src/core/SkDraw.cpp

/* libs/graphics/sgl/SkDraw.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 "SkDraw.h"
#include "SkBlitter.h"
#include "SkBounder.h"
#include "SkCanvas.h"
#include "SkColorPriv.h"
#include "SkDevice.h"
#include "SkMaskFilter.h"
#include "SkPaint.h"
#include "SkPathEffect.h"
#include "SkRasterizer.h"
#include "SkScan.h"
#include "SkShader.h"
#include "SkStroke.h"
#include "SkTemplatesPriv.h"
#include "SkUtils.h"

#include "SkAutoKern.h"
#include "SkBitmapProcShader.h"
#include "SkDrawProcs.h"

//#define TRACE_BITMAP_DRAWS

class SkAutoRestoreBounder : SkNoncopyable {
public:
    // note: initializing fBounder is done only to fix a warning
    SkAutoRestoreBounder() : fDraw(NULL), fBounder(NULL) {}
    ~SkAutoRestoreBounder() {
        if (fDraw) {
            fDraw->fBounder = fBounder;
        }
    }

    void clearBounder(const SkDraw* draw) {
        fDraw = const_cast<SkDraw*>(draw);
        fBounder = draw->fBounder;
        fDraw->fBounder = NULL;
    }

private:
    SkDraw*     fDraw;
    SkBounder*  fBounder;
};

static SkPoint* rect_points(SkRect& r, int index) {
    SkASSERT((unsigned)index < 2);
    return &((SkPoint*)(void*)&r)[index];
}

/** Helper for allocating small blitters on the stack.
*/

#define kBlitterStorageLongCount    (sizeof(SkBitmapProcShader) >> 2)

class SkAutoBlitterChoose {
public:
    SkAutoBlitterChoose(const SkBitmap& device, const SkMatrix& matrix,
                        const SkPaint& paint) {
        fBlitter = SkBlitter::Choose(device, matrix, paint,
                                     fStorage, sizeof(fStorage));
    }
    ~SkAutoBlitterChoose();

    SkBlitter*  operator->() { return fBlitter; }
    SkBlitter*  get() const { return fBlitter; }

private:
    SkBlitter*  fBlitter;
    uint32_t    fStorage[kBlitterStorageLongCount];
};

SkAutoBlitterChoose::~SkAutoBlitterChoose() {
    if ((void*)fBlitter == (void*)fStorage) {
        fBlitter->~SkBlitter();
    } else {
        SkDELETE(fBlitter);
    }
}

class SkAutoBitmapShaderInstall {
public:
    SkAutoBitmapShaderInstall(const SkBitmap& src, const SkPaint* paint)
            : fPaint((SkPaint*)paint) {
        fPrevShader = paint->getShader();
        fPrevShader->safeRef();
        fPaint->setShader(SkShader::CreateBitmapShader( src,
                           SkShader::kClamp_TileMode, SkShader::kClamp_TileMode,
                           fStorage, sizeof(fStorage)));
    }
    ~SkAutoBitmapShaderInstall() {
        SkShader* shader = fPaint->getShader();

        fPaint->setShader(fPrevShader);
        fPrevShader->safeUnref();

        if ((void*)shader == (void*)fStorage) {
            shader->~SkShader();
        } else {
            SkDELETE(shader);
        }
    }
private:
    SkPaint*    fPaint;
    SkShader*   fPrevShader;
    uint32_t    fStorage[kBlitterStorageLongCount];
};

class SkAutoPaintStyleRestore {
public:
    SkAutoPaintStyleRestore(const SkPaint& paint, SkPaint::Style style)
            : fPaint((SkPaint&)paint) {
        fStyle = paint.getStyle();  // record the old
        fPaint.setStyle(style);     // change it to the specified style
    }
    ~SkAutoPaintStyleRestore() {
        fPaint.setStyle(fStyle);    // restore the old
    }
private:
    SkPaint&        fPaint;
    SkPaint::Style  fStyle;

    // illegal
    SkAutoPaintStyleRestore(const SkAutoPaintStyleRestore&);
    SkAutoPaintStyleRestore& operator=(const SkAutoPaintStyleRestore&);
};

///////////////////////////////////////////////////////////////////////////////

SkDraw::SkDraw(const SkDraw& src) {
    memcpy(this, &src, sizeof(*this));
}

///////////////////////////////////////////////////////////////////////////////

typedef void (*BitmapXferProc)(void* pixels, size_t bytes, uint32_t data);

static void D_Clear_BitmapXferProc(void* pixels, size_t bytes, uint32_t) {
    sk_bzero(pixels, bytes);
}

static void D_Dst_BitmapXferProc(void*, size_t, uint32_t data) {}

static void D32_Src_BitmapXferProc(void* pixels, size_t bytes, uint32_t data) {
    sk_memset32((uint32_t*)pixels, data, bytes >> 2);
}

static void D16_Src_BitmapXferProc(void* pixels, size_t bytes, uint32_t data) {
    sk_memset16((uint16_t*)pixels, data, bytes >> 1);
}

static void DA8_Src_BitmapXferProc(void* pixels, size_t bytes, uint32_t data) {
    memset(pixels, data, bytes);
}

static BitmapXferProc ChooseBitmapXferProc(const SkBitmap& bitmap,
                                           const SkPaint& paint,
                                           uint32_t* data) {
    // todo: we can apply colorfilter up front if no shader, so we wouldn't
    // need to abort this fastpath
    if (paint.getShader() || paint.getColorFilter()) {
        return NULL;
    }

    SkXfermode::Mode mode;
    if (!SkXfermode::IsMode(paint.getXfermode(), &mode)) {
        return NULL;
    }

    SkColor color = paint.getColor();

    // collaps modes based on color...
    if (SkXfermode::kSrcOver_Mode == mode) {
        unsigned alpha = SkColorGetA(color);
        if (0 == alpha) {
            mode = SkXfermode::kDst_Mode;
        } else if (0xFF == alpha) {
            mode = SkXfermode::kSrc_Mode;
        }
    }

    switch (mode) {
        case SkXfermode::kClear_Mode:
//            SkDebugf("--- D_Clear_BitmapXferProc\n");
            return D_Clear_BitmapXferProc;  // ignore data
        case SkXfermode::kDst_Mode:
//            SkDebugf("--- D_Dst_BitmapXferProc\n");
            return D_Dst_BitmapXferProc;    // ignore data
        case SkXfermode::kSrc_Mode: {
            /*
                should I worry about dithering for the lower depths?
            */
            SkPMColor pmc = SkPreMultiplyColor(color);
            switch (bitmap.config()) {
                case SkBitmap::kARGB_8888_Config:
                    if (data) {
                        *data = pmc;
                    }
//                    SkDebugf("--- D32_Src_BitmapXferProc\n");
                    return D32_Src_BitmapXferProc;
                case SkBitmap::kARGB_4444_Config:
                    if (data) {
                        *data = SkPixel32ToPixel4444(pmc);
                    }
//                    SkDebugf("--- D16_Src_BitmapXferProc\n");
                    return D16_Src_BitmapXferProc;
                case SkBitmap::kRGB_565_Config:
                    if (data) {
                        *data = SkPixel32ToPixel16(pmc);
                    }
//                    SkDebugf("--- D16_Src_BitmapXferProc\n");
                    return D16_Src_BitmapXferProc;
                case SkBitmap::kA8_Config:
                    if (data) {
                        *data = SkGetPackedA32(pmc);
                    }
//                    SkDebugf("--- DA8_Src_BitmapXferProc\n");
                    return DA8_Src_BitmapXferProc;
                default:
                    break;
            }
            break;
        }
        default:
            break;
    }
    return NULL;
}

static void CallBitmapXferProc(const SkBitmap& bitmap, const SkIRect& rect,
                               BitmapXferProc proc, uint32_t procData) {
    int shiftPerPixel;
    switch (bitmap.config()) {
        case SkBitmap::kARGB_8888_Config:
            shiftPerPixel = 2;
            break;
        case SkBitmap::kARGB_4444_Config:
        case SkBitmap::kRGB_565_Config:
            shiftPerPixel = 1;
            break;
        case SkBitmap::kA8_Config:
            shiftPerPixel = 0;
            break;
        default:
            SkASSERT(!"Can't use xferproc on this config");
            return;
    }

    uint8_t* pixels = (uint8_t*)bitmap.getPixels();
    SkASSERT(pixels);
    const size_t rowBytes = bitmap.rowBytes();
    const int widthBytes = rect.width() << shiftPerPixel;

    // skip down to the first scanline and X position
    pixels += rect.fTop * rowBytes + (rect.fLeft << shiftPerPixel);
    for (int scans = rect.height() - 1; scans >= 0; --scans) {
        proc(pixels, widthBytes, procData);
        pixels += rowBytes;
    }
}

void SkDraw::drawPaint(const SkPaint& paint) const {
    SkDEBUGCODE(this->validate();)

    if (fClip->isEmpty()) {
        return;
    }

    SkIRect    devRect;
    devRect.set(0, 0, fBitmap->width(), fBitmap->height());
    if (fBounder && !fBounder->doIRect(devRect)) {
        return;
    }

    /*  If we don't have a shader (i.e. we're just a solid color) we may
        be faster to operate directly on the device bitmap, rather than invoking
        a blitter. Esp. true for xfermodes, which require a colorshader to be
        present, which is just redundant work. Since we're drawing everywhere
        in the clip, we don't have to worry about antialiasing.
    */
    uint32_t procData = 0;  // to avoid the warning
    BitmapXferProc proc = ChooseBitmapXferProc(*fBitmap, paint, &procData);
    if (proc) {
        if (D_Dst_BitmapXferProc == proc) { // nothing to do
            return;
        }

        SkRegion::Iterator iter(*fClip);
        while (!iter.done()) {
            CallBitmapXferProc(*fBitmap, iter.rect(), proc, procData);
            iter.next();
        }
    } else {
        // normal case: use a blitter
        SkAutoBlitterChoose blitter(*fBitmap, *fMatrix, paint);
        SkScan::FillIRect(devRect, fClip, blitter.get());
    }
}

///////////////////////////////////////////////////////////////////////////////

struct PtProcRec {
    SkCanvas::PointMode fMode;
    const SkPaint*  fPaint;
    const SkRegion* fClip;

    // computed values
    SkFixed fRadius;

    typedef void (*Proc)(const PtProcRec&, const SkPoint devPts[], int count,
                         SkBlitter*);

    bool init(SkCanvas::PointMode, const SkPaint&, const SkMatrix* matrix,
              const SkRegion* clip);
    Proc chooseProc(SkBlitter* blitter);
};

static void bw_pt_rect_hair_proc(const PtProcRec& rec, const SkPoint devPts[],
                                 int count, SkBlitter* blitter) {
    SkASSERT(rec.fClip->isRect());
    const SkIRect& r = rec.fClip->getBounds();

    for (int i = 0; i < count; i++) {
        int x = SkScalarFloor(devPts[i].fX);
        int y = SkScalarFloor(devPts[i].fY);
        if (r.contains(x, y)) {
            blitter->blitH(x, y, 1);
        }
    }
}

static void bw_pt_rect_16_hair_proc(const PtProcRec& rec,
                                    const SkPoint devPts[], int count,
                                    SkBlitter* blitter) {
    SkASSERT(rec.fClip->isRect());
    const SkIRect& r = rec.fClip->getBounds();
    uint32_t value;
    const SkBitmap* bitmap = blitter->justAnOpaqueColor(&value);
    SkASSERT(bitmap);

    uint16_t* addr = bitmap->getAddr16(0, 0);
    int rb = bitmap->rowBytes();

    for (int i = 0; i < count; i++) {
        int x = SkScalarFloor(devPts[i].fX);
        int y = SkScalarFloor(devPts[i].fY);
        if (r.contains(x, y)) {
//            *bitmap->getAddr16(x, y) = SkToU16(value);
            ((uint16_t*)((char*)addr + y * rb))[x] = SkToU16(value);
        }
    }
}

static void bw_pt_hair_proc(const PtProcRec& rec, const SkPoint devPts[],
                            int count, SkBlitter* blitter) {
    for (int i = 0; i < count; i++) {
        int x = SkScalarFloor(devPts[i].fX);
        int y = SkScalarFloor(devPts[i].fY);
        if (rec.fClip->contains(x, y)) {
            blitter->blitH(x, y, 1);
        }
    }
}

static void bw_line_hair_proc(const PtProcRec& rec, const SkPoint devPts[],
                              int count, SkBlitter* blitter) {
    for (int i = 0; i < count; i += 2) {
        SkScan::HairLine(devPts[i], devPts[i+1], rec.fClip, blitter);
    }
}

static void bw_poly_hair_proc(const PtProcRec& rec, const SkPoint devPts[],
                              int count, SkBlitter* blitter) {
    for (int i = 0; i < count - 1; i++) {
        SkScan::HairLine(devPts[i], devPts[i+1], rec.fClip, blitter);
    }
}

// aa versions

static void aa_line_hair_proc(const PtProcRec& rec, const SkPoint devPts[],
                              int count, SkBlitter* blitter) {
    for (int i = 0; i < count; i += 2) {
        SkScan::AntiHairLine(devPts[i], devPts[i+1], rec.fClip, blitter);
    }
}

static void aa_poly_hair_proc(const PtProcRec& rec, const SkPoint devPts[],
                              int count, SkBlitter* blitter) {
    for (int i = 0; i < count - 1; i++) {
        SkScan::AntiHairLine(devPts[i], devPts[i+1], rec.fClip, blitter);
    }
}

// square procs (strokeWidth > 0 but matrix is square-scale (sx == sy)

static void bw_square_proc(const PtProcRec& rec, const SkPoint devPts[],
                           int count, SkBlitter* blitter) {
    const SkFixed radius = rec.fRadius;
    for (int i = 0; i < count; i++) {
        SkFixed x = SkScalarToFixed(devPts[i].fX);
        SkFixed y = SkScalarToFixed(devPts[i].fY);

        SkXRect r;
        r.fLeft = x - radius;
        r.fTop = y - radius;
        r.fRight = x + radius;
        r.fBottom = y + radius;

        SkScan::FillXRect(r, rec.fClip, blitter);
    }
}

static void aa_square_proc(const PtProcRec& rec, const SkPoint devPts[],
                           int count, SkBlitter* blitter) {
    const SkFixed radius = rec.fRadius;
    for (int i = 0; i < count; i++) {
        SkFixed x = SkScalarToFixed(devPts[i].fX);
        SkFixed y = SkScalarToFixed(devPts[i].fY);

        SkXRect r;
        r.fLeft = x - radius;
        r.fTop = y - radius;
        r.fRight = x + radius;
        r.fBottom = y + radius;

        SkScan::AntiFillXRect(r, rec.fClip, blitter);
    }
}

// If this guy returns true, then chooseProc() must return a valid proc
bool PtProcRec::init(SkCanvas::PointMode mode, const SkPaint& paint,
                     const SkMatrix* matrix, const SkRegion* clip) {
    if (paint.getPathEffect()) {
        return false;
    }
    SkScalar width = paint.getStrokeWidth();
    if (0 == width) {
        fMode = mode;
        fPaint = &paint;
        fClip = clip;
        fRadius = SK_Fixed1 >> 1;
        return true;
    }
    if (paint.getStrokeCap() != SkPaint::kRound_Cap &&
            matrix->rectStaysRect() && SkCanvas::kPoints_PointMode == mode) {
        SkScalar sx = matrix->get(SkMatrix::kMScaleX);
        SkScalar sy = matrix->get(SkMatrix::kMScaleY);
        if (SkScalarNearlyZero(sx - sy)) {
            if (sx < 0) {
                sx = -sx;
            }

            fMode = mode;
            fPaint = &paint;
            fClip = clip;
            fRadius = SkScalarToFixed(SkScalarMul(width, sx)) >> 1;
            return true;
        }
    }
    return false;
}

PtProcRec::Proc PtProcRec::chooseProc(SkBlitter* blitter) {
    Proc proc = NULL;

    // for our arrays
    SkASSERT(0 == SkCanvas::kPoints_PointMode);
    SkASSERT(1 == SkCanvas::kLines_PointMode);
    SkASSERT(2 == SkCanvas::kPolygon_PointMode);
    SkASSERT((unsigned)fMode <= (unsigned)SkCanvas::kPolygon_PointMode);

    // first check for hairlines
    if (0 == fPaint->getStrokeWidth()) {
        if (fPaint->isAntiAlias()) {
            static const Proc gAAProcs[] = {
                aa_square_proc, aa_line_hair_proc, aa_poly_hair_proc
            };
            proc = gAAProcs[fMode];
        } else {
            if (SkCanvas::kPoints_PointMode == fMode && fClip->isRect()) {
                uint32_t value;
                const SkBitmap* bm = blitter->justAnOpaqueColor(&value);
                if (bm && bm->config() == SkBitmap::kRGB_565_Config) {
                    proc = bw_pt_rect_16_hair_proc;
                } else {
                    proc = bw_pt_rect_hair_proc;
                }
            } else {
                static Proc gBWProcs[] = {
                    bw_pt_hair_proc, bw_line_hair_proc, bw_poly_hair_proc
                };
                proc = gBWProcs[fMode];
            }
        }
    } else if (fPaint->getStrokeCap() != SkPaint::kRound_Cap) {
        SkASSERT(SkCanvas::kPoints_PointMode == fMode);
        if (fPaint->isAntiAlias()) {
            proc = aa_square_proc;
        } else {
            proc = bw_square_proc;
        }
    }
    return proc;
}

static bool bounder_points(SkBounder* bounder, SkCanvas::PointMode mode,
                           size_t count, const SkPoint pts[],
                           const SkPaint& paint, const SkMatrix& matrix) {
    SkIRect ibounds;
    SkRect bounds;
    SkScalar inset = paint.getStrokeWidth();

    bounds.set(pts, count);
    bounds.inset(-inset, -inset);
    matrix.mapRect(&bounds);

    bounds.roundOut(&ibounds);
    return bounder->doIRect(ibounds);
}

// each of these costs 8-bytes of stack space, so don't make it too large
// must be even for lines/polygon to work
#define MAX_DEV_PTS     32

void SkDraw::drawPoints(SkCanvas::PointMode mode, size_t count,
                        const SkPoint pts[], const SkPaint& paint) const {
    // if we're in lines mode, force count to be even
    if (SkCanvas::kLines_PointMode == mode) {
        count &= ~(size_t)1;
    }

    if ((long)count <= 0) {
        return;
    }

    SkAutoRestoreBounder arb;

    if (fBounder) {
        if (!bounder_points(fBounder, mode, count, pts, paint, *fMatrix)) {
            return;
        }
        // clear the bounder for the rest of this function, so we don't call it
        // again later if we happen to call ourselves for drawRect, drawPath,
        // etc.
        arb.clearBounder(this);
    }

    SkASSERT(pts != NULL);
    SkDEBUGCODE(this->validate();)

     // nothing to draw
    if (fClip->isEmpty() ||
        (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    PtProcRec rec;
    if (rec.init(mode, paint, fMatrix, fClip)) {
        SkAutoBlitterChoose blitter(*fBitmap, *fMatrix, paint);

        SkPoint             devPts[MAX_DEV_PTS];
        const SkMatrix*     matrix = fMatrix;
        SkBlitter*          bltr = blitter.get();
        PtProcRec::Proc     proc = rec.chooseProc(bltr);
        // we have to back up subsequent passes if we're in polygon mode
        const size_t backup = (SkCanvas::kPolygon_PointMode == mode);

        do {
            size_t n = count;
            if (n > MAX_DEV_PTS) {
                n = MAX_DEV_PTS;
            }
            matrix->mapPoints(devPts, pts, n);
            proc(rec, devPts, n, bltr);
            pts += n - backup;
            SkASSERT(count >= n);
            count -= n;
            if (count > 0) {
                count += backup;
            }
        } while (count != 0);
    } else {
        switch (mode) {
            case SkCanvas::kPoints_PointMode: {
                // temporarily mark the paint as filling.
                SkAutoPaintStyleRestore restore(paint, SkPaint::kFill_Style);

                SkScalar width = paint.getStrokeWidth();
                SkScalar radius = SkScalarHalf(width);

                if (paint.getStrokeCap() == SkPaint::kRound_Cap) {
                    SkPath      path;
                    SkMatrix    preMatrix;

                    path.addCircle(0, 0, radius);
                    for (size_t i = 0; i < count; i++) {
                        preMatrix.setTranslate(pts[i].fX, pts[i].fY);
                        // pass true for the last point, since we can modify
                        // then path then
                        this->drawPath(path, paint, &preMatrix, (count-1) == i);
                    }
                } else {
                    SkRect  r;

                    for (size_t i = 0; i < count; i++) {
                        r.fLeft = pts[i].fX - radius;
                        r.fTop = pts[i].fY - radius;
                        r.fRight = r.fLeft + width;
                        r.fBottom = r.fTop + width;
                        this->drawRect(r, paint);
                    }
                }
                break;
            }
            case SkCanvas::kLines_PointMode:
            case SkCanvas::kPolygon_PointMode: {
                count -= 1;
                SkPath path;
                SkPaint p(paint);
                p.setStyle(SkPaint::kStroke_Style);
                size_t inc = (SkCanvas::kLines_PointMode == mode) ? 2 : 1;
                for (size_t i = 0; i < count; i += inc) {
                    path.moveTo(pts[i]);
                    path.lineTo(pts[i+1]);
                    this->drawPath(path, p, NULL, true);
                    path.rewind();
                }
                break;
            }
        }
    }
}

static inline SkPoint* as_lefttop(SkRect* r) {
    return (SkPoint*)(void*)r;
}

static inline SkPoint* as_rightbottom(SkRect* r) {
    return ((SkPoint*)(void*)r) + 1;
}

void SkDraw::drawRect(const SkRect& rect, const SkPaint& paint) const {
    SkDEBUGCODE(this->validate();)

    // nothing to draw
    if (fClip->isEmpty() ||
        (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    // complex enough to draw as a path
    if (paint.getPathEffect() || paint.getMaskFilter() ||
            paint.getRasterizer() || !fMatrix->rectStaysRect() ||
            (paint.getStyle() != SkPaint::kFill_Style &&
             SkScalarHalf(paint.getStrokeWidth()) > 0)) {
        SkPath  tmp;
        tmp.addRect(rect);
        tmp.setFillType(SkPath::kWinding_FillType);
        this->drawPath(tmp, paint, NULL, true);
        return;
    }

    const SkMatrix& matrix = *fMatrix;
    SkRect          devRect;

    // transform rect into devRect
    {
        matrix.mapXY(rect.fLeft, rect.fTop, rect_points(devRect, 0));
        matrix.mapXY(rect.fRight, rect.fBottom, rect_points(devRect, 1));
        devRect.sort();
    }

    if (fBounder && !fBounder->doRect(devRect, paint)) {
        return;
    }

    // look for the quick exit, before we build a blitter
    {
        SkIRect ir;
        devRect.roundOut(&ir);
        if (paint.getStyle() != SkPaint::kFill_Style) {
            // extra space for hairlines
            ir.inset(-1, -1);
        }
        if (fClip->quickReject(ir))
            return;
    }

    SkAutoBlitterChoose blitterStorage(*fBitmap, matrix, paint);
    SkBlitter*          blitter = blitterStorage.get();
    const SkRegion*     clip = fClip;

    // we want to "fill" if we are kFill or kStrokeAndFill, since in the latter
    // case we are also hairline (if we've gotten to here), which devolves to
    // effectively just kFill
    if (paint.getStyle() != SkPaint::kStroke_Style) {
        if (paint.isAntiAlias()) {
            SkScan::AntiFillRect(devRect, clip, blitter);
        } else {
            SkScan::FillRect(devRect, clip, blitter);
        }
    } else {
        if (paint.isAntiAlias()) {
            SkScan::AntiHairRect(devRect, clip, blitter);
        } else {
            SkScan::HairRect(devRect, clip, blitter);
        }
    }
}

void SkDraw::drawDevMask(const SkMask& srcM, const SkPaint& paint) const {
    if (srcM.fBounds.isEmpty()) {
        return;
    }

    SkMask          dstM;
    const SkMask*   mask = &srcM;

    dstM.fImage = NULL;
    SkAutoMaskImage ami(&dstM, false);

    if (paint.getMaskFilter() &&
            paint.getMaskFilter()->filterMask(&dstM, srcM, *fMatrix, NULL)) {
        mask = &dstM;
    }

    if (fBounder && !fBounder->doIRect(mask->fBounds)) {
        return;
    }

    SkAutoBlitterChoose blitter(*fBitmap, *fMatrix, paint);

    blitter->blitMaskRegion(*mask, *fClip);
}

class SkAutoPaintRestoreColorStrokeWidth {
public:
    SkAutoPaintRestoreColorStrokeWidth(const SkPaint& paint) {
        fPaint = (SkPaint*)&paint;
        fColor = paint.getColor();
        fWidth = paint.getStrokeWidth();
    }
    ~SkAutoPaintRestoreColorStrokeWidth() {
        fPaint->setColor(fColor);
        fPaint->setStrokeWidth(fWidth);
    }

private:
    SkPaint*    fPaint;
    SkColor     fColor;
    SkScalar    fWidth;
};

static SkScalar fast_len(const SkVector& vec) {
    SkScalar x = SkScalarAbs(vec.fX);
    SkScalar y = SkScalarAbs(vec.fY);
    if (x < y) {
        SkTSwap(x, y);
    }
    return x + SkScalarHalf(y);
}

// our idea is to return true if there is no appreciable skew or non-square scale
// for that we'll transform (0,1) and (1,0), and check that the resulting dot-prod
// is nearly one
static bool map_radius(const SkMatrix& matrix, SkScalar* value) {
    if (matrix.getType() & SkMatrix::kPerspective_Mask) {
        return false;
    }
    SkVector src[2], dst[2];
    src[0].set(*value, 0);
    src[1].set(0, *value);
    matrix.mapVectors(dst, src, 2);
    SkScalar len0 = fast_len(dst[0]);
    SkScalar len1 = fast_len(dst[1]);
    if (len0 < SK_Scalar1 && len1 < SK_Scalar1) {
        *value = SkScalarAve(len0, len1);
        return true;
    }
    return false;
}

void SkDraw::drawPath(const SkPath& origSrcPath, const SkPaint& paint,
                      const SkMatrix* prePathMatrix, bool pathIsMutable) const {
    SkDEBUGCODE(this->validate();)

    // nothing to draw
    if (fClip->isEmpty() ||
        (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    SkPath*         pathPtr = (SkPath*)&origSrcPath;
    bool            doFill = true;
    SkPath          tmpPath;
    SkMatrix        tmpMatrix;
    const SkMatrix* matrix = fMatrix;

    if (prePathMatrix) {
        if (paint.getPathEffect() || paint.getStyle() != SkPaint::kFill_Style ||
                paint.getRasterizer()) {
            SkPath* result = pathPtr;

            if (!pathIsMutable) {
                result = &tmpPath;
                pathIsMutable = true;
            }
            pathPtr->transform(*prePathMatrix, result);
            pathPtr = result;
        } else {
            if (!tmpMatrix.setConcat(*matrix, *prePathMatrix)) {
                // overflow
                return;
            }
            matrix = &tmpMatrix;
        }
    }
    // at this point we're done with prePathMatrix
    SkDEBUGCODE(prePathMatrix = (const SkMatrix*)0x50FF8001;)

    /*
        If the device thickness < 1.0, then make it a hairline, and
        modulate alpha if the thickness is even smaller (e.g. thickness == 0.5
        should modulate the alpha by 1/2)
    */

    SkAutoPaintRestoreColorStrokeWidth aprc(paint);

    // can we approximate a thin (but not hairline) stroke with an alpha-modulated
    // hairline? Only if the matrix scales evenly in X and Y, and the device-width is
    // less than a pixel
    if (paint.getStyle() == SkPaint::kStroke_Style && paint.getXfermode() == NULL) {
        SkScalar width = paint.getStrokeWidth();
        if (width > 0 && map_radius(*matrix, &width)) {
            int scale = (int)SkScalarMul(width, 256);
            int alpha = paint.getAlpha() * scale >> 8;

            // pretend to be a hairline, with a modulated alpha
            ((SkPaint*)&paint)->setAlpha(alpha);
            ((SkPaint*)&paint)->setStrokeWidth(0);
        }
    }

    if (paint.getPathEffect() || paint.getStyle() != SkPaint::kFill_Style) {
        doFill = paint.getFillPath(*pathPtr, &tmpPath);
        pathPtr = &tmpPath;
    }

    if (paint.getRasterizer()) {
        SkMask  mask;
        if (paint.getRasterizer()->rasterize(*pathPtr, *matrix,
                            &fClip->getBounds(), paint.getMaskFilter(), &mask,
                            SkMask::kComputeBoundsAndRenderImage_CreateMode)) {
            this->drawDevMask(mask, paint);
            SkMask::FreeImage(mask.fImage);
        }
        return;
    }

    // avoid possibly allocating a new path in transform if we can
    SkPath* devPathPtr = pathIsMutable ? pathPtr : &tmpPath;

    // transform the path into device space
    pathPtr->transform(*matrix, devPathPtr);

    SkAutoBlitterChoose blitter(*fBitmap, *fMatrix, paint);

    // how does filterPath() know to fill or hairline the path??? <mrr>
    if (paint.getMaskFilter() &&
            paint.getMaskFilter()->filterPath(*devPathPtr, *fMatrix, *fClip,
                                              fBounder, blitter.get())) {
        return; // filterPath() called the blitter, so we're done
    }

    if (fBounder && !fBounder->doPath(*devPathPtr, paint, doFill)) {
        return;
    }

    if (doFill) {
        if (paint.isAntiAlias()) {
            SkScan::AntiFillPath(*devPathPtr, *fClip, blitter.get());
        } else {
            SkScan::FillPath(*devPathPtr, *fClip, blitter.get());
        }
    } else {    // hairline
        if (paint.isAntiAlias()) {
            SkScan::AntiHairPath(*devPathPtr, fClip, blitter.get());
        } else {
            SkScan::HairPath(*devPathPtr, fClip, blitter.get());
        }
    }
}

/** For the purposes of drawing bitmaps, if a matrix is "almost" translate
    go ahead and treat it as if it were, so that subsequent code can go fast.
 */
static bool just_translate(const SkMatrix& matrix, const SkBitmap& bitmap) {
    SkMatrix::TypeMask mask = matrix.getType();

    if (mask & (SkMatrix::kAffine_Mask | SkMatrix::kPerspective_Mask)) {
        return false;
    }
    if (mask & SkMatrix::kScale_Mask) {
        SkScalar sx = matrix[SkMatrix::kMScaleX];
        SkScalar sy = matrix[SkMatrix::kMScaleY];
        int w = bitmap.width();
        int h = bitmap.height();
        int sw = SkScalarRound(SkScalarMul(sx, SkIntToScalar(w)));
        int sh = SkScalarRound(SkScalarMul(sy, SkIntToScalar(h)));
        return sw == w && sh == h;
    }
    // if we got here, we're either kTranslate_Mask or identity
    return true;
}

void SkDraw::drawBitmapAsMask(const SkBitmap& bitmap,
                              const SkPaint& paint) const {
    SkASSERT(bitmap.getConfig() == SkBitmap::kA8_Config);

    if (just_translate(*fMatrix, bitmap)) {
        int ix = SkScalarRound(fMatrix->getTranslateX());
        int iy = SkScalarRound(fMatrix->getTranslateY());

        SkMask  mask;
        mask.fBounds.set(ix, iy, ix + bitmap.width(), iy + bitmap.height());
        mask.fFormat = SkMask::kA8_Format;
        mask.fRowBytes = bitmap.rowBytes();
        mask.fImage = bitmap.getAddr8(0, 0);

        this->drawDevMask(mask, paint);
    } else {    // need to xform the bitmap first
        SkRect  r;
        SkMask  mask;

        r.set(0, 0,
              SkIntToScalar(bitmap.width()), SkIntToScalar(bitmap.height()));
        fMatrix->mapRect(&r);
        r.round(&mask.fBounds);

        // set the mask's bounds to the transformed bitmap-bounds,
        // clipped to the actual device
        {
            SkIRect    devBounds;
            devBounds.set(0, 0, fBitmap->width(), fBitmap->height());
            // need intersect(l, t, r, b) on irect
            if (!mask.fBounds.intersect(devBounds)) {
                return;
            }
        }

        mask.fFormat = SkMask::kA8_Format;
        mask.fRowBytes = SkAlign4(mask.fBounds.width());
        size_t size = mask.computeImageSize();
        if (0 == size) {
            // the mask is too big to allocated, draw nothing
            return;
        }

        // allocate (and clear) our temp buffer to hold the transformed bitmap
        SkAutoMalloc    storage(size);
        mask.fImage = (uint8_t*)storage.get();
        memset(mask.fImage, 0, size);

        // now draw our bitmap(src) into mask(dst), transformed by the matrix
        {
            SkBitmap    device;
            device.setConfig(SkBitmap::kA8_Config, mask.fBounds.width(),
                             mask.fBounds.height(), mask.fRowBytes);
            device.setPixels(mask.fImage);

            SkCanvas c(device);
            // need the unclipped top/left for the translate
            c.translate(-SkIntToScalar(mask.fBounds.fLeft),
                        -SkIntToScalar(mask.fBounds.fTop));
            c.concat(*fMatrix);

            // We can't call drawBitmap, or we'll infinitely recurse. Instead
            // we manually build a shader and draw that into our new mask
            SkPaint tmpPaint;
            tmpPaint.setFlags(paint.getFlags());
            SkAutoBitmapShaderInstall   install(bitmap, &tmpPaint);
            SkRect rr;
            rr.set(0, 0, SkIntToScalar(bitmap.width()),
                   SkIntToScalar(bitmap.height()));
            c.drawRect(rr, tmpPaint);
        }
        this->drawDevMask(mask, paint);
    }
}

static bool clipped_out(const SkMatrix& m, const SkRegion& c,
                        const SkRect& srcR) {
    SkRect  dstR;
    SkIRect devIR;

    m.mapRect(&dstR, srcR);
    dstR.roundOut(&devIR);
    return c.quickReject(devIR);
}

static bool clipped_out(const SkMatrix& matrix, const SkRegion& clip,
                        int width, int height) {
    SkRect  r;
    r.set(0, 0, SkIntToScalar(width), SkIntToScalar(height));
    return clipped_out(matrix, clip, r);
}

void SkDraw::drawBitmap(const SkBitmap& bitmap, const SkMatrix& prematrix,
                        const SkPaint& paint) const {
    SkDEBUGCODE(this->validate();)

    // nothing to draw
    if (fClip->isEmpty() ||
            bitmap.width() == 0 || bitmap.height() == 0 ||
            bitmap.getConfig() == SkBitmap::kNo_Config ||
            (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    // run away on too-big bitmaps for now (exceed 16.16)
    if (bitmap.width() > 32767 || bitmap.height() > 32767) {
        return;
    }

    SkAutoPaintStyleRestore restore(paint, SkPaint::kFill_Style);

    SkMatrix matrix;
    if (!matrix.setConcat(*fMatrix, prematrix)) {
        return;
    }

    if (clipped_out(matrix, *fClip, bitmap.width(), bitmap.height())) {
        return;
    }

    if (fBounder && just_translate(matrix, bitmap)) {
        SkIRect ir;
        int32_t ix = SkScalarRound(matrix.getTranslateX());
        int32_t iy = SkScalarRound(matrix.getTranslateY());
        ir.set(ix, iy, ix + bitmap.width(), iy + bitmap.height());
        if (!fBounder->doIRect(ir)) {
            return;
        }
    }

    // only lock the pixels if we passed the clip and bounder tests
    SkAutoLockPixels alp(bitmap);
    // after the lock, check if we are valid
    if (!bitmap.readyToDraw()) {
        return;
    }

    if (bitmap.getConfig() != SkBitmap::kA8_Config &&
            just_translate(matrix, bitmap)) {
        int         ix = SkScalarRound(matrix.getTranslateX());
        int         iy = SkScalarRound(matrix.getTranslateY());
        uint32_t    storage[kBlitterStorageLongCount];
        SkBlitter*  blitter = SkBlitter::ChooseSprite(*fBitmap, paint, bitmap,
                                            ix, iy, storage, sizeof(storage));
        if (blitter) {
            SkAutoTPlacementDelete<SkBlitter>   ad(blitter, storage);

            SkIRect    ir;
            ir.set(ix, iy, ix + bitmap.width(), iy + bitmap.height());

            SkRegion::Cliperator iter(*fClip, ir);
            const SkIRect&       cr = iter.rect();

            for (; !iter.done(); iter.next()) {
                SkASSERT(!cr.isEmpty());
                blitter->blitRect(cr.fLeft, cr.fTop, cr.width(), cr.height());
            }
            return;
        }
#if 0
        SkDebugf("---- MISSING sprite case: config=%d [%d %d], device=%d, xfer=%p, alpha=0x%X colorFilter=%p\n",
                bitmap.config(), bitmap.width(), bitmap.height(), fBitmap->config(),
                paint.getXfermode(), paint.getAlpha(), paint.getColorFilter());
#endif
    }

    // now make a temp draw on the stack, and use it
    //
    SkDraw draw(*this);
    draw.fMatrix = &matrix;

    if (bitmap.getConfig() == SkBitmap::kA8_Config) {
        draw.drawBitmapAsMask(bitmap, paint);
    } else {
        SkAutoBitmapShaderInstall   install(bitmap, &paint);

        SkRect  r;
        r.set(0, 0, SkIntToScalar(bitmap.width()),
              SkIntToScalar(bitmap.height()));
        // is this ok if paint has a rasterizer?
        draw.drawRect(r, paint);
    }
}

void SkDraw::drawSprite(const SkBitmap& bitmap, int x, int y,
                        const SkPaint& paint) const {
    SkDEBUGCODE(this->validate();)

    // nothing to draw
    if (fClip->isEmpty() ||
            bitmap.width() == 0 || bitmap.height() == 0 ||
            bitmap.getConfig() == SkBitmap::kNo_Config ||
            (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    SkIRect    bounds;
    bounds.set(x, y, x + bitmap.width(), y + bitmap.height());

    if (fClip->quickReject(bounds)) {
        return; // nothing to draw
    }

    SkAutoPaintStyleRestore restore(paint, SkPaint::kFill_Style);

    if (NULL == paint.getColorFilter()) {
        uint32_t    storage[kBlitterStorageLongCount];
        SkBlitter*  blitter = SkBlitter::ChooseSprite(*fBitmap, paint, bitmap,
                                                x, y, storage, sizeof(storage));

        if (blitter) {
            SkAutoTPlacementDelete<SkBlitter> ad(blitter, storage);

            if (fBounder && !fBounder->doIRect(bounds)) {
                return;
            }

            SkRegion::Cliperator iter(*fClip, bounds);
            const SkIRect&       cr = iter.rect();

            for (; !iter.done(); iter.next()) {
                SkASSERT(!cr.isEmpty());
                blitter->blitRect(cr.fLeft, cr.fTop, cr.width(), cr.height());
            }
            return;
        }
    }

    SkAutoBitmapShaderInstall   install(bitmap, &paint);

    SkMatrix        matrix;
    SkRect          r;

    // get a scalar version of our rect
    r.set(bounds);

    // tell the shader our offset
    matrix.setTranslate(r.fLeft, r.fTop);
    paint.getShader()->setLocalMatrix(matrix);

    SkDraw draw(*this);
    matrix.reset();
    draw.fMatrix = &matrix;
    // call ourself with a rect
    // is this OK if paint has a rasterizer?
    draw.drawRect(r, paint);
}

///////////////////////////////////////////////////////////////////////////////

#include "SkScalerContext.h"
#include "SkGlyphCache.h"
#include "SkUtils.h"

static void measure_text(SkGlyphCache* cache, SkDrawCacheProc glyphCacheProc,
                const char text[], size_t byteLength, SkVector* stopVector) {
    SkFixed     x = 0, y = 0;
    const char* stop = text + byteLength;

    SkAutoKern  autokern;

    while (text < stop) {
        // don't need x, y here, since all subpixel variants will have the
        // same advance
        const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);

        x += autokern.adjust(glyph) + glyph.fAdvanceX;
        y += glyph.fAdvanceY;
    }
    stopVector->set(SkFixedToScalar(x), SkFixedToScalar(y));

    SkASSERT(text == stop);
}

void SkDraw::drawText_asPaths(const char text[], size_t byteLength,
                              SkScalar x, SkScalar y,
                              const SkPaint& paint) const {
    SkDEBUGCODE(this->validate();)

    SkTextToPathIter iter(text, byteLength, paint, true, true);

    SkMatrix    matrix;
    matrix.setScale(iter.getPathScale(), iter.getPathScale());
    matrix.postTranslate(x, y);

    const SkPath* iterPath;
    SkScalar xpos, prevXPos = 0;

    while ((iterPath = iter.next(&xpos)) != NULL) {
        matrix.postTranslate(xpos - prevXPos, 0);
        this->drawPath(*iterPath, iter.getPaint(), &matrix, false);
        prevXPos = xpos;
    }
}

#define kStdStrikeThru_Offset       (-SK_Scalar1 * 6 / 21)
#define kStdUnderline_Offset        (SK_Scalar1 / 9)
#define kStdUnderline_Thickness     (SK_Scalar1 / 18)

static void draw_paint_rect(const SkDraw* draw, const SkPaint& paint,
                            const SkRect& r, SkScalar textSize) {
    if (paint.getStyle() == SkPaint::kFill_Style) {
        draw->drawRect(r, paint);
    } else {
        SkPaint p(paint);
        p.setStrokeWidth(SkScalarMul(textSize, paint.getStrokeWidth()));
        draw->drawRect(r, p);
    }
}

static void handle_aftertext(const SkDraw* draw, const SkPaint& paint,
                             SkScalar width, const SkPoint& start) {
    uint32_t flags = paint.getFlags();

    if (flags & (SkPaint::kUnderlineText_Flag |
                 SkPaint::kStrikeThruText_Flag)) {
        SkScalar textSize = paint.getTextSize();
        SkScalar height = SkScalarMul(textSize, kStdUnderline_Thickness);
        SkRect   r;

        r.fLeft = start.fX;
        r.fRight = start.fX + width;

        if (flags & SkPaint::kUnderlineText_Flag) {
            SkScalar offset = SkScalarMulAdd(textSize, kStdUnderline_Offset,
                                             start.fY);
            r.fTop = offset;
            r.fBottom = offset + height;
            draw_paint_rect(draw, paint, r, textSize);
        }
        if (flags & SkPaint::kStrikeThruText_Flag) {
            SkScalar offset = SkScalarMulAdd(textSize, kStdStrikeThru_Offset,
                                             start.fY);
            r.fTop = offset;
            r.fBottom = offset + height;
            draw_paint_rect(draw, paint, r, textSize);
        }
    }
}

// disable warning : local variable used without having been initialized
#if defined _WIN32 && _MSC_VER >= 1300
#pragma warning ( push )
#pragma warning ( disable : 4701 )
#endif

//////////////////////////////////////////////////////////////////////////////

static void D1G_NoBounder_RectClip(const SkDraw1Glyph& state,
								   const SkGlyph& glyph, int left, int top) {
    SkASSERT(glyph.fWidth > 0 && glyph.fHeight > 0);
	SkASSERT(state.fClip->isRect());
	SkASSERT(NULL == state.fBounder);
	SkASSERT(state.fClipBounds == state.fClip->getBounds());

    left += glyph.fLeft;
    top  += glyph.fTop;

    int right   = left + glyph.fWidth;
    int bottom  = top + glyph.fHeight;

	SkMask		mask;
	SkIRect		storage;
	SkIRect*	bounds = &mask.fBounds;

	mask.fBounds.set(left, top, right, bottom);

	// this extra test is worth it, assuming that most of the time it succeeds
	// since we can avoid writing to storage
	if (!state.fClipBounds.containsNoEmptyCheck(left, top, right, bottom)) {
		if (!storage.intersectNoEmptyCheck(mask.fBounds, state.fClipBounds))
			return;
		bounds = &storage;
	}

	uint8_t* aa = (uint8_t*)glyph.fImage;
	if (NULL == aa) {
		aa = (uint8_t*)state.fCache->findImage(glyph);
		if (NULL == aa) {
			return; // can't rasterize glyph
        }
	}

	mask.fRowBytes = glyph.rowBytes();
	mask.fFormat = static_cast<SkMask::Format>(glyph.fMaskFormat);
	mask.fImage = aa;
	state.fBlitter->blitMask(mask, *bounds);
}

static void D1G_NoBounder_RgnClip(const SkDraw1Glyph& state,
								  const SkGlyph& glyph, int left, int top) {
    SkASSERT(glyph.fWidth > 0 && glyph.fHeight > 0);
	SkASSERT(!state.fClip->isRect());
	SkASSERT(NULL == state.fBounder);

    SkMask  mask;

    left += glyph.fLeft;
    top  += glyph.fTop;

    mask.fBounds.set(left, top, left + glyph.fWidth, top + glyph.fHeight);
	SkRegion::Cliperator clipper(*state.fClip, mask.fBounds);

	if (!clipper.done()) {
		const SkIRect&  cr = clipper.rect();
		const uint8_t*  aa = (const uint8_t*)glyph.fImage;
		if (NULL == aa) {
			aa = (uint8_t*)state.fCache->findImage(glyph);
			if (NULL == aa) {
				return;
            }
		}

		mask.fRowBytes = glyph.rowBytes();
		mask.fFormat = static_cast<SkMask::Format>(glyph.fMaskFormat);
		mask.fImage = (uint8_t*)aa;
		do {
			state.fBlitter->blitMask(mask, cr);
			clipper.next();
		} while (!clipper.done());
	}
}

static void D1G_Bounder(const SkDraw1Glyph& state,
						const SkGlyph& glyph, int left, int top) {
    SkASSERT(glyph.fWidth > 0 && glyph.fHeight > 0);

    SkMask  mask;

    left += glyph.fLeft;
    top  += glyph.fTop;

    mask.fBounds.set(left, top, left + glyph.fWidth, top + glyph.fHeight);
    SkRegion::Cliperator clipper(*state.fClip, mask.fBounds);

	if (!clipper.done()) {
		const SkIRect&  cr = clipper.rect();
		const uint8_t*  aa = (const uint8_t*)glyph.fImage;
		if (NULL == aa) {
			aa = (uint8_t*)state.fCache->findImage(glyph);
			if (NULL == aa) {
				return;
            }
		}

        // we need to pass the origin, which we approximate with our
        // (unadjusted) left,top coordinates (the caller called fixedfloor)
		if (state.fBounder->doIRectGlyph(cr,
                                         left - glyph.fLeft,
                                         top - glyph.fTop, glyph)) {
			mask.fRowBytes = glyph.rowBytes();
			mask.fFormat = static_cast<SkMask::Format>(glyph.fMaskFormat);
			mask.fImage = (uint8_t*)aa;
			do {
				state.fBlitter->blitMask(mask, cr);
				clipper.next();
			} while (!clipper.done());
		}
	}
}

SkDraw1Glyph::Proc SkDraw1Glyph::init(const SkDraw* draw, SkBlitter* blitter,
                                      SkGlyphCache* cache) {
    fDraw = draw;
	fBounder = draw->fBounder;
	fClip = draw->fClip;
    fClipBounds = fClip->getBounds();
	fBlitter = blitter;
	fCache = cache;

    if (draw->fProcs && draw->fProcs->fD1GProc) {
        return draw->fProcs->fD1GProc;
    }

    if (NULL == fBounder) {
        if (fClip->isRect()) {
            return D1G_NoBounder_RectClip;
        } else {
            return D1G_NoBounder_RgnClip;
        }
    } else {
        return D1G_Bounder;
    }
}

enum RoundBaseline {
    kDont_Round_Baseline,
    kRound_X_Baseline,
    kRound_Y_Baseline
};

static RoundBaseline computeRoundBaseline(const SkMatrix& mat) {
    if (mat[1] == 0 && mat[3] == 0) {
        // we're 0 or 180 degrees, round the y coordinate of the baseline
        return kRound_Y_Baseline;
    } else if (mat[0] == 0 && mat[4] == 0) {
        // we're 90 or 270 degrees, round the x coordinate of the baseline
        return kRound_X_Baseline;
    } else {
        return kDont_Round_Baseline;
    }
}

///////////////////////////////////////////////////////////////////////////////

void SkDraw::drawText(const char text[], size_t byteLength,
                      SkScalar x, SkScalar y, const SkPaint& paint) const {
    SkASSERT(byteLength == 0 || text != NULL);

    SkDEBUGCODE(this->validate();)

    // nothing to draw
    if (text == NULL || byteLength == 0 ||
        fClip->isEmpty() ||
        (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    SkScalar    underlineWidth = 0;
    SkPoint     underlineStart;

    underlineStart.set(0, 0);    // to avoid warning
    if (paint.getFlags() & (SkPaint::kUnderlineText_Flag |
                            SkPaint::kStrikeThruText_Flag)) {
        underlineWidth = paint.measureText(text, byteLength);

        SkScalar offsetX = 0;
        if (paint.getTextAlign() == SkPaint::kCenter_Align) {
            offsetX = SkScalarHalf(underlineWidth);
        } else if (paint.getTextAlign() == SkPaint::kRight_Align) {
            offsetX = underlineWidth;
        }
        underlineStart.set(x - offsetX, y);
    }

    if (/*paint.isLinearText() ||*/
        (fMatrix->getType() & SkMatrix::kPerspective_Mask)) {
        this->drawText_asPaths(text, byteLength, x, y, paint);
        handle_aftertext(this, paint, underlineWidth, underlineStart);
        return;
    }

    SkDrawCacheProc glyphCacheProc = paint.getDrawCacheProc();

    SkAutoGlyphCache    autoCache(paint, fMatrix);
    SkGlyphCache*       cache = autoCache.getCache();
    SkAutoBlitterChoose blitter(*fBitmap, *fMatrix, paint);

    // transform our starting point
    {
        SkPoint loc;
        fMatrix->mapXY(x, y, &loc);
        x = loc.fX;
        y = loc.fY;
    }

    // need to measure first
    if (paint.getTextAlign() != SkPaint::kLeft_Align) {
        SkVector    stop;

        measure_text(cache, glyphCacheProc, text, byteLength, &stop);

        SkScalar    stopX = stop.fX;
        SkScalar    stopY = stop.fY;

        if (paint.getTextAlign() == SkPaint::kCenter_Align) {
            stopX = SkScalarHalf(stopX);
            stopY = SkScalarHalf(stopY);
        }
        x -= stopX;
        y -= stopY;
    }

    SkFixed fx = SkScalarToFixed(x);
    SkFixed fy = SkScalarToFixed(y);
    const char* stop = text + byteLength;

    if (paint.isSubpixelText()) {
        RoundBaseline roundBaseline = computeRoundBaseline(*fMatrix);
        if (kRound_Y_Baseline == roundBaseline) {
            fy = (fy + 0x8000) & ~0xFFFF;
        } else if (kRound_X_Baseline == roundBaseline) {
            fx = (fx + 0x8000) & ~0xFFFF;
        }
    } else {
        // apply the bias here, so we don't have to add 1/2 in the loop
        fx += SK_Fixed1/2;
        fy += SK_Fixed1/2;
    }

    SkAutoKern          autokern;
	SkDraw1Glyph        d1g;
	SkDraw1Glyph::Proc  proc = d1g.init(this, blitter.get(), cache);

    while (text < stop) {
        const SkGlyph& glyph  = glyphCacheProc(cache, &text, fx, fy);

        fx += autokern.adjust(glyph);

        if (glyph.fWidth) {
			proc(d1g, glyph, SkFixedFloor(fx), SkFixedFloor(fy));
        }
        fx += glyph.fAdvanceX;
        fy += glyph.fAdvanceY;
    }

    if (underlineWidth) {
        autoCache.release();    // release this now to free up the RAM
        handle_aftertext(this, paint, underlineWidth, underlineStart);
    }
}

// last parameter is interpreted as SkFixed [x, y]
// return the fixed position, which may be rounded or not by the caller
//   e.g. subpixel doesn't round
typedef void (*AlignProc)(const SkPoint&, const SkGlyph&, SkIPoint*);

static void leftAlignProc(const SkPoint& loc, const SkGlyph& glyph,
                          SkIPoint* dst) {
    dst->set(SkScalarToFixed(loc.fX), SkScalarToFixed(loc.fY));
}

static void centerAlignProc(const SkPoint& loc, const SkGlyph& glyph,
                            SkIPoint* dst) {
    dst->set(SkScalarToFixed(loc.fX) - (glyph.fAdvanceX >> 1),
             SkScalarToFixed(loc.fY) - (glyph.fAdvanceY >> 1));
}

static void rightAlignProc(const SkPoint& loc, const SkGlyph& glyph,
                           SkIPoint* dst) {
    dst->set(SkScalarToFixed(loc.fX) - glyph.fAdvanceX,
             SkScalarToFixed(loc.fY) - glyph.fAdvanceY);
}

static AlignProc pick_align_proc(SkPaint::Align align) {
    static const AlignProc gProcs[] = {
        leftAlignProc, centerAlignProc, rightAlignProc
    };

    SkASSERT((unsigned)align < SK_ARRAY_COUNT(gProcs));

    return gProcs[align];
}

class TextMapState {
public:
    mutable SkPoint fLoc;

    TextMapState(const SkMatrix& matrix, SkScalar y)
        : fMatrix(matrix), fProc(matrix.getMapXYProc()), fY(y) {}

    typedef void (*Proc)(const TextMapState&, const SkScalar pos[]);

    Proc pickProc(int scalarsPerPosition);

private:
    const SkMatrix&     fMatrix;
    SkMatrix::MapXYProc fProc;
    SkScalar            fY; // ignored by MapXYProc
    // these are only used by Only... procs
    SkScalar            fScaleX, fTransX, fTransformedY;

    static void MapXProc(const TextMapState& state, const SkScalar pos[]) {
        state.fProc(state.fMatrix, *pos, state.fY, &state.fLoc);
    }

    static void MapXYProc(const TextMapState& state, const SkScalar pos[]) {
        state.fProc(state.fMatrix, pos[0], pos[1], &state.fLoc);
    }

    static void MapOnlyScaleXProc(const TextMapState& state,
                                  const SkScalar pos[]) {
        state.fLoc.set(SkScalarMul(state.fScaleX, *pos) + state.fTransX,
                       state.fTransformedY);
    }

    static void MapOnlyTransXProc(const TextMapState& state,
                                  const SkScalar pos[]) {
        state.fLoc.set(*pos + state.fTransX, state.fTransformedY);
    }
};

TextMapState::Proc TextMapState::pickProc(int scalarsPerPosition) {
    SkASSERT(1 == scalarsPerPosition || 2 == scalarsPerPosition);

    if (1 == scalarsPerPosition) {
        unsigned mtype = fMatrix.getType();
        if (mtype & (SkMatrix::kAffine_Mask | SkMatrix::kPerspective_Mask)) {
            return MapXProc;
        } else {
            fScaleX = fMatrix.getScaleX();
            fTransX = fMatrix.getTranslateX();
            fTransformedY = SkScalarMul(fY, fMatrix.getScaleY()) +
                            fMatrix.getTranslateY();
            return (mtype & SkMatrix::kScale_Mask) ?
                        MapOnlyScaleXProc : MapOnlyTransXProc;
        }
    } else {
        return MapXYProc;
    }
}

//////////////////////////////////////////////////////////////////////////////

void SkDraw::drawPosText(const char text[], size_t byteLength,
                         const SkScalar pos[], SkScalar constY,
                         int scalarsPerPosition, const SkPaint& paint) const {
    SkASSERT(byteLength == 0 || text != NULL);
    SkASSERT(1 == scalarsPerPosition || 2 == scalarsPerPosition);

    SkDEBUGCODE(this->validate();)

    // nothing to draw
    if (text == NULL || byteLength == 0 ||
        fClip->isEmpty() ||
        (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    if (/*paint.isLinearText() ||*/
        (fMatrix->getType() & SkMatrix::kPerspective_Mask)) {
        // TODO !!!!
//      this->drawText_asPaths(text, byteLength, x, y, paint);
        return;
    }

    SkDrawCacheProc     glyphCacheProc = paint.getDrawCacheProc();
    SkAutoGlyphCache    autoCache(paint, fMatrix);
    SkGlyphCache*       cache = autoCache.getCache();
    SkAutoBlitterChoose blitter(*fBitmap, *fMatrix, paint);

    const char*        stop = text + byteLength;
    AlignProc          alignProc = pick_align_proc(paint.getTextAlign());
	SkDraw1Glyph	   d1g;
	SkDraw1Glyph::Proc  proc = d1g.init(this, blitter.get(), cache);
    TextMapState       tms(*fMatrix, constY);
    TextMapState::Proc tmsProc = tms.pickProc(scalarsPerPosition);

    if (paint.isSubpixelText()) {
        // maybe we should skip the rounding if linearText is set
        RoundBaseline roundBaseline = computeRoundBaseline(*fMatrix);

        if (SkPaint::kLeft_Align == paint.getTextAlign()) {
            while (text < stop) {
                tmsProc(tms, pos);

                SkFixed fx = SkScalarToFixed(tms.fLoc.fX);
                SkFixed fy = SkScalarToFixed(tms.fLoc.fY);

                if (kRound_Y_Baseline == roundBaseline) {
                    fy = (fy + 0x8000) & ~0xFFFF;
                } else if (kRound_X_Baseline == roundBaseline) {
                    fx = (fx + 0x8000) & ~0xFFFF;
                }

                const SkGlyph& glyph = glyphCacheProc(cache, &text, fx, fy);

                if (glyph.fWidth) {
                    proc(d1g, glyph, SkFixedFloor(fx), SkFixedFloor(fy));
                }
                pos += scalarsPerPosition;
            }
        } else {
            while (text < stop) {
                const SkGlyph* glyph = &glyphCacheProc(cache, &text, 0, 0);

                if (glyph->fWidth) {
                    SkDEBUGCODE(SkFixed prevAdvX = glyph->fAdvanceX;)
                    SkDEBUGCODE(SkFixed prevAdvY = glyph->fAdvanceY;)

                    SkFixed fx, fy;
                    tmsProc(tms, pos);

                    {
                        SkIPoint fixedLoc;
                        alignProc(tms.fLoc, *glyph, &fixedLoc);
                        fx = fixedLoc.fX;
                        fy = fixedLoc.fY;

                        if (kRound_Y_Baseline == roundBaseline) {
                            fy = (fy + 0x8000) & ~0xFFFF;
                        } else if (kRound_X_Baseline == roundBaseline) {
                            fx = (fx + 0x8000) & ~0xFFFF;
                        }
                    }

                    // have to call again, now that we've been "aligned"
                    glyph = &glyphCacheProc(cache, &text, fx, fy);
                    // the assumption is that the advance hasn't changed
                    SkASSERT(prevAdvX == glyph->fAdvanceX);
                    SkASSERT(prevAdvY == glyph->fAdvanceY);

                    proc(d1g, *glyph, SkFixedFloor(fx), SkFixedFloor(fy));
                }
                pos += scalarsPerPosition;
            }
        }
    } else {    // not subpixel
        while (text < stop) {
            // the last 2 parameters are ignored
            const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);

            if (glyph.fWidth) {
                tmsProc(tms, pos);

                SkIPoint fixedLoc;
                alignProc(tms.fLoc, glyph, &fixedLoc);

                proc(d1g, glyph,
                     SkFixedRound(fixedLoc.fX), SkFixedRound(fixedLoc.fY));
            }
            pos += scalarsPerPosition;
        }
    }
}

#if defined _WIN32 && _MSC_VER >= 1300
#pragma warning ( pop )
#endif

///////////////////////////////////////////////////////////////////////////////

#include "SkPathMeasure.h"

static void morphpoints(SkPoint dst[], const SkPoint src[], int count,
                        SkPathMeasure& meas, const SkMatrix& matrix) {
    SkMatrix::MapXYProc proc = matrix.getMapXYProc();

    for (int i = 0; i < count; i++) {
        SkPoint pos;
        SkVector tangent;

        proc(matrix, src[i].fX, src[i].fY, &pos);
        SkScalar sx = pos.fX;
        SkScalar sy = pos.fY;

        meas.getPosTan(sx, &pos, &tangent);

        /*  This is the old way (that explains our approach but is way too slow
            SkMatrix    matrix;
            SkPoint     pt;

            pt.set(sx, sy);
            matrix.setSinCos(tangent.fY, tangent.fX);
            matrix.preTranslate(-sx, 0);
            matrix.postTranslate(pos.fX, pos.fY);
            matrix.mapPoints(&dst[i], &pt, 1);
        */
        dst[i].set(pos.fX - SkScalarMul(tangent.fY, sy),
                   pos.fY + SkScalarMul(tangent.fX, sy));
    }
}

/*  TODO

    Need differentially more subdivisions when the follow-path is curvy. Not sure how to
    determine that, but we need it. I guess a cheap answer is let the caller tell us,
    but that seems like a cop-out. Another answer is to get Rob Johnson to figure it out.
*/
static void morphpath(SkPath* dst, const SkPath& src, SkPathMeasure& meas,
                      const SkMatrix& matrix) {
    SkPath::Iter    iter(src, false);
    SkPoint         srcP[4], dstP[3];
    SkPath::Verb    verb;

    while ((verb = iter.next(srcP)) != SkPath::kDone_Verb) {
        switch (verb) {
            case SkPath::kMove_Verb:
                morphpoints(dstP, srcP, 1, meas, matrix);
                dst->moveTo(dstP[0]);
                break;
            case SkPath::kLine_Verb:
                // turn lines into quads to look bendy
                srcP[0].fX = SkScalarAve(srcP[0].fX, srcP[1].fX);
                srcP[0].fY = SkScalarAve(srcP[0].fY, srcP[1].fY);
                morphpoints(dstP, srcP, 2, meas, matrix);
                dst->quadTo(dstP[0], dstP[1]);
                break;
            case SkPath::kQuad_Verb:
                morphpoints(dstP, &srcP[1], 2, meas, matrix);
                dst->quadTo(dstP[0], dstP[1]);
                break;
            case SkPath::kCubic_Verb:
                morphpoints(dstP, &srcP[1], 3, meas, matrix);
                dst->cubicTo(dstP[0], dstP[1], dstP[2]);
                break;
            case SkPath::kClose_Verb:
                dst->close();
                break;
            default:
                SkASSERT(!"unknown verb");
                break;
        }
    }
}

void SkDraw::drawTextOnPath(const char text[], size_t byteLength,
                            const SkPath& follow, const SkMatrix* matrix,
                            const SkPaint& paint) const {
    SkASSERT(byteLength == 0 || text != NULL);

    // nothing to draw
    if (text == NULL || byteLength == 0 ||
        fClip->isEmpty() ||
        (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    SkTextToPathIter    iter(text, byteLength, paint, true, true);
    SkPathMeasure       meas(follow, false);
    SkScalar            hOffset = 0;

    // need to measure first
    if (paint.getTextAlign() != SkPaint::kLeft_Align) {
        SkScalar pathLen = meas.getLength();
        if (paint.getTextAlign() == SkPaint::kCenter_Align) {
            pathLen = SkScalarHalf(pathLen);
        }
        hOffset += pathLen;
    }

    const SkPath*   iterPath;
    SkScalar        xpos;
    SkMatrix        scaledMatrix;
    SkScalar        scale = iter.getPathScale();

    scaledMatrix.setScale(scale, scale);

    while ((iterPath = iter.next(&xpos)) != NULL) {
        SkPath      tmp;
        SkMatrix    m(scaledMatrix);

        m.postTranslate(xpos + hOffset, 0);
        if (matrix) {
            m.postConcat(*matrix);
        }
        morphpath(&tmp, *iterPath, meas, m);
        this->drawPath(tmp, iter.getPaint());
    }
}

void SkDraw::drawPosTextOnPath(const char text[], size_t byteLength,
                               const SkPoint pos[], const SkPaint& paint,
                               const SkPath& path, const SkMatrix* matrix) const {
    // nothing to draw
    if (text == NULL || byteLength == 0 || fClip->isEmpty() ||
        (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    SkMatrix scaledMatrix;
    SkPathMeasure meas(path, false);

    SkMeasureCacheProc glyphCacheProc = paint.getMeasureCacheProc(
            SkPaint::kForward_TextBufferDirection, true);

    // Copied (modified) from SkTextToPathIter constructor to setup paint
    SkPaint tempPaint(paint);

    tempPaint.setLinearText(true);
    tempPaint.setMaskFilter(NULL); // don't want this affecting our path-cache lookup

    if (tempPaint.getPathEffect() == NULL && !(tempPaint.getStrokeWidth() > 0
            && tempPaint.getStyle() != SkPaint::kFill_Style)) {
        tempPaint.setStyle(SkPaint::kFill_Style);
        tempPaint.setPathEffect(NULL);
    }
    // End copied from SkTextToPathIter constructor

    // detach cache
    SkGlyphCache* cache = tempPaint.detachCache(NULL);

    // Must set scale, even if 1
    SkScalar scale = SK_Scalar1;
    scaledMatrix.setScale(scale, scale);

    // Loop over all glyph ids
    for (const char* stop = text + byteLength; text < stop; pos++) {

        const SkGlyph& glyph = glyphCacheProc(cache, &text);
        SkPath tmp;

        const SkPath* glyphPath = cache->findPath(glyph);
        if (glyphPath == NULL) {
            continue;
        }

        SkMatrix m(scaledMatrix);
        m.postTranslate(pos->fX, 0);

        if (matrix) {
            m.postConcat(*matrix);
        }

        morphpath(&tmp, *glyphPath, meas, m);
        this->drawPath(tmp, tempPaint);

    }

    // re-attach cache
    SkGlyphCache::AttachCache(cache);
}

///////////////////////////////////////////////////////////////////////////////

struct VertState {
    int f0, f1, f2;

    VertState(int vCount, const uint16_t indices[], int indexCount)
            : fIndices(indices) {
        fCurrIndex = 0;
        if (indices) {
            fCount = indexCount;
        } else {
            fCount = vCount;
        }
    }

    typedef bool (*Proc)(VertState*);
    Proc chooseProc(SkCanvas::VertexMode mode);

private:
    int             fCount;
    int             fCurrIndex;
    const uint16_t* fIndices;

    static bool Triangles(VertState*);
    static bool TrianglesX(VertState*);
    static bool TriangleStrip(VertState*);
    static bool TriangleStripX(VertState*);
    static bool TriangleFan(VertState*);
    static bool TriangleFanX(VertState*);
};

bool VertState::Triangles(VertState* state) {
    int index = state->fCurrIndex;
    if (index + 3 > state->fCount) {
        return false;
    }
    state->f0 = index + 0;
    state->f1 = index + 1;
    state->f2 = index + 2;
    state->fCurrIndex = index + 3;
    return true;
}

bool VertState::TrianglesX(VertState* state) {
    const uint16_t* indices = state->fIndices;
    int index = state->fCurrIndex;
    if (index + 3 > state->fCount) {
        return false;
    }
    state->f0 = indices[index + 0];
    state->f1 = indices[index + 1];
    state->f2 = indices[index + 2];
    state->fCurrIndex = index + 3;
    return true;
}

bool VertState::TriangleStrip(VertState* state) {
    int index = state->fCurrIndex;
    if (index + 3 > state->fCount) {
        return false;
    }
    state->f2 = index + 2;
    if (index & 1) {
        state->f0 = index + 1;
        state->f1 = index + 0;
    } else {
        state->f0 = index + 0;
        state->f1 = index + 1;
    }
    state->fCurrIndex = index + 1;
    return true;
}

bool VertState::TriangleStripX(VertState* state) {
    const uint16_t* indices = state->fIndices;
    int index = state->fCurrIndex;
    if (index + 3 > state->fCount) {
        return false;
    }
    state->f2 = indices[index + 2];
    if (index & 1) {
        state->f0 = indices[index + 1];
        state->f1 = indices[index + 0];
    } else {
        state->f0 = indices[index + 0];
        state->f1 = indices[index + 1];
    }
    state->fCurrIndex = index + 1;
    return true;
}

bool VertState::TriangleFan(VertState* state) {
    int index = state->fCurrIndex;
    if (index + 3 > state->fCount) {
        return false;
    }
    state->f0 = 0;
    state->f1 = index + 1;
    state->f2 = index + 2;
    state->fCurrIndex = index + 1;
    return true;
}

bool VertState::TriangleFanX(VertState* state) {
    const uint16_t* indices = state->fIndices;
    int index = state->fCurrIndex;
    if (index + 3 > state->fCount) {
        return false;
    }
    state->f0 = indices[0];
    state->f1 = indices[index + 1];
    state->f2 = indices[index + 2];
    state->fCurrIndex = index + 1;
    return true;
}

VertState::Proc VertState::chooseProc(SkCanvas::VertexMode mode) {
    switch (mode) {
        case SkCanvas::kTriangles_VertexMode:
            return fIndices ? TrianglesX : Triangles;
        case SkCanvas::kTriangleStrip_VertexMode:
            return fIndices ? TriangleStripX : TriangleStrip;
        case SkCanvas::kTriangleFan_VertexMode:
            return fIndices ? TriangleFanX : TriangleFan;
        default:
            return NULL;
    }
}

typedef void (*HairProc)(const SkPoint&, const SkPoint&, const SkRegion*,
                         SkBlitter*);

static HairProc ChooseHairProc(bool doAntiAlias) {
    return doAntiAlias ? SkScan::AntiHairLine : SkScan::HairLine;
}

static bool texture_to_matrix(const VertState& state, const SkPoint verts[],
                              const SkPoint texs[], SkMatrix* matrix) {
    SkPoint src[3], dst[3];

    src[0] = texs[state.f0];
    src[1] = texs[state.f1];
    src[2] = texs[state.f2];
    dst[0] = verts[state.f0];
    dst[1] = verts[state.f1];
    dst[2] = verts[state.f2];
    return matrix->setPolyToPoly(src, dst, 3);
}

class SkTriColorShader : public SkShader {
public:
    SkTriColorShader() {}

    bool setup(const SkPoint pts[], const SkColor colors[], int, int, int);

    virtual void shadeSpan(int x, int y, SkPMColor dstC[], int count);

protected:
    SkTriColorShader(SkFlattenableReadBuffer& buffer) : SkShader(buffer) {}

    virtual Factory getFactory() { return CreateProc; }

private:
    SkMatrix    fDstToUnit;
    SkPMColor   fColors[3];

    static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) {
        return SkNEW_ARGS(SkTriColorShader, (buffer));
    }
    typedef SkShader INHERITED;
};

bool SkTriColorShader::setup(const SkPoint pts[], const SkColor colors[],
                             int index0, int index1, int index2) {

    fColors[0] = SkPreMultiplyColor(colors[index0]);
    fColors[1] = SkPreMultiplyColor(colors[index1]);
    fColors[2] = SkPreMultiplyColor(colors[index2]);

    SkMatrix m, im;
    m.reset();
    m.set(0, pts[index1].fX - pts[index0].fX);
    m.set(1, pts[index2].fX - pts[index0].fX);
    m.set(2, pts[index0].fX);
    m.set(3, pts[index1].fY - pts[index0].fY);
    m.set(4, pts[index2].fY - pts[index0].fY);
    m.set(5, pts[index0].fY);
    if (!m.invert(&im)) {
        return false;
    }
    return fDstToUnit.setConcat(im, this->getTotalInverse());
}

#include "SkColorPriv.h"
#include "SkComposeShader.h"

static int ScalarTo256(SkScalar v) {
    int scale = SkScalarToFixed(v) >> 8;
    if (scale < 0) {
        scale = 0;
    }
    if (scale > 255) {
        scale = 255;
    }
    return SkAlpha255To256(scale);
}

void SkTriColorShader::shadeSpan(int x, int y, SkPMColor dstC[], int count) {
    SkPoint src;

    for (int i = 0; i < count; i++) {
        fDstToUnit.mapXY(SkIntToScalar(x), SkIntToScalar(y), &src);
        x += 1;

        int scale1 = ScalarTo256(src.fX);
        int scale2 = ScalarTo256(src.fY);
        int scale0 = 256 - scale1 - scale2;
        if (scale0 < 0) {
            if (scale1 > scale2) {
                scale2 = 256 - scale1;
            } else {
                scale1 = 256 - scale2;
            }
            scale0 = 0;
        }

        dstC[i] = SkAlphaMulQ(fColors[0], scale0) +
        SkAlphaMulQ(fColors[1], scale1) +
        SkAlphaMulQ(fColors[2], scale2);
    }
}

void SkDraw::drawVertices(SkCanvas::VertexMode vmode, int count,
                          const SkPoint vertices[], const SkPoint textures[],
                          const SkColor colors[], SkXfermode* xmode,
                          const uint16_t indices[], int indexCount,
                          const SkPaint& paint) const {
    SkASSERT(0 == count || NULL != vertices);

    // abort early if there is nothing to draw
    if (count < 3 || (indices && indexCount < 3) || fClip->isEmpty() ||
            (paint.getAlpha() == 0 && paint.getXfermode() == NULL)) {
        return;
    }

    // transform out vertices into device coordinates
    SkAutoSTMalloc<16, SkPoint> storage(count);
    SkPoint* devVerts = storage.get();
    fMatrix->mapPoints(devVerts, vertices, count);

    if (fBounder) {
        SkRect bounds;
        bounds.set(devVerts, count);
        if (!fBounder->doRect(bounds, paint)) {
            return;
        }
    }

    /*
        We can draw the vertices in 1 of 4 ways:

        - solid color (no shader/texture[], no colors[])
        - just colors (no shader/texture[], has colors[])
        - just texture (has shader/texture[], no colors[])
        - colors * texture (has shader/texture[], has colors[])

        Thus for texture drawing, we need both texture[] and a shader.
    */

    SkTriColorShader triShader; // must be above declaration of p
    SkPaint p(paint);

    SkShader* shader = p.getShader();
    if (NULL == shader) {
        // if we have no shader, we ignore the texture coordinates
        textures = NULL;
    } else if (NULL == textures) {
        // if we don't have texture coordinates, ignore the shader
        p.setShader(NULL);
        shader = NULL;
    }

    // setup the custom shader (if needed)
    if (NULL != colors) {
        if (NULL == textures) {
            // just colors (no texture)
            p.setShader(&triShader);
        } else {
            // colors * texture
            SkASSERT(shader);
            bool releaseMode = false;
            if (NULL == xmode) {
                xmode = SkXfermode::Create(SkXfermode::kMultiply_Mode);
                releaseMode = true;
            }
            SkShader* compose = SkNEW_ARGS(SkComposeShader,
                                           (&triShader, shader, xmode));
            p.setShader(compose)->unref();
            if (releaseMode) {
                xmode->unref();
            }
        }
    }

    SkAutoBlitterChoose blitter(*fBitmap, *fMatrix, p);
    // setup our state and function pointer for iterating triangles
    VertState       state(count, indices, indexCount);
    VertState::Proc vertProc = state.chooseProc(vmode);

    if (NULL != textures || NULL != colors) {
        SkMatrix  localM, tempM;
        bool      hasLocalM = shader && shader->getLocalMatrix(&localM);

        if (NULL != colors) {
            if (!triShader.setContext(*fBitmap, p, *fMatrix)) {
                colors = NULL;
            }
        }

        while (vertProc(&state)) {
            if (NULL != textures) {
                if (texture_to_matrix(state, vertices, textures, &tempM)) {
                    if (hasLocalM) {
                        tempM.postConcat(localM);
                    }
                    shader->setLocalMatrix(tempM);
                    // need to recal setContext since we changed the local matrix
                    if (!shader->setContext(*fBitmap, p, *fMatrix)) {
                        continue;
                    }
                }
            }
            if (NULL != colors) {
                if (!triShader.setup(vertices, colors,
                                     state.f0, state.f1, state.f2)) {
                    continue;
                }
            }
            SkScan::FillTriangle(devVerts[state.f0], devVerts[state.f1],
                                 devVerts[state.f2], fClip, blitter.get());
        }
        // now restore the shader's original local matrix
        if (NULL != shader) {
            if (hasLocalM) {
                shader->setLocalMatrix(localM);
            } else {
                shader->resetLocalMatrix();
            }
        }
    } else {
        // no colors[] and no texture
        HairProc hairProc = ChooseHairProc(paint.isAntiAlias());
        while (vertProc(&state)) {
            hairProc(devVerts[state.f0], devVerts[state.f1], fClip, blitter.get());
            hairProc(devVerts[state.f1], devVerts[state.f2], fClip, blitter.get());
            hairProc(devVerts[state.f2], devVerts[state.f0], fClip, blitter.get());
        }
    }
}

////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////

#ifdef SK_DEBUG

void SkDraw::validate() const {
    SkASSERT(fBitmap != NULL);
    SkASSERT(fMatrix != NULL);
    SkASSERT(fClip != NULL);

    const SkIRect&  cr = fClip->getBounds();
    SkIRect         br;

    br.set(0, 0, fBitmap->width(), fBitmap->height());
    SkASSERT(cr.isEmpty() || br.contains(cr));
}

#endif

//////////////////////////////////////////////////////////////////////////////////////////

bool SkBounder::doIRect(const SkIRect& r) {
    SkIRect    rr;
    return rr.intersect(fClip->getBounds(), r) && this->onIRect(rr);
}

// TODO: change the prototype to take fixed, and update the callers
bool SkBounder::doIRectGlyph(const SkIRect& r, int x, int y,
                             const SkGlyph& glyph) {
    SkIRect    rr;
    if (!rr.intersect(fClip->getBounds(), r)) {
        return false;
    }
    GlyphRec rec;
    rec.fLSB.set(SkIntToFixed(x), SkIntToFixed(y));
    rec.fRSB.set(rec.fLSB.fX + glyph.fAdvanceX,
                 rec.fLSB.fY + glyph.fAdvanceY);
    rec.fGlyphID = glyph.getGlyphID();
    rec.fFlags = 0;
    return this->onIRectGlyph(rr, rec);
}

bool SkBounder::doHairline(const SkPoint& pt0, const SkPoint& pt1,
                           const SkPaint& paint) {
    SkIRect     r;
    SkScalar    v0, v1;

    v0 = pt0.fX;
    v1 = pt1.fX;
    if (v0 > v1) {
        SkTSwap<SkScalar>(v0, v1);
    }
    r.fLeft     = SkScalarFloor(v0);
    r.fRight    = SkScalarCeil(v1);

    v0 = pt0.fY;
    v1 = pt1.fY;
    if (v0 > v1) {
        SkTSwap<SkScalar>(v0, v1);
    }
    r.fTop      = SkScalarFloor(v0);
    r.fBottom   = SkScalarCeil(v1);

    if (paint.isAntiAlias()) {
        r.inset(-1, -1);
    }
    return this->doIRect(r);
}

bool SkBounder::doRect(const SkRect& rect, const SkPaint& paint) {
    SkIRect    r;

    if (paint.getStyle() == SkPaint::kFill_Style) {
        rect.round(&r);
    } else {
        int rad = -1;
        rect.roundOut(&r);
        if (paint.isAntiAlias()) {
            rad = -2;
        }
        r.inset(rad, rad);
    }
    return this->doIRect(r);
}

bool SkBounder::doPath(const SkPath& path, const SkPaint& paint, bool doFill) {
    SkIRect       r;
    const SkRect& bounds = path.getBounds();

    if (doFill) {
        bounds.round(&r);
    } else {    // hairline
        bounds.roundOut(&r);
    }

    if (paint.isAntiAlias()) {
        r.inset(-1, -1);
    }
    return this->doIRect(r);
}

void SkBounder::commit() {
    // override in subclass
}

////////////////////////////////////////////////////////////////////////////////////////////////

#include "SkPath.h"
#include "SkDraw.h"
#include "SkRegion.h"
#include "SkBlitter.h"

static bool compute_bounds(const SkPath& devPath, const SkIRect* clipBounds,
                           SkMaskFilter* filter, const SkMatrix* filterMatrix,
                           SkIRect* bounds) {
    if (devPath.isEmpty()) {
        return false;
    }

    SkIPoint   margin;
    margin.set(0, 0);

    //  init our bounds from the path
    {
        SkRect pathBounds = devPath.getBounds();
        pathBounds.inset(-SK_ScalarHalf, -SK_ScalarHalf);
        pathBounds.roundOut(bounds);
    }

    if (filter) {
        SkASSERT(filterMatrix);

        SkMask  srcM, dstM;

        srcM.fBounds = *bounds;
        srcM.fFormat = SkMask::kA8_Format;
        srcM.fImage = NULL;
        if (!filter->filterMask(&dstM, srcM, *filterMatrix, &margin)) {
            return false;
        }
        *bounds = dstM.fBounds;
    }

    if (clipBounds && !SkIRect::Intersects(*clipBounds, *bounds)) {
        return false;
    }

    // (possibly) trim the srcM bounds to reflect the clip
    // (plus whatever slop the filter needs)
    if (clipBounds && !clipBounds->contains(*bounds)) {
        SkIRect tmp = *bounds;
        (void)tmp.intersect(*clipBounds);
        // Ugh. Guard against gigantic margins from wacky filters. Without this
        // check we can request arbitrary amounts of slop beyond our visible
        // clip, and bring down the renderer (at least on finite RAM machines
        // like handsets, etc.). Need to balance this invented value between
        // quality of large filters like blurs, and the corresponding memory
        // requests.
        static const int MAX_MARGIN = 128;
        tmp.inset(-SkMin32(margin.fX, MAX_MARGIN),
                  -SkMin32(margin.fY, MAX_MARGIN));
        (void)bounds->intersect(tmp);
    }

    return true;
}

static void draw_into_mask(const SkMask& mask, const SkPath& devPath) {
    SkBitmap    bm;
    SkDraw      draw;
    SkRegion    clipRgn;
    SkMatrix    matrix;
    SkPaint     paint;

    bm.setConfig(SkBitmap::kA8_Config, mask.fBounds.width(), mask.fBounds.height(), mask.fRowBytes);
    bm.setPixels(mask.fImage);

    clipRgn.setRect(0, 0, mask.fBounds.width(), mask.fBounds.height());
    matrix.setTranslate(-SkIntToScalar(mask.fBounds.fLeft),
                        -SkIntToScalar(mask.fBounds.fTop));

    draw.fBitmap    = &bm;
    draw.fClip      = &clipRgn;
    draw.fMatrix    = &matrix;
    draw.fBounder   = NULL;
    paint.setAntiAlias(true);
    draw.drawPath(devPath, paint);
}

bool SkDraw::DrawToMask(const SkPath& devPath, const SkIRect* clipBounds,
                        SkMaskFilter* filter, const SkMatrix* filterMatrix,
                        SkMask* mask, SkMask::CreateMode mode) {
    if (SkMask::kJustRenderImage_CreateMode != mode) {
        if (!compute_bounds(devPath, clipBounds, filter, filterMatrix, &mask->fBounds))
            return false;
    }

    if (SkMask::kComputeBoundsAndRenderImage_CreateMode == mode) {
        mask->fFormat = SkMask::kA8_Format;
        mask->fRowBytes = mask->fBounds.width();
        size_t size = mask->computeImageSize();
        if (0 == size) {
            // we're too big to allocate the mask, abort
            return false;
        }
        mask->fImage = SkMask::AllocImage(size);
        memset(mask->fImage, 0, mask->computeImageSize());
    }

    if (SkMask::kJustComputeBounds_CreateMode != mode) {
        draw_into_mask(*mask, devPath);
    }

    return true;
}