Add skia to the repository.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@16 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 1270 insertions, 0 deletions

diff --git a/skia/sgl/SkBitmap.cpp b/skia/sgl/SkBitmap.cpp
new file mode 100644
index 0000000..914fc77
--- /dev/null
+++ b/skia/sgl/SkBitmap.cpp
@@ -0,0 +1,1270 @@
+/*
+ * Copyright (C) 2006-2008 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SkBitmap.h"
+#include "SkColorPriv.h"
+#include "SkDither.h"
+#include "SkFlattenable.h"
+#include "SkMask.h"
+#include "SkPixelRef.h"
+#include "SkThread.h"
+#include "SkUtils.h"
+#include "SkPackBits.h"
+#include <new>
+
+#ifdef SK_SUPPORT_MIPMAP
+struct MipLevel {
+    void*       fPixels;
+    uint32_t    fRowBytes;
+    uint16_t    fWidth, fHeight;
+};
+
+struct SkBitmap::MipMap : SkNoncopyable {
+    int fRefCnt;
+    int fLevelCount;
+//  MipLevel    fLevel[fLevelCount];
+//  Pixels[]
+    
+    static MipMap* Alloc(int levelCount, size_t pixelSize) {
+        MipMap* mm = (MipMap*)sk_malloc_throw(sizeof(MipMap) +
+                                              levelCount * sizeof(MipLevel) +
+                                              pixelSize);
+        mm->fRefCnt = 1;
+        mm->fLevelCount = levelCount;
+        return mm;
+    }
+
+    const MipLevel* levels() const { return (const MipLevel*)(this + 1); }
+    MipLevel* levels() { return (MipLevel*)(this + 1); }
+
+    const void* pixels() const { return levels() + fLevelCount; }
+    void* pixels() { return levels() + fLevelCount; }
+    
+    void safeRef() {
+        if (this) {
+            SkASSERT(fRefCnt > 0);
+            sk_atomic_inc(&fRefCnt);
+        }
+    }
+    void safeUnref() {
+        if (this) {
+            SkASSERT(fRefCnt > 0);
+            if (sk_atomic_dec(&fRefCnt) == 1) {
+                sk_free(this);
+            }
+        }
+    }
+};
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////
+
+SkBitmap::SkBitmap() {
+    bzero(this, sizeof(*this));
+}
+
+SkBitmap::SkBitmap(const SkBitmap& src) {
+    SkDEBUGCODE(src.validate();)
+    bzero(this, sizeof(*this));
+    *this = src;
+    SkDEBUGCODE(this->validate();)
+}
+
+SkBitmap::~SkBitmap() {
+    SkDEBUGCODE(this->validate();)
+    this->freePixels();
+}
+
+SkBitmap& SkBitmap::operator=(const SkBitmap& src) {
+    if (this != &src) {
+        this->freePixels();
+        memcpy(this, &src, sizeof(src));
+
+        // inc src reference counts
+        src.fPixelRef->safeRef();
+#ifdef SK_SUPPORT_MIPMAP
+        src.fMipMap->safeRef();
+#endif
+
+        // we reset our locks if we get blown away
+        fPixelLockCount = 0;
+        
+        /*  The src could be in 3 states
+            1. no pixelref, in which case we just copy/ref the pixels/ctable
+            2. unlocked pixelref, pixels/ctable should be null
+            3. locked pixelref, we should lock the ref again ourselves
+        */
+        if (NULL == fPixelRef) {
+            // leave fPixels as it is
+            fColorTable->safeRef(); // ref the user's ctable if present
+        } else {    // we have a pixelref, so pixels/ctable reflect it
+            // ignore the values from the memcpy
+            fPixels = NULL;
+            fColorTable = NULL;
+        }
+    }
+
+    SkDEBUGCODE(this->validate();)
+    return *this;
+}
+
+void SkBitmap::swap(SkBitmap& other) {
+    SkTSwap<SkColorTable*>(fColorTable, other.fColorTable);
+    SkTSwap<SkPixelRef*>(fPixelRef, other.fPixelRef);
+    SkTSwap<size_t>(fPixelRefOffset, other.fPixelRefOffset);
+    SkTSwap<int>(fPixelLockCount, other.fPixelLockCount);
+#ifdef SK_SUPPORT_MIPMAP
+    SkTSwap<MipMap*>(fMipMap, other.fMipMap);
+#endif
+    SkTSwap<void*>(fPixels, other.fPixels);
+    SkTSwap<uint16_t>(fWidth, other.fWidth);
+    SkTSwap<uint16_t>(fHeight, other.fHeight);
+    SkTSwap<uint32_t>(fRowBytes, other.fRowBytes);
+    SkTSwap<uint8_t>(fConfig, other.fConfig);
+    SkTSwap<uint8_t>(fFlags, other.fFlags);
+    SkTSwap<uint8_t>(fBytesPerPixel, other.fBytesPerPixel);
+
+    SkDEBUGCODE(this->validate();)
+}
+
+void SkBitmap::reset() {
+    this->freePixels();
+    bzero(this, sizeof(*this));
+}
+
+int SkBitmap::ComputeBytesPerPixel(SkBitmap::Config config) {
+    int bpp;
+    switch (config) {
+        case kNo_Config:
+        case kA1_Config:
+            bpp = 0;   // not applicable
+            break;
+        case kRLE_Index8_Config:
+        case kA8_Config:
+        case kIndex8_Config:
+            bpp = 1;
+            break;
+        case kRGB_565_Config:
+        case kARGB_4444_Config:
+            bpp = 2;
+            break;
+        case kARGB_8888_Config:
+            bpp = 4;
+            break;
+        default:
+            SkASSERT(!"unknown config");
+            bpp = 0;   // error
+            break;
+    }
+    return bpp;
+}
+
+int SkBitmap::ComputeRowBytes(Config c, int width) {
+    int rowBytes = 0;
+
+    switch (c) {
+        case kNo_Config:
+        case kRLE_Index8_Config:
+            // assume that the bitmap has no pixels to draw to
+            rowBytes = 0;
+            break;
+        case kA1_Config:
+            rowBytes = (width + 7) >> 3;
+            break;
+        case kA8_Config:
+        case kIndex8_Config:
+            rowBytes = width;
+            break;
+        case kRGB_565_Config:
+        case kARGB_4444_Config:
+            rowBytes = width << 1;
+            break;
+        case kARGB_8888_Config:
+            rowBytes = width << 2;
+            break;
+        default:
+            SkASSERT(!"unknown config");
+            break;
+    }
+    return rowBytes;
+}
+
+void SkBitmap::setConfig(Config c, int width, int height, int rowBytes) {
+    this->freePixels();
+
+    if (rowBytes == 0) {
+        rowBytes = SkBitmap::ComputeRowBytes(c, width);
+    }
+    fConfig     = SkToU8(c);
+    fWidth      = SkToU16(width);
+    fHeight     = SkToU16(height);
+    fRowBytes   = rowBytes;
+
+    fBytesPerPixel = (uint8_t)ComputeBytesPerPixel(c);
+
+    SkDEBUGCODE(this->validate();)
+}
+
+void SkBitmap::updatePixelsFromRef() const {
+    if (NULL != fPixelRef) {
+        if (fPixelLockCount > 0) {
+            SkASSERT(fPixelRef->getLockCount() > 0);
+            
+            void* p = fPixelRef->pixels();
+            if (NULL != p) {
+                p = (char*)p + fPixelRefOffset;
+            }
+            fPixels = p;
+            SkRefCnt_SafeAssign(fColorTable, fPixelRef->colorTable());
+        } else {
+            SkASSERT(0 == fPixelLockCount);
+            fPixels = NULL;
+            fColorTable->safeUnref();
+            fColorTable = NULL;
+        }
+    }
+}
+
+SkPixelRef* SkBitmap::setPixelRef(SkPixelRef* pr, size_t offset) {
+    // do this first, we that we never have a non-zero offset with a null ref
+    if (NULL == pr) {
+        offset = 0;
+    }
+
+    if (fPixelRef != pr || fPixelRefOffset != offset) {
+        if (fPixelRef != pr) {
+            this->freePixels();
+            SkASSERT(NULL == fPixelRef);
+            
+            pr->safeRef();
+            fPixelRef = pr;
+        }
+        fPixelRefOffset = offset;
+        this->updatePixelsFromRef();
+    }
+
+    SkDEBUGCODE(this->validate();)
+    return pr;
+}
+
+void SkBitmap::lockPixels() const {
+    if (NULL != fPixelRef && 1 == ++fPixelLockCount) {
+        fPixelRef->lockPixels();
+        this->updatePixelsFromRef();
+    }
+    SkDEBUGCODE(this->validate();)
+}
+
+void SkBitmap::unlockPixels() const {
+    SkASSERT(NULL == fPixelRef || fPixelLockCount > 0);
+
+    if (NULL != fPixelRef && 0 == --fPixelLockCount) {
+        fPixelRef->unlockPixels();
+        this->updatePixelsFromRef();
+    }
+    SkDEBUGCODE(this->validate();)
+}
+
+void SkBitmap::setPixels(void* p, SkColorTable* ctable) {
+    this->freePixels();
+    fPixels = p;
+    SkRefCnt_SafeAssign(fColorTable, ctable);
+
+    SkDEBUGCODE(this->validate();)
+}
+
+bool SkBitmap::allocPixels(Allocator* allocator, SkColorTable* ctable) {
+    HeapAllocator stdalloc;
+
+    if (NULL == allocator) {
+        allocator = &stdalloc;
+    }
+    return allocator->allocPixelRef(this, ctable);
+}
+
+void SkBitmap::freePixels() {
+    // if we're gonna free the pixels, we certainly need to free the mipmap
+    this->freeMipMap();
+
+    fColorTable->safeUnref();
+    fColorTable = NULL;
+
+    if (NULL != fPixelRef) {
+        if (fPixelLockCount > 0) {
+            fPixelRef->unlockPixels();
+        }
+        fPixelRef->unref();
+        fPixelRef = NULL;
+        fPixelRefOffset = 0;
+    }
+    fPixelLockCount = 0;
+    fPixels = NULL;
+}
+
+void SkBitmap::freeMipMap() {
+#ifdef SK_SUPPORT_MIPMAP
+    fMipMap->safeUnref();
+    fMipMap = NULL;
+#endif
+}
+
+uint32_t SkBitmap::getGenerationID() const {
+    return fPixelRef ? fPixelRef->getGenerationID() : 0;
+}
+
+void SkBitmap::notifyPixelsChanged() const {
+    if (fPixelRef) {
+        fPixelRef->notifyPixelsChanged();
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+/** We explicitly use the same allocator for our pixels that SkMask does,
+ so that we can freely assign memory allocated by one class to the other.
+ */
+class SkMallocPixelRef : public SkPixelRef {
+public:
+    /** Allocate the specified buffer for pixels. The memory is freed when the
+     last owner of this pixelref is gone.
+     */
+    SkMallocPixelRef(void* addr, size_t size, SkColorTable* ctable);
+    virtual ~SkMallocPixelRef();
+
+    virtual void flatten(SkFlattenableWriteBuffer&) const;
+    virtual Factory getFactory() const {
+        return Create;
+    }
+    static SkPixelRef* Create(SkFlattenableReadBuffer& buffer) {
+        return SkNEW_ARGS(SkMallocPixelRef, (buffer));
+    }
+
+protected:
+    // overrides from SkPixelRef
+    virtual void* onLockPixels(SkColorTable**);
+    virtual void onUnlockPixels();
+
+    SkMallocPixelRef(SkFlattenableReadBuffer& buffer);
+
+private:
+    void*           fStorage;
+    size_t          fSize;
+    SkColorTable*   fCTable;
+
+    typedef SkPixelRef INHERITED;
+};
+
+SkMallocPixelRef::SkMallocPixelRef(void* storage, size_t size,
+                                   SkColorTable* ctable) {
+    SkASSERT(storage);
+    fStorage = storage;
+    fSize = size;
+    fCTable = ctable;
+    ctable->safeRef();
+}
+
+SkMallocPixelRef::~SkMallocPixelRef() {
+    fCTable->safeUnref();
+    sk_free(fStorage);
+}
+
+void* SkMallocPixelRef::onLockPixels(SkColorTable** ct) {
+    *ct = fCTable;
+    return fStorage;
+}
+
+void SkMallocPixelRef::onUnlockPixels() {
+    // nothing to do
+}
+
+void SkMallocPixelRef::flatten(SkFlattenableWriteBuffer& buffer) const {
+    this->INHERITED::flatten(buffer);
+    
+    buffer.write32(fSize);
+    buffer.writePad(fStorage, fSize);
+    if (fCTable) {
+        buffer.writeBool(true);
+        fCTable->flatten(buffer);
+    } else {
+        buffer.writeBool(false);
+    }
+}
+
+SkMallocPixelRef::SkMallocPixelRef(SkFlattenableReadBuffer& buffer) : INHERITED(buffer, NULL) {
+    fSize = buffer.readU32();
+    fStorage = sk_malloc_throw(fSize);
+    buffer.read(fStorage, fSize);
+    if (buffer.readBool()) {
+        fCTable = SkNEW_ARGS(SkColorTable, (buffer));
+    } else {
+        fCTable = NULL;
+    }
+}
+
+static SkPixelRef::Registrar reg("SkMallocPixelRef",
+                                            SkMallocPixelRef::Create);
+
+/** We explicitly use the same allocator for our pixels that SkMask does,
+ so that we can freely assign memory allocated by one class to the other.
+ */
+bool SkBitmap::HeapAllocator::allocPixelRef(SkBitmap* dst,
+                                            SkColorTable* ctable) {
+    Sk64 size = dst->getSize64();
+    if (size.isNeg() || !size.is32()) {
+        return false;
+    }
+    
+    void* addr = sk_malloc_flags(size.get32(), 0);  // returns NULL on failure
+    if (NULL == addr) {
+        return false;
+    }
+    
+    dst->setPixelRef(new SkMallocPixelRef(addr, size.get32(), ctable))->unref();
+    // since we're already allocated, we lockPixels right away
+    dst->lockPixels();
+    return true;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+bool SkBitmap::isOpaque() const {
+    switch (fConfig) {
+        case kNo_Config:
+            return true;
+
+        case kA1_Config:
+        case kA8_Config:
+        case kARGB_4444_Config:
+        case kARGB_8888_Config:
+            return (fFlags & kImageIsOpaque_Flag) != 0;
+
+        case kIndex8_Config:
+        case kRLE_Index8_Config: {
+                uint32_t flags = 0;
+
+                this->lockPixels();
+                // if lockPixels failed, we may not have a ctable ptr
+                if (fColorTable) {
+                    flags = fColorTable->getFlags();
+                }
+                this->unlockPixels();
+
+                return (flags & SkColorTable::kColorsAreOpaque_Flag) != 0;
+            }
+
+        case kRGB_565_Config:
+            return true;
+
+        default:
+            SkASSERT(!"unknown bitmap config pased to isOpaque");
+            return false;
+    }
+}
+
+void SkBitmap::setIsOpaque(bool isOpaque) {
+    /*  we record this regardless of fConfig, though it is ignored in
+        isOpaque() for configs that can't support per-pixel alpha.
+    */
+    if (isOpaque) {
+        fFlags |= kImageIsOpaque_Flag;
+    } else {
+        fFlags &= ~kImageIsOpaque_Flag;
+    }
+}
+
+void* SkBitmap::getAddr(int x, int y) const {
+    SkASSERT((unsigned)x < (unsigned)this->width());
+    SkASSERT((unsigned)y < (unsigned)this->height());
+
+    char* base = (char*)this->getPixels();
+    if (base) {
+        base += y * this->rowBytes();
+        switch (this->config()) {
+            case SkBitmap::kARGB_8888_Config:
+                base += x << 2;
+                break;
+            case SkBitmap::kARGB_4444_Config:
+            case SkBitmap::kRGB_565_Config:
+                base += x << 1;
+                break;
+            case SkBitmap::kA8_Config:
+            case SkBitmap::kIndex8_Config:
+                base += x;
+                break;
+            case SkBitmap::kA1_Config:
+                base += x >> 3;
+                break;
+            case kRLE_Index8_Config:
+                SkASSERT(!"Can't return addr for kRLE_Index8_Config");
+                base = NULL;
+                break;
+            default:
+                SkASSERT(!"Can't return addr for config");
+                base = NULL;
+                break;
+        }
+    }
+    return base;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////
+
+void SkBitmap::eraseARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) const {
+    SkDEBUGCODE(this->validate();)
+
+    if (0 == fWidth || 0 == fHeight ||
+            kNo_Config == fConfig || kIndex8_Config == fConfig) {
+        return;
+    }
+
+    SkAutoLockPixels alp(*this);
+    // perform this check after the lock call
+    if (NULL == fPixels) {
+        return;
+    }
+
+    int height = fHeight;
+    const int width = fWidth;
+    const int rowBytes = fRowBytes;
+
+    // make rgb premultiplied
+    if (255 != a) {
+        r = SkAlphaMul(r, a);
+        g = SkAlphaMul(g, a);
+        b = SkAlphaMul(b, a);
+    }
+
+    switch (fConfig) {
+        case kA1_Config: {
+            uint8_t* p = (uint8_t*)fPixels;
+            const int count = (width + 7) >> 3;
+            a = (a >> 7) ? 0xFF : 0;
+            SkASSERT(count <= rowBytes);
+            while (--height >= 0) {
+                memset(p, a, count);
+                p += rowBytes;
+            }
+            break;
+        }
+        case kA8_Config: {
+            uint8_t* p = (uint8_t*)fPixels;
+            while (--height >= 0) {
+                memset(p, a, width);
+                p += rowBytes;
+            }
+            break;
+        }
+        case kARGB_4444_Config:
+        case kRGB_565_Config: {
+            uint16_t* p = (uint16_t*)fPixels;
+            uint16_t v;
+            
+            if (kARGB_4444_Config == fConfig) {
+                v = SkPackARGB4444(a >> 4, r >> 4, g >> 4, b >> 4);
+            } else {    // kRGB_565_Config
+                v = SkPackRGB16(r >> (8 - SK_R16_BITS), g >> (8 - SK_G16_BITS),
+                                b >> (8 - SK_B16_BITS));
+            }
+            while (--height >= 0) {
+                sk_memset16(p, v, width);
+                p = (uint16_t*)((char*)p + rowBytes);
+            }
+            break;
+        }
+        case kARGB_8888_Config: {
+            uint32_t* p = (uint32_t*)fPixels;
+            uint32_t  v = SkPackARGB32(a, r, g, b);
+
+            while (--height >= 0) {
+                sk_memset32(p, v, width);
+                p = (uint32_t*)((char*)p + rowBytes);
+            }
+            break;
+        }
+    }
+    
+    this->notifyPixelsChanged();
+}
+
+//////////////////////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////////////////
+
+#define SUB_OFFSET_FAILURE  ((size_t)-1)
+
+static size_t getSubOffset(const SkBitmap& bm, int x, int y) {
+    SkASSERT((unsigned)x < (unsigned)bm.width());
+    SkASSERT((unsigned)y < (unsigned)bm.height());
+    
+    switch (bm.getConfig()) {
+        case SkBitmap::kA8_Config:
+        case SkBitmap:: kIndex8_Config:
+            // x is fine as is for the calculation
+            break;
+
+        case SkBitmap::kRGB_565_Config:
+        case SkBitmap::kARGB_4444_Config:
+            x <<= 1;
+            break;
+
+        case SkBitmap::kARGB_8888_Config:
+            x <<= 2;
+            break;
+
+        case SkBitmap::kNo_Config:
+        case SkBitmap::kA1_Config:
+        default:
+            return SUB_OFFSET_FAILURE;
+    }
+    return y * bm.rowBytes() + x;
+}
+
+bool SkBitmap::extractSubset(SkBitmap* result, const SkIRect& subset) const {
+    SkDEBUGCODE(this->validate();)
+
+    if (NULL == result || (NULL == fPixelRef && NULL == fPixels)) {
+        return false;   // no src pixels
+    }
+
+    SkIRect srcRect, r;
+    srcRect.set(0, 0, this->width(), this->height());
+    if (!r.intersect(srcRect, subset)) {
+        return false;   // r is empty (i.e. no intersection)
+    }
+
+    if (kRLE_Index8_Config == fConfig) {
+        SkAutoLockPixels alp(*this);
+        if (this->getPixels() == NULL) {
+            return false;
+        }
+        SkBitmap bm;
+        
+        bm.setConfig(kIndex8_Config, r.width(), r.height());
+        bm.allocPixels(this->getColorTable());
+        if (NULL == bm.getPixels()) {
+            return false;
+        }
+        
+        const RLEPixels* rle = (const RLEPixels*)this->getPixels();
+        uint8_t* dst = bm.getAddr8(0, 0);
+        const int width = bm.width();
+        const int rowBytes = bm.rowBytes();
+            
+        for (int y = r.fTop; y < r.fBottom; y++) {
+            SkPackBits::Unpack8(dst, r.fLeft, width, rle->packedAtY(y));
+            dst += rowBytes;
+        }
+        result->swap(bm);
+        return true;
+    }
+
+    size_t offset = getSubOffset(*this, r.fLeft, r.fTop);
+    if (SUB_OFFSET_FAILURE == offset) {
+        return false;   // config not supported
+    }
+
+    SkBitmap dst;
+    dst.setConfig(this->config(), r.width(), r.height(), this->rowBytes());
+
+    if (fPixelRef) {
+        // share the pixelref with a custom offset
+        dst.setPixelRef(fPixelRef, fPixelRefOffset + offset);
+    } else {
+        // share the pixels (owned by the caller)
+        dst.setPixels((char*)fPixels + offset, this->getColorTable());
+    }
+    SkDEBUGCODE(dst.validate();)
+
+    // we know we're good, so commit to result
+    result->swap(dst);
+    return true;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+#include "SkCanvas.h"
+#include "SkPaint.h"
+
+bool SkBitmap::copyTo(SkBitmap* dst, Config dstConfig, Allocator* alloc) const {
+    if (NULL == dst || this->width() == 0 || this->height() == 0) {
+        return false;
+    }
+
+    switch (dstConfig) {
+        case kA8_Config:
+        case kARGB_4444_Config:
+        case kRGB_565_Config:
+        case kARGB_8888_Config:
+            break;
+        default:
+            return false;
+    }
+    
+    SkBitmap    tmp;
+    
+    tmp.setConfig(dstConfig, this->width(), this->height());
+    // pass null for colortable, since we don't support Index8 config for dst
+    if (!tmp.allocPixels(alloc, NULL)) {
+        return false;
+    }
+    
+    SkAutoLockPixels srclock(*this);
+    SkAutoLockPixels dstlock(tmp);
+    
+    if (NULL == this->getPixels() || NULL == tmp.getPixels()) {
+        // allocator/lock failed
+        return false;
+    }
+
+    // if the src has alpha, we have to clear the dst first
+    if (!this->isOpaque()) {
+        tmp.eraseColor(0);
+    }
+
+    SkCanvas canvas(tmp);
+    SkPaint  paint;
+    
+    paint.setDither(true);
+    canvas.drawBitmap(*this, 0, 0, &paint);
+    
+    dst->swap(tmp);
+    return true;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////
+
+static void downsampleby2_proc32(SkBitmap* dst, int x, int y,
+                                 const SkBitmap& src) {
+    x <<= 1;
+    y <<= 1;
+    const SkPMColor* p = src.getAddr32(x, y);
+    SkPMColor c, ag, rb;
+
+    c = *p; ag = (c >> 8) & 0xFF00FF; rb = c & 0xFF00FF;
+    if (x < src.width() - 1) {
+        p += 1;
+    }
+    c = *p; ag += (c >> 8) & 0xFF00FF; rb += c & 0xFF00FF;
+
+    if (y < src.height() - 1) {
+        p = src.getAddr32(x, y + 1);
+    }
+    c = *p; ag += (c >> 8) & 0xFF00FF; rb += c & 0xFF00FF;
+    if (x < src.width() - 1) {
+        p += 1;
+    }
+    c = *p; ag += (c >> 8) & 0xFF00FF; rb += c & 0xFF00FF;
+
+    *dst->getAddr32(x >> 1, y >> 1) =
+        ((rb >> 2) & 0xFF00FF) | ((ag << 6) & 0xFF00FF00);
+}
+
+static inline uint32_t expand16(U16CPU c) {
+    return (c & ~SK_G16_MASK_IN_PLACE) | ((c & SK_G16_MASK_IN_PLACE) << 16);
+}
+
+// returns dirt in the top 16bits, but we don't care, since we only
+// store the low 16bits.
+static inline U16CPU pack16(uint32_t c) {
+    return (c & ~SK_G16_MASK_IN_PLACE) | ((c >> 16) & SK_G16_MASK_IN_PLACE);
+}
+
+static void downsampleby2_proc16(SkBitmap* dst, int x, int y,
+                                 const SkBitmap& src) {
+    x <<= 1;
+    y <<= 1;
+    const uint16_t* p = src.getAddr16(x, y);
+    SkPMColor       c;
+    
+    c = expand16(*p);
+    if (x < (int)src.width() - 1) {
+        p += 1;
+    }
+    c += expand16(*p);
+    
+    if (y < (int)src.height() - 1) {
+        p = src.getAddr16(x, y + 1);
+    }
+    c += expand16(*p);
+    if (x < (int)src.width() - 1) {
+        p += 1;
+    }
+    c += expand16(*p);
+    
+    *dst->getAddr16(x >> 1, y >> 1) = (uint16_t)pack16(c >> 2);
+}
+
+static uint32_t expand4444(U16CPU c) {
+    return (c & 0xF0F) | ((c & ~0xF0F) << 12);
+}
+
+static U16CPU collaps4444(uint32_t c) {
+    return (c & 0xF0F) | ((c >> 12) & ~0xF0F);
+}
+
+static void downsampleby2_proc4444(SkBitmap* dst, int x, int y,
+                                   const SkBitmap& src) {
+    x <<= 1;
+    y <<= 1;
+    const uint16_t* p = src.getAddr16(x, y);
+    uint32_t        c;
+    
+    c = expand4444(*p);
+    if (x < src.width() - 1) {
+        p += 1;
+    }
+    c += expand4444(*p);
+    
+    if (y < src.height() - 1) {
+        p = src.getAddr16(x, y + 1);
+    }
+    c += expand4444(*p);
+    if (x < src.width() - 1) {
+        p += 1;
+    }
+    c += expand4444(*p);
+    
+    *dst->getAddr16(x >> 1, y >> 1) = (uint16_t)collaps4444(c >> 2);
+}
+
+void SkBitmap::buildMipMap(bool forceRebuild) {
+#ifdef SK_SUPPORT_MIPMAP
+    if (forceRebuild)
+        this->freeMipMap();
+    else if (fMipMap)
+        return; // we're already built
+
+    SkASSERT(NULL == fMipMap);
+
+    void (*proc)(SkBitmap* dst, int x, int y, const SkBitmap& src);
+
+    const SkBitmap::Config config = this->getConfig();
+
+    switch (config) {
+        case kARGB_8888_Config:
+            proc = downsampleby2_proc32;
+            break;
+        case kRGB_565_Config:
+            proc = downsampleby2_proc16;
+            break;
+        case kARGB_4444_Config:
+            proc = downsampleby2_proc4444;
+            break;
+        case kIndex8_Config:
+        case kA8_Config:
+        default:
+            return; // don't build mipmaps for these configs
+    }
+
+    // whip through our loop to compute the exact size needed
+    size_t  size = 0;
+    int     maxLevels = 0;
+    {
+        unsigned    width = this->width();
+        unsigned    height = this->height();
+        for (;;) {
+            width >>= 1;
+            height >>= 1;
+            if (0 == width || 0 == height) {
+                break;
+            }
+            size += ComputeRowBytes(config, width) * height;
+            maxLevels += 1;
+        }
+    }
+    if (0 == maxLevels) {
+        return;
+    }
+
+    MipMap*     mm = MipMap::Alloc(maxLevels, size);
+    MipLevel*   level = mm->levels();
+    uint8_t*    addr = (uint8_t*)mm->pixels();
+
+    unsigned    width = this->width();
+    unsigned    height = this->height();
+    unsigned    rowBytes = this->rowBytes();
+    SkBitmap    srcBM(*this), dstBM;
+
+    srcBM.lockPixels();
+
+    for (int i = 0; i < maxLevels; i++) {
+        width >>= 1;
+        height >>= 1;
+        rowBytes = ComputeRowBytes(config, width);
+
+        level[i].fPixels   = addr;
+        level[i].fWidth    = SkToU16(width);
+        level[i].fHeight   = SkToU16(height);
+        level[i].fRowBytes = SkToU16(rowBytes);
+
+        dstBM.setConfig(config, width, height, rowBytes);
+        dstBM.setPixels(addr);
+    
+        for (unsigned y = 0; y < height; y++) {
+            for (unsigned x = 0; x < width; x++) {
+                proc(&dstBM, x, y, srcBM);
+            }
+        }
+
+        srcBM = dstBM;
+        addr += height * rowBytes;
+    }
+    SkASSERT(addr == (uint8_t*)mm->pixels() + size);
+    fMipMap = mm;
+#endif
+}
+
+bool SkBitmap::hasMipMap() const {
+#ifdef SK_SUPPORT_MIPMAP
+    return fMipMap != NULL;
+#else
+    return false;
+#endif
+}
+
+int SkBitmap::extractMipLevel(SkBitmap* dst, SkFixed sx, SkFixed sy) {
+#ifdef SK_SUPPORT_MIPMAP
+    if (NULL == fMipMap)
+        return 0;
+    
+    int level = ComputeMipLevel(sx, sy) >> 16;
+    SkASSERT(level >= 0);
+    if (level <= 0) {
+        return 0;
+    }
+
+    if (level >= fMipMap->fLevelCount) {
+        level = fMipMap->fLevelCount - 1;
+    }
+    if (dst) {
+        const MipLevel& mip = fMipMap->levels()[level - 1];
+        dst->setConfig((SkBitmap::Config)this->config(),
+                       mip.fWidth, mip.fHeight, mip.fRowBytes);
+        dst->setPixels(mip.fPixels);
+    }
+    return level;
+#else
+    return 0;
+#endif
+}
+
+SkFixed SkBitmap::ComputeMipLevel(SkFixed sx, SkFixed sy) {
+#ifdef SK_SUPPORT_MIPMAP
+    sx = SkAbs32(sx);
+    sy = SkAbs32(sy);
+    if (sx < sy) {
+        sx = sy;
+    }
+    if (sx < SK_Fixed1) {
+        return 0;
+    }
+    int clz = SkCLZ(sx);
+    SkASSERT(clz >= 1 && clz <= 15);
+    return SkIntToFixed(15 - clz) + ((unsigned)(sx << (clz + 1)) >> 16);
+#else
+    return 0;
+#endif
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+static void GetBitmapAlpha(const SkBitmap& src, uint8_t SK_RESTRICT alpha[],
+                           int alphaRowBytes) {
+    SkASSERT(alpha != NULL);
+    SkASSERT(alphaRowBytes >= src.width());
+
+    SkBitmap::Config config = src.getConfig();
+    int              w = src.width();
+    int              h = src.height();
+    int              rb = src.rowBytes();
+
+    if (SkBitmap::kA8_Config == config && !src.isOpaque()) {
+        const uint8_t* s = src.getAddr8(0, 0);
+        while (--h >= 0) {
+            memcpy(alpha, s, w);
+            s += rb;
+            alpha += alphaRowBytes;
+        }
+    } else if (SkBitmap::kARGB_8888_Config == config && !src.isOpaque()) {
+        const SkPMColor* SK_RESTRICT s = src.getAddr32(0, 0);
+        while (--h >= 0) {
+            for (int x = 0; x < w; x++) {
+                alpha[x] = SkGetPackedA32(s[x]);
+            }
+            s = (const SkPMColor*)((const char*)s + rb);
+            alpha += alphaRowBytes;
+        }
+    } else if (SkBitmap::kARGB_4444_Config == config && !src.isOpaque()) {
+        const SkPMColor16* SK_RESTRICT s = src.getAddr16(0, 0);
+        while (--h >= 0) {
+            for (int x = 0; x < w; x++) {
+                alpha[x] = SkPacked4444ToA32(s[x]);
+            }
+            s = (const SkPMColor16*)((const char*)s + rb);
+            alpha += alphaRowBytes;
+        }
+    } else if (SkBitmap::kIndex8_Config == config && !src.isOpaque()) {
+        SkColorTable* ct = src.getColorTable();
+        if (ct) {
+            const SkPMColor* SK_RESTRICT table = ct->lockColors();
+            const uint8_t* SK_RESTRICT s = src.getAddr8(0, 0);
+            while (--h >= 0) {
+                for (int x = 0; x < w; x++) {
+                    alpha[x] = SkGetPackedA32(table[s[x]]);
+                }
+                s += rb;
+                alpha += alphaRowBytes;
+            }
+            ct->unlockColors(false);
+        }
+    } else {    // src is opaque, so just fill alpha[] with 0xFF
+        memset(alpha, 0xFF, h * alphaRowBytes);
+    }
+}
+
+#include "SkPaint.h"
+#include "SkMaskFilter.h"
+#include "SkMatrix.h"
+
+void SkBitmap::extractAlpha(SkBitmap* dst, const SkPaint* paint,
+                            SkIPoint* offset) const {
+    SkDEBUGCODE(this->validate();)
+
+    SkMatrix    identity;
+    SkMask      srcM, dstM;
+
+    srcM.fBounds.set(0, 0, this->width(), this->height());
+    srcM.fRowBytes = SkAlign4(this->width());
+    srcM.fFormat = SkMask::kA8_Format;
+
+    SkMaskFilter* filter = paint ? paint->getMaskFilter() : NULL;
+
+    // compute our (larger?) dst bounds if we have a filter
+    if (NULL != filter) {
+        identity.reset();
+        srcM.fImage = NULL;
+        if (!filter->filterMask(&dstM, srcM, identity, NULL)) {
+            goto NO_FILTER_CASE;
+        }
+        dstM.fRowBytes = SkAlign4(dstM.fBounds.width());
+    } else {
+    NO_FILTER_CASE:
+        dst->setConfig(SkBitmap::kA8_Config, this->width(), this->height(),
+                       srcM.fRowBytes);
+        dst->allocPixels();        
+        GetBitmapAlpha(*this, dst->getAddr8(0, 0), srcM.fRowBytes);
+        if (offset) {
+            offset->set(0, 0);
+        }
+        return;
+    }
+
+    SkAutoMaskImage srcCleanup(&srcM, true);
+
+    GetBitmapAlpha(*this, srcM.fImage, srcM.fRowBytes);
+    if (!filter->filterMask(&dstM, srcM, identity, NULL)) {
+        goto NO_FILTER_CASE;
+    }
+
+    SkAutoMaskImage dstCleanup(&dstM, false);
+
+    dst->setConfig(SkBitmap::kA8_Config, dstM.fBounds.width(),
+                   dstM.fBounds.height(), dstM.fRowBytes);
+    dst->allocPixels();
+    memcpy(dst->getPixels(), dstM.fImage, dstM.computeImageSize());
+    if (offset) {
+        offset->set(dstM.fBounds.fLeft, dstM.fBounds.fTop);
+    }
+    SkDEBUGCODE(dst->validate();)
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+enum {
+    SERIALIZE_PIXELTYPE_NONE,
+    SERIALIZE_PIXELTYPE_RAW_WITH_CTABLE,
+    SERIALIZE_PIXELTYPE_RAW_NO_CTABLE,
+    SERIALIZE_PIXELTYPE_REF_DATA,
+    SERIALIZE_PIXELTYPE_REF_PTR,
+};
+
+static void writeString(SkFlattenableWriteBuffer& buffer, const char str[]) {
+    size_t len = strlen(str);
+    buffer.write32(len);
+    buffer.writePad(str, len);
+}
+
+static SkPixelRef::Factory deserialize_factory(SkFlattenableReadBuffer& buffer) {
+    size_t len = buffer.readInt();
+    SkAutoSMalloc<256> storage(len + 1);
+    char* str = (char*)storage.get();
+    buffer.read(str, len);
+    str[len] = 0;
+    return SkPixelRef::NameToFactory(str);
+}
+
+/*
+    It is tricky to know how much to flatten. If we don't have a pixelref (i.e.
+    we just have pixels, then we can only flatten the pixels, or write out an
+    empty bitmap.
+ 
+    With a pixelref, we still have the question of recognizing when two sitings
+    of the same pixelref are the same, and when they are different. Perhaps we
+    should look at the generationID and keep a record of that in some dictionary
+    associated with the buffer. SkGLTextureCache does this sort of thing to know
+    when to create a new texture.
+*/
+void SkBitmap::flatten(SkFlattenableWriteBuffer& buffer) const {
+    buffer.write32(fWidth);
+    buffer.write32(fHeight);
+    buffer.write32(fRowBytes);
+    buffer.write8(fConfig);
+    buffer.writeBool(this->isOpaque());
+    
+    /*  If we are called in this mode, then it is up to the caller to manage
+        the owner-counts on the pixelref, as we just record the ptr itself.
+    */
+    if (!buffer.persistBitmapPixels()) {
+        if (fPixelRef) {
+            buffer.write8(SERIALIZE_PIXELTYPE_REF_PTR);
+            buffer.write32(fPixelRefOffset);
+            buffer.writeRefCnt(fPixelRef);
+            return;
+        } else {
+            // we ignore the non-persist request, since we don't have a ref
+            // ... or we could just write an empty bitmap...
+            // (true) will write an empty bitmap, (false) will flatten the pix
+            if (true) {
+                buffer.write8(SERIALIZE_PIXELTYPE_NONE);
+                return;
+            }
+        }
+    }
+
+    if (fPixelRef) {
+        SkPixelRef::Factory fact = fPixelRef->getFactory();
+        if (fact) {
+            const char* name = SkPixelRef::FactoryToName(fact);
+            if (name && *name) {
+                buffer.write8(SERIALIZE_PIXELTYPE_REF_DATA);
+                buffer.write32(fPixelRefOffset);
+                writeString(buffer, name);
+                fPixelRef->flatten(buffer);
+                return;
+            }
+        }
+        // if we get here, we can't record the pixels
+        buffer.write8(SERIALIZE_PIXELTYPE_NONE);
+    } else if (fPixels) {
+        if (fColorTable) {
+            buffer.write8(SERIALIZE_PIXELTYPE_RAW_WITH_CTABLE);
+            fColorTable->flatten(buffer);
+        } else {
+            buffer.write8(SERIALIZE_PIXELTYPE_RAW_NO_CTABLE);
+        }
+        buffer.writePad(fPixels, this->getSize());
+    } else {
+        buffer.write8(SERIALIZE_PIXELTYPE_NONE);
+    }
+}
+
+void SkBitmap::unflatten(SkFlattenableReadBuffer& buffer) {
+    this->reset();
+    
+    int width = buffer.readInt();
+    int height = buffer.readInt();
+    int rowBytes = buffer.readInt();
+    int config = buffer.readU8();
+    
+    this->setConfig((Config)config, width, height, rowBytes);
+    this->setIsOpaque(buffer.readBool());
+    
+    size_t size = this->getSize();
+    int reftype = buffer.readU8();
+    switch (reftype) {
+        case SERIALIZE_PIXELTYPE_REF_PTR: {
+            size_t offset = buffer.readU32();
+            SkPixelRef* pr = (SkPixelRef*)buffer.readRefCnt();
+            this->setPixelRef(pr, offset);
+            break;
+        }
+        case SERIALIZE_PIXELTYPE_REF_DATA: {
+            size_t offset = buffer.readU32();
+            SkPixelRef::Factory fact = deserialize_factory(buffer);
+            SkPixelRef* pr = fact(buffer);
+            this->setPixelRef(pr, offset)->safeUnref();
+            break;
+        }
+        case SERIALIZE_PIXELTYPE_RAW_WITH_CTABLE:
+        case SERIALIZE_PIXELTYPE_RAW_NO_CTABLE: {
+            SkColorTable* ctable = NULL;
+            if (SERIALIZE_PIXELTYPE_RAW_WITH_CTABLE == reftype) {
+                ctable = SkNEW_ARGS(SkColorTable, (buffer));
+            }
+            if (this->allocPixels(ctable)) {
+                this->lockPixels();
+                buffer.read(this->getPixels(), size);
+                this->unlockPixels();
+            } else {
+                buffer.skip(size);
+            }
+            ctable->safeUnref();
+            break;
+        }
+        case SERIALIZE_PIXELTYPE_NONE:
+            break;
+        default:
+            SkASSERT(!"unrecognized pixeltype in serialized data");
+            sk_throw();
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+SkBitmap::RLEPixels::RLEPixels(int width, int height) {
+    fHeight = height;
+    fYPtrs = (uint8_t**)sk_malloc_throw(height * sizeof(uint8_t*));
+    bzero(fYPtrs, height * sizeof(uint8_t*));
+}
+
+SkBitmap::RLEPixels::~RLEPixels() {
+    sk_free(fYPtrs);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+#ifdef SK_DEBUG
+void SkBitmap::validate() const {
+    SkASSERT(fConfig < kConfigCount);
+    SkASSERT(fRowBytes >= (unsigned)ComputeRowBytes((Config)fConfig, fWidth));
+    SkASSERT(fFlags <= kImageIsOpaque_Flag);
+    SkASSERT(fPixelLockCount >= 0);
+    SkASSERT(NULL == fColorTable || (unsigned)fColorTable->getRefCnt() < 10000);
+    SkASSERT((uint8_t)ComputeBytesPerPixel((Config)fConfig) == fBytesPerPixel);
+
+    if (fPixelRef) {
+        if (fPixelLockCount > 0) {
+            SkASSERT(fPixelRef->getLockCount() > 0);
+        } else {
+            SkASSERT(NULL == fPixels);
+            SkASSERT(NULL == fColorTable);
+        }
+    }
+}
+#endif
+