The Tor Browser: gfx/skia/trunk/src/core/SkScalerContext.cpp@6474c204b198 (annotated)

gfx/skia/trunk/src/core/SkScalerContext.cpp@6474c204b198 (annotated)

gfx/skia/trunk/src/core/SkScalerContext.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*
  * 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"
 #ifdef SK_BUILD_FOR_ANDROID
     #include "SkTypeface_android.h"
 #endif
 #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)))
     , fBaseGlyphCount(0)
     , 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)
     , fNextContext(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
 #ifdef SK_BUILD_FOR_ANDROID
     uint32_t len;
     const void* data = desc->findEntry(kAndroidOpts_SkDescriptorTag, &len);
     if (data) {
         SkReadBuffer buffer(data, len);
         fPaintOptionsAndroid.unflatten(buffer);
         SkASSERT(buffer.offset() == buffer.size());
     }
 #endif
 }
 SkScalerContext::~SkScalerContext() {
     SkDELETE(fNextContext);
     SkSafeUnref(fPathEffect);
     SkSafeUnref(fMaskFilter);
     SkSafeUnref(fRasterizer);
 }
 // Return the context associated with the next logical typeface, or NULL if
 // there are no more entries in the fallback chain.
 SkScalerContext* SkScalerContext::allocNextContext() const {
 #ifdef SK_BUILD_FOR_ANDROID
     SkTypeface* newFace = SkAndroidNextLogicalTypeface(fRec.fFontID,
                                                        fRec.fOrigFontID,
                                                        fPaintOptionsAndroid);
     if (0 == newFace) {
         return NULL;
     }
     SkAutoTUnref<SkTypeface> aur(newFace);
     uint32_t newFontID = newFace->uniqueID();
     SkWriteBuffer androidBuffer;
     fPaintOptionsAndroid.flatten(androidBuffer);
     SkAutoDescriptor    ad(sizeof(fRec) + androidBuffer.bytesWritten()
                            + SkDescriptor::ComputeOverhead(2));
     SkDescriptor*       desc = ad.getDesc();
     desc->init();
     SkScalerContext::Rec* newRec =
     (SkScalerContext::Rec*)desc->addEntry(kRec_SkDescriptorTag,
                                           sizeof(fRec), &fRec);
     androidBuffer.writeToMemory(desc->addEntry(kAndroidOpts_SkDescriptorTag,
                                                androidBuffer.bytesWritten(), NULL));
     newRec->fFontID = newFontID;
     desc->computeChecksum();
     return newFace->createScalerContext(desc);
 #else
     return NULL;
 #endif
 }
 /*  Return the next context, creating it if its not already created, but return
     NULL if the fonthost says there are no more fonts to fallback to.
  */
 SkScalerContext* SkScalerContext::getNextContext() {
     SkScalerContext* next = fNextContext;
     // if next is null, then either it isn't cached yet, or we're at the
     // end of our possible chain
     if (NULL == next) {
         next = this->allocNextContext();
         if (NULL == next) {
             return NULL;
         }
         // next's base is our base + our local count
         next->setBaseGlyphCount(fBaseGlyphCount + this->getGlyphCount());
         // cache the answer
         fNextContext = next;
     }
     return next;
 }
 SkScalerContext* SkScalerContext::getGlyphContext(const SkGlyph& glyph) {
     unsigned glyphID = glyph.getGlyphID();
     SkScalerContext* ctx = this;
     for (;;) {
         unsigned count = ctx->getGlyphCount();
         if (glyphID < count) {
             break;
         }
         glyphID -= count;
         ctx = ctx->getNextContext();
         if (NULL == ctx) {
 //            SkDebugf("--- no context for glyph %x\n", glyph.getGlyphID());
             // just return the original context (this)
             return this;
         }
     }
     return ctx;
 }
 SkScalerContext* SkScalerContext::getContextFromChar(SkUnichar uni,
                                                      uint16_t* glyphID) {
     SkScalerContext* ctx = this;
     for (;;) {
         const uint16_t glyph = ctx->generateCharToGlyph(uni);
         if (glyph) {
             if (NULL != glyphID) {
                 *glyphID = glyph;
             }
             break;  // found it
         }
         ctx = ctx->getNextContext();
         if (NULL == ctx) {
             return NULL;
         }
     }
     return ctx;
 }
 #ifdef SK_BUILD_FOR_ANDROID
 SkFontID SkScalerContext::findTypefaceIdForChar(SkUnichar uni) {
     SkScalerContext* ctx = this->getContextFromChar(uni, NULL);
     if (NULL != ctx) {
         return ctx->fRec.fFontID;
     } else {
         return 0;
     }
 }
 /*  This loops through all available fallback contexts (if needed) until it
     finds some context that can handle the unichar and return it.
     As this is somewhat expensive operation, it should only be done on the first
     char of a run.
  */
 unsigned SkScalerContext::getBaseGlyphCount(SkUnichar uni) {
     SkScalerContext* ctx = this->getContextFromChar(uni, NULL);
     if (NULL != ctx) {
         return ctx->fBaseGlyphCount;
     } else {
         SkDEBUGF(("--- no context for char %x\n", uni));
         return this->fBaseGlyphCount;
     }
 }
 #endif
 /*  This loops through all available fallback contexts (if needed) until it
     finds some context that can handle the unichar. If all fail, returns 0
  */
 uint16_t SkScalerContext::charToGlyphID(SkUnichar uni) {
     uint16_t tempID;
     SkScalerContext* ctx = this->getContextFromChar(uni, &tempID);
     if (NULL == ctx) {
         return 0; // no more contexts, return missing glyph
     }
     // add the ctx's base, making glyphID unique for chain of contexts
     unsigned glyphID = tempID + ctx->fBaseGlyphCount;
     // check for overflow of 16bits, since our glyphID cannot exceed that
     if (glyphID > 0xFFFF) {
         glyphID = 0;
     }
     return SkToU16(glyphID);
 }
 SkUnichar SkScalerContext::glyphIDToChar(uint16_t glyphID) {
     SkScalerContext* ctx = this;
     unsigned rangeEnd = 0;
     do {
         unsigned rangeStart = rangeEnd;
         rangeEnd += ctx->getGlyphCount();
         if (rangeStart <= glyphID && glyphID < rangeEnd) {
             return ctx->generateGlyphToChar(glyphID - rangeStart);
         }
         ctx = ctx->getNextContext();
     } while (NULL != ctx);
     return 0;
 }
 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
     this->getGlyphContext(*glyph)->generateAdvance(glyph);
 }
 void SkScalerContext::getMetrics(SkGlyph* glyph) {
     this->getGlyphContext(*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
             SkIRect ir;
             devPath.getBounds().roundOut(&ir);
             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:
                 case SkMask::kLCD32_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);
     }
 }
 template<bool APPLY_PREBLEND>
 static void pack4xHToLCD32(const SkBitmap& src, const SkMask& dst,
                            const SkMaskGamma::PreBlend& maskPreBlend) {
     SkASSERT(kAlpha_8_SkColorType == src.colorType());
     SkASSERT(SkMask::kLCD32_Format == dst.fFormat);
     const int width = dst.fBounds.width();
     const int height = dst.fBounds.height();
     SkPMColor* dstP = (SkPMColor*)dst.fImage;
     size_t dstRB = dst.fRowBytes;
     for (int y = 0; y < height; ++y) {
         const uint8_t* srcP = src.getAddr8(0, y);
         // TODO: need to use fir filter here as well.
         for (int x = 0; x < width; ++x) {
             U8CPU r = sk_apply_lut_if<APPLY_PREBLEND>(*srcP++, maskPreBlend.fR);
             U8CPU g = sk_apply_lut_if<APPLY_PREBLEND>(*srcP++, maskPreBlend.fG);
             U8CPU b = sk_apply_lut_if<APPLY_PREBLEND>(*srcP++, maskPreBlend.fB);
             dstP[x] = SkPackARGB32(0xFF, r, g, b);
         }
         dstP = (SkPMColor*)((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);
     const int srcPad = srcRB - width;
     SkASSERT(srcPad >= 0);
     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));
     SkBitmap::Config config = SkBitmap::kA8_Config;
     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:
         case SkMask::kLCD32_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));
     SkBitmap bm;
     bm.setConfig(config, dstW, dstH, dstRB);
     if (0 == dstRB) {
         if (!bm.allocPixels()) {
             // can't allocate offscreen, so empty the mask and return
             sk_bzero(mask.fImage, mask.computeImageSize());
             return;
         }
         bm.lockPixels();
     } else {
         bm.setPixels(mask.fImage);
     }
     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;
         case SkMask::kLCD32_Format:
             if (maskPreBlend.isApplicable()) {
                 pack4xHToLCD32<true>(bm, mask, maskPreBlend);
             } else {
                 pack4xHToLCD32<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 {
         this->getGlyphContext(*glyph)->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) {
     // All of this complexity should go away when we change generateFontMetrics
     // to just take one parameter (since it knows if it is vertical or not)
     SkPaint::FontMetrics* mx = NULL;
     SkPaint::FontMetrics* my = NULL;
     if (fRec.fFlags & kVertical_Flag) {
         mx = fm;
     } else {
         my = fm;
     }
     this->generateFontMetrics(mx, my);
 }
 SkUnichar SkScalerContext::generateGlyphToChar(uint16_t glyph) {
     return 0;
 }
 ///////////////////////////////////////////////////////////////////////////////
 void SkScalerContext::internalGetPath(const SkGlyph& glyph, SkPath* fillPath,
                                   SkPath* devPath, SkMatrix* fillToDevMatrix) {
     SkPath  path;
     this->getGlyphContext(glyph)->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,              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* mx,
                                      SkPaint::FontMetrics* my) SK_OVERRIDE {
         if (mx) {
             sk_bzero(mx, sizeof(*mx));
         }
         if (my) {
             sk_bzero(my, sizeof(*my));
         }
     }
 };
 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;
 }

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gfx/skia/trunk/src/core/SkScalerContext.cpp@6474c204b198 (annotated)

gfx/skia/trunk/src/core/SkScalerContext.cpp