grab from latest android

git-svn-id: http://skia.googlecode.com/svn/trunk@27 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 923 insertions, 0 deletions

diff --git a/src/core/SkBlitter.cpp b/src/core/SkBlitter.cpp
new file mode 100644
index 0000000000..920842937c
--- /dev/null
+++ b/src/core/SkBlitter.cpp
@@ -0,0 +1,923 @@
+/* libs/graphics/sgl/SkBlitter.cpp
+**
+** Copyright 2006, The Android Open Source Project
+**
+** 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 "SkBlitter.h"
+#include "SkAntiRun.h"
+#include "SkColor.h"
+#include "SkColorFilter.h"
+#include "SkMask.h"
+#include "SkMaskFilter.h"
+#include "SkTemplatesPriv.h"
+#include "SkUtils.h"
+#include "SkXfermode.h"
+
+SkBlitter::~SkBlitter()
+{
+}
+
+const SkBitmap* SkBlitter::justAnOpaqueColor(uint32_t* value)
+{
+    return NULL;
+}
+
+void SkBlitter::blitH(int x, int y, int width)
+{
+    SkASSERT(!"unimplemented");
+}
+
+void SkBlitter::blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[])
+{
+    SkASSERT(!"unimplemented");
+}
+
+void SkBlitter::blitV(int x, int y, int height, SkAlpha alpha)
+{
+    if (alpha == 255)
+        this->blitRect(x, y, 1, height);
+    else
+    {
+        int16_t runs[2];
+        runs[0] = 1;
+        runs[1] = 0;
+
+        while (--height >= 0)
+            this->blitAntiH(x, y++, &alpha, runs);
+    }
+}
+
+void SkBlitter::blitRect(int x, int y, int width, int height)
+{
+    while (--height >= 0)
+        this->blitH(x, y++, width);
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
+static inline void bits_to_runs(SkBlitter* blitter, int x, int y, const uint8_t bits[],
+                                U8CPU left_mask, int rowBytes, U8CPU right_mask)
+{
+    int inFill = 0;
+    int pos = 0;
+
+    while (--rowBytes >= 0)
+    {
+        unsigned b = *bits++ & left_mask;
+        if (rowBytes == 0)
+            b &= right_mask;
+
+        for (unsigned test = 0x80; test != 0; test >>= 1)
+        {
+            if (b & test)
+            {
+                if (!inFill)
+                {
+                    pos = x;
+                    inFill = true;
+                }
+            }
+            else
+            {
+                if (inFill)
+                {
+                    blitter->blitH(pos, y, x - pos);
+                    inFill = false;
+                }
+            }
+            x += 1;
+        }
+        left_mask = 0xFF;
+    }
+
+    // final cleanup
+    if (inFill)
+        blitter->blitH(pos, y, x - pos);
+}
+
+void SkBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
+{
+    SkASSERT(mask.fBounds.contains(clip));
+
+    if (mask.fFormat == SkMask::kBW_Format)
+    {
+        int cx = clip.fLeft;
+        int cy = clip.fTop;
+        int maskLeft = mask.fBounds.fLeft;
+        int mask_rowBytes = mask.fRowBytes;
+        int height = clip.height();
+
+        const uint8_t* bits = mask.getAddr1(cx, cy);
+
+        if (cx == maskLeft && clip.fRight == mask.fBounds.fRight)
+        {
+            while (--height >= 0)
+            {
+                bits_to_runs(this, cx, cy, bits, 0xFF, mask_rowBytes, 0xFF);
+                bits += mask_rowBytes;
+                cy += 1;
+            }
+        }
+        else
+        {
+            int left_edge = cx - maskLeft;
+            SkASSERT(left_edge >= 0);
+            int rite_edge = clip.fRight - maskLeft;
+            SkASSERT(rite_edge > left_edge);
+
+            int left_mask = 0xFF >> (left_edge & 7);
+            int rite_mask = 0xFF << (8 - (rite_edge & 7));
+            int full_runs = (rite_edge >> 3) - ((left_edge + 7) >> 3);
+
+            // check for empty right mask, so we don't read off the end (or go slower than we need to)
+            if (rite_mask == 0)
+            {
+                SkASSERT(full_runs >= 0);
+                full_runs -= 1;
+                rite_mask = 0xFF;
+            }
+            if (left_mask == 0xFF)
+                full_runs -= 1;
+
+            // back up manually so we can keep in sync with our byte-aligned src
+            // have cx reflect our actual starting x-coord
+            cx -= left_edge & 7;
+
+            if (full_runs < 0)
+            {
+                SkASSERT((left_mask & rite_mask) != 0);
+                while (--height >= 0)
+                {
+                    bits_to_runs(this, cx, cy, bits, left_mask, 1, rite_mask);
+                    bits += mask_rowBytes;
+                    cy += 1;
+                }
+            }
+            else
+            {
+                while (--height >= 0)
+                {
+                    bits_to_runs(this, cx, cy, bits, left_mask, full_runs + 2, rite_mask);
+                    bits += mask_rowBytes;
+                    cy += 1;
+                }
+            }
+        }
+    }
+    else
+    {
+        int                         width = clip.width();
+        SkAutoSTMalloc<64, int16_t> runStorage(width + 1);
+        int16_t*                    runs = runStorage.get();
+        const uint8_t*              aa = mask.getAddr(clip.fLeft, clip.fTop);
+
+        sk_memset16((uint16_t*)runs, 1, width);
+        runs[width] = 0;
+
+        int height = clip.height();
+        int y = clip.fTop;
+        while (--height >= 0)
+        {
+            this->blitAntiH(clip.fLeft, y, aa, runs);
+            aa += mask.fRowBytes;
+            y += 1;
+        }
+    }
+}
+
+/////////////////////// these guys are not virtual, just a helpers
+
+void SkBlitter::blitMaskRegion(const SkMask& mask, const SkRegion& clip) {
+    if (clip.quickReject(mask.fBounds)) {
+        return;
+    }
+    
+    SkRegion::Cliperator clipper(clip, mask.fBounds);
+    
+    while (!clipper.done()) {
+        const SkIRect& cr = clipper.rect();
+        this->blitMask(mask, cr);
+        clipper.next();
+    }
+}
+
+void SkBlitter::blitRectRegion(const SkIRect& rect, const SkRegion& clip) {
+    SkRegion::Cliperator clipper(clip, rect);
+    
+    while (!clipper.done()) {
+        const SkIRect& cr = clipper.rect();
+        this->blitRect(cr.fLeft, cr.fTop, cr.width(), cr.height());
+        clipper.next();
+    }
+}
+
+void SkBlitter::blitRegion(const SkRegion& clip) {
+    SkRegion::Iterator iter(clip);
+    
+    while (!iter.done()) {
+        const SkIRect& cr = iter.rect();
+        this->blitRect(cr.fLeft, cr.fTop, cr.width(), cr.height());
+        iter.next();
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////////////
+
+void SkNullBlitter::blitH(int x, int y, int width)
+{
+}
+
+void SkNullBlitter::blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[])
+{
+}
+
+void SkNullBlitter::blitV(int x, int y, int height, SkAlpha alpha)
+{
+}
+
+void SkNullBlitter::blitRect(int x, int y, int width, int height)
+{
+}
+
+void SkNullBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
+{
+}
+
+const SkBitmap* SkNullBlitter::justAnOpaqueColor(uint32_t* value)
+{
+    return NULL;
+}
+
+///////////////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////////////
+
+static int compute_anti_width(const int16_t runs[])
+{
+    int width = 0;
+    
+    for (;;)
+    {
+        int count = runs[0];
+        
+        SkASSERT(count >= 0);
+        if (count == 0)
+            break;
+        width += count;
+        runs += count;
+        
+        SkASSERT(width < 20000);
+    }
+    return width;
+}
+
+static inline bool y_in_rect(int y, const SkIRect& rect)
+{
+    return (unsigned)(y - rect.fTop) < (unsigned)rect.height();
+}
+
+static inline bool x_in_rect(int x, const SkIRect& rect)
+{
+    return (unsigned)(x - rect.fLeft) < (unsigned)rect.width();
+}
+
+void SkRectClipBlitter::blitH(int left, int y, int width)
+{
+    SkASSERT(width > 0);
+
+    if (!y_in_rect(y, fClipRect))
+        return;
+
+    int right = left + width;
+
+    if (left < fClipRect.fLeft)
+        left = fClipRect.fLeft;
+    if (right > fClipRect.fRight)
+        right = fClipRect.fRight;
+
+    width = right - left;
+    if (width > 0)
+        fBlitter->blitH(left, y, width);
+}
+
+void SkRectClipBlitter::blitAntiH(int left, int y, const SkAlpha aa[], const int16_t runs[])
+{
+    if (!y_in_rect(y, fClipRect) || left >= fClipRect.fRight)
+        return;
+
+    int x0 = left;
+    int x1 = left + compute_anti_width(runs);
+
+    if (x1 <= fClipRect.fLeft)
+        return;
+
+    SkASSERT(x0 < x1);
+    if (x0 < fClipRect.fLeft)
+    {
+        int dx = fClipRect.fLeft - x0;
+        SkAlphaRuns::BreakAt((int16_t*)runs, (uint8_t*)aa, dx);
+        runs += dx;
+        aa += dx;
+        x0 = fClipRect.fLeft;
+    }
+
+    SkASSERT(x0 < x1 && runs[x1 - x0] == 0);
+    if (x1 > fClipRect.fRight)
+    {
+        x1 = fClipRect.fRight;
+        SkAlphaRuns::BreakAt((int16_t*)runs, (uint8_t*)aa, x1 - x0);
+        ((int16_t*)runs)[x1 - x0] = 0;
+    }
+
+    SkASSERT(x0 < x1 && runs[x1 - x0] == 0);
+    SkASSERT(compute_anti_width(runs) == x1 - x0);
+
+    fBlitter->blitAntiH(x0, y, aa, runs);
+}
+
+void SkRectClipBlitter::blitV(int x, int y, int height, SkAlpha alpha)
+{
+    SkASSERT(height > 0);
+
+    if (!x_in_rect(x, fClipRect))
+        return;
+
+    int y0 = y;
+    int y1 = y + height;
+
+    if (y0 < fClipRect.fTop)
+        y0 = fClipRect.fTop;
+    if (y1 > fClipRect.fBottom)
+        y1 = fClipRect.fBottom;
+
+    if (y0 < y1)
+        fBlitter->blitV(x, y0, y1 - y0, alpha);
+}
+
+void SkRectClipBlitter::blitRect(int left, int y, int width, int height)
+{
+    SkIRect    r;
+
+    r.set(left, y, left + width, y + height);
+    if (r.intersect(fClipRect))
+        fBlitter->blitRect(r.fLeft, r.fTop, r.width(), r.height());
+}
+
+void SkRectClipBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
+{
+    SkASSERT(mask.fBounds.contains(clip));
+
+    SkIRect    r = clip;
+
+    if (r.intersect(fClipRect))
+        fBlitter->blitMask(mask, r);
+}
+
+const SkBitmap* SkRectClipBlitter::justAnOpaqueColor(uint32_t* value)
+{
+    return fBlitter->justAnOpaqueColor(value);
+}
+
+///////////////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////////////
+
+void SkRgnClipBlitter::blitH(int x, int y, int width)
+{
+    SkRegion::Spanerator span(*fRgn, y, x, x + width);
+    int left, right;
+
+    while (span.next(&left, &right))
+    {
+        SkASSERT(left < right);
+        fBlitter->blitH(left, y, right - left);
+    }
+}
+
+void SkRgnClipBlitter::blitAntiH(int x, int y, const SkAlpha aa[], const int16_t runs[])
+{
+    int width = compute_anti_width(runs);
+    SkRegion::Spanerator span(*fRgn, y, x, x + width);
+    int left, right;
+    SkDEBUGCODE(const SkIRect& bounds = fRgn->getBounds();)
+        
+    int prevRite = x;
+    while (span.next(&left, &right))
+    {
+        SkASSERT(x <= left);
+        SkASSERT(left < right);
+        SkASSERT(left >= bounds.fLeft && right <= bounds.fRight);
+        
+        SkAlphaRuns::Break((int16_t*)runs, (uint8_t*)aa, left - x, right - left);
+
+        // now zero before left
+        if (left > prevRite)
+        {
+            int index = prevRite - x;
+            ((uint8_t*)aa)[index] = 0;   // skip runs after right
+            ((int16_t*)runs)[index] = SkToS16(left - prevRite);
+        }
+        
+        prevRite = right;
+    }
+    
+    if (prevRite > x)
+    {
+        ((int16_t*)runs)[prevRite - x] = 0;
+        
+        if (x < 0) {
+            int skip = runs[0];
+            SkASSERT(skip >= -x);
+            aa += skip;
+            runs += skip;
+            x += skip;
+        }
+        fBlitter->blitAntiH(x, y, aa, runs);
+    }
+}
+
+void SkRgnClipBlitter::blitV(int x, int y, int height, SkAlpha alpha)
+{
+    SkIRect    bounds;
+    bounds.set(x, y, x + 1, y + height);
+
+    SkRegion::Cliperator    iter(*fRgn, bounds);
+
+    while (!iter.done())
+    {
+        const SkIRect& r = iter.rect();
+        SkASSERT(bounds.contains(r));
+
+        fBlitter->blitV(x, r.fTop, r.height(), alpha);
+        iter.next();
+    }
+}
+
+void SkRgnClipBlitter::blitRect(int x, int y, int width, int height)
+{
+    SkIRect    bounds;
+    bounds.set(x, y, x + width, y + height);
+
+    SkRegion::Cliperator    iter(*fRgn, bounds);
+
+    while (!iter.done())
+    {
+        const SkIRect& r = iter.rect();
+        SkASSERT(bounds.contains(r));
+
+        fBlitter->blitRect(r.fLeft, r.fTop, r.width(), r.height());
+        iter.next();
+    }
+}
+
+void SkRgnClipBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
+{
+    SkASSERT(mask.fBounds.contains(clip));
+
+    SkRegion::Cliperator iter(*fRgn, clip);
+    const SkIRect&       r = iter.rect();
+    SkBlitter*           blitter = fBlitter;
+
+    while (!iter.done())
+    {
+        blitter->blitMask(mask, r);
+        iter.next();
+    }
+}
+
+const SkBitmap* SkRgnClipBlitter::justAnOpaqueColor(uint32_t* value)
+{
+    return fBlitter->justAnOpaqueColor(value);
+}
+
+///////////////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////////////
+
+SkBlitter* SkBlitterClipper::apply(SkBlitter* blitter, const SkRegion* clip, const SkIRect* ir)
+{
+    if (clip)
+    {
+        const SkIRect& clipR = clip->getBounds();
+
+        if (clip->isEmpty() || (ir && !SkIRect::Intersects(clipR, *ir)))
+            blitter = &fNullBlitter;
+        else if (clip->isRect())
+        {
+            if (ir == NULL || !clipR.contains(*ir))
+            {
+                fRectBlitter.init(blitter, clipR);
+                blitter = &fRectBlitter;
+            }
+        }
+        else
+        {
+            fRgnBlitter.init(blitter, clip);
+            blitter = &fRgnBlitter;
+        }
+    }
+    return blitter;
+}
+
+///////////////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////////////
+
+#include "SkColorShader.h"
+#include "SkColorPriv.h"
+
+class Sk3DShader : public SkShader {
+public:
+    Sk3DShader(SkShader* proxy) : fProxy(proxy)
+    {
+        proxy->safeRef();
+        fMask = NULL;
+    }
+    virtual ~Sk3DShader()
+    {
+        fProxy->safeUnref();
+    }
+    void setMask(const SkMask* mask) { fMask = mask; }
+
+    virtual bool setContext(const SkBitmap& device, const SkPaint& paint, const SkMatrix& matrix)
+    {
+        if (fProxy)
+            return fProxy->setContext(device, paint, matrix);
+        else
+        {
+            fPMColor = SkPreMultiplyColor(paint.getColor());
+            return this->INHERITED::setContext(device, paint, matrix);
+        }
+    }
+    virtual void shadeSpan(int x, int y, SkPMColor span[], int count)
+    {
+        if (fProxy)
+            fProxy->shadeSpan(x, y, span, count);
+
+        if (fMask == NULL)
+        {
+            if (fProxy == NULL)
+                sk_memset32(span, fPMColor, count);
+            return;
+        }
+
+        SkASSERT(fMask->fBounds.contains(x, y));
+        SkASSERT(fMask->fBounds.contains(x + count - 1, y));
+
+        size_t          size = fMask->computeImageSize();
+        const uint8_t*  alpha = fMask->getAddr(x, y);
+        const uint8_t*  mulp = alpha + size;
+        const uint8_t*  addp = mulp + size;
+
+        if (fProxy)
+        {
+            for (int i = 0; i < count; i++)
+            {
+                if (alpha[i])
+                {
+                    SkPMColor c = span[i];
+                    if (c)
+                    {
+                        unsigned a = SkGetPackedA32(c);
+                        unsigned r = SkGetPackedR32(c);
+                        unsigned g = SkGetPackedG32(c);
+                        unsigned b = SkGetPackedB32(c);
+
+                        unsigned mul = SkAlpha255To256(mulp[i]);
+                        unsigned add = addp[i];
+
+                        r = SkFastMin32(SkAlphaMul(r, mul) + add, a);
+                        g = SkFastMin32(SkAlphaMul(g, mul) + add, a);
+                        b = SkFastMin32(SkAlphaMul(b, mul) + add, a);
+
+                        span[i] = SkPackARGB32(a, r, g, b);
+                    }
+                }
+                else
+                    span[i] = 0;
+            }
+        }
+        else    // color
+        {
+            unsigned a = SkGetPackedA32(fPMColor);
+            unsigned r = SkGetPackedR32(fPMColor);
+            unsigned g = SkGetPackedG32(fPMColor);
+            unsigned b = SkGetPackedB32(fPMColor);
+            for (int i = 0; i < count; i++)
+            {
+                if (alpha[i])
+                {
+                    unsigned mul = SkAlpha255To256(mulp[i]);
+                    unsigned add = addp[i];
+
+                    span[i] = SkPackARGB32( a,
+                                            SkFastMin32(SkAlphaMul(r, mul) + add, a),
+                                            SkFastMin32(SkAlphaMul(g, mul) + add, a),
+                                            SkFastMin32(SkAlphaMul(b, mul) + add, a));
+                }
+                else
+                    span[i] = 0;
+            }
+        }
+    }
+    
+    virtual void beginSession()
+    {
+        this->INHERITED::beginSession();
+        if (fProxy)
+            fProxy->beginSession();
+    }
+    
+    virtual void endSession()
+    {
+        if (fProxy)
+            fProxy->endSession();
+        this->INHERITED::endSession();
+    }
+
+protected:
+    Sk3DShader(SkFlattenableReadBuffer& buffer) :
+        INHERITED(buffer)
+    {
+        fProxy = static_cast<SkShader*>(buffer.readFlattenable());
+        fPMColor = buffer.readU32();
+        fMask = NULL;
+    }
+    
+    virtual void flatten(SkFlattenableWriteBuffer& buffer) 
+    {
+        this->INHERITED::flatten(buffer);
+        buffer.writeFlattenable(fProxy);
+        buffer.write32(fPMColor);
+    }
+    
+    virtual Factory getFactory() 
+    { 
+        return CreateProc;
+    }
+
+private:
+    static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) 
+    {
+        return SkNEW_ARGS(Sk3DShader, (buffer));
+    }
+
+    SkShader*       fProxy;
+    SkPMColor       fPMColor;
+    const SkMask*   fMask;
+
+    typedef SkShader INHERITED;
+};
+
+class Sk3DBlitter : public SkBlitter {
+public:
+    Sk3DBlitter(SkBlitter* proxy, Sk3DShader* shader, void (*killProc)(void*))
+        : fProxy(proxy), f3DShader(shader), fKillProc(killProc)
+    {
+        shader->ref();
+    }
+    virtual ~Sk3DBlitter()
+    {
+        f3DShader->unref();
+        fKillProc(fProxy);
+    }
+
+    virtual void blitH(int x, int y, int width)
+    {
+        fProxy->blitH(x, y, width);
+    }
+    virtual void blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[])
+    {
+        fProxy->blitAntiH(x, y, antialias, runs);
+    }
+    virtual void blitV(int x, int y, int height, SkAlpha alpha)
+    {
+        fProxy->blitV(x, y, height, alpha);
+    }
+    virtual void blitRect(int x, int y, int width, int height)
+    {
+        fProxy->blitRect(x, y, width, height);
+    }
+    virtual void blitMask(const SkMask& mask, const SkIRect& clip)
+    {
+        if (mask.fFormat == SkMask::k3D_Format)
+        {
+            f3DShader->setMask(&mask);
+
+            ((SkMask*)&mask)->fFormat = SkMask::kA8_Format;
+            fProxy->blitMask(mask, clip);
+            ((SkMask*)&mask)->fFormat = SkMask::k3D_Format;
+
+            f3DShader->setMask(NULL);
+        }
+        else
+            fProxy->blitMask(mask, clip);
+    }
+private:
+    SkBlitter*  fProxy;
+    Sk3DShader* f3DShader;
+    void        (*fKillProc)(void*);
+};
+
+///////////////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////////////
+
+#include "SkCoreBlitters.h"
+
+class SkAutoRestoreShader {
+public:
+    SkAutoRestoreShader(const SkPaint& p) : fPaint((SkPaint*)&p)
+    {
+        fShader = fPaint->getShader();
+        fShader->safeRef();
+    }
+    ~SkAutoRestoreShader()
+    {
+        fPaint->setShader(fShader);
+        fShader->safeUnref();
+    }
+private:
+    SkPaint*    fPaint;
+    SkShader*   fShader;
+};
+
+class SkAutoCallProc {
+public:
+    typedef void (*Proc)(void*);
+    SkAutoCallProc(void* obj, Proc proc)
+        : fObj(obj), fProc(proc)
+    {
+    }
+    ~SkAutoCallProc()
+    {
+        if (fObj && fProc)
+            fProc(fObj);
+    }
+    void* get() const { return fObj; }
+    void* detach()
+    {
+        void* obj = fObj;
+        fObj = NULL;
+        return obj;
+    }
+private:
+    void*   fObj;
+    Proc    fProc;
+};
+
+static void destroy_blitter(void* blitter)
+{
+    ((SkBlitter*)blitter)->~SkBlitter();
+}
+
+static void delete_blitter(void* blitter)
+{
+    SkDELETE((SkBlitter*)blitter);
+}
+
+SkBlitter* SkBlitter::Choose(const SkBitmap& device,
+                             const SkMatrix& matrix,
+                             const SkPaint& paint,
+                             void* storage, size_t storageSize)
+{
+    SkASSERT(storageSize == 0 || storage != NULL);
+
+    SkBlitter*  blitter = NULL;
+
+    // which check, in case we're being called by a client with a dummy device
+    // (e.g. they have a bounder that always aborts the draw)
+    if (SkBitmap::kNo_Config == device.getConfig())
+    {
+        SK_PLACEMENT_NEW(blitter, SkNullBlitter, storage, storageSize);
+        return blitter;
+    }
+
+    SkAutoRestoreShader restore(paint);
+    SkShader* shader = paint.getShader();
+
+    Sk3DShader* shader3D = NULL;
+    if (paint.getMaskFilter() != NULL && paint.getMaskFilter()->getFormat() == SkMask::k3D_Format)
+    {
+        shader3D = SkNEW_ARGS(Sk3DShader, (shader));
+        ((SkPaint*)&paint)->setShader(shader3D)->unref();
+        shader = shader3D;
+    }
+
+    SkXfermode* mode = paint.getXfermode();
+    if (NULL == shader && (NULL != mode || paint.getColorFilter() != NULL))
+    {
+        // xfermodes require shaders for our current set of blitters
+        shader = SkNEW(SkColorShader);
+        ((SkPaint*)&paint)->setShader(shader)->unref();
+    }
+    
+    if (paint.getColorFilter() != NULL)
+    {
+        SkASSERT(shader);
+        shader = SkNEW_ARGS(SkFilterShader, (shader, paint.getColorFilter()));
+        ((SkPaint*)&paint)->setShader(shader)->unref();
+    }
+    
+    bool doDither = paint.isDither();
+
+    if (shader)
+    {
+        if (!shader->setContext(device, paint, matrix))
+            return SkNEW(SkNullBlitter);
+        
+        // disable dither if our shader is natively 16bit (no need to upsample)
+        if (shader->getFlags() & SkShader::kIntrinsicly16_Flag)
+            doDither = false;
+    }
+
+    switch (device.getConfig()) {
+    case SkBitmap::kA1_Config:
+        SK_PLACEMENT_NEW_ARGS(blitter, SkA1_Blitter, storage, storageSize, (device, paint));
+        break;
+
+    case SkBitmap::kA8_Config:
+        if (shader)
+            SK_PLACEMENT_NEW_ARGS(blitter, SkA8_Shader_Blitter, storage, storageSize, (device, paint));
+        else
+            SK_PLACEMENT_NEW_ARGS(blitter, SkA8_Blitter, storage, storageSize, (device, paint));
+        break;
+        
+    case SkBitmap::kARGB_4444_Config:
+        blitter = SkBlitter_ChooseD4444(device, paint, storage, storageSize);
+        break;
+
+    case SkBitmap::kRGB_565_Config:
+        if (shader)
+        {
+            if (mode)
+                SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Shader_Xfermode_Blitter, storage, storageSize, (device, paint));
+            else if (SkShader::CanCallShadeSpan16(shader->getFlags()) && !doDither)
+                SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Shader16_Blitter, storage, storageSize, (device, paint));
+            else
+                SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Shader_Blitter, storage, storageSize, (device, paint));
+        }
+        else if (paint.getColor() == SK_ColorBLACK)
+            SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Black_Blitter, storage, storageSize, (device, paint));
+        else
+            SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Blitter, storage, storageSize, (device, paint));
+        break;
+
+    case SkBitmap::kARGB_8888_Config:
+        if (shader)
+            SK_PLACEMENT_NEW_ARGS(blitter, SkARGB32_Shader_Blitter, storage, storageSize, (device, paint));
+        else if (paint.getColor() == SK_ColorBLACK)
+            SK_PLACEMENT_NEW_ARGS(blitter, SkARGB32_Black_Blitter, storage, storageSize, (device, paint));
+        else if (paint.getAlpha() == 0xFF)
+            SK_PLACEMENT_NEW_ARGS(blitter, SkARGB32_Opaque_Blitter, storage, storageSize, (device, paint));
+        else
+            SK_PLACEMENT_NEW_ARGS(blitter, SkARGB32_Blitter, storage, storageSize, (device, paint));
+        break;
+
+    default:
+        SkASSERT(!"unsupported device config");
+        SK_PLACEMENT_NEW(blitter, SkNullBlitter, storage, storageSize);
+    }
+
+    if (shader3D)
+    {
+        void (*proc)(void*) = ((void*)storage == (void*)blitter) ? destroy_blitter : delete_blitter;
+        SkAutoCallProc  tmp(blitter, proc);
+
+        blitter = SkNEW_ARGS(Sk3DBlitter, (blitter, shader3D, proc));
+        (void)tmp.detach();
+    }
+    return blitter;
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////////////////
+
+const uint16_t gMask_0F0F = 0xF0F;
+const uint32_t gMask_00FF00FF = 0xFF00FF;
+
+//////////////////////////////////////////////////////////////////////////////////////////////////////
+
+SkShaderBlitter::SkShaderBlitter(const SkBitmap& device, const SkPaint& paint)
+    : INHERITED(device)
+{
+    fShader = paint.getShader();
+    SkASSERT(fShader);
+
+    fShader->ref();
+    fShader->beginSession();
+}
+
+SkShaderBlitter::~SkShaderBlitter()
+{
+    fShader->endSession();
+    fShader->unref();
+}
+