SkBlitter Class Reference

#include <SkBlitter.h>

Inheritance diagram for SkBlitter:

Public Member Functions
virtual	~SkBlitter ()
virtual void	blitH (int x, int y, int width)=0
	Blit a horizontal run of one or more pixels. More...
virtual void	blitAntiH (int x, int y, const SkAlpha antialias[], const int16_t runs[])=0
virtual void	blitV (int x, int y, int height, SkAlpha alpha)
	Blit a vertical run of pixels with a constant alpha value. More...
virtual void	blitRect (int x, int y, int width, int height)
	Blit a solid rectangle one or more pixels wide. More...
virtual void	blitAntiRect (int x, int y, int width, int height, SkAlpha leftAlpha, SkAlpha rightAlpha)
void	blitFatAntiRect (const SkRect &rect)
virtual void	blitMask (const SkMask &, const SkIRect &clip)
virtual void	blitAntiH2 (int x, int y, U8CPU a0, U8CPU a1)
virtual void	blitAntiV2 (int x, int y, U8CPU a0, U8CPU a1)
virtual bool	isNullBlitter () const
virtual int	requestRowsPreserved () const
virtual void *	allocBlitMemory (size_t sz)
non-virtual helpers
void	blitRectRegion (const SkIRect &rect, const SkRegion &clip)
void	blitRegion (const SkRegion &clip)

Static Public Member Functions
static bool	UseLegacyBlitter (const SkPixmap &, const SkPaint &, const SkMatrix &)
Factories
Return the correct blitter to use given the specified context.
static SkBlitter *	Choose (const SkPixmap &dst, const SkMatrix &ctm, const SkPaint &paint, SkArenaAlloc *, bool drawCoverage, sk_sp< SkShader > clipShader, const SkSurfaceProps &props)
static SkBlitter *	ChooseSprite (const SkPixmap &dst, const SkPaint &, const SkPixmap &src, int left, int top, SkArenaAlloc *, sk_sp< SkShader > clipShader)

Protected Attributes
SkAutoMalloc	fBlitMemory

Detailed Description

SkBlitter and its subclasses are responsible for actually writing pixels into memory. Besides efficiency, they handle clipping and antialiasing. A SkBlitter subclass contains all the context needed to generate pixels for the destination and how src/generated pixels map to the destination. The coordinates passed to the blitX calls are in destination pixel space.

Definition at line 38 of file SkBlitter.h.

Constructor & Destructor Documentation

~SkBlitter()

SkBlitter::~SkBlitter ( )

virtual

Definition at line 46 of file SkBlitter.cpp.

{}

Member Function Documentation

allocBlitMemory()

virtual void * SkBlitter::allocBlitMemory ( size_t  sz )

inlinevirtual

This function allocates memory for the blitter that the blitter then owns. The memory can be used by the calling function at will, but it will be released when the blitter's destructor is called. This function returns nullptr if no persistent memory is needed by the blitter.

Reimplemented in SkRectClipBlitter, and SkRgnClipBlitter.

Definition at line 130 of file SkBlitter.h.

                                             {
        return fBlitMemory.reset(sz, SkAutoMalloc::kReuse_OnShrink);
    }

blitAntiH()

virtual void SkBlitter::blitAntiH ( int  x, int  y, const SkAlpha  antialias[], const int16_t  runs[]  )

pure virtual

Blit a horizontal run of antialiased pixels; runs[] is a sparse zero-terminated run-length encoding of spans of constant alpha values. The runs[] and antialias[] work together to represent long runs of pixels with the same alphas. The runs[] contains the number of pixels with the same alpha, and antialias[] contain the coverage value for that number of pixels. The runs[] (and antialias[]) are encoded in a clever way. The runs array is zero terminated, and has enough entries for each pixel plus one, in most cases some of the entries will not contain valid data. An entry in the runs array contains the number of pixels (np) that have the same alpha value. The next np value is found np entries away. For example, if runs[0] = 7, then the next valid entry will by at runs[7]. The runs array and antialias[] are coupled by index. So, if the np entry is at runs[45] = 12 then the alpha value can be found at antialias[45] = 0x88. This would mean to use an alpha value of 0x88 for the next 12 pixels starting at pixel 45.

Implemented in SkAAClip::Builder::Blitter, SkA8_Blitter, SkA8_Coverage_Blitter, SkARGB32_Blitter, SkARGB32_Black_Blitter, SkRgnBuilder, AdditiveBlitter, SkSpriteBlitter, TestBlitter, FakeBlitter, SkAAClipBlitter, SkNullBlitter, SkRectClipBlitter, SkRgnClipBlitter, SkARGB32_Shader_Blitter, SkRasterPipelineBlitter, and InverseBlitter.

blitAntiH2()

virtual void SkBlitter::blitAntiH2 ( int  x, int  y, U8CPU  a0, U8CPU  a1  )

inlinevirtual

Reimplemented in SkARGB32_Blitter, SkARGB32_Opaque_Blitter, SkARGB32_Black_Blitter, and SkRasterPipelineBlitter.

Definition at line 81 of file SkBlitter.h.

                                                              {
        int16_t runs[3];
        uint8_t aa[2];
 
        runs[0] = 1;
        runs[1] = 1;
        runs[2] = 0;
        aa[0] = SkToU8(a0);
        aa[1] = SkToU8(a1);
        this->blitAntiH(x, y, aa, runs);
    }

blitAntiRect()

void SkBlitter::blitAntiRect ( int  x, int  y, int  width, int  height, SkAlpha  leftAlpha, SkAlpha  rightAlpha  )

virtual

Blit a rectangle with one alpha-blended column on the left, width (zero or more) opaque pixels, and one alpha-blended column on the right. The result will always be at least two pixels wide.

Default implementation doesn't check for easy optimizations such as alpha == 255; also uses blitV(), which some subclasses may not support.

Reimplemented in SkAAClip::Builder::Blitter, SkRectClipBlitter, SkRgnClipBlitter, AdditiveBlitter, and MaskAdditiveBlitter.

Definition at line 143 of file SkBlitter.cpp.

                                                                    {
    if (leftAlpha > 0) { // we may send in x = -1 with leftAlpha = 0
        this->blitV(x, y, height, leftAlpha);
    }
    x++;
    if (width > 0) {
        this->blitRect(x, y, width, height);
        x += width;
    }
    if (rightAlpha > 0) {
        this->blitV(x, y, height, rightAlpha);
    }
}

blitAntiV2()

virtual void SkBlitter::blitAntiV2 ( int  x, int  y, U8CPU  a0, U8CPU  a1  )

inlinevirtual

Reimplemented in SkARGB32_Blitter, SkARGB32_Opaque_Blitter, SkARGB32_Black_Blitter, and SkRasterPipelineBlitter.

Definition at line 94 of file SkBlitter.h.

                                                              {
        int16_t runs[2];
        uint8_t aa[1];
 
        runs[0] = 1;
        runs[1] = 0;
        aa[0] = SkToU8(a0);
        this->blitAntiH(x, y, aa, runs);
        // reset in case the clipping blitter modified runs
        runs[0] = 1;
        runs[1] = 0;
        aa[0] = SkToU8(a1);
        this->blitAntiH(x, y + 1, aa, runs);
    }

blitFatAntiRect()

void SkBlitter::blitFatAntiRect

(

const SkRect &

rect

)

Definition at line 67 of file SkBlitter.cpp.

                                                  {
    SkIRect bounds = rect.roundOut();
    SkASSERT(bounds.width() >= 3);
 
    // skbug.com/7813
    // To ensure consistency of the threaded backend (a rect that's considered fat in the init-once
    // phase must also be considered fat in the draw phase), we have to deal with rects with small
    // heights because the horizontal tiling in the threaded backend may change the height.
    //
    // This also implies that we cannot do vertical tiling unless we can blit any rect (not just the
    // fat one.)
    if (bounds.height() == 0) {
        return;
    }
 
    int         runSize = bounds.width() + 1; // +1 so we can set runs[bounds.width()] = 0
    void*       storage = this->allocBlitMemory(runSize * (sizeof(int16_t) + sizeof(SkAlpha)));
    int16_t*    runs    = reinterpret_cast<int16_t*>(storage);
    SkAlpha*    alphas  = reinterpret_cast<SkAlpha*>(runs + runSize);
 
    runs[0] = 1;
    runs[1] = bounds.width() - 2;
    runs[bounds.width() - 1] = 1;
    runs[bounds.width()]  = 0;
 
    SkScalar partialL = bounds.fLeft + 1 - rect.fLeft;
    SkScalar partialR = rect.fRight - (bounds.fRight - 1);
    SkScalar partialT = bounds.fTop + 1 - rect.fTop;
    SkScalar partialB = rect.fBottom - (bounds.fBottom - 1);
 
    if (bounds.height() == 1) {
        partialT = rect.fBottom - rect.fTop;
    }
 
    alphas[0] = ScalarToAlpha(partialL * partialT);
    alphas[1] = ScalarToAlpha(partialT);
    alphas[bounds.width() - 1] = ScalarToAlpha(partialR * partialT);
    this->blitAntiH(bounds.fLeft, bounds.fTop, alphas, runs);
 
    if (bounds.height() > 2) {
        this->blitAntiRect(bounds.fLeft, bounds.fTop + 1, bounds.width() - 2, bounds.height() - 2,
                           ScalarToAlpha(partialL), ScalarToAlpha(partialR));
    }
 
    if (bounds.height() > 1) {
        alphas[0] = ScalarToAlpha(partialL * partialB);
        alphas[1] = ScalarToAlpha(partialB);
        alphas[bounds.width() - 1] = ScalarToAlpha(partialR * partialB);
        this->blitAntiH(bounds.fLeft, bounds.fBottom - 1, alphas, runs);
    }
}

blitH()

virtual void SkBlitter::blitH ( int  x, int  y, int  width  )

pure virtual

Blit a horizontal run of one or more pixels.

Implemented in SkRasterPipelineBlitter, SkAAClip::Builder::Blitter, SkAAClipBlitter, SkNullBlitter, SkRectClipBlitter, SkRgnClipBlitter, SkA8_Blitter, SkA8_Coverage_Blitter, SkARGB32_Blitter, SkARGB32_Shader_Blitter, SkRgnBuilder, AdditiveBlitter, InverseBlitter, SkSpriteBlitter, TestBlitter, and FakeBlitter.

blitMask()

void SkBlitter::blitMask ( const SkMask &  mask, const SkIRect &  clip  )

virtual

Blit a pattern of pixels defined by a rectangle-clipped mask; typically used for text.

Reimplemented in SkA8_Blitter, SkA8_Coverage_Blitter, SkARGB32_Blitter, SkARGB32_Opaque_Blitter, SkARGB32_Shader_Blitter, SkAAClip::Builder::Blitter, SkAAClipBlitter, SkNullBlitter, SkRectClipBlitter, SkRgnClipBlitter, SkRasterPipelineBlitter, InverseBlitter, and SkSpriteBlitter.

Definition at line 201 of file SkBlitter.cpp.

                                                                {
    SkASSERT(mask.fBounds.contains(clip));
 
    if (mask.fFormat == SkMask::kLCD16_Format) {
        return; // needs to be handled by subclass
    }
 
    if (mask.fFormat == SkMask::kBW_Format) {
        int cx = clip.fLeft;
        int cy = clip.fTop;
        int maskLeft = mask.fBounds.fLeft;
        int maskRowBytes = mask.fRowBytes;
        int height = clip.height();
 
        const uint8_t* bits = mask.getAddr1(cx, cy);
 
        SkDEBUGCODE(const uint8_t* endOfImage =
            mask.fImage + (mask.fBounds.height() - 1) * maskRowBytes
            + ((mask.fBounds.width() + 7) >> 3));
 
        if (cx == maskLeft && clip.fRight == mask.fBounds.fRight) {
            while (--height >= 0) {
                int affectedRightBit = mask.fBounds.width() - 1;
                ptrdiff_t rowBytes = (affectedRightBit >> 3) + 1;
                SkASSERT(bits + rowBytes <= endOfImage);
                U8CPU rightMask = generate_right_mask((affectedRightBit & 7) + 1);
                bits_to_runs(this, cx, cy, bits, 0xFF, rowBytes, rightMask);
                bits += maskRowBytes;
                cy += 1;
            }
        } else {
            // Bits is calculated as the offset into the mask at the point {cx, cy} therefore, all
            // addressing into the bit mask is relative to that point. Since this is an address
            // calculated from a arbitrary bit in that byte, calculate the left most bit.
            int bitsLeft = cx - ((cx - maskLeft) & 7);
 
            // Everything is relative to the bitsLeft.
            int leftEdge = cx - bitsLeft;
            SkASSERT(leftEdge >= 0);
            int rightEdge = clip.fRight - bitsLeft;
            SkASSERT(rightEdge > leftEdge);
 
            // Calculate left byte and mask
            const uint8_t* leftByte = bits;
            U8CPU leftMask = 0xFFU >> (leftEdge & 7);
 
            // Calculate right byte and mask
            int affectedRightBit = rightEdge - 1;
            const uint8_t* rightByte = bits + (affectedRightBit >> 3);
            U8CPU rightMask = generate_right_mask((affectedRightBit & 7) + 1);
 
            // leftByte and rightByte are byte locations therefore, to get a count of bytes the
            // code must add one.
            ptrdiff_t rowBytes = rightByte - leftByte + 1;
 
            while (--height >= 0) {
                SkASSERT(bits + rowBytes <= endOfImage);
                bits_to_runs(this, bitsLeft, cy, bits, leftMask, rowBytes, rightMask);
                bits += maskRowBytes;
                cy += 1;
            }
        }
    } else {
        int                         width = clip.width();
        AutoSTMalloc<64, int16_t> runStorage(width + 1);
        int16_t*                    runs = runStorage.get();
        const uint8_t*              aa = mask.getAddr8(clip.fLeft, clip.fTop);
 
        SkOpts::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;
        }
    }
}

blitRect()

void SkBlitter::blitRect ( int  x, int  y, int  width, int  height  )

virtual

Blit a solid rectangle one or more pixels wide.

Reimplemented in SkAAClip::Builder::Blitter, SkAAClipBlitter, SkNullBlitter, SkRectClipBlitter, SkRgnClipBlitter, SkA8_Blitter, SkA8_Coverage_Blitter, SkSpriteBlitter_Memcpy, SkRasterPipelineSpriteBlitter, SkARGB32_Blitter, SkARGB32_Shader_Blitter, SkRasterPipelineBlitter, AdditiveBlitter, MaskAdditiveBlitter, InverseBlitter, Sprite_D32_S32, and SkSpriteBlitter.

Definition at line 133 of file SkBlitter.cpp.

                                                            {
    SkASSERT(width > 0);
    while (--height >= 0) {
        this->blitH(x, y++, width);
    }
}

blitRectRegion()

void SkBlitter::blitRectRegion	(	const SkIRect &	rect,
		const SkRegion &	clip
	)

Definition at line 300 of file SkBlitter.cpp.

                                                                        {
    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();
    }
}

blitRegion()

void SkBlitter::blitRegion

(

const SkRegion &

clip

)

Definition at line 310 of file SkBlitter.cpp.

                                               {
    SkRegionPriv::VisitSpans(clip, [this](const SkIRect& r) {
        this->blitRect(r.left(), r.top(), r.width(), r.height());
    });
}

blitV()

void SkBlitter::blitV ( int  x, int  y, int  height, SkAlpha  alpha  )

virtual

Blit a vertical run of pixels with a constant alpha value.

Reimplemented in SkAAClip::Builder::Blitter, SkAAClipBlitter, SkNullBlitter, SkRectClipBlitter, SkRgnClipBlitter, SkA8_Blitter, SkA8_Coverage_Blitter, SkARGB32_Blitter, SkARGB32_Shader_Blitter, SkRasterPipelineBlitter, AdditiveBlitter, MaskAdditiveBlitter, InverseBlitter, and SkSpriteBlitter.

Definition at line 119 of file SkBlitter.cpp.

                                                             {
    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);
        }
    }
}

Choose()

SkBlitter * SkBlitter::Choose ( const SkPixmap &  dst, const SkMatrix &  ctm, const SkPaint &  paint, SkArenaAlloc *  alloc, bool  drawCoverage, sk_sp< SkShader >  clipShader, const SkSurfaceProps &  props  )

static

Definition at line 685 of file SkBlitter.cpp.

                                                          {
    SkASSERT(alloc);
 
    if (kUnknown_SkColorType == device.colorType()) {
        return alloc->make<SkNullBlitter>();
    }
 
    // We may tweak the original paint as we go.
    SkTCopyOnFirstWrite<SkPaint> paint(origPaint);
 
    if (auto mode = paint->asBlendMode()) {
        // We have the most fast-paths for SrcOver, so see if we can act like SrcOver.
        if (mode.value() != SkBlendMode::kSrcOver) {
            switch (CheckFastPath(*paint, SkColorTypeIsAlwaysOpaque(device.colorType()))) {
                case SkBlendFastPath::kSrcOver:
                    paint.writable()->setBlendMode(SkBlendMode::kSrcOver);
                    break;
                case SkBlendFastPath::kSkipDrawing:
                    return alloc->make<SkNullBlitter>();
                default:
                    break;
            }
        }
 
        // A Clear blend mode will ignore the entire color pipeline, as if Src mode with 0x00000000.
        if (mode.value() == SkBlendMode::kClear) {
            SkPaint* p = paint.writable();
            p->setShader(nullptr);
            p->setColorFilter(nullptr);
            p->setBlendMode(SkBlendMode::kSrc);
            p->setColor(0x00000000);
        }
    }
 
    if (paint->getColorFilter()) {
        SkPaintPriv::RemoveColorFilter(paint.writable(), device.colorSpace());
    }
    SkASSERT(!paint->getColorFilter());
 
    if (drawCoverage) {
        if (device.colorType() == kAlpha_8_SkColorType) {
            SkASSERT(!paint->getShader());
            SkASSERT(paint->isSrcOver());
            return alloc->make<SkA8_Coverage_Blitter>(device, *paint);
        }
        return alloc->make<SkNullBlitter>();
    }
 
    if (paint->isDither() && !SkPaintPriv::ShouldDither(*paint, device.colorType())) {
        paint.writable()->setDither(false);
    }
 
    auto CreateSkRPBlitter = [&]() -> SkBlitter* {
        auto blitter = SkCreateRasterPipelineBlitter(device, *paint, ctm, alloc, clipShader, props);
        return blitter ? blitter
                       : alloc->make<SkNullBlitter>();
    };
 
    // We'll end here for many interesting cases: color spaces, color filters, most color types.
    if (clipShader || !UseLegacyBlitter(device, *paint, ctm)) {
        return CreateSkRPBlitter();
    }
 
    // Everything but legacy kN32_SkColorType should already be handled.
    SkASSERT(device.colorType() == kN32_SkColorType);
 
    // And we should be blending with SrcOver
    SkASSERT(paint->asBlendMode() == SkBlendMode::kSrcOver);
 
    // Legacy blitters keep their shader state on a shader context.
    SkShaderBase::Context* shaderContext = nullptr;
    if (paint->getShader()) {
        shaderContext = as_SB(paint->getShader())
                                ->makeContext({paint->getAlpha(),
                                               SkShaders::MatrixRec(ctm),
                                               device.colorType(),
                                               device.colorSpace(),
                                               props},
                                              alloc);
 
        // Creating the context isn't always possible... try fallbacks before giving up.
        if (!shaderContext) {
            return CreateSkRPBlitter();
        }
    }
 
    if (shaderContext) {
        return alloc->make<SkARGB32_Shader_Blitter>(device, *paint, shaderContext);
    } else if (paint->getColor() == SK_ColorBLACK) {
        return alloc->make<SkARGB32_Black_Blitter>(device, *paint);
    } else if (paint->getAlpha() == 0xFF) {
        return alloc->make<SkARGB32_Opaque_Blitter>(device, *paint);
    } else {
        return alloc->make<SkARGB32_Blitter>(device, *paint);
    }
}

ChooseSprite()

SkBlitter * SkBlitter::ChooseSprite ( const SkPixmap &  dst, const SkPaint &  paint, const SkPixmap &  src, int  left, int  top, SkArenaAlloc *  alloc, sk_sp< SkShader >  clipShader  )

static

Definition at line 195 of file SkBlitter_Sprite.cpp.

                                                                                    {
    /*  We currently ignore antialiasing and filtertype, meaning we will take our
        special blitters regardless of these settings. Ignoring filtertype seems fine
        since by definition there is no scale in the matrix. Ignoring antialiasing is
        a bit of a hack, since we "could" pass in the fractional left/top for the bitmap,
        and respect that by blending the edges of the bitmap against the device. To support
        this we could either add more special blitters here, or detect antialiasing in the
        paint and return null if it is set, forcing the client to take the slow shader case
        (which does respect soft edges).
    */
    SkASSERT(alloc != nullptr);
 
    // TODO: in principle SkRasterPipelineSpriteBlitter could be made to handle this.
    if (source.alphaType() == kUnpremul_SkAlphaType) {
        return nullptr;
    }
 
    SkSpriteBlitter* blitter = nullptr;
 
    if (gSkForceRasterPipelineBlitter) {
        // Do not use any of these optimized memory blitters
    } else if (0 == SkColorSpaceXformSteps(source,dst).flags.mask() && !clipShader) {
        if (!blitter && SkSpriteBlitter_Memcpy::Supports(dst, source, paint)) {
            blitter = alloc->make<SkSpriteBlitter_Memcpy>(source);
        }
        if (!blitter) {
            switch (dst.colorType()) {
                case kN32_SkColorType:
                    blitter = SkSpriteBlitter::ChooseL32(source, paint, alloc);
                    break;
                default:
                    break;
            }
        }
    }
    if (!blitter && !paint.getMaskFilter()) {
        blitter = alloc->make<SkRasterPipelineSpriteBlitter>(source, alloc, clipShader);
    }
 
    if (blitter && blitter->setup(dst, left,top, paint)) {
        return blitter;
    }
 
    return nullptr;
}

isNullBlitter()

bool SkBlitter::isNullBlitter ( ) const

virtual

Special method just to identify the null blitter, which is returned from Choose() if the request cannot be fulfilled. Default impl returns false.

Reimplemented in SkNullBlitter.

Definition at line 48 of file SkBlitter.cpp.

{ return false; }

requestRowsPreserved()

virtual int SkBlitter::requestRowsPreserved ( ) const

inlinevirtual

Special methods for blitters that can blit more than one row at a time. This function returns the number of rows that this blitter could optimally process at a time. It is still required to support blitting one scanline at a time.

Reimplemented in SkRectClipBlitter, and SkRgnClipBlitter.

Definition at line 122 of file SkBlitter.h.

{ return 1; }

UseLegacyBlitter()

bool SkBlitter::UseLegacyBlitter ( const SkPixmap &  device, const SkPaint &  paint, const SkMatrix &  matrix  )

static

Definition at line 648 of file SkBlitter.cpp.

                                                         {
    if (gSkForceRasterPipelineBlitter) {
        return false;
    }
#if defined(SK_FORCE_RASTER_PIPELINE_BLITTER)
    return false;
#else
 
    if (paint.isDither()) {
        return false;
    }
 
    const SkMaskFilterBase* mf = as_MFB(paint.getMaskFilter());
 
    // The legacy blitters cannot handle any of these "complex" features (anymore).
    if (device.alphaType() == kUnpremul_SkAlphaType   ||
        !paint.isSrcOver()                            ||
        (mf && mf->getFormat() == SkMask::k3D_Format)) {
        return false;
    }
 
    auto cs = device.colorSpace();
    // We check (indirectly via makeContext()) later on if the shader can handle the colorspace
    // in legacy mode, so here we just focus on if a single color needs raster-pipeline.
    if (cs && !paint.getShader()) {
        if (!paint.getColor4f().fitsInBytes() || !cs->isSRGB()) {
            return false;
        }
    }
 
    // Only kN32 is handled by legacy blitters now
    return device.colorType() == kN32_SkColorType;
#endif
}

Member Data Documentation

fBlitMemory

SkAutoMalloc SkBlitter::fBlitMemory

protected

Definition at line 163 of file SkBlitter.h.

---

The documentation for this class was generated from the following files:

• third_party/skia/src/core/SkBlitter.h
• third_party/skia/src/core/SkBlitter.cpp
• third_party/skia/src/core/SkBlitter_Sprite.cpp