|  | 
 | /* | 
 |  * Copyright 2006 The Android Open Source Project | 
 |  * | 
 |  * Use of this source code is governed by a BSD-style license that can be | 
 |  * found in the LICENSE file. | 
 |  */ | 
 |  | 
 |  | 
 | #include "SkScalerContext.h" | 
 | #include "SkColorPriv.h" | 
 | #include "SkDescriptor.h" | 
 | #include "SkDraw.h" | 
 | #include "SkFontHost.h" | 
 | #include "SkGlyph.h" | 
 | #include "SkMaskFilter.h" | 
 | #include "SkMaskGamma.h" | 
 | #include "SkReadBuffer.h" | 
 | #include "SkWriteBuffer.h" | 
 | #include "SkPathEffect.h" | 
 | #include "SkRasterizer.h" | 
 | #include "SkRasterClip.h" | 
 | #include "SkStroke.h" | 
 | #include "SkThread.h" | 
 |  | 
 | #define ComputeBWRowBytes(width)        (((unsigned)(width) + 7) >> 3) | 
 |  | 
 | void SkGlyph::toMask(SkMask* mask) const { | 
 |     SkASSERT(mask); | 
 |  | 
 |     mask->fImage = (uint8_t*)fImage; | 
 |     mask->fBounds.set(fLeft, fTop, fLeft + fWidth, fTop + fHeight); | 
 |     mask->fRowBytes = this->rowBytes(); | 
 |     mask->fFormat = static_cast<SkMask::Format>(fMaskFormat); | 
 | } | 
 |  | 
 | size_t SkGlyph::computeImageSize() const { | 
 |     const size_t size = this->rowBytes() * fHeight; | 
 |  | 
 |     switch (fMaskFormat) { | 
 |         case SkMask::k3D_Format: | 
 |             return 3 * size; | 
 |         default: | 
 |             return size; | 
 |     } | 
 | } | 
 |  | 
 | void SkGlyph::zeroMetrics() { | 
 |     fAdvanceX = 0; | 
 |     fAdvanceY = 0; | 
 |     fWidth    = 0; | 
 |     fHeight   = 0; | 
 |     fTop      = 0; | 
 |     fLeft     = 0; | 
 |     fRsbDelta = 0; | 
 |     fLsbDelta = 0; | 
 | } | 
 |  | 
 | /////////////////////////////////////////////////////////////////////////////// | 
 |  | 
 | #ifdef SK_DEBUG | 
 |     #define DUMP_RECx | 
 | #endif | 
 |  | 
 | static SkFlattenable* load_flattenable(const SkDescriptor* desc, uint32_t tag, | 
 |                                        SkFlattenable::Type ft) { | 
 |     SkFlattenable*  obj = NULL; | 
 |     uint32_t        len; | 
 |     const void*     data = desc->findEntry(tag, &len); | 
 |  | 
 |     if (data) { | 
 |         SkReadBuffer buffer(data, len); | 
 |         obj = buffer.readFlattenable(ft); | 
 |         SkASSERT(buffer.offset() == buffer.size()); | 
 |     } | 
 |     return obj; | 
 | } | 
 |  | 
 | SkScalerContext::SkScalerContext(SkTypeface* typeface, const SkDescriptor* desc) | 
 |     : fRec(*static_cast<const Rec*>(desc->findEntry(kRec_SkDescriptorTag, NULL))) | 
 |  | 
 |     , fTypeface(SkRef(typeface)) | 
 |     , fPathEffect(static_cast<SkPathEffect*>(load_flattenable(desc, kPathEffect_SkDescriptorTag, | 
 |                                              SkFlattenable::kSkPathEffect_Type))) | 
 |     , fMaskFilter(static_cast<SkMaskFilter*>(load_flattenable(desc, kMaskFilter_SkDescriptorTag, | 
 |                                              SkFlattenable::kSkMaskFilter_Type))) | 
 |     , fRasterizer(static_cast<SkRasterizer*>(load_flattenable(desc, kRasterizer_SkDescriptorTag, | 
 |                                              SkFlattenable::kSkRasterizer_Type))) | 
 |       // Initialize based on our settings. Subclasses can also force this. | 
 |     , fGenerateImageFromPath(fRec.fFrameWidth > 0 || fPathEffect != NULL || fRasterizer != NULL) | 
 |  | 
 |     , fPreBlend(fMaskFilter ? SkMaskGamma::PreBlend() : SkScalerContext::GetMaskPreBlend(fRec)) | 
 |     , fPreBlendForFilter(fMaskFilter ? SkScalerContext::GetMaskPreBlend(fRec) | 
 |                                      : SkMaskGamma::PreBlend()) | 
 | { | 
 | #ifdef DUMP_REC | 
 |     desc->assertChecksum(); | 
 |     SkDebugf("SkScalerContext checksum %x count %d length %d\n", | 
 |              desc->getChecksum(), desc->getCount(), desc->getLength()); | 
 |     SkDebugf(" textsize %g prescale %g preskew %g post [%g %g %g %g]\n", | 
 |         rec->fTextSize, rec->fPreScaleX, rec->fPreSkewX, rec->fPost2x2[0][0], | 
 |         rec->fPost2x2[0][1], rec->fPost2x2[1][0], rec->fPost2x2[1][1]); | 
 |     SkDebugf("  frame %g miter %g hints %d framefill %d format %d join %d\n", | 
 |         rec->fFrameWidth, rec->fMiterLimit, rec->fHints, rec->fFrameAndFill, | 
 |         rec->fMaskFormat, rec->fStrokeJoin); | 
 |     SkDebugf("  pathEffect %x maskFilter %x\n", | 
 |              desc->findEntry(kPathEffect_SkDescriptorTag, NULL), | 
 |         desc->findEntry(kMaskFilter_SkDescriptorTag, NULL)); | 
 | #endif | 
 | } | 
 |  | 
 | SkScalerContext::~SkScalerContext() { | 
 |     SkSafeUnref(fPathEffect); | 
 |     SkSafeUnref(fMaskFilter); | 
 |     SkSafeUnref(fRasterizer); | 
 | } | 
 |  | 
 | void SkScalerContext::getAdvance(SkGlyph* glyph) { | 
 |     // mark us as just having a valid advance | 
 |     glyph->fMaskFormat = MASK_FORMAT_JUST_ADVANCE; | 
 |     // we mark the format before making the call, in case the impl | 
 |     // internally ends up calling its generateMetrics, which is OK | 
 |     // albeit slower than strictly necessary | 
 |     generateAdvance(glyph); | 
 | } | 
 |  | 
 | void SkScalerContext::getMetrics(SkGlyph* glyph) { | 
 |     generateMetrics(glyph); | 
 |  | 
 |     // for now we have separate cache entries for devkerning on and off | 
 |     // in the future we might share caches, but make our measure/draw | 
 |     // code make the distinction. Thus we zap the values if the caller | 
 |     // has not asked for them. | 
 |     if ((fRec.fFlags & SkScalerContext::kDevKernText_Flag) == 0) { | 
 |         // no devkern, so zap the fields | 
 |         glyph->fLsbDelta = glyph->fRsbDelta = 0; | 
 |     } | 
 |  | 
 |     // if either dimension is empty, zap the image bounds of the glyph | 
 |     if (0 == glyph->fWidth || 0 == glyph->fHeight) { | 
 |         glyph->fWidth   = 0; | 
 |         glyph->fHeight  = 0; | 
 |         glyph->fTop     = 0; | 
 |         glyph->fLeft    = 0; | 
 |         glyph->fMaskFormat = 0; | 
 |         return; | 
 |     } | 
 |  | 
 |     if (fGenerateImageFromPath) { | 
 |         SkPath      devPath, fillPath; | 
 |         SkMatrix    fillToDevMatrix; | 
 |  | 
 |         this->internalGetPath(*glyph, &fillPath, &devPath, &fillToDevMatrix); | 
 |  | 
 |         if (fRasterizer) { | 
 |             SkMask  mask; | 
 |  | 
 |             if (fRasterizer->rasterize(fillPath, fillToDevMatrix, NULL, | 
 |                                        fMaskFilter, &mask, | 
 |                                        SkMask::kJustComputeBounds_CreateMode)) { | 
 |                 glyph->fLeft    = mask.fBounds.fLeft; | 
 |                 glyph->fTop     = mask.fBounds.fTop; | 
 |                 glyph->fWidth   = SkToU16(mask.fBounds.width()); | 
 |                 glyph->fHeight  = SkToU16(mask.fBounds.height()); | 
 |             } else { | 
 |                 goto SK_ERROR; | 
 |             } | 
 |         } else { | 
 |             // just use devPath | 
 |             const SkIRect ir = devPath.getBounds().roundOut(); | 
 |  | 
 |             if (ir.isEmpty() || !ir.is16Bit()) { | 
 |                 goto SK_ERROR; | 
 |             } | 
 |             glyph->fLeft    = ir.fLeft; | 
 |             glyph->fTop     = ir.fTop; | 
 |             glyph->fWidth   = SkToU16(ir.width()); | 
 |             glyph->fHeight  = SkToU16(ir.height()); | 
 |  | 
 |             if (glyph->fWidth > 0) { | 
 |                 switch (fRec.fMaskFormat) { | 
 |                 case SkMask::kLCD16_Format: | 
 |                     glyph->fWidth += 2; | 
 |                     glyph->fLeft -= 1; | 
 |                     break; | 
 |                 default: | 
 |                     break; | 
 |                 } | 
 |             } | 
 |         } | 
 |     } | 
 |  | 
 |     if (SkMask::kARGB32_Format != glyph->fMaskFormat) { | 
 |         glyph->fMaskFormat = fRec.fMaskFormat; | 
 |     } | 
 |  | 
 |     // If we are going to create the mask, then we cannot keep the color | 
 |     if ((fGenerateImageFromPath || fMaskFilter) && | 
 |             SkMask::kARGB32_Format == glyph->fMaskFormat) { | 
 |         glyph->fMaskFormat = SkMask::kA8_Format; | 
 |     } | 
 |  | 
 |     if (fMaskFilter) { | 
 |         SkMask      src, dst; | 
 |         SkMatrix    matrix; | 
 |  | 
 |         glyph->toMask(&src); | 
 |         fRec.getMatrixFrom2x2(&matrix); | 
 |  | 
 |         src.fImage = NULL;  // only want the bounds from the filter | 
 |         if (fMaskFilter->filterMask(&dst, src, matrix, NULL)) { | 
 |             if (dst.fBounds.isEmpty() || !dst.fBounds.is16Bit()) { | 
 |                 goto SK_ERROR; | 
 |             } | 
 |             SkASSERT(dst.fImage == NULL); | 
 |             glyph->fLeft    = dst.fBounds.fLeft; | 
 |             glyph->fTop     = dst.fBounds.fTop; | 
 |             glyph->fWidth   = SkToU16(dst.fBounds.width()); | 
 |             glyph->fHeight  = SkToU16(dst.fBounds.height()); | 
 |             glyph->fMaskFormat = dst.fFormat; | 
 |         } | 
 |     } | 
 |     return; | 
 |  | 
 | SK_ERROR: | 
 |     // draw nothing 'cause we failed | 
 |     glyph->fLeft    = 0; | 
 |     glyph->fTop     = 0; | 
 |     glyph->fWidth   = 0; | 
 |     glyph->fHeight  = 0; | 
 |     // put a valid value here, in case it was earlier set to | 
 |     // MASK_FORMAT_JUST_ADVANCE | 
 |     glyph->fMaskFormat = fRec.fMaskFormat; | 
 | } | 
 |  | 
 | #define SK_SHOW_TEXT_BLIT_COVERAGE 0 | 
 |  | 
 | static void applyLUTToA8Mask(const SkMask& mask, const uint8_t* lut) { | 
 |     uint8_t* SK_RESTRICT dst = (uint8_t*)mask.fImage; | 
 |     unsigned rowBytes = mask.fRowBytes; | 
 |  | 
 |     for (int y = mask.fBounds.height() - 1; y >= 0; --y) { | 
 |         for (int x = mask.fBounds.width() - 1; x >= 0; --x) { | 
 |             dst[x] = lut[dst[x]]; | 
 |         } | 
 |         dst += rowBytes; | 
 |     } | 
 | } | 
 |  | 
 | template<bool APPLY_PREBLEND> | 
 | static void pack4xHToLCD16(const SkBitmap& src, const SkMask& dst, | 
 |                            const SkMaskGamma::PreBlend& maskPreBlend) { | 
 | #define SAMPLES_PER_PIXEL 4 | 
 | #define LCD_PER_PIXEL 3 | 
 |     SkASSERT(kAlpha_8_SkColorType == src.colorType()); | 
 |     SkASSERT(SkMask::kLCD16_Format == dst.fFormat); | 
 |  | 
 |     const int sample_width = src.width(); | 
 |     const int height = src.height(); | 
 |  | 
 |     uint16_t* dstP = (uint16_t*)dst.fImage; | 
 |     size_t dstRB = dst.fRowBytes; | 
 |     // An N tap FIR is defined by | 
 |     // out[n] = coeff[0]*x[n] + coeff[1]*x[n-1] + ... + coeff[N]*x[n-N] | 
 |     // or | 
 |     // out[n] = sum(i, 0, N, coeff[i]*x[n-i]) | 
 |  | 
 |     // The strategy is to use one FIR (different coefficients) for each of r, g, and b. | 
 |     // This means using every 4th FIR output value of each FIR and discarding the rest. | 
 |     // The FIRs are aligned, and the coefficients reach 5 samples to each side of their 'center'. | 
 |     // (For r and b this is technically incorrect, but the coeffs outside round to zero anyway.) | 
 |  | 
 |     // These are in some fixed point repesentation. | 
 |     // Adding up to more than one simulates ink spread. | 
 |     // For implementation reasons, these should never add up to more than two. | 
 |  | 
 |     // Coefficients determined by a gausian where 5 samples = 3 std deviations (0x110 'contrast'). | 
 |     // Calculated using tools/generate_fir_coeff.py | 
 |     // With this one almost no fringing is ever seen, but it is imperceptibly blurry. | 
 |     // The lcd smoothed text is almost imperceptibly different from gray, | 
 |     // but is still sharper on small stems and small rounded corners than gray. | 
 |     // This also seems to be about as wide as one can get and only have a three pixel kernel. | 
 |     // TODO: caculate these at runtime so parameters can be adjusted (esp contrast). | 
 |     static const unsigned int coefficients[LCD_PER_PIXEL][SAMPLES_PER_PIXEL*3] = { | 
 |         //The red subpixel is centered inside the first sample (at 1/6 pixel), and is shifted. | 
 |         { 0x03, 0x0b, 0x1c, 0x33,  0x40, 0x39, 0x24, 0x10,  0x05, 0x01, 0x00, 0x00, }, | 
 |         //The green subpixel is centered between two samples (at 1/2 pixel), so is symetric | 
 |         { 0x00, 0x02, 0x08, 0x16,  0x2b, 0x3d, 0x3d, 0x2b,  0x16, 0x08, 0x02, 0x00, }, | 
 |         //The blue subpixel is centered inside the last sample (at 5/6 pixel), and is shifted. | 
 |         { 0x00, 0x00, 0x01, 0x05,  0x10, 0x24, 0x39, 0x40,  0x33, 0x1c, 0x0b, 0x03, }, | 
 |     }; | 
 |  | 
 |     for (int y = 0; y < height; ++y) { | 
 |         const uint8_t* srcP = src.getAddr8(0, y); | 
 |  | 
 |         // TODO: this fir filter implementation is straight forward, but slow. | 
 |         // It should be possible to make it much faster. | 
 |         for (int sample_x = -4, pixel_x = 0; sample_x < sample_width + 4; sample_x += 4, ++pixel_x) { | 
 |             int fir[LCD_PER_PIXEL] = { 0 }; | 
 |             for (int sample_index = SkMax32(0, sample_x - 4), coeff_index = sample_index - (sample_x - 4) | 
 |                 ; sample_index < SkMin32(sample_x + 8, sample_width) | 
 |                 ; ++sample_index, ++coeff_index) | 
 |             { | 
 |                 int sample_value = srcP[sample_index]; | 
 |                 for (int subpxl_index = 0; subpxl_index < LCD_PER_PIXEL; ++subpxl_index) { | 
 |                     fir[subpxl_index] += coefficients[subpxl_index][coeff_index] * sample_value; | 
 |                 } | 
 |             } | 
 |             for (int subpxl_index = 0; subpxl_index < LCD_PER_PIXEL; ++subpxl_index) { | 
 |                 fir[subpxl_index] /= 0x100; | 
 |                 fir[subpxl_index] = SkMin32(fir[subpxl_index], 255); | 
 |             } | 
 |  | 
 |             U8CPU r = sk_apply_lut_if<APPLY_PREBLEND>(fir[0], maskPreBlend.fR); | 
 |             U8CPU g = sk_apply_lut_if<APPLY_PREBLEND>(fir[1], maskPreBlend.fG); | 
 |             U8CPU b = sk_apply_lut_if<APPLY_PREBLEND>(fir[2], maskPreBlend.fB); | 
 | #if SK_SHOW_TEXT_BLIT_COVERAGE | 
 |             r = SkMax32(r, 10); g = SkMax32(g, 10); b = SkMax32(b, 10); | 
 | #endif | 
 |             dstP[pixel_x] = SkPack888ToRGB16(r, g, b); | 
 |         } | 
 |         dstP = (uint16_t*)((char*)dstP + dstRB); | 
 |     } | 
 | } | 
 |  | 
 | static inline int convert_8_to_1(unsigned byte) { | 
 |     SkASSERT(byte <= 0xFF); | 
 |     return byte >> 7; | 
 | } | 
 |  | 
 | static uint8_t pack_8_to_1(const uint8_t alpha[8]) { | 
 |     unsigned bits = 0; | 
 |     for (int i = 0; i < 8; ++i) { | 
 |         bits <<= 1; | 
 |         bits |= convert_8_to_1(alpha[i]); | 
 |     } | 
 |     return SkToU8(bits); | 
 | } | 
 |  | 
 | static void packA8ToA1(const SkMask& mask, const uint8_t* src, size_t srcRB) { | 
 |     const int height = mask.fBounds.height(); | 
 |     const int width = mask.fBounds.width(); | 
 |     const int octs = width >> 3; | 
 |     const int leftOverBits = width & 7; | 
 |  | 
 |     uint8_t* dst = mask.fImage; | 
 |     const int dstPad = mask.fRowBytes - SkAlign8(width)/8; | 
 |     SkASSERT(dstPad >= 0); | 
 |  | 
 |     SkASSERT(width >= 0); | 
 |     SkASSERT(srcRB >= (size_t)width); | 
 |     const size_t srcPad = srcRB - width; | 
 |  | 
 |     for (int y = 0; y < height; ++y) { | 
 |         for (int i = 0; i < octs; ++i) { | 
 |             *dst++ = pack_8_to_1(src); | 
 |             src += 8; | 
 |         } | 
 |         if (leftOverBits > 0) { | 
 |             unsigned bits = 0; | 
 |             int shift = 7; | 
 |             for (int i = 0; i < leftOverBits; ++i, --shift) { | 
 |                 bits |= convert_8_to_1(*src++) << shift; | 
 |             } | 
 |             *dst++ = bits; | 
 |         } | 
 |         src += srcPad; | 
 |         dst += dstPad; | 
 |     } | 
 | } | 
 |  | 
 | static void generateMask(const SkMask& mask, const SkPath& path, | 
 |                          const SkMaskGamma::PreBlend& maskPreBlend) { | 
 |     SkPaint paint; | 
 |  | 
 |     int srcW = mask.fBounds.width(); | 
 |     int srcH = mask.fBounds.height(); | 
 |     int dstW = srcW; | 
 |     int dstH = srcH; | 
 |     int dstRB = mask.fRowBytes; | 
 |  | 
 |     SkMatrix matrix; | 
 |     matrix.setTranslate(-SkIntToScalar(mask.fBounds.fLeft), | 
 |                         -SkIntToScalar(mask.fBounds.fTop)); | 
 |  | 
 |     paint.setAntiAlias(SkMask::kBW_Format != mask.fFormat); | 
 |     switch (mask.fFormat) { | 
 |         case SkMask::kBW_Format: | 
 |             dstRB = 0;  // signals we need a copy | 
 |             break; | 
 |         case SkMask::kA8_Format: | 
 |             break; | 
 |         case SkMask::kLCD16_Format: | 
 |             // TODO: trigger off LCD orientation | 
 |             dstW = 4*dstW - 8; | 
 |             matrix.setTranslate(-SkIntToScalar(mask.fBounds.fLeft + 1), | 
 |                                 -SkIntToScalar(mask.fBounds.fTop)); | 
 |             matrix.postScale(SkIntToScalar(4), SK_Scalar1); | 
 |             dstRB = 0;  // signals we need a copy | 
 |             break; | 
 |         default: | 
 |             SkDEBUGFAIL("unexpected mask format"); | 
 |     } | 
 |  | 
 |     SkRasterClip clip; | 
 |     clip.setRect(SkIRect::MakeWH(dstW, dstH)); | 
 |  | 
 |     const SkImageInfo info = SkImageInfo::MakeA8(dstW, dstH); | 
 |     SkBitmap bm; | 
 |  | 
 |     if (0 == dstRB) { | 
 |         if (!bm.tryAllocPixels(info)) { | 
 |             // can't allocate offscreen, so empty the mask and return | 
 |             sk_bzero(mask.fImage, mask.computeImageSize()); | 
 |             return; | 
 |         } | 
 |     } else { | 
 |         bm.installPixels(info, mask.fImage, dstRB); | 
 |     } | 
 |     sk_bzero(bm.getPixels(), bm.getSafeSize()); | 
 |  | 
 |     SkDraw  draw; | 
 |     draw.fRC    = &clip; | 
 |     draw.fClip  = &clip.bwRgn(); | 
 |     draw.fMatrix = &matrix; | 
 |     draw.fBitmap = &bm; | 
 |     draw.drawPath(path, paint); | 
 |  | 
 |     switch (mask.fFormat) { | 
 |         case SkMask::kBW_Format: | 
 |             packA8ToA1(mask, bm.getAddr8(0, 0), bm.rowBytes()); | 
 |             break; | 
 |         case SkMask::kA8_Format: | 
 |             if (maskPreBlend.isApplicable()) { | 
 |                 applyLUTToA8Mask(mask, maskPreBlend.fG); | 
 |             } | 
 |             break; | 
 |         case SkMask::kLCD16_Format: | 
 |             if (maskPreBlend.isApplicable()) { | 
 |                 pack4xHToLCD16<true>(bm, mask, maskPreBlend); | 
 |             } else { | 
 |                 pack4xHToLCD16<false>(bm, mask, maskPreBlend); | 
 |             } | 
 |             break; | 
 |         default: | 
 |             break; | 
 |     } | 
 | } | 
 |  | 
 | static void extract_alpha(const SkMask& dst, | 
 |                           const SkPMColor* srcRow, size_t srcRB) { | 
 |     int width = dst.fBounds.width(); | 
 |     int height = dst.fBounds.height(); | 
 |     int dstRB = dst.fRowBytes; | 
 |     uint8_t* dstRow = dst.fImage; | 
 |  | 
 |     for (int y = 0; y < height; ++y) { | 
 |         for (int x = 0; x < width; ++x) { | 
 |             dstRow[x] = SkGetPackedA32(srcRow[x]); | 
 |         } | 
 |         // zero any padding on each row | 
 |         for (int x = width; x < dstRB; ++x) { | 
 |             dstRow[x] = 0; | 
 |         } | 
 |         dstRow += dstRB; | 
 |         srcRow = (const SkPMColor*)((const char*)srcRow + srcRB); | 
 |     } | 
 | } | 
 |  | 
 | void SkScalerContext::getImage(const SkGlyph& origGlyph) { | 
 |     const SkGlyph*  glyph = &origGlyph; | 
 |     SkGlyph         tmpGlyph; | 
 |  | 
 |     // in case we need to call generateImage on a mask-format that is different | 
 |     // (i.e. larger) than what our caller allocated by looking at origGlyph. | 
 |     SkAutoMalloc tmpGlyphImageStorage; | 
 |  | 
 |     // If we are going to draw-from-path, then we cannot generate color, since | 
 |     // the path only makes a mask. This case should have been caught up in | 
 |     // generateMetrics(). | 
 |     SkASSERT(!fGenerateImageFromPath || | 
 |              SkMask::kARGB32_Format != origGlyph.fMaskFormat); | 
 |  | 
 |     if (fMaskFilter) {   // restore the prefilter bounds | 
 |         tmpGlyph.init(origGlyph.fID); | 
 |  | 
 |         // need the original bounds, sans our maskfilter | 
 |         SkMaskFilter* mf = fMaskFilter; | 
 |         fMaskFilter = NULL;             // temp disable | 
 |         this->getMetrics(&tmpGlyph); | 
 |         fMaskFilter = mf;               // restore | 
 |  | 
 |         // we need the prefilter bounds to be <= filter bounds | 
 |         SkASSERT(tmpGlyph.fWidth <= origGlyph.fWidth); | 
 |         SkASSERT(tmpGlyph.fHeight <= origGlyph.fHeight); | 
 |  | 
 |         if (tmpGlyph.fMaskFormat == origGlyph.fMaskFormat) { | 
 |             tmpGlyph.fImage = origGlyph.fImage; | 
 |         } else { | 
 |             tmpGlyphImageStorage.reset(tmpGlyph.computeImageSize()); | 
 |             tmpGlyph.fImage = tmpGlyphImageStorage.get(); | 
 |         } | 
 |         glyph = &tmpGlyph; | 
 |     } | 
 |  | 
 |     if (fGenerateImageFromPath) { | 
 |         SkPath      devPath, fillPath; | 
 |         SkMatrix    fillToDevMatrix; | 
 |         SkMask      mask; | 
 |  | 
 |         this->internalGetPath(*glyph, &fillPath, &devPath, &fillToDevMatrix); | 
 |         glyph->toMask(&mask); | 
 |  | 
 |         if (fRasterizer) { | 
 |             mask.fFormat = SkMask::kA8_Format; | 
 |             sk_bzero(glyph->fImage, mask.computeImageSize()); | 
 |  | 
 |             if (!fRasterizer->rasterize(fillPath, fillToDevMatrix, NULL, | 
 |                                         fMaskFilter, &mask, | 
 |                                         SkMask::kJustRenderImage_CreateMode)) { | 
 |                 return; | 
 |             } | 
 |             if (fPreBlend.isApplicable()) { | 
 |                 applyLUTToA8Mask(mask, fPreBlend.fG); | 
 |             } | 
 |         } else { | 
 |             SkASSERT(SkMask::kARGB32_Format != mask.fFormat); | 
 |             generateMask(mask, devPath, fPreBlend); | 
 |         } | 
 |     } else { | 
 |         generateImage(*glyph); | 
 |     } | 
 |  | 
 |     if (fMaskFilter) { | 
 |         SkMask      srcM, dstM; | 
 |         SkMatrix    matrix; | 
 |  | 
 |         // the src glyph image shouldn't be 3D | 
 |         SkASSERT(SkMask::k3D_Format != glyph->fMaskFormat); | 
 |  | 
 |         SkAutoSMalloc<32*32> a8storage; | 
 |         glyph->toMask(&srcM); | 
 |         if (SkMask::kARGB32_Format == srcM.fFormat) { | 
 |             // now we need to extract the alpha-channel from the glyph's image | 
 |             // and copy it into a temp buffer, and then point srcM at that temp. | 
 |             srcM.fFormat = SkMask::kA8_Format; | 
 |             srcM.fRowBytes = SkAlign4(srcM.fBounds.width()); | 
 |             size_t size = srcM.computeImageSize(); | 
 |             a8storage.reset(size); | 
 |             srcM.fImage = (uint8_t*)a8storage.get(); | 
 |             extract_alpha(srcM, | 
 |                           (const SkPMColor*)glyph->fImage, glyph->rowBytes()); | 
 |         } | 
 |  | 
 |         fRec.getMatrixFrom2x2(&matrix); | 
 |  | 
 |         if (fMaskFilter->filterMask(&dstM, srcM, matrix, NULL)) { | 
 |             int width = SkFastMin32(origGlyph.fWidth, dstM.fBounds.width()); | 
 |             int height = SkFastMin32(origGlyph.fHeight, dstM.fBounds.height()); | 
 |             int dstRB = origGlyph.rowBytes(); | 
 |             int srcRB = dstM.fRowBytes; | 
 |  | 
 |             const uint8_t* src = (const uint8_t*)dstM.fImage; | 
 |             uint8_t* dst = (uint8_t*)origGlyph.fImage; | 
 |  | 
 |             if (SkMask::k3D_Format == dstM.fFormat) { | 
 |                 // we have to copy 3 times as much | 
 |                 height *= 3; | 
 |             } | 
 |  | 
 |             // clean out our glyph, since it may be larger than dstM | 
 |             //sk_bzero(dst, height * dstRB); | 
 |  | 
 |             while (--height >= 0) { | 
 |                 memcpy(dst, src, width); | 
 |                 src += srcRB; | 
 |                 dst += dstRB; | 
 |             } | 
 |             SkMask::FreeImage(dstM.fImage); | 
 |  | 
 |             if (fPreBlendForFilter.isApplicable()) { | 
 |                 applyLUTToA8Mask(srcM, fPreBlendForFilter.fG); | 
 |             } | 
 |         } | 
 |     } | 
 | } | 
 |  | 
 | void SkScalerContext::getPath(const SkGlyph& glyph, SkPath* path) { | 
 |     this->internalGetPath(glyph, NULL, path, NULL); | 
 | } | 
 |  | 
 | void SkScalerContext::getFontMetrics(SkPaint::FontMetrics* fm) { | 
 |     this->generateFontMetrics(fm); | 
 | } | 
 |  | 
 | SkUnichar SkScalerContext::generateGlyphToChar(uint16_t glyph) { | 
 |     return 0; | 
 | } | 
 |  | 
 | /////////////////////////////////////////////////////////////////////////////// | 
 |  | 
 | void SkScalerContext::internalGetPath(const SkGlyph& glyph, SkPath* fillPath, | 
 |                                   SkPath* devPath, SkMatrix* fillToDevMatrix) { | 
 |     SkPath  path; | 
 |     generatePath(glyph, &path); | 
 |  | 
 |     if (fRec.fFlags & SkScalerContext::kSubpixelPositioning_Flag) { | 
 |         SkFixed dx = glyph.getSubXFixed(); | 
 |         SkFixed dy = glyph.getSubYFixed(); | 
 |         if (dx | dy) { | 
 |             path.offset(SkFixedToScalar(dx), SkFixedToScalar(dy)); | 
 |         } | 
 |     } | 
 |  | 
 |     if (fRec.fFrameWidth > 0 || fPathEffect != NULL) { | 
 |         // need the path in user-space, with only the point-size applied | 
 |         // so that our stroking and effects will operate the same way they | 
 |         // would if the user had extracted the path themself, and then | 
 |         // called drawPath | 
 |         SkPath      localPath; | 
 |         SkMatrix    matrix, inverse; | 
 |  | 
 |         fRec.getMatrixFrom2x2(&matrix); | 
 |         if (!matrix.invert(&inverse)) { | 
 |             // assume fillPath and devPath are already empty. | 
 |             return; | 
 |         } | 
 |         path.transform(inverse, &localPath); | 
 |         // now localPath is only affected by the paint settings, and not the canvas matrix | 
 |  | 
 |         SkStrokeRec rec(SkStrokeRec::kFill_InitStyle); | 
 |  | 
 |         if (fRec.fFrameWidth > 0) { | 
 |             rec.setStrokeStyle(fRec.fFrameWidth, | 
 |                                SkToBool(fRec.fFlags & kFrameAndFill_Flag)); | 
 |             // glyphs are always closed contours, so cap type is ignored, | 
 |             // so we just pass something. | 
 |             rec.setStrokeParams(SkPaint::kButt_Cap, | 
 |                                 (SkPaint::Join)fRec.fStrokeJoin, | 
 |                                 fRec.fMiterLimit); | 
 |         } | 
 |  | 
 |         if (fPathEffect) { | 
 |             SkPath effectPath; | 
 |             if (fPathEffect->filterPath(&effectPath, localPath, &rec, NULL)) { | 
 |                 localPath.swap(effectPath); | 
 |             } | 
 |         } | 
 |  | 
 |         if (rec.needToApply()) { | 
 |             SkPath strokePath; | 
 |             if (rec.applyToPath(&strokePath, localPath)) { | 
 |                 localPath.swap(strokePath); | 
 |             } | 
 |         } | 
 |  | 
 |         // now return stuff to the caller | 
 |         if (fillToDevMatrix) { | 
 |             *fillToDevMatrix = matrix; | 
 |         } | 
 |         if (devPath) { | 
 |             localPath.transform(matrix, devPath); | 
 |         } | 
 |         if (fillPath) { | 
 |             fillPath->swap(localPath); | 
 |         } | 
 |     } else {   // nothing tricky to do | 
 |         if (fillToDevMatrix) { | 
 |             fillToDevMatrix->reset(); | 
 |         } | 
 |         if (devPath) { | 
 |             if (fillPath == NULL) { | 
 |                 devPath->swap(path); | 
 |             } else { | 
 |                 *devPath = path; | 
 |             } | 
 |         } | 
 |  | 
 |         if (fillPath) { | 
 |             fillPath->swap(path); | 
 |         } | 
 |     } | 
 |  | 
 |     if (devPath) { | 
 |         devPath->updateBoundsCache(); | 
 |     } | 
 |     if (fillPath) { | 
 |         fillPath->updateBoundsCache(); | 
 |     } | 
 | } | 
 |  | 
 |  | 
 | void SkScalerContextRec::getMatrixFrom2x2(SkMatrix* dst) const { | 
 |     dst->setAll(fPost2x2[0][0], fPost2x2[0][1], 0, | 
 |                 fPost2x2[1][0], fPost2x2[1][1], 0, | 
 |                 0,              0,              SkScalarToPersp(SK_Scalar1)); | 
 | } | 
 |  | 
 | void SkScalerContextRec::getLocalMatrix(SkMatrix* m) const { | 
 |     SkPaint::SetTextMatrix(m, fTextSize, fPreScaleX, fPreSkewX); | 
 | } | 
 |  | 
 | void SkScalerContextRec::getSingleMatrix(SkMatrix* m) const { | 
 |     this->getLocalMatrix(m); | 
 |  | 
 |     //  now concat the device matrix | 
 |     SkMatrix    deviceMatrix; | 
 |     this->getMatrixFrom2x2(&deviceMatrix); | 
 |     m->postConcat(deviceMatrix); | 
 | } | 
 |  | 
 | SkAxisAlignment SkComputeAxisAlignmentForHText(const SkMatrix& matrix) { | 
 |     SkASSERT(!matrix.hasPerspective()); | 
 |  | 
 |     if (0 == matrix[SkMatrix::kMSkewY]) { | 
 |         return kX_SkAxisAlignment; | 
 |     } | 
 |     if (0 == matrix[SkMatrix::kMScaleX]) { | 
 |         return kY_SkAxisAlignment; | 
 |     } | 
 |     return kNone_SkAxisAlignment; | 
 | } | 
 |  | 
 | /////////////////////////////////////////////////////////////////////////////// | 
 |  | 
 | #include "SkFontHost.h" | 
 |  | 
 | class SkScalerContext_Empty : public SkScalerContext { | 
 | public: | 
 |     SkScalerContext_Empty(SkTypeface* face, const SkDescriptor* desc) | 
 |         : SkScalerContext(face, desc) {} | 
 |  | 
 | protected: | 
 |     virtual unsigned generateGlyphCount() SK_OVERRIDE { | 
 |         return 0; | 
 |     } | 
 |     virtual uint16_t generateCharToGlyph(SkUnichar uni) SK_OVERRIDE { | 
 |         return 0; | 
 |     } | 
 |     virtual void generateAdvance(SkGlyph* glyph) SK_OVERRIDE { | 
 |         glyph->zeroMetrics(); | 
 |     } | 
 |     virtual void generateMetrics(SkGlyph* glyph) SK_OVERRIDE { | 
 |         glyph->zeroMetrics(); | 
 |     } | 
 |     virtual void generateImage(const SkGlyph& glyph) SK_OVERRIDE {} | 
 |     virtual void generatePath(const SkGlyph& glyph, SkPath* path) SK_OVERRIDE {} | 
 |     virtual void generateFontMetrics(SkPaint::FontMetrics* metrics) SK_OVERRIDE { | 
 |         if (metrics) { | 
 |             sk_bzero(metrics, sizeof(*metrics)); | 
 |         } | 
 |     } | 
 | }; | 
 |  | 
 | extern SkScalerContext* SkCreateColorScalerContext(const SkDescriptor* desc); | 
 |  | 
 | SkScalerContext* SkTypeface::createScalerContext(const SkDescriptor* desc, | 
 |                                                  bool allowFailure) const { | 
 |     SkScalerContext* c = this->onCreateScalerContext(desc); | 
 |  | 
 |     if (!c && !allowFailure) { | 
 |         c = SkNEW_ARGS(SkScalerContext_Empty, | 
 |                        (const_cast<SkTypeface*>(this), desc)); | 
 |     } | 
 |     return c; | 
 | } |