   SkColorGetR(*color) * aDiv255,
    872                   SkColorGetG(*color) * aDiv255,
    873                   SkColorGetB(*color) * aDiv255,
    874                   a);
    875 }
    876 
    877 void GrGLGradientEffect::setData(const GrGLUniformManager& uman,
    878                                  const GrDrawEffect& drawEffect) {
    879 
    880     const GrGradientEffect& e = drawEffect.castEffect<GrGradientEffect>();
    881 
    882 
    883     if (GrGradientEffect::kTwo_ColorType == e.getColorType()){
    884 
    885         if (GrGradientEffect::kBeforeInterp_PremulType == e.getPremulType()) {
    886             set_mul_color_uni(uman, fColorStartUni, e.getColors(0));
    887             set_mul_color_uni(uman, fColorEndUni,   e.getColors(1));
    888         } else {
    889             set_color_uni(uman, fColorStartUni, e.getColors(0));
    890             set_color_uni(uman, fColorEndUni,   e.getColors(1));
    891         }
    892 
    893     } else if (GrGradientEffect::kThree_ColorType == e.getColorType()){
    894 
    895         if (GrGradientEffect::kBeforeInterp_PremulType == e.getPremulType()) {
    896             set_mul_color_uni(uman, fColorStartUni, e.getColors(0));
    897             set_mul_color_uni(uman, fColorMidUni,   e.getColors(1));
    898             set_mul_color_uni(uman, fColorEndUni,   e.getColors(2));
    899         } else {
    900             set_color_uni(uman, fColorStartUni, e.getColors(0));
    901             set_color_uni(uman, fColorMidUni,   e.getColors(1));
    902             set_color_uni(uman, fColorEndUni,   e.getColors(2));
    903         }
    904     } else {
    905 
    906         SkScalar yCoord = e.getYCoord();
    907         if (yCoord != fCachedYCoord) {
    908             uman.set1f(fFSYUni, yCoord);
    909             fCachedYCoord = yCoord;
    910         }
    911     }
    912 }
    913 
    914 
    915 GrGLEffect::EffectKey GrGLGradientEffect::GenBaseGradientKey(const GrDrawEffect& drawEffect) {
    916     const GrGradientEffect& e = drawEffect.castEffect<GrGradientEffect>();
    917 
    918     EffectKey key = 0;
    919 
    920     if (GrGradientEffect::kTwo_ColorType == e.getColorType()) {
    921         key |= kTwoColorKey;
    922     } else if (GrGradientEffect::kThree_ColorType == e.getColorType()){
    923         key |= kThreeColorKey;
    924     }
    925 
    926     if (GrGradientEffect::kBeforeInterp_PremulType == e.getPremulType()) {
    927         key |= kPremulBeforeInterpKey;
    928     }
    929 
    930     return key;
    931 }
    932 
    933 void GrGLGradientEffect::emitColor(GrGLShaderBuilder* builder,
    934                                    const char* gradientTValue,
    935                                    EffectKey key,
    936                                    const char* outputColor,
    937                                    const char* inputColor,
    938                                    const TextureSamplerArray& samplers) {
    939     if (GrGradientEffect::kTwo_ColorType == ColorTypeFromKey(key)){
    940         builder->fsCodeAppendf("\tvec4 colorTemp = mix(%s, %s, clamp(%s, 0.0, 1.0));\n",
    941                                builder->getUniformVariable(fColorStartUni).c_str(),
    942                                builder->getUniformVariable(fColorEndUni).c_str(),
    943                                gradientTValue);
    944         // Note that we could skip this step if both colors are known to be opaque. Two
    945         // considerations:
    946         // The gradient SkShader reporting opaque is more restrictive than necessary in the two pt
    947         // case. Make sure the key reflects this optimization (and note that it can use the same
    948         // shader as thekBeforeIterp case). This same optimization applies to the 3 color case below.
    949         if (GrGradientEffect::kAfterInterp_PremulType == PremulTypeFromKey(key)) {
    950             builder->fsCodeAppend("\tcolorTemp.rgb *= colorTemp.a;\n");
    951         }
    952 
    953         builder->fsCodeAppendf("\t%s = %s;\n", outputColor,
    954                                (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
    955     } else if (GrGradientEffect::kThree_ColorType == ColorTypeFromKey(key)){
    956         builder->fsCodeAppendf("\tfloat oneMinus2t = 1.0 - (2.0 * (%s));\n",
    957                                gradientTValue);
    958         builder->fsCodeAppendf("\tvec4 colorTemp = clamp(oneMinus2t, 0.0, 1.0) * %s;\n",
    959                                builder->getUniformVariable(fColorStartUni).c_str());
    960         if (kTegra3_GrGLRenderer == builder->ctxInfo().renderer()) {
    961             // The Tegra3 compiler will sometimes never return if we have
    962             // min(abs(oneMinus2t), 1.0), or do the abs first in a separate expression.
    963             builder->fsCodeAppend("\tfloat minAbs = abs(oneMinus2t);\n");
    964             builder->fsCodeAppend("\tminAbs = minAbs > 1.0 ? 1.0 : minAbs;\n");
    965             builder->fsCodeAppendf("\tcolorTemp += (1.0 - minAbs) * %s;\n",
    966                                    builder->getUniformVariable(fColorMidUni).c_str());
    967         } else {
    968             builder->fsCodeAppendf("\tcolorTemp += (1.0 - min(abs(oneMinus2t), 1.0)) * %s;\n",
    969                                    builder->getUniformVariable(fColorMidUni).c_str());
    970         }
    971         builder->fsCodeAppendf("\tcolorTemp += clamp(-oneMinus2t, 0.0, 1.0) * %s;\n",
    972                                builder->getUniformVariable(fColorEndUni).c_str());
    973         if (GrGradientEffect::kAfterInterp_PremulType == PremulTypeFromKey(key)) {
    974             builder->fsCodeAppend("\tcolorTemp.rgb *= colorTemp.a;\n");
    975         }
    976 
    977         builder->fsCodeAppendf("\t%s = %s;\n", outputColor,
    978                                (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
    979     } else {
    980         builder->fsCodeAppendf("\tvec2 coord = vec2(%s, %s);\n",
    981                                gradientTValue,
    982                                builder->getUniformVariable(fFSYUni).c_str());
    983         builder->fsCodeAppendf("\t%s = ", outputColor);
    984         builder->fsAppendTextureLookupAndModulate(inputColor,
    985                                                   samplers[0],
    986                                                   "coord");
    987         builder->fsCodeAppend(";\n");
    988     }
    989 }
    990 
    991 /////////////////////////////////////////////////////////////////////
    992 
    993 GrGradientEffect::GrGradientEffect(GrContext* ctx,
    994                                    const SkGradientShaderBase& shader,
    995                                    const SkMatrix& matrix,
    996                                    SkShader::TileMode tileMode) {
    997 
    998     fIsOpaque = shader.isOpaque();
    999 
   1000     SkShader::GradientInfo info;
   1001     SkScalar pos[3] = {0};
   1002 
   1003     info.fColorCount = 3;
   1004     info.fColors = &fColors[0];
   1005     info.fColorOffsets = &pos[0];
   1006     shader.asAGradient(&info);
   1007 
   1008     // The two and three color specializations do not currently support tiling.
   1009     bool foundSpecialCase = false;
   1010     if (SkShader::kClamp_TileMode == info.fTileMode) {
   1011         if (2 == info.fColorCount) {
   1012             fRow = -1; // flag for no atlas
   1013             fColorType = kTwo_ColorType;
   1014             foundSpecialCase = true;
   1015         } else if (3 == info.fColorCount &&
   1016                    (SkScalarAbs(pos[1] - SK_ScalarHalf) < SK_Scalar1 / 1000)) { // 3 color symmetric
   1017             fRow = -1; // flag for no atlas
   1018             fColorType = kThree_ColorType;
   1019             foundSpecialCase = true;
   1020         }
   1021     }
   1022     if (foundSpecialCase) {
   1023         if (SkGradientShader::kInterpolateColorsInPremul_Flag & info.fGradientFlags) {
   1024             fPremulType = kBeforeInterp_PremulType;
   1025         } else {
   1026             fPremulType = kAfterInterp_PremulType;
   1027         }
   1028         fCoordTransform.reset(kCoordSet, matrix);
   1029     } else {
   1030         // doesn't matter how this is set, just be consistent because it is part of the effect key.
   1031         fPremulType = kBeforeInterp_PremulType;
   1032         SkBitmap bitmap;
   1033         shader.getGradientTableBitmap(&bitmap);
   1034         fColorType = kTexture_ColorType;
   1035 
   1036         GrTextureStripAtlas::Desc desc;
   1037         desc.fWidth  = bitmap.width();
   1038         desc.fHeight = 32;
   1039         desc.fRowHeight = bitmap.height();
   1040         desc.fContext = ctx;
   1041         desc.fConfig = SkBitmapConfig2GrPixelConfig(bitmap.config());
   1042         fAtlas = GrTextureStripAtlas::GetAtlas(desc);
   1043         SkASSERT(NULL != fAtlas);
   1044 
   1045         // We always filter the gradient table. Each table is one row of a texture, always y-clamp.
   1046         GrTextureParams params;
   1047         params.setFilterMode(GrTextureParams::kBilerp_FilterMode);
   1048         params.setTileModeX(tileMode);
   1049 
   1050         fRow = fAtlas->lockRow(bitmap);
   1051         if (-1 != fRow) {
   1052             fYCoord = fAtlas->getYOffset(fRow) + SK_ScalarHalf *
   1053             fAtlas->getVerticalScaleFactor();
   1054             fCoordTransform.reset(kCoordSet, matrix, fAtlas->getTexture());
   1055             fTextureAccess.reset(fAtlas->getTexture(), params);
   1056         } else {
   1057             GrTexture* texture = GrLockAndRefCachedBitmapTexture(ctx, bitmap, &params);
   1058             fCoordTransform.reset(kCoordSet, matrix, texture);
   1059             fTextureAccess.reset(texture, params);
   1060             fYCoord = SK_ScalarHalf;
   1061 
   1062             // Unlock immediately, this is not great, but we don't have a way of
   1063             // knowing when else to unlock it currently, so it may get purged from
   1064             // the cache, but it'll still be ref'd until it's no longer being used.
   1065             GrUnlockAndUnrefCachedBitmapTexture(texture);
   1066         }
   1067         this->addTextureAccess(&fTextureAccess);
   1068     }
   1069     this->addCoordTransform(&fCoordTransform);
   1070 }
   1071 
   1072 GrGradientEffect::~GrGradientEffect() {
   1073     if (this->useAtlas()) {
   1074         fAtlas->unlockRow(fRow);
   1075     }
   1076 }
   1077 
   1078 bool GrGradientEffect::onIsEqual(const GrEffect& effect) const {
   1079     const GrGradientEffect& s = CastEffect<GrGradientEffect>(effect);
   1080 
   1081     if (this->fColorType == s.getColorType()){
   1082 
   1083         if (kTwo_ColorType == fColorType) {
   1084             if (*this->getColors(0) != *s.getColors(0) ||
   1085                 *this->getColors(1) != *s.getColors(1)) {
   1086                 return false;
   1087             }
   1088         } else if (kThree_ColorType == fColorType) {
   1089             if (*this->getColors(0) != *s.getColors(0) ||
   1090                 *this->getColors(1) != *s.getColors(1) ||
   1091                 *this->getColors(2) != *s.getColors(2)) {
   1092                 return false;
   1093             }
   1094         } else {
   1095             if (fYCoord != s.getYCoord()) {
   1096                 return false;
   1097             }
   1098         }
   1099 
   1100         return fTextureAccess.getTexture() == s.fTextureAccess.getTexture()  &&
   1101             fTextureAccess.getParams().getTileModeX() ==
   1102                 s.fTextureAccess.getParams().getTileModeX() &&
   1103             this->useAtlas() == s.useAtlas() &&
   1104             fCoordTransform.getMatrix().cheapEqualTo(s.fCoordTransform.getMatrix());
   1105     }
   1106 
   1107     return false;
   1108 }
   1109 
   1110 void GrGradientEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
   1111     if (fIsOpaque && (kA_GrColorComponentFlag & *validFlags) && 0xff == GrColorUnpackA(*color)) {
   1112         *validFlags = kA_GrColorComponentFlag;
   1113     } else {
   1114         *validFlags = 0;
   1115     }
   1116 }
   1117 
   1118 int GrGradientEffect::RandomGradientParams(SkRandom* random,
   1119                                            SkColor colors[],
   1120                                            SkScalar** stops,
   1121                                            SkShader::TileMode* tm) {
   1122     int outColors = random->nextRangeU(1, kMaxRandomGradientColors);
   1123 
   1124     // if one color, omit stops, otherwise randomly decide whether or not to
   1125     if (outColors == 1 || (outColors >= 2 && random->nextBool())) {
   1126         *stops = NULL;
   1127     }
   1128 
   1129     SkScalar stop = 0.f;
   1130     for (int i = 0; i < outColors; ++i) {
   1131         colors[i] = random->nextU();
   1132         if (NULL != *stops) {
   1133             (*stops)[i] = stop;
   1134             stop = i < outColors - 1 ? stop + random->nextUScalar1() * (1.f - stop) : 1.f;
   1135         }
   1136     }
   1137     *tm = static_cast<SkShader::TileMode>(random->nextULessThan(SkShader::kTileModeCount));
   1138 
   1139     return outColors;
   1140 }
   1141 
   1142 #endif
   1143