SkBitmap.cpp revision 2cb1480ff8ae030946cb5f218f9c5cbc1e54c7a9 
1
2/*
3 * Copyright 2008 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#include "SkBitmap.h"
11#include "SkColorPriv.h"
12#include "SkDither.h"
13#include "SkFlattenable.h"
14#include "SkMallocPixelRef.h"
15#include "SkMask.h"
16#include "SkOrderedReadBuffer.h"
17#include "SkOrderedWriteBuffer.h"
18#include "SkPixelRef.h"
19#include "SkThread.h"
20#include "SkUnPreMultiply.h"
21#include "SkUtils.h"
22#include "SkPackBits.h"
23#include <new>
24
25SK_DEFINE_INST_COUNT(SkBitmap::Allocator)
26
27static bool isPos32Bits(const Sk64& value) {
28    return !value.isNeg() && value.is32();
29}
30
31struct MipLevel {
32    void*       fPixels;
33    uint32_t    fRowBytes;
34    uint32_t    fWidth, fHeight;
35};
36
37struct SkBitmap::MipMap : SkNoncopyable {
38    int32_t fRefCnt;
39    int     fLevelCount;
40//  MipLevel    fLevel[fLevelCount];
41//  Pixels[]
42
43    static MipMap* Alloc(int levelCount, size_t pixelSize) {
44        if (levelCount < 0) {
45            return NULL;
46        }
47        Sk64 size;
48        size.setMul(levelCount + 1, sizeof(MipLevel));
49        size.add(sizeof(MipMap));
50        size.add(SkToS32(pixelSize));
51        if (!isPos32Bits(size)) {
52            return NULL;
53        }
54        MipMap* mm = (MipMap*)sk_malloc_throw(size.get32());
55        mm->fRefCnt = 1;
56        mm->fLevelCount = levelCount;
57        return mm;
58    }
59
60    const MipLevel* levels() const { return (const MipLevel*)(this + 1); }
61    MipLevel* levels() { return (MipLevel*)(this + 1); }
62
63    const void* pixels() const { return levels() + fLevelCount; }
64    void* pixels() { return levels() + fLevelCount; }
65
66    void ref() {
67        if (SK_MaxS32 == sk_atomic_inc(&fRefCnt)) {
68            sk_throw();
69        }
70    }
71    void unref() {
72        SkASSERT(fRefCnt > 0);
73        if (sk_atomic_dec(&fRefCnt) == 1) {
74            sk_free(this);
75        }
76    }
77};
78
79///////////////////////////////////////////////////////////////////////////////
80///////////////////////////////////////////////////////////////////////////////
81
82SkBitmap::SkBitmap() {
83    sk_bzero(this, sizeof(*this));
84}
85
86SkBitmap::SkBitmap(const SkBitmap& src) {
87    SkDEBUGCODE(src.validate();)
88    sk_bzero(this, sizeof(*this));
89    *this = src;
90    SkDEBUGCODE(this->validate();)
91}
92
93SkBitmap::~SkBitmap() {
94    SkDEBUGCODE(this->validate();)
95    this->freePixels();
96}
97
98SkBitmap& SkBitmap::operator=(const SkBitmap& src) {
99    if (this != &src) {
100        this->freePixels();
101        memcpy(this, &src, sizeof(src));
102
103        // inc src reference counts
104        SkSafeRef(src.fPixelRef);
105        SkSafeRef(src.fMipMap);
106
107        // we reset our locks if we get blown away
108        fPixelLockCount = 0;
109
110        /*  The src could be in 3 states
111            1. no pixelref, in which case we just copy/ref the pixels/ctable
112            2. unlocked pixelref, pixels/ctable should be null
113            3. locked pixelref, we should lock the ref again ourselves
114        */
115        if (NULL == fPixelRef) {
116            // leave fPixels as it is
117            SkSafeRef(fColorTable); // ref the user's ctable if present
118        } else {    // we have a pixelref, so pixels/ctable reflect it
119            // ignore the values from the memcpy
120            fPixels = NULL;
121            fColorTable = NULL;
122            // Note that what to for genID is somewhat arbitrary. We have no
123            // way to track changes to raw pixels across multiple SkBitmaps.
124            // Would benefit from an SkRawPixelRef type created by
125            // setPixels.
126            // Just leave the memcpy'ed one but they'll get out of sync
127            // as soon either is modified.
128        }
129    }
130
131    SkDEBUGCODE(this->validate();)
132    return *this;
133}
134
135void SkBitmap::swap(SkBitmap& other) {
136    SkTSwap(fColorTable, other.fColorTable);
137    SkTSwap(fPixelRef, other.fPixelRef);
138    SkTSwap(fPixelRefOffset, other.fPixelRefOffset);
139    SkTSwap(fPixelLockCount, other.fPixelLockCount);
140    SkTSwap(fMipMap, other.fMipMap);
141    SkTSwap(fPixels, other.fPixels);
142    SkTSwap(fRowBytes, other.fRowBytes);
143    SkTSwap(fWidth, other.fWidth);
144    SkTSwap(fHeight, other.fHeight);
145    SkTSwap(fConfig, other.fConfig);
146    SkTSwap(fFlags, other.fFlags);
147    SkTSwap(fBytesPerPixel, other.fBytesPerPixel);
148
149    SkDEBUGCODE(this->validate();)
150}
151
152void SkBitmap::reset() {
153    this->freePixels();
154    sk_bzero(this, sizeof(*this));
155}
156
157int SkBitmap::ComputeBytesPerPixel(SkBitmap::Config config) {
158    int bpp;
159    switch (config) {
160        case kNo_Config:
161        case kA1_Config:
162            bpp = 0;   // not applicable
163            break;
164        case kA8_Config:
165        case kIndex8_Config:
166            bpp = 1;
167            break;
168        case kRGB_565_Config:
169        case kARGB_4444_Config:
170            bpp = 2;
171            break;
172        case kARGB_8888_Config:
173            bpp = 4;
174            break;
175        default:
176            SkDEBUGFAIL("unknown config");
177            bpp = 0;   // error
178            break;
179    }
180    return bpp;
181}
182
183size_t SkBitmap::ComputeRowBytes(Config c, int width) {
184    if (width < 0) {
185        return 0;
186    }
187
188    Sk64 rowBytes;
189    rowBytes.setZero();
190
191    switch (c) {
192        case kNo_Config:
193            break;
194        case kA1_Config:
195            rowBytes.set(width);
196            rowBytes.add(7);
197            rowBytes.shiftRight(3);
198            break;
199        case kA8_Config:
200        case kIndex8_Config:
201            rowBytes.set(width);
202            break;
203        case kRGB_565_Config:
204        case kARGB_4444_Config:
205            rowBytes.set(width);
206            rowBytes.shiftLeft(1);
207            break;
208        case kARGB_8888_Config:
209            rowBytes.set(width);
210            rowBytes.shiftLeft(2);
211            break;
212        default:
213            SkDEBUGFAIL("unknown config");
214            break;
215    }
216    return isPos32Bits(rowBytes) ? rowBytes.get32() : 0;
217}
218
219Sk64 SkBitmap::ComputeSize64(Config c, int width, int height) {
220    Sk64 size;
221    size.setMul(SkToS32(SkBitmap::ComputeRowBytes(c, width)), height);
222    return size;
223}
224
225size_t SkBitmap::ComputeSize(Config c, int width, int height) {
226    Sk64 size = SkBitmap::ComputeSize64(c, width, height);
227    return isPos32Bits(size) ? size.get32() : 0;
228}
229
230Sk64 SkBitmap::ComputeSafeSize64(Config config,
231                                 uint32_t width,
232                                 uint32_t height,
233                                 size_t rowBytes) {
234    Sk64 safeSize;
235    safeSize.setZero();
236    if (height > 0) {
237        // TODO: Handle the case where the return value from
238        // ComputeRowBytes is more than 31 bits.
239        safeSize.set(SkToS32(ComputeRowBytes(config, width)));
240        Sk64 sizeAllButLastRow;
241        sizeAllButLastRow.setMul(height - 1, SkToS32(rowBytes));
242        safeSize.add(sizeAllButLastRow);
243    }
244    SkASSERT(!safeSize.isNeg());
245    return safeSize;
246}
247
248size_t SkBitmap::ComputeSafeSize(Config config,
249                                 uint32_t width,
250                                 uint32_t height,
251                                 size_t rowBytes) {
252    Sk64 safeSize = ComputeSafeSize64(config, width, height, rowBytes);
253    return (safeSize.is32() ? safeSize.get32() : 0);
254}
255
256void SkBitmap::getBounds(SkRect* bounds) const {
257    SkASSERT(bounds);
258    bounds->set(0, 0,
259                SkIntToScalar(fWidth), SkIntToScalar(fHeight));
260}
261
262void SkBitmap::getBounds(SkIRect* bounds) const {
263    SkASSERT(bounds);
264    bounds->set(0, 0, fWidth, fHeight);
265}
266
267///////////////////////////////////////////////////////////////////////////////
268
269void SkBitmap::setConfig(Config c, int width, int height, size_t rowBytes) {
270    this->freePixels();
271
272    if ((width | height) < 0) {
273        goto err;
274    }
275
276    if (rowBytes == 0) {
277        rowBytes = SkBitmap::ComputeRowBytes(c, width);
278        if (0 == rowBytes && kNo_Config != c) {
279            goto err;
280        }
281    }
282
283    fConfig     = SkToU8(c);
284    fWidth      = width;
285    fHeight     = height;
286    fRowBytes   = SkToU32(rowBytes);
287
288    fBytesPerPixel = (uint8_t)ComputeBytesPerPixel(c);
289
290    SkDEBUGCODE(this->validate();)
291    return;
292
293    // if we got here, we had an error, so we reset the bitmap to empty
294err:
295    this->reset();
296}
297
298void SkBitmap::updatePixelsFromRef() const {
299    if (NULL != fPixelRef) {
300        if (fPixelLockCount > 0) {
301            SkASSERT(fPixelRef->isLocked());
302
303            void* p = fPixelRef->pixels();
304            if (NULL != p) {
305                p = (char*)p + fPixelRefOffset;
306            }
307            fPixels = p;
308            SkRefCnt_SafeAssign(fColorTable, fPixelRef->colorTable());
309        } else {
310            SkASSERT(0 == fPixelLockCount);
311            fPixels = NULL;
312            if (fColorTable) {
313                fColorTable->unref();
314                fColorTable = NULL;
315            }
316        }
317    }
318}
319
320SkPixelRef* SkBitmap::setPixelRef(SkPixelRef* pr, size_t offset) {
321    // do this first, we that we never have a non-zero offset with a null ref
322    if (NULL == pr) {
323        offset = 0;
324    }
325
326    if (fPixelRef != pr || fPixelRefOffset != offset) {
327        if (fPixelRef != pr) {
328            this->freePixels();
329            SkASSERT(NULL == fPixelRef);
330
331            SkSafeRef(pr);
332            fPixelRef = pr;
333        }
334        fPixelRefOffset = offset;
335        this->updatePixelsFromRef();
336    }
337
338    SkDEBUGCODE(this->validate();)
339    return pr;
340}
341
342void SkBitmap::lockPixels() const {
343    if (NULL != fPixelRef && 1 == ++fPixelLockCount) {
344        fPixelRef->lockPixels();
345        this->updatePixelsFromRef();
346    }
347    SkDEBUGCODE(this->validate();)
348}
349
350void SkBitmap::unlockPixels() const {
351    SkASSERT(NULL == fPixelRef || fPixelLockCount > 0);
352
353    if (NULL != fPixelRef && 0 == --fPixelLockCount) {
354        fPixelRef->unlockPixels();
355        this->updatePixelsFromRef();
356    }
357    SkDEBUGCODE(this->validate();)
358}
359
360bool SkBitmap::lockPixelsAreWritable() const {
361    return (fPixelRef) ? fPixelRef->lockPixelsAreWritable() : false;
362}
363
364void SkBitmap::setPixels(void* p, SkColorTable* ctable) {
365    if (NULL == p) {
366        this->setPixelRef(NULL, 0);
367        return;
368    }
369
370    Sk64 size = this->getSize64();
371    SkASSERT(!size.isNeg() && size.is32());
372
373    this->setPixelRef(new SkMallocPixelRef(p, size.get32(), ctable, false))->unref();
374    // since we're already allocated, we lockPixels right away
375    this->lockPixels();
376    SkDEBUGCODE(this->validate();)
377}
378
379bool SkBitmap::allocPixels(Allocator* allocator, SkColorTable* ctable) {
380    HeapAllocator stdalloc;
381
382    if (NULL == allocator) {
383        allocator = &stdalloc;
384    }
385    return allocator->allocPixelRef(this, ctable);
386}
387
388void SkBitmap::freePixels() {
389    // if we're gonna free the pixels, we certainly need to free the mipmap
390    this->freeMipMap();
391
392    if (fColorTable) {
393        fColorTable->unref();
394        fColorTable = NULL;
395    }
396
397    if (NULL != fPixelRef) {
398        if (fPixelLockCount > 0) {
399            fPixelRef->unlockPixels();
400        }
401        fPixelRef->unref();
402        fPixelRef = NULL;
403        fPixelRefOffset = 0;
404    }
405    fPixelLockCount = 0;
406    fPixels = NULL;
407}
408
409void SkBitmap::freeMipMap() {
410    if (fMipMap) {
411        fMipMap->unref();
412        fMipMap = NULL;
413    }
414}
415
416uint32_t SkBitmap::getGenerationID() const {
417    return (fPixelRef) ? fPixelRef->getGenerationID() : 0;
418}
419
420void SkBitmap::notifyPixelsChanged() const {
421    SkASSERT(!this->isImmutable());
422    if (fPixelRef) {
423        fPixelRef->notifyPixelsChanged();
424    }
425}
426
427SkGpuTexture* SkBitmap::getTexture() const {
428    return fPixelRef ? fPixelRef->getTexture() : NULL;
429}
430
431///////////////////////////////////////////////////////////////////////////////
432
433/** We explicitly use the same allocator for our pixels that SkMask does,
434 so that we can freely assign memory allocated by one class to the other.
435 */
436bool SkBitmap::HeapAllocator::allocPixelRef(SkBitmap* dst,
437                                            SkColorTable* ctable) {
438    Sk64 size = dst->getSize64();
439    if (size.isNeg() || !size.is32()) {
440        return false;
441    }
442
443    void* addr = sk_malloc_flags(size.get32(), 0);  // returns NULL on failure
444    if (NULL == addr) {
445        return false;
446    }
447
448    dst->setPixelRef(new SkMallocPixelRef(addr, size.get32(), ctable))->unref();
449    // since we're already allocated, we lockPixels right away
450    dst->lockPixels();
451    return true;
452}
453
454///////////////////////////////////////////////////////////////////////////////
455
456size_t SkBitmap::getSafeSize() const {
457    // This is intended to be a size_t version of ComputeSafeSize64(), just
458    // faster. The computation is meant to be identical.
459    return (fHeight ? ((fHeight - 1) * fRowBytes) +
460            ComputeRowBytes(getConfig(), fWidth): 0);
461}
462
463Sk64 SkBitmap::getSafeSize64() const {
464    return ComputeSafeSize64(getConfig(), fWidth, fHeight, fRowBytes);
465}
466
467bool SkBitmap::copyPixelsTo(void* const dst, size_t dstSize,
468                            size_t dstRowBytes, bool preserveDstPad) const {
469
470    if (0 == dstRowBytes) {
471        dstRowBytes = fRowBytes;
472    }
473
474    if (dstRowBytes < ComputeRowBytes(getConfig(), fWidth) ||
475        dst == NULL || (getPixels() == NULL && pixelRef() == NULL))
476        return false;
477
478    if (!preserveDstPad && static_cast<uint32_t>(dstRowBytes) == fRowBytes) {
479        size_t safeSize = getSafeSize();
480        if (safeSize > dstSize || safeSize == 0)
481            return false;
482        else {
483            SkAutoLockPixels lock(*this);
484            // This implementation will write bytes beyond the end of each row,
485            // excluding the last row, if the bitmap's stride is greater than
486            // strictly required by the current config.
487            memcpy(dst, getPixels(), safeSize);
488
489            return true;
490        }
491    } else {
492        // If destination has different stride than us, then copy line by line.
493        if (ComputeSafeSize(getConfig(), fWidth, fHeight, dstRowBytes) >
494            dstSize)
495            return false;
496        else {
497            // Just copy what we need on each line.
498            size_t rowBytes = ComputeRowBytes(getConfig(), fWidth);
499            SkAutoLockPixels lock(*this);
500            const uint8_t* srcP = reinterpret_cast<const uint8_t*>(getPixels());
501            uint8_t* dstP = reinterpret_cast<uint8_t*>(dst);
502            for (uint32_t row = 0; row < fHeight;
503                 row++, srcP += fRowBytes, dstP += dstRowBytes) {
504                memcpy(dstP, srcP, rowBytes);
505            }
506
507            return true;
508        }
509    }
510}
511
512///////////////////////////////////////////////////////////////////////////////
513
514bool SkBitmap::isImmutable() const {
515    return fPixelRef ? fPixelRef->isImmutable() :
516        fFlags & kImageIsImmutable_Flag;
517}
518
519void SkBitmap::setImmutable() {
520    if (fPixelRef) {
521        fPixelRef->setImmutable();
522    } else {
523        fFlags |= kImageIsImmutable_Flag;
524    }
525}
526
527bool SkBitmap::isOpaque() const {
528    switch (fConfig) {
529        case kNo_Config:
530            return true;
531
532        case kA1_Config:
533        case kA8_Config:
534        case kARGB_4444_Config:
535        case kARGB_8888_Config:
536            return (fFlags & kImageIsOpaque_Flag) != 0;
537
538        case kIndex8_Config: {
539            uint32_t flags = 0;
540
541            this->lockPixels();
542            // if lockPixels failed, we may not have a ctable ptr
543            if (fColorTable) {
544                flags = fColorTable->getFlags();
545            }
546            this->unlockPixels();
547
548            return (flags & SkColorTable::kColorsAreOpaque_Flag) != 0;
549        }
550
551        case kRGB_565_Config:
552            return true;
553
554        default:
555            SkDEBUGFAIL("unknown bitmap config pased to isOpaque");
556            return false;
557    }
558}
559
560void SkBitmap::setIsOpaque(bool isOpaque) {
561    /*  we record this regardless of fConfig, though it is ignored in
562        isOpaque() for configs that can't support per-pixel alpha.
563    */
564    if (isOpaque) {
565        fFlags |= kImageIsOpaque_Flag;
566    } else {
567        fFlags &= ~kImageIsOpaque_Flag;
568    }
569}
570
571bool SkBitmap::isVolatile() const {
572    return (fFlags & kImageIsVolatile_Flag) != 0;
573}
574
575void SkBitmap::setIsVolatile(bool isVolatile) {
576    if (isVolatile) {
577        fFlags |= kImageIsVolatile_Flag;
578    } else {
579        fFlags &= ~kImageIsVolatile_Flag;
580    }
581}
582
583void* SkBitmap::getAddr(int x, int y) const {
584    SkASSERT((unsigned)x < (unsigned)this->width());
585    SkASSERT((unsigned)y < (unsigned)this->height());
586
587    char* base = (char*)this->getPixels();
588    if (base) {
589        base += y * this->rowBytes();
590        switch (this->config()) {
591            case SkBitmap::kARGB_8888_Config:
592                base += x << 2;
593                break;
594            case SkBitmap::kARGB_4444_Config:
595            case SkBitmap::kRGB_565_Config:
596                base += x << 1;
597                break;
598            case SkBitmap::kA8_Config:
599            case SkBitmap::kIndex8_Config:
600                base += x;
601                break;
602            case SkBitmap::kA1_Config:
603                base += x >> 3;
604                break;
605            default:
606                SkDEBUGFAIL("Can't return addr for config");
607                base = NULL;
608                break;
609        }
610    }
611    return base;
612}
613
614SkColor SkBitmap::getColor(int x, int y) const {
615    SkASSERT((unsigned)x < (unsigned)this->width());
616    SkASSERT((unsigned)y < (unsigned)this->height());
617
618    switch (this->config()) {
619        case SkBitmap::kA1_Config: {
620            uint8_t* addr = this->getAddr1(x, y);
621            uint8_t mask = 1 << (7  - (x % 8));
622            if (addr[0] & mask) {
623                return SK_ColorBLACK;
624            } else {
625                return 0;
626            }
627        }
628        case SkBitmap::kA8_Config: {
629            uint8_t* addr = this->getAddr8(x, y);
630            return SkColorSetA(0, addr[0]);
631        }
632        case SkBitmap::kIndex8_Config: {
633            SkPMColor c = this->getIndex8Color(x, y);
634            return SkUnPreMultiply::PMColorToColor(c);
635        }
636        case SkBitmap::kRGB_565_Config: {
637            uint16_t* addr = this->getAddr16(x, y);
638            return SkPixel16ToColor(addr[0]);
639        }
640        case SkBitmap::kARGB_4444_Config: {
641            uint16_t* addr = this->getAddr16(x, y);
642            SkPMColor c = SkPixel4444ToPixel32(addr[0]);
643            return SkUnPreMultiply::PMColorToColor(c);
644        }
645        case SkBitmap::kARGB_8888_Config: {
646            uint32_t* addr = this->getAddr32(x, y);
647            return SkUnPreMultiply::PMColorToColor(addr[0]);
648        }
649        case kNo_Config:
650            SkASSERT(false);
651            return 0;
652    }
653    SkASSERT(false);  // Not reached.
654    return 0;
655}
656
657bool SkBitmap::ComputeIsOpaque(const SkBitmap& bm) {
658    SkAutoLockPixels alp(bm);
659    if (!bm.getPixels()) {
660        return false;
661    }
662
663    const int height = bm.height();
664    const int width = bm.width();
665
666    switch (bm.config()) {
667        case SkBitmap::kA1_Config: {
668            // TODO
669        } break;
670        case SkBitmap::kA8_Config: {
671            unsigned a = 0xFF;
672            for (int y = 0; y < height; ++y) {
673                const uint8_t* row = bm.getAddr8(0, y);
674                for (int x = 0; x < width; ++x) {
675                    a &= row[x];
676                }
677                if (0xFF != a) {
678                    return false;
679                }
680            }
681            return true;
682        } break;
683        case SkBitmap::kIndex8_Config: {
684            SkAutoLockColors alc(bm);
685            const SkPMColor* table = alc.colors();
686            if (!table) {
687                return false;
688            }
689            SkPMColor c = (SkPMColor)~0;
690            for (int i = bm.getColorTable()->count() - 1; i >= 0; --i) {
691                c &= table[i];
692            }
693            return 0xFF == SkGetPackedA32(c);
694        } break;
695        case SkBitmap::kRGB_565_Config:
696            return true;
697            break;
698        case SkBitmap::kARGB_4444_Config: {
699            unsigned c = 0xFFFF;
700            for (int y = 0; y < height; ++y) {
701                const SkPMColor16* row = bm.getAddr16(0, y);
702                for (int x = 0; x < width; ++x) {
703                    c &= row[x];
704                }
705                if (0xF != SkGetPackedA4444(c)) {
706                    return false;
707                }
708            }
709            return true;
710        } break;
711        case SkBitmap::kARGB_8888_Config: {
712            SkPMColor c = (SkPMColor)~0;
713            for (int y = 0; y < height; ++y) {
714                const SkPMColor* row = bm.getAddr32(0, y);
715                for (int x = 0; x < width; ++x) {
716                    c &= row[x];
717                }
718                if (0xFF != SkGetPackedA32(c)) {
719                    return false;
720                }
721            }
722            return true;
723        }
724        default:
725            break;
726    }
727    return false;
728}
729
730
731///////////////////////////////////////////////////////////////////////////////
732///////////////////////////////////////////////////////////////////////////////
733
734static uint16_t pack_8888_to_4444(unsigned a, unsigned r, unsigned g, unsigned b) {
735    unsigned pixel = (SkA32To4444(a) << SK_A4444_SHIFT) |
736                     (SkR32To4444(r) << SK_R4444_SHIFT) |
737                     (SkG32To4444(g) << SK_G4444_SHIFT) |
738                     (SkB32To4444(b) << SK_B4444_SHIFT);
739    return SkToU16(pixel);
740}
741
742void SkBitmap::eraseARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) const {
743    SkDEBUGCODE(this->validate();)
744
745    if (0 == fWidth || 0 == fHeight ||
746            kNo_Config == fConfig || kIndex8_Config == fConfig) {
747        return;
748    }
749
750    SkAutoLockPixels alp(*this);
751    // perform this check after the lock call
752    if (!this->readyToDraw()) {
753        return;
754    }
755
756    int height = fHeight;
757    const int width = fWidth;
758    const int rowBytes = fRowBytes;
759
760    // make rgb premultiplied
761    if (255 != a) {
762        r = SkAlphaMul(r, a);
763        g = SkAlphaMul(g, a);
764        b = SkAlphaMul(b, a);
765    }
766
767    switch (fConfig) {
768        case kA1_Config: {
769            uint8_t* p = (uint8_t*)fPixels;
770            const int count = (width + 7) >> 3;
771            a = (a >> 7) ? 0xFF : 0;
772            SkASSERT(count <= rowBytes);
773            while (--height >= 0) {
774                memset(p, a, count);
775                p += rowBytes;
776            }
777            break;
778        }
779        case kA8_Config: {
780            uint8_t* p = (uint8_t*)fPixels;
781            while (--height >= 0) {
782                memset(p, a, width);
783                p += rowBytes;
784            }
785            break;
786        }
787        case kARGB_4444_Config:
788        case kRGB_565_Config: {
789            uint16_t* p = (uint16_t*)fPixels;
790            uint16_t v;
791
792            if (kARGB_4444_Config == fConfig) {
793                v = pack_8888_to_4444(a, r, g, b);
794            } else {
795                v = SkPackRGB16(r >> (8 - SK_R16_BITS),
796                                g >> (8 - SK_G16_BITS),
797                                b >> (8 - SK_B16_BITS));
798            }
799            while (--height >= 0) {
800                sk_memset16(p, v, width);
801                p = (uint16_t*)((char*)p + rowBytes);
802            }
803            break;
804        }
805        case kARGB_8888_Config: {
806            uint32_t* p = (uint32_t*)fPixels;
807            uint32_t  v = SkPackARGB32(a, r, g, b);
808
809            while (--height >= 0) {
810                sk_memset32(p, v, width);
811                p = (uint32_t*)((char*)p + rowBytes);
812            }
813            break;
814        }
815    }
816
817    this->notifyPixelsChanged();
818}
819
820//////////////////////////////////////////////////////////////////////////////////////
821//////////////////////////////////////////////////////////////////////////////////////
822
823#define SUB_OFFSET_FAILURE  ((size_t)-1)
824
825/**
826 *  Based on the Config and rowBytes() of bm, return the offset into an SkPixelRef of the pixel at
827 *  (x, y).
828 *  Note that the SkPixelRef does not need to be set yet. deepCopyTo takes advantage of this fact.
829 *  Also note that (x, y) may be outside the range of (0 - width(), 0 - height()), so long as it is
830 *  within the bounds of the SkPixelRef being used.
831 */
832static size_t get_sub_offset(const SkBitmap& bm, int x, int y) {
833    switch (bm.getConfig()) {
834        case SkBitmap::kA8_Config:
835        case SkBitmap:: kIndex8_Config:
836            // x is fine as is for the calculation
837            break;
838
839        case SkBitmap::kRGB_565_Config:
840        case SkBitmap::kARGB_4444_Config:
841            x <<= 1;
842            break;
843
844        case SkBitmap::kARGB_8888_Config:
845            x <<= 2;
846            break;
847
848        case SkBitmap::kNo_Config:
849        case SkBitmap::kA1_Config:
850        default:
851            return SUB_OFFSET_FAILURE;
852    }
853    return y * bm.rowBytes() + x;
854}
855
856/**
857 *  Using the pixelRefOffset(), rowBytes(), and Config of bm, determine the (x, y) coordinate of the
858 *  upper left corner of bm relative to its SkPixelRef.
859 *  x and y must be non-NULL.
860 */
861bool get_upper_left_from_offset(SkBitmap::Config config, size_t offset, size_t rowBytes,
862                                   int32_t* x, int32_t* y);
863bool get_upper_left_from_offset(SkBitmap::Config config, size_t offset, size_t rowBytes,
864                                   int32_t* x, int32_t* y) {
865    SkASSERT(x != NULL && y != NULL);
866    if (0 == offset) {
867        *x = *y = 0;
868        return true;
869    }
870    // Use integer division to find the correct y position.
871    *y = SkToS32(offset / rowBytes);
872    // The remainder will be the x position, after we reverse get_sub_offset.
873    *x = SkToS32(offset % rowBytes);
874    switch (config) {
875        case SkBitmap::kA8_Config:
876            // Fall through.
877        case SkBitmap::kIndex8_Config:
878            // x is unmodified
879            break;
880
881        case SkBitmap::kRGB_565_Config:
882            // Fall through.
883        case SkBitmap::kARGB_4444_Config:
884            *x >>= 1;
885            break;
886
887        case SkBitmap::kARGB_8888_Config:
888            *x >>= 2;
889            break;
890
891        case SkBitmap::kNo_Config:
892            // Fall through.
893        case SkBitmap::kA1_Config:
894            // Fall through.
895        default:
896            return false;
897    }
898    return true;
899}
900
901static bool get_upper_left_from_offset(const SkBitmap& bm, int32_t* x, int32_t* y) {
902    return get_upper_left_from_offset(bm.config(), bm.pixelRefOffset(), bm.rowBytes(), x, y);
903}
904
905bool SkBitmap::extractSubset(SkBitmap* result, const SkIRect& subset) const {
906    SkDEBUGCODE(this->validate();)
907
908    if (NULL == result || NULL == fPixelRef) {
909        return false;   // no src pixels
910    }
911
912    SkIRect srcRect, r;
913    srcRect.set(0, 0, this->width(), this->height());
914    if (!r.intersect(srcRect, subset)) {
915        return false;   // r is empty (i.e. no intersection)
916    }
917
918    if (fPixelRef->getTexture() != NULL) {
919        // Do a deep copy
920        SkPixelRef* pixelRef = fPixelRef->deepCopy(this->config(), &subset);
921        if (pixelRef != NULL) {
922            SkBitmap dst;
923            dst.setConfig(this->config(), subset.width(), subset.height());
924            dst.setIsVolatile(this->isVolatile());
925            dst.setIsOpaque(this->isOpaque());
926            dst.setPixelRef(pixelRef)->unref();
927            SkDEBUGCODE(dst.validate());
928            result->swap(dst);
929            return true;
930        }
931    }
932
933    // If the upper left of the rectangle was outside the bounds of this SkBitmap, we should have
934    // exited above.
935    SkASSERT(static_cast<unsigned>(r.fLeft) < static_cast<unsigned>(this->width()));
936    SkASSERT(static_cast<unsigned>(r.fTop) < static_cast<unsigned>(this->height()));
937
938    size_t offset = get_sub_offset(*this, r.fLeft, r.fTop);
939    if (SUB_OFFSET_FAILURE == offset) {
940        return false;   // config not supported
941    }
942
943    SkBitmap dst;
944    dst.setConfig(this->config(), r.width(), r.height(), this->rowBytes());
945    dst.setIsVolatile(this->isVolatile());
946    dst.setIsOpaque(this->isOpaque());
947
948    if (fPixelRef) {
949        // share the pixelref with a custom offset
950        dst.setPixelRef(fPixelRef, fPixelRefOffset + offset);
951    }
952    SkDEBUGCODE(dst.validate();)
953
954    // we know we're good, so commit to result
955    result->swap(dst);
956    return true;
957}
958
959///////////////////////////////////////////////////////////////////////////////
960
961#include "SkCanvas.h"
962#include "SkPaint.h"
963
964bool SkBitmap::canCopyTo(Config dstConfig) const {
965    if (this->getConfig() == kNo_Config) {
966        return false;
967    }
968
969    bool sameConfigs = (this->config() == dstConfig);
970    switch (dstConfig) {
971        case kA8_Config:
972        case kRGB_565_Config:
973        case kARGB_8888_Config:
974            break;
975        case kA1_Config:
976        case kIndex8_Config:
977        case kARGB_4444_Config:
978            if (!sameConfigs) {
979                return false;
980            }
981            break;
982        default:
983            return false;
984    }
985
986    // do not copy src if srcConfig == kA1_Config while dstConfig != kA1_Config
987    if (this->getConfig() == kA1_Config && !sameConfigs) {
988        return false;
989    }
990
991    return true;
992}
993
994bool SkBitmap::copyTo(SkBitmap* dst, Config dstConfig, Allocator* alloc) const {
995    if (!this->canCopyTo(dstConfig)) {
996        return false;
997    }
998
999    // if we have a texture, first get those pixels
1000    SkBitmap tmpSrc;
1001    const SkBitmap* src = this;
1002
1003    if (fPixelRef) {
1004        SkIRect subset;
1005        if (get_upper_left_from_offset(*this, &subset.fLeft, &subset.fTop)) {
1006            subset.fRight = subset.fLeft + fWidth;
1007            subset.fBottom = subset.fTop + fHeight;
1008            if (fPixelRef->readPixels(&tmpSrc, &subset)) {
1009                SkASSERT(tmpSrc.width() == this->width());
1010                SkASSERT(tmpSrc.height() == this->height());
1011
1012                // did we get lucky and we can just return tmpSrc?
1013                if (tmpSrc.config() == dstConfig && NULL == alloc) {
1014                    dst->swap(tmpSrc);
1015                    if (dst->pixelRef() && this->config() == dstConfig) {
1016                        dst->pixelRef()->fGenerationID = fPixelRef->getGenerationID();
1017                    }
1018                    return true;
1019                }
1020
1021                // fall through to the raster case
1022                src = &tmpSrc;
1023            }
1024        }
1025    }
1026
1027    // we lock this now, since we may need its colortable
1028    SkAutoLockPixels srclock(*src);
1029    if (!src->readyToDraw()) {
1030        return false;
1031    }
1032
1033    SkBitmap tmpDst;
1034    tmpDst.setConfig(dstConfig, src->width(), src->height());
1035
1036    // allocate colortable if srcConfig == kIndex8_Config
1037    SkColorTable* ctable = (dstConfig == kIndex8_Config) ?
1038    new SkColorTable(*src->getColorTable()) : NULL;
1039    SkAutoUnref au(ctable);
1040    if (!tmpDst.allocPixels(alloc, ctable)) {
1041        return false;
1042    }
1043
1044    if (!tmpDst.readyToDraw()) {
1045        // allocator/lock failed
1046        return false;
1047    }
1048
1049    /* do memcpy for the same configs cases, else use drawing
1050    */
1051    if (src->config() == dstConfig) {
1052        if (tmpDst.getSize() == src->getSize()) {
1053            memcpy(tmpDst.getPixels(), src->getPixels(), src->getSafeSize());
1054            SkPixelRef* pixelRef = tmpDst.pixelRef();
1055            if (pixelRef != NULL) {
1056                pixelRef->fGenerationID = this->getGenerationID();
1057            }
1058        } else {
1059            const char* srcP = reinterpret_cast<const char*>(src->getPixels());
1060            char* dstP = reinterpret_cast<char*>(tmpDst.getPixels());
1061            // to be sure we don't read too much, only copy our logical pixels
1062            size_t bytesToCopy = tmpDst.width() * tmpDst.bytesPerPixel();
1063            for (int y = 0; y < tmpDst.height(); y++) {
1064                memcpy(dstP, srcP, bytesToCopy);
1065                srcP += src->rowBytes();
1066                dstP += tmpDst.rowBytes();
1067            }
1068        }
1069    } else {
1070        // if the src has alpha, we have to clear the dst first
1071        if (!src->isOpaque()) {
1072            tmpDst.eraseColor(SK_ColorTRANSPARENT);
1073        }
1074
1075        SkCanvas canvas(tmpDst);
1076        SkPaint  paint;
1077
1078        paint.setDither(true);
1079        canvas.drawBitmap(*src, 0, 0, &paint);
1080    }
1081
1082    tmpDst.setIsOpaque(src->isOpaque());
1083
1084    dst->swap(tmpDst);
1085    return true;
1086}
1087
1088bool SkBitmap::deepCopyTo(SkBitmap* dst, Config dstConfig) const {
1089    if (!this->canCopyTo(dstConfig)) {
1090        return false;
1091    }
1092
1093    // If we have a PixelRef, and it supports deep copy, use it.
1094    // Currently supported only by texture-backed bitmaps.
1095    if (fPixelRef) {
1096        SkPixelRef* pixelRef = fPixelRef->deepCopy(dstConfig);
1097        if (pixelRef) {
1098            uint32_t rowBytes;
1099            if (dstConfig == fConfig) {
1100                pixelRef->fGenerationID = fPixelRef->getGenerationID();
1101                // Use the same rowBytes as the original.
1102                rowBytes = fRowBytes;
1103            } else {
1104                // With the new config, an appropriate fRowBytes will be computed by setConfig.
1105                rowBytes = 0;
1106            }
1107            dst->setConfig(dstConfig, fWidth, fHeight, rowBytes);
1108
1109            size_t pixelRefOffset;
1110            if (0 == fPixelRefOffset || dstConfig == fConfig) {
1111                // Use the same offset as the original.
1112                pixelRefOffset = fPixelRefOffset;
1113            } else {
1114                // Find the correct offset in the new config. This needs to be done after calling
1115                // setConfig so dst's fConfig and fRowBytes have been set properly.
1116                int32_t x, y;
1117                if (!get_upper_left_from_offset(*this, &x, &y)) {
1118                    return false;
1119                }
1120                pixelRefOffset = get_sub_offset(*dst, x, y);
1121                if (SUB_OFFSET_FAILURE == pixelRefOffset) {
1122                    return false;
1123                }
1124            }
1125            dst->setPixelRef(pixelRef, pixelRefOffset)->unref();
1126            return true;
1127        }
1128    }
1129
1130    if (this->getTexture()) {
1131        return false;
1132    } else {
1133        return this->copyTo(dst, dstConfig, NULL);
1134    }
1135}
1136
1137///////////////////////////////////////////////////////////////////////////////
1138///////////////////////////////////////////////////////////////////////////////
1139
1140static void downsampleby2_proc32(SkBitmap* dst, int x, int y,
1141                                 const SkBitmap& src) {
1142    x <<= 1;
1143    y <<= 1;
1144    const SkPMColor* p = src.getAddr32(x, y);
1145    const SkPMColor* baseP = p;
1146    SkPMColor c, ag, rb;
1147
1148    c = *p; ag = (c >> 8) & 0xFF00FF; rb = c & 0xFF00FF;
1149    if (x < src.width() - 1) {
1150        p += 1;
1151    }
1152    c = *p; ag += (c >> 8) & 0xFF00FF; rb += c & 0xFF00FF;
1153
1154    p = baseP;
1155    if (y < src.height() - 1) {
1156        p += src.rowBytes() >> 2;
1157    }
1158    c = *p; ag += (c >> 8) & 0xFF00FF; rb += c & 0xFF00FF;
1159    if (x < src.width() - 1) {
1160        p += 1;
1161    }
1162    c = *p; ag += (c >> 8) & 0xFF00FF; rb += c & 0xFF00FF;
1163
1164    *dst->getAddr32(x >> 1, y >> 1) =
1165        ((rb >> 2) & 0xFF00FF) | ((ag << 6) & 0xFF00FF00);
1166}
1167
1168static inline uint32_t expand16(U16CPU c) {
1169    return (c & ~SK_G16_MASK_IN_PLACE) | ((c & SK_G16_MASK_IN_PLACE) << 16);
1170}
1171
1172// returns dirt in the top 16bits, but we don't care, since we only
1173// store the low 16bits.
1174static inline U16CPU pack16(uint32_t c) {
1175    return (c & ~SK_G16_MASK_IN_PLACE) | ((c >> 16) & SK_G16_MASK_IN_PLACE);
1176}
1177
1178static void downsampleby2_proc16(SkBitmap* dst, int x, int y,
1179                                 const SkBitmap& src) {
1180    x <<= 1;
1181    y <<= 1;
1182    const uint16_t* p = src.getAddr16(x, y);
1183    const uint16_t* baseP = p;
1184    SkPMColor       c;
1185
1186    c = expand16(*p);
1187    if (x < src.width() - 1) {
1188        p += 1;
1189    }
1190    c += expand16(*p);
1191
1192    p = baseP;
1193    if (y < src.height() - 1) {
1194        p += src.rowBytes() >> 1;
1195    }
1196    c += expand16(*p);
1197    if (x < src.width() - 1) {
1198        p += 1;
1199    }
1200    c += expand16(*p);
1201
1202    *dst->getAddr16(x >> 1, y >> 1) = (uint16_t)pack16(c >> 2);
1203}
1204
1205static uint32_t expand4444(U16CPU c) {
1206    return (c & 0xF0F) | ((c & ~0xF0F) << 12);
1207}
1208
1209static U16CPU collaps4444(uint32_t c) {
1210    return (c & 0xF0F) | ((c >> 12) & ~0xF0F);
1211}
1212
1213static void downsampleby2_proc4444(SkBitmap* dst, int x, int y,
1214                                   const SkBitmap& src) {
1215    x <<= 1;
1216    y <<= 1;
1217    const uint16_t* p = src.getAddr16(x, y);
1218    const uint16_t* baseP = p;
1219    uint32_t        c;
1220
1221    c = expand4444(*p);
1222    if (x < src.width() - 1) {
1223        p += 1;
1224    }
1225    c += expand4444(*p);
1226
1227    p = baseP;
1228    if (y < src.height() - 1) {
1229        p += src.rowBytes() >> 1;
1230    }
1231    c += expand4444(*p);
1232    if (x < src.width() - 1) {
1233        p += 1;
1234    }
1235    c += expand4444(*p);
1236
1237    *dst->getAddr16(x >> 1, y >> 1) = (uint16_t)collaps4444(c >> 2);
1238}
1239
1240void SkBitmap::buildMipMap(bool forceRebuild) {
1241    if (forceRebuild)
1242        this->freeMipMap();
1243    else if (fMipMap)
1244        return; // we're already built
1245
1246    SkASSERT(NULL == fMipMap);
1247
1248    void (*proc)(SkBitmap* dst, int x, int y, const SkBitmap& src);
1249
1250    const SkBitmap::Config config = this->getConfig();
1251
1252    switch (config) {
1253        case kARGB_8888_Config:
1254            proc = downsampleby2_proc32;
1255            break;
1256        case kRGB_565_Config:
1257            proc = downsampleby2_proc16;
1258            break;
1259        case kARGB_4444_Config:
1260            proc = downsampleby2_proc4444;
1261            break;
1262        case kIndex8_Config:
1263        case kA8_Config:
1264        default:
1265            return; // don't build mipmaps for these configs
1266    }
1267
1268    SkAutoLockPixels alp(*this);
1269    if (!this->readyToDraw()) {
1270        return;
1271    }
1272
1273    // whip through our loop to compute the exact size needed
1274    size_t  size = 0;
1275    int     maxLevels = 0;
1276    {
1277        int width = this->width();
1278        int height = this->height();
1279        for (;;) {
1280            width >>= 1;
1281            height >>= 1;
1282            if (0 == width || 0 == height) {
1283                break;
1284            }
1285            size += ComputeRowBytes(config, width) * height;
1286            maxLevels += 1;
1287        }
1288    }
1289
1290    // nothing to build
1291    if (0 == maxLevels) {
1292        return;
1293    }
1294
1295    SkBitmap srcBM(*this);
1296    srcBM.lockPixels();
1297    if (!srcBM.readyToDraw()) {
1298        return;
1299    }
1300
1301    MipMap* mm = MipMap::Alloc(maxLevels, size);
1302    if (NULL == mm) {
1303        return;
1304    }
1305
1306    MipLevel*   level = mm->levels();
1307    uint8_t*    addr = (uint8_t*)mm->pixels();
1308    int         width = this->width();
1309    int         height = this->height();
1310    uint32_t    rowBytes;
1311    SkBitmap    dstBM;
1312
1313    for (int i = 0; i < maxLevels; i++) {
1314        width >>= 1;
1315        height >>= 1;
1316        rowBytes = SkToU32(ComputeRowBytes(config, width));
1317
1318        level[i].fPixels   = addr;
1319        level[i].fWidth    = width;
1320        level[i].fHeight   = height;
1321        level[i].fRowBytes = rowBytes;
1322
1323        dstBM.setConfig(config, width, height, rowBytes);
1324        dstBM.setPixels(addr);
1325
1326        srcBM.lockPixels();
1327        for (int y = 0; y < height; y++) {
1328            for (int x = 0; x < width; x++) {
1329                proc(&dstBM, x, y, srcBM);
1330            }
1331        }
1332        srcBM.unlockPixels();
1333
1334        srcBM = dstBM;
1335        addr += height * rowBytes;
1336    }
1337    SkASSERT(addr == (uint8_t*)mm->pixels() + size);
1338    fMipMap = mm;
1339}
1340
1341bool SkBitmap::hasMipMap() const {
1342    return fMipMap != NULL;
1343}
1344
1345int SkBitmap::extractMipLevel(SkBitmap* dst, SkFixed sx, SkFixed sy) {
1346    if (NULL == fMipMap) {
1347        return 0;
1348    }
1349
1350    int level = ComputeMipLevel(sx, sy) >> 16;
1351    SkASSERT(level >= 0);
1352    if (level <= 0) {
1353        return 0;
1354    }
1355
1356    if (level >= fMipMap->fLevelCount) {
1357        level = fMipMap->fLevelCount - 1;
1358    }
1359    if (dst) {
1360        const MipLevel& mip = fMipMap->levels()[level - 1];
1361        dst->setConfig((SkBitmap::Config)this->config(),
1362                       mip.fWidth, mip.fHeight, mip.fRowBytes);
1363        dst->setPixels(mip.fPixels);
1364    }
1365    return level;
1366}
1367
1368SkFixed SkBitmap::ComputeMipLevel(SkFixed sx, SkFixed sy) {
1369    sx = SkAbs32(sx);
1370    sy = SkAbs32(sy);
1371    if (sx < sy) {
1372        sx = sy;
1373    }
1374    if (sx < SK_Fixed1) {
1375        return 0;
1376    }
1377    int clz = SkCLZ(sx);
1378    SkASSERT(clz >= 1 && clz <= 15);
1379    return SkIntToFixed(15 - clz) + ((unsigned)(sx << (clz + 1)) >> 16);
1380}
1381
1382///////////////////////////////////////////////////////////////////////////////
1383
1384static bool GetBitmapAlpha(const SkBitmap& src, uint8_t* SK_RESTRICT alpha,
1385                           int alphaRowBytes) {
1386    SkASSERT(alpha != NULL);
1387    SkASSERT(alphaRowBytes >= src.width());
1388
1389    SkBitmap::Config config = src.getConfig();
1390    int              w = src.width();
1391    int              h = src.height();
1392    size_t           rb = src.rowBytes();
1393
1394    SkAutoLockPixels alp(src);
1395    if (!src.readyToDraw()) {
1396        // zero out the alpha buffer and return
1397        while (--h >= 0) {
1398            memset(alpha, 0, w);
1399            alpha += alphaRowBytes;
1400        }
1401        return false;
1402    }
1403
1404    if (SkBitmap::kA8_Config == config && !src.isOpaque()) {
1405        const uint8_t* s = src.getAddr8(0, 0);
1406        while (--h >= 0) {
1407            memcpy(alpha, s, w);
1408            s += rb;
1409            alpha += alphaRowBytes;
1410        }
1411    } else if (SkBitmap::kARGB_8888_Config == config && !src.isOpaque()) {
1412        const SkPMColor* SK_RESTRICT s = src.getAddr32(0, 0);
1413        while (--h >= 0) {
1414            for (int x = 0; x < w; x++) {
1415                alpha[x] = SkGetPackedA32(s[x]);
1416            }
1417            s = (const SkPMColor*)((const char*)s + rb);
1418            alpha += alphaRowBytes;
1419        }
1420    } else if (SkBitmap::kARGB_4444_Config == config && !src.isOpaque()) {
1421        const SkPMColor16* SK_RESTRICT s = src.getAddr16(0, 0);
1422        while (--h >= 0) {
1423            for (int x = 0; x < w; x++) {
1424                alpha[x] = SkPacked4444ToA32(s[x]);
1425            }
1426            s = (const SkPMColor16*)((const char*)s + rb);
1427            alpha += alphaRowBytes;
1428        }
1429    } else if (SkBitmap::kIndex8_Config == config && !src.isOpaque()) {
1430        SkColorTable* ct = src.getColorTable();
1431        if (ct) {
1432            const SkPMColor* SK_RESTRICT table = ct->lockColors();
1433            const uint8_t* SK_RESTRICT s = src.getAddr8(0, 0);
1434            while (--h >= 0) {
1435                for (int x = 0; x < w; x++) {
1436                    alpha[x] = SkGetPackedA32(table[s[x]]);
1437                }
1438                s += rb;
1439                alpha += alphaRowBytes;
1440            }
1441            ct->unlockColors(false);
1442        }
1443    } else {    // src is opaque, so just fill alpha[] with 0xFF
1444        memset(alpha, 0xFF, h * alphaRowBytes);
1445    }
1446    return true;
1447}
1448
1449#include "SkPaint.h"
1450#include "SkMaskFilter.h"
1451#include "SkMatrix.h"
1452
1453bool SkBitmap::extractAlpha(SkBitmap* dst, const SkPaint* paint,
1454                            Allocator *allocator, SkIPoint* offset) const {
1455    SkDEBUGCODE(this->validate();)
1456
1457    SkBitmap    tmpBitmap;
1458    SkMatrix    identity;
1459    SkMask      srcM, dstM;
1460
1461    srcM.fBounds.set(0, 0, this->width(), this->height());
1462    srcM.fRowBytes = SkAlign4(this->width());
1463    srcM.fFormat = SkMask::kA8_Format;
1464
1465    SkMaskFilter* filter = paint ? paint->getMaskFilter() : NULL;
1466
1467    // compute our (larger?) dst bounds if we have a filter
1468    if (NULL != filter) {
1469        identity.reset();
1470        srcM.fImage = NULL;
1471        if (!filter->filterMask(&dstM, srcM, identity, NULL)) {
1472            goto NO_FILTER_CASE;
1473        }
1474        dstM.fRowBytes = SkAlign4(dstM.fBounds.width());
1475    } else {
1476    NO_FILTER_CASE:
1477        tmpBitmap.setConfig(SkBitmap::kA8_Config, this->width(), this->height(),
1478                       srcM.fRowBytes);
1479        if (!tmpBitmap.allocPixels(allocator, NULL)) {
1480            // Allocation of pixels for alpha bitmap failed.
1481            SkDebugf("extractAlpha failed to allocate (%d,%d) alpha bitmap\n",
1482                    tmpBitmap.width(), tmpBitmap.height());
1483            return false;
1484        }
1485        GetBitmapAlpha(*this, tmpBitmap.getAddr8(0, 0), srcM.fRowBytes);
1486        if (offset) {
1487            offset->set(0, 0);
1488        }
1489        tmpBitmap.swap(*dst);
1490        return true;
1491    }
1492    srcM.fImage = SkMask::AllocImage(srcM.computeImageSize());
1493    SkAutoMaskFreeImage srcCleanup(srcM.fImage);
1494
1495    GetBitmapAlpha(*this, srcM.fImage, srcM.fRowBytes);
1496    if (!filter->filterMask(&dstM, srcM, identity, NULL)) {
1497        goto NO_FILTER_CASE;
1498    }
1499    SkAutoMaskFreeImage dstCleanup(dstM.fImage);
1500
1501    tmpBitmap.setConfig(SkBitmap::kA8_Config, dstM.fBounds.width(),
1502                   dstM.fBounds.height(), dstM.fRowBytes);
1503    if (!tmpBitmap.allocPixels(allocator, NULL)) {
1504        // Allocation of pixels for alpha bitmap failed.
1505        SkDebugf("extractAlpha failed to allocate (%d,%d) alpha bitmap\n",
1506                tmpBitmap.width(), tmpBitmap.height());
1507        return false;
1508    }
1509    memcpy(tmpBitmap.getPixels(), dstM.fImage, dstM.computeImageSize());
1510    if (offset) {
1511        offset->set(dstM.fBounds.fLeft, dstM.fBounds.fTop);
1512    }
1513    SkDEBUGCODE(tmpBitmap.validate();)
1514
1515    tmpBitmap.swap(*dst);
1516    return true;
1517}
1518
1519///////////////////////////////////////////////////////////////////////////////
1520
1521enum {
1522    SERIALIZE_PIXELTYPE_NONE,
1523    SERIALIZE_PIXELTYPE_REF_DATA
1524};
1525
1526void SkBitmap::flatten(SkFlattenableWriteBuffer& buffer) const {
1527    buffer.writeInt(fWidth);
1528    buffer.writeInt(fHeight);
1529    buffer.writeInt(fRowBytes);
1530    buffer.writeInt(fConfig);
1531    buffer.writeBool(this->isOpaque());
1532
1533    if (fPixelRef) {
1534        if (fPixelRef->getFactory()) {
1535            buffer.writeInt(SERIALIZE_PIXELTYPE_REF_DATA);
1536            buffer.writeUInt(SkToU32(fPixelRefOffset));
1537            buffer.writeFlattenable(fPixelRef);
1538            return;
1539        }
1540        // if we get here, we can't record the pixels
1541        buffer.writeInt(SERIALIZE_PIXELTYPE_NONE);
1542    } else {
1543        buffer.writeInt(SERIALIZE_PIXELTYPE_NONE);
1544    }
1545}
1546
1547void SkBitmap::unflatten(SkFlattenableReadBuffer& buffer) {
1548    this->reset();
1549
1550    int width = buffer.readInt();
1551    int height = buffer.readInt();
1552    int rowBytes = buffer.readInt();
1553    int config = buffer.readInt();
1554
1555    this->setConfig((Config)config, width, height, rowBytes);
1556    this->setIsOpaque(buffer.readBool());
1557
1558    int reftype = buffer.readInt();
1559    switch (reftype) {
1560        case SERIALIZE_PIXELTYPE_REF_DATA: {
1561            size_t offset = buffer.readUInt();
1562            SkPixelRef* pr = buffer.readFlattenableT<SkPixelRef>();
1563            SkSafeUnref(this->setPixelRef(pr, offset));
1564            break;
1565        }
1566        case SERIALIZE_PIXELTYPE_NONE:
1567            break;
1568        default:
1569            SkDEBUGFAIL("unrecognized pixeltype in serialized data");
1570            sk_throw();
1571    }
1572}
1573
1574///////////////////////////////////////////////////////////////////////////////
1575
1576SkBitmap::RLEPixels::RLEPixels(int width, int height) {
1577    fHeight = height;
1578    fYPtrs = (uint8_t**)sk_malloc_throw(height * sizeof(uint8_t*));
1579    sk_bzero(fYPtrs, height * sizeof(uint8_t*));
1580}
1581
1582SkBitmap::RLEPixels::~RLEPixels() {
1583    sk_free(fYPtrs);
1584}
1585
1586///////////////////////////////////////////////////////////////////////////////
1587
1588#ifdef SK_DEBUG
1589void SkBitmap::validate() const {
1590    SkASSERT(fConfig < kConfigCount);
1591    SkASSERT(fRowBytes >= (unsigned)ComputeRowBytes((Config)fConfig, fWidth));
1592    uint8_t allFlags = kImageIsOpaque_Flag | kImageIsVolatile_Flag | kImageIsImmutable_Flag;
1593#ifdef SK_BUILD_FOR_ANDROID
1594    allFlags |= kHasHardwareMipMap_Flag;
1595#endif
1596    SkASSERT(fFlags <= allFlags);
1597    SkASSERT(fPixelLockCount >= 0);
1598    SkASSERT(NULL == fColorTable || (unsigned)fColorTable->getRefCnt() < 10000);
1599    SkASSERT((uint8_t)ComputeBytesPerPixel((Config)fConfig) == fBytesPerPixel);
1600
1601#if 0   // these asserts are not thread-correct, so disable for now
1602    if (fPixelRef) {
1603        if (fPixelLockCount > 0) {
1604            SkASSERT(fPixelRef->isLocked());
1605        } else {
1606            SkASSERT(NULL == fPixels);
1607            SkASSERT(NULL == fColorTable);
1608        }
1609    }
1610#endif
1611}
1612#endif
1613
1614#ifdef SK_DEVELOPER
1615void SkBitmap::toString(SkString* str) const {
1616
1617    static const char* gConfigNames[kConfigCount] = {
1618        "NONE", "A1", "A8", "INDEX8", "565", "4444", "8888", "RLE"
1619    };
1620
1621    str->appendf("bitmap: ((%d, %d) %s", this->width(), this->height(),
1622                 gConfigNames[this->config()]);
1623
1624    str->append(" (");
1625    if (this->isOpaque()) {
1626        str->append("opaque");
1627    } else {
1628        str->append("transparent");
1629    }
1630    if (this->isImmutable()) {
1631        str->append(", immutable");
1632    } else {
1633        str->append(", not-immutable");
1634    }
1635    str->append(")");
1636
1637    SkPixelRef* pr = this->pixelRef();
1638    if (NULL == pr) {
1639        // show null or the explicit pixel address (rare)
1640        str->appendf(" pixels:%p", this->getPixels());
1641    } else {
1642        const char* uri = pr->getURI();
1643        if (NULL != uri) {
1644            str->appendf(" uri:\"%s\"", uri);
1645        } else {
1646            str->appendf(" pixelref:%p", pr);
1647        }
1648    }
1649
1650    str->append(")");
1651}
1652#endif
1653