text: /*
   * Copyright 2014 Google Inc.
   *
   * Use of this source code is governed by a BSD-style license that can be
   * found in the LICENSE file.
   */
  
  #include "GrStencilAndCoverTextContext.h"
  #include "GrAtlasTextContext.h"
  #include "GrDrawContext.h"
  #include "GrDrawTarget.h"
  #include "GrPath.h"
  #include "GrPathRange.h"
  #include "GrResourceProvider.h"
  #include "SkAutoKern.h"
  #include "SkDraw.h"
  #include "SkDrawProcs.h"
  #include "SkGlyphCache.h"
  #include "SkGpuDevice.h"
  #include "SkGrPriv.h"
  #include "SkPath.h"
  #include "SkTextBlobRunIterator.h"
  #include "SkTextMapStateProc.h"
  #include "SkTextFormatParams.h"
  
  #include "batches/GrDrawPathBatch.h"
  
  template<typename Key, typename Val> static void delete_hash_map_entry(const Key&, Val* val) {
      SkASSERT(*val);
      delete *val;
  }
  
  template<typename T> static void delete_hash_table_entry(T* val) {
      SkASSERT(*val);
      delete *val;
  }
  
  GrStencilAndCoverTextContext::GrStencilAndCoverTextContext(GrContext* context,
                                                             const SkSurfaceProps& surfaceProps)
      : INHERITED(context, surfaceProps),
        fCacheSize(0) {
  }
  
  GrStencilAndCoverTextContext*
  GrStencilAndCoverTextContext::Create(GrContext* context, const SkSurfaceProps& surfaceProps) {
      GrStencilAndCoverTextContext* textContext = 
          new GrStencilAndCoverTextContext(context, surfaceProps);
      textContext->fFallbackTextContext = GrAtlasTextContext::Create(context, surfaceProps);
  
      return textContext;
  }
  
  GrStencilAndCoverTextContext::~GrStencilAndCoverTextContext() {
      fBlobIdCache.foreach(delete_hash_map_entry<uint32_t, TextBlob*>);
      fBlobKeyCache.foreach(delete_hash_table_entry<TextBlob*>);
  }
  
  bool GrStencilAndCoverTextContext::internalCanDraw(const SkPaint& skPaint) {
      if (skPaint.getRasterizer()) {
          return false;
      }
      if (skPaint.getMaskFilter()) {
          return false;
      }
      if (SkPathEffect* pe = skPaint.getPathEffect()) {
          if (pe->asADash(nullptr) != SkPathEffect::kDash_DashType) {
              return false;
          }
      }
      // No hairlines. They would require new paths with customized strokes for every new draw matrix.
      return SkPaint::kStroke_Style != skPaint.getStyle() || 0 != skPaint.getStrokeWidth();
  }
  
  void GrStencilAndCoverTextContext::onDrawText(GrDrawContext* dc,
                                                const GrClip& clip,
                                                const GrPaint& paint,
                                                const SkPaint& skPaint,
                                                const SkMatrix& viewMatrix,
                                                const char text[],
                                                size_t byteLength,
                                                SkScalar x, SkScalar y,
                                                const SkIRect& clipBounds) {
      TextRun run(skPaint);
      GrPipelineBuilder pipelineBuilder(paint, dc->accessRenderTarget(), clip);
      run.setText(text, byteLength, x, y);
      run.draw(fContext, dc, &pipelineBuilder, paint.getColor(), viewMatrix, 0, 0, clipBounds,
               fFallbackTextContext, skPaint);
  }
  
  void GrStencilAndCoverTextContext::onDrawPosText(GrDrawContext* dc,
                                                   const GrClip& clip,
                                                   const GrPaint& paint,
                                                   const SkPaint& skPaint,
                                                   const SkMatrix& viewMatrix,
                                                   const char text[],
                                                   size_t byteLength,
                                                   const SkScalar pos[],
                                                   int scalarsPerPosition,
                                                   const SkPoint& offset,
                                                   const SkIRect& clipBounds) {
      TextRun run(skPaint);
      GrPipelineBuilder pipelineBuilder(paint, dc->accessRenderTarget(), clip);
      run.setPosText(text, byteLength, pos, scalarsPerPosition, offset);
      run.draw(fContext, dc, &pipelineBuilder, paint.getColor(), viewMatrix, 0, 0, clipBounds,
               fFallbackTextContext, skPaint);
  }
  
  void GrStencilAndCoverTextContext::drawTextBlob(GrDrawContext* dc,
                                                  const GrClip& clip, const SkPaint& skPaint,
                                                  const SkMatrix& viewMatrix,
                                                  const SkTextBlob* skBlob, SkScalar x, SkScalar y,
                                                  SkDrawFilter* drawFilter,
                                                  const SkIRect& clipBounds) {
      if (!this->internalCanDraw(skPaint)) {
          fFallbackTextContext->drawTextBlob(dc, clip, skPaint, viewMatrix, skBlob, x, y,
                                             drawFilter, clipBounds);
          return;
      }
  
      if (drawFilter || skPaint.getPathEffect()) {
          // This draw can't be cached.
          INHERITED::drawTextBlob(dc, clip, skPaint, viewMatrix, skBlob, x, y, drawFilter,
                                  clipBounds);
          return;
      }
  
      if (fContext->abandoned()) {
          return;
      }
  
      GrPaint paint;
      if (!SkPaintToGrPaint(fContext, skPaint, viewMatrix, &paint)) {
          return;
      }
  
      const TextBlob& blob = this->findOrCreateTextBlob(skBlob, skPaint);
      GrPipelineBuilder pipelineBuilder(paint, dc->accessRenderTarget(), clip);
  
      TextBlob::Iter iter(blob);
      for (TextRun* run = iter.get(); run; run = iter.next()) {
          run->draw(fContext, dc, &pipelineBuilder, paint.getColor(), viewMatrix, x, y, clipBounds,
                    fFallbackTextContext, skPaint);
          run->releaseGlyphCache();
      }
  }
  
  const GrStencilAndCoverTextContext::TextBlob&
  GrStencilAndCoverTextContext::findOrCreateTextBlob(const SkTextBlob* skBlob,
                                                     const SkPaint& skPaint) {
      // The font-related parameters are baked into the text blob and will override this skPaint, so
      // the only remaining properties that can affect a TextBlob are the ones related to stroke.
      if (SkPaint::kFill_Style == skPaint.getStyle()) { // Fast path.
          if (TextBlob** found = fBlobIdCache.find(skBlob->uniqueID())) {
              fLRUList.remove(*found);
              fLRUList.addToTail(*found);
              return **found;
          }
          TextBlob* blob = new TextBlob(skBlob->uniqueID(), skBlob, skPaint);
          this->purgeToFit(*blob);
          fBlobIdCache.set(skBlob->uniqueID(), blob);
          fLRUList.addToTail(blob);
          fCacheSize += blob->cpuMemorySize();
          return *blob;
      } else {
          GrStrokeInfo stroke(skPaint);
          SkSTArray<4, uint32_t, true> key;
          key.reset(1 + stroke.computeUniqueKeyFragmentData32Cnt());
          key[0] = skBlob->uniqueID();
          stroke.asUniqueKeyFragment(&key[1]);
          if (TextBlob** found = fBlobKeyCache.find(key)) {
              fLRUList.remove(*found);
              fLRUList.addToTail(*found);
              return **found;
          }
          TextBlob* blob = new TextBlob(key, skBlob, skPaint);
          this->purgeToFit(*blob);
          fBlobKeyCache.set(blob);
          fLRUList.addToTail(blob);
          fCacheSize += blob->cpuMemorySize();
          return *blob;
      }
  }
  
  void GrStencilAndCoverTextContext::purgeToFit(const TextBlob& blob) {
      static const size_t maxCacheSize = 4 * 1024 * 1024; // Allow up to 4 MB for caching text blobs.
  
      size_t maxSizeForNewBlob = maxCacheSize - blob.cpuMemorySize();
      while (fCacheSize && fCacheSize > maxSizeForNewBlob) {
          TextBlob* lru = fLRUList.head();
          if (1 == lru->key().count()) {
              // 1-length keys are unterstood to be the blob id.
              fBlobIdCache.remove(lru->key()[0]);
          } else {
              fBlobKeyCache.remove(lru->key());
          }
          fLRUList.remove(lru);
          fCacheSize -= lru->cpuMemorySize();
          delete lru;
      }
  }
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  
  void GrStencilAndCoverTextContext::TextBlob::init(const SkTextBlob* skBlob,
                                                    const SkPaint& skPaint) {
      fCpuMemorySize = sizeof(TextBlob);
      SkPaint runPaint(skPaint);
      for (SkTextBlobRunIterator iter(skBlob); !iter.done(); iter.next()) {
          iter.applyFontToPaint(&runPaint); // No need to re-seed the paint.
          TextRun* run = this->addToTail(runPaint);
  
          const char* text = reinterpret_cast<const char*>(iter.glyphs());
          size_t byteLength = sizeof(uint16_t) * iter.glyphCount();
          const SkPoint& runOffset = iter.offset();
  
          switch (iter.positioning()) {
              case SkTextBlob::kDefault_Positioning:
                  run->setText(text, byteLength, runOffset.fX, runOffset.fY);
                  break;
              case SkTextBlob::kHorizontal_Positioning:
                  run->setPosText(text, byteLength, iter.pos(), 1, SkPoint::Make(0, runOffset.fY));
                  break;
              case SkTextBlob::kFull_Positioning:
                  run->setPosText(text, byteLength, iter.pos(), 2, SkPoint::Make(0, 0));
                  break;
          }
  
          fCpuMemorySize += run->computeSizeInCache();
      }
  }
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  
  class GrStencilAndCoverTextContext::FallbackBlobBuilder {
  public:
      FallbackBlobBuilder() : fBuffIdx(0), fCount(0) {}
  
      bool isInitialized() const { return SkToBool(fBuilder); }
  
      void init(const SkPaint& font, SkScalar textRatio);
  
      void appendGlyph(uint16_t glyphId, const SkPoint& pos);
  
      const SkTextBlob* buildIfNeeded(int* count);
  
  private:
      enum { kWriteBufferSize = 1024 };
  
      void flush();
  
      SkAutoTDelete<SkTextBlobBuilder>   fBuilder;
      SkPaint                            fFont;
      int                                fBuffIdx;
      int                                fCount;
      uint16_t                           fGlyphIds[kWriteBufferSize];
      SkPoint                            fPositions[kWriteBufferSize];
  };
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  
  GrStencilAndCoverTextContext::TextRun::TextRun(const SkPaint& fontAndStroke)
      : fStroke(fontAndStroke),
        fFont(fontAndStroke),
        fTotalGlyphCount(0),
        fFallbackGlyphCount(0),
        fDetachedGlyphCache(nullptr),
        fLastDrawnGlyphsID(SK_InvalidUniqueID) {
      SkASSERT(!fStroke.isHairlineStyle()); // Hairlines are not supported.
  
      // Setting to "fill" ensures that no strokes get baked into font outlines. (We use the GPU path
      // rendering API for stroking).
      fFont.setStyle(SkPaint::kFill_Style);
  
      if (fFont.isFakeBoldText() && SkStrokeRec::kStroke_Style != fStroke.getStyle()) {
          // Instead of letting fake bold get baked into the glyph outlines, do it with GPU stroke.
          SkScalar fakeBoldScale = SkScalarInterpFunc(fFont.getTextSize(),
                                                      kStdFakeBoldInterpKeys,
                                                      kStdFakeBoldInterpValues,
                                                      kStdFakeBoldInterpLength);
          SkScalar extra = SkScalarMul(fFont.getTextSize(), fakeBoldScale);
          fStroke.setStrokeStyle(fStroke.needToApply() ? fStroke.getWidth() + extra : extra,
                                 true /*strokeAndFill*/);
  
          fFont.setFakeBoldText(false);
      }
  
      if (!fFont.getPathEffect() && !fStroke.isDashed()) {
          // We can draw the glyphs from canonically sized paths.
          fTextRatio = fFont.getTextSize() / SkPaint::kCanonicalTextSizeForPaths;
          fTextInverseRatio = SkPaint::kCanonicalTextSizeForPaths / fFont.getTextSize();
  
          // Compensate for the glyphs being scaled by fTextRatio.
          if (!fStroke.isFillStyle()) {
              fStroke.setStrokeStyle(fStroke.getWidth() / fTextRatio,
                                     SkStrokeRec::kStrokeAndFill_Style == fStroke.getStyle());
          }
  
          fFont.setLinearText(true);
          fFont.setLCDRenderText(false);
          fFont.setAutohinted(false);
          fFont.setHinting(SkPaint::kNo_Hinting);
          fFont.setSubpixelText(true);
          fFont.setTextSize(SkIntToScalar(SkPaint::kCanonicalTextSizeForPaths));
  
          fUsingRawGlyphPaths = SK_Scalar1 == fFont.getTextScaleX() &&
                                0 == fFont.getTextSkewX() &&
                                !fFont.isFakeBoldText() &&
                                !fFont.isVerticalText();
      } else {
          fTextRatio = fTextInverseRatio = 1.0f;
          fUsingRawGlyphPaths = false;
      }
  
      // Generate the key that will be used to cache the GPU glyph path objects.
      if (fUsingRawGlyphPaths && fStroke.isFillStyle()) {
          static const GrUniqueKey::Domain kRawFillPathGlyphDomain = GrUniqueKey::GenerateDomain();
  
          const SkTypeface* typeface = fFont.getTypeface();
          GrUniqueKey::Builder builder(&fGlyphPathsKey, kRawFillPathGlyphDomain, 1);
          reinterpret_cast<uint32_t&>(builder[0]) = typeface ? typeface->uniqueID() : 0;
      } else {
          static const GrUniqueKey::Domain kPathGlyphDomain = GrUniqueKey::GenerateDomain();
  
          int strokeDataCount = fStroke.computeUniqueKeyFragmentData32Cnt();
          if (fUsingRawGlyphPaths) {
              const SkTypeface* typeface = fFont.getTypeface();
              GrUniqueKey::Builder builder(&fGlyphPathsKey, kPathGlyphDomain, 2 + strokeDataCount);
              reinterpret_cast<uint32_t&>(builder[0]) = typeface ? typeface->uniqueID() : 0;
              reinterpret_cast<uint32_t&>(builder[1]) = strokeDataCount;
              fStroke.asUniqueKeyFragment(&builder[2]);
          } else {
              SkGlyphCache* glyphCache = this->getGlyphCache();
              const SkTypeface* typeface = glyphCache->getScalerContext()->getTypeface();
              const SkDescriptor* desc = &glyphCache->getDescriptor();
              int descDataCount = (desc->getLength() + 3) / 4;
              GrUniqueKey::Builder builder(&fGlyphPathsKey, kPathGlyphDomain,
                                           2 + strokeDataCount + descDataCount);
              reinterpret_cast<uint32_t&>(builder[0]) = typeface ? typeface->uniqueID() : 0;
              reinterpret_cast<uint32_t&>(builder[1]) = strokeDataCount | (descDataCount << 16);
              fStroke.asUniqueKeyFragment(&builder[2]);
              memcpy(&builder[2 + strokeDataCount], desc, desc->getLength());
          }
      }
  }
  
  GrStencilAndCoverTextContext::TextRun::~TextRun() {
      this->releaseGlyphCache();
  }
  
  void GrStencilAndCoverTextContext::TextRun::setText(const char text[], size_t byteLength,
                                                      SkScalar x, SkScalar y) {
      SkASSERT(byteLength == 0 || text != nullptr);
  
      SkGlyphCache* glyphCache = this->getGlyphCache();
      SkDrawCacheProc glyphCacheProc = fFont.getDrawCacheProc();
  
      fTotalGlyphCount = fFont.countText(text, byteLength);
      fInstanceData.reset(InstanceData::Alloc(GrPathRendering::kTranslate_PathTransformType,
                                              fTotalGlyphCount));
  
      const char* stop = text + byteLength;
  
      // Measure first if needed.
      if (fFont.getTextAlign() != SkPaint::kLeft_Align) {
          SkFixed    stopX = 0;
          SkFixed    stopY = 0;
  
          const char* textPtr = text;
          while (textPtr < stop) {
              // We don't need x, y here, since all subpixel variants will have the
              // same advance.
              const SkGlyph& glyph = glyphCacheProc(glyphCache, &textPtr, 0, 0);
  
              stopX += glyph.fAdvanceX;
              stopY += glyph.fAdvanceY;
          }
          SkASSERT(textPtr == stop);
  
          SkScalar alignX = SkFixedToScalar(stopX) * fTextRatio;
          SkScalar alignY = SkFixedToScalar(stopY) * fTextRatio;
  
          if (fFont.getTextAlign() == SkPaint::kCenter_Align) {
              alignX = SkScalarHalf(alignX);
              alignY = SkScalarHalf(alignY);
          }
  
          x -= alignX;
          y -= alignY;
      }
  
      SkAutoKern autokern;
  
      SkFixed fixedSizeRatio = SkScalarToFixed(fTextRatio);
  
      SkFixed fx = SkScalarToFixed(x);
      SkFixed fy = SkScalarToFixed(y);
      FallbackBlobBuilder fallback;
      while (text < stop) {
          const SkGlyph& glyph = glyphCacheProc(glyphCache, &text, 0, 0);
          fx += SkFixedMul(autokern.adjust(glyph), fixedSizeRatio);
          if (glyph.fWidth) {
              this->appendGlyph(glyph, SkPoint::Make(SkFixedToScalar(fx), SkFixedToScalar(fy)),
                                &fallback);
          }
  
          fx += SkFixedMul(glyph.fAdvanceX, fixedSizeRatio);
          fy += SkFixedMul(glyph.fAdvanceY, fixedSizeRatio);
      }
  
      fFallbackTextBlob.reset(fallback.buildIfNeeded(&fFallbackGlyphCount));
  }
  
  void GrStencilAndCoverTextContext::TextRun::setPosText(const char text[], size_t byteLength,
                                                         const SkScalar pos[], int scalarsPerPosition,
                                                         const SkPoint& offset) {
      SkASSERT(byteLength == 0 || text != nullptr);
      SkASSERT(1 == scalarsPerPosition || 2 == scalarsPerPosition);
  
      SkGlyphCache* glyphCache = this->getGlyphCache();
      SkDrawCacheProc glyphCacheProc = fFont.getDrawCacheProc();
  
      fTotalGlyphCount = fFont.countText(text, byteLength);
      fInstanceData.reset(InstanceData::Alloc(GrPathRendering::kTranslate_PathTransformType,
                                              fTotalGlyphCount));
  
      const char* stop = text + byteLength;
  
      SkTextMapStateProc tmsProc(SkMatrix::I(), offset, scalarsPerPosition);
      SkTextAlignProc alignProc(fFont.getTextAlign());
      FallbackBlobBuilder fallback;
      while (text < stop) {
          const SkGlyph& glyph = glyphCacheProc(glyphCache, &text, 0, 0);
          if (glyph.fWidth) {
              SkPoint tmsLoc;
              tmsProc(pos, &tmsLoc);
              SkPoint loc;
              alignProc(tmsLoc, glyph, &loc);
  
              this->appendGlyph(glyph, loc, &fallback);
          }
          pos += scalarsPerPosition;
      }
  
      fFallbackTextBlob.reset(fallback.buildIfNeeded(&fFallbackGlyphCount));
  }
  
  GrPathRange* GrStencilAndCoverTextContext::TextRun::createGlyphs(GrContext* ctx) const {
      GrPathRange* glyphs = static_cast<GrPathRange*>(
              ctx->resourceProvider()->findAndRefResourceByUniqueKey(fGlyphPathsKey));
      if (nullptr == glyphs) {
          if (fUsingRawGlyphPaths) {
              glyphs = ctx->resourceProvider()->createGlyphs(fFont.getTypeface(), nullptr, fStroke);
          } else {
              SkGlyphCache* cache = this->getGlyphCache();
              glyphs = ctx->resourceProvider()->createGlyphs(cache->getScalerContext()->getTypeface(),
                                                             &cache->getDescriptor(),
                                                             fStroke);
          }
          ctx->resourceProvider()->assignUniqueKeyToResource(fGlyphPathsKey, glyphs);
      }
      return glyphs;
  }
  
  inline void GrStencilAndCoverTextContext::TextRun::appendGlyph(const SkGlyph& glyph,
                                                                 const SkPoint& pos,
                                                                 FallbackBlobBuilder* fallback) {
      // Stick the glyphs we can't draw into the fallback text blob.
      if (SkMask::kARGB32_Format == glyph.fMaskFormat) {
          if (!fallback->isInitialized()) {
              fallback->init(fFont, fTextRatio);
          }
          fallback->appendGlyph(glyph.getGlyphID(), pos);
      } else {
          fInstanceData->append(glyph.getGlyphID(), fTextInverseRatio * pos.x(),
                                fTextInverseRatio * pos.y());
      }
  }
  
  void GrStencilAndCoverTextContext::TextRun::draw(GrContext* ctx,
                                                   GrDrawContext* dc,
                                                   GrPipelineBuilder* pipelineBuilder,
                                                   GrColor color,
                                                   const SkMatrix& viewMatrix,
                                                   SkScalar x, SkScalar y,
                                                   const SkIRect& clipBounds,
                                                   GrTextContext* fallbackTextContext,
                                                   const SkPaint& originalSkPaint) const {
      SkASSERT(fInstanceData);
      SkASSERT(dc->accessRenderTarget()->isStencilBufferMultisampled() || !fFont.isAntiAlias());
  
      if (fInstanceData->count()) {
          pipelineBuilder->setState(GrPipelineBuilder::kHWAntialias_Flag, fFont.isAntiAlias());
  
          GR_STATIC_CONST_SAME_STENCIL(kStencilPass,
                                       kZero_StencilOp,
                                       kKeep_StencilOp,
                                       kNotEqual_StencilFunc,
                                       0xffff,
                                       0x0000,
                                       0xffff);
  
          *pipelineBuilder->stencil() = kStencilPass;
  
          SkAutoTUnref<GrPathRange> glyphs(this->createGlyphs(ctx));
          if (fLastDrawnGlyphsID != glyphs->getUniqueID()) {
              // Either this is the first draw or the glyphs object was purged since last draw.
              glyphs->loadPathsIfNeeded(fInstanceData->indices(), fInstanceData->count());
              fLastDrawnGlyphsID = glyphs->getUniqueID();
          }
  
          // Don't compute a bounding box. For dst copy texture, we'll opt instead for it to just copy
          // the entire dst. Realistically this is a moot point, because any context that supports
          // NV_path_rendering will also support NV_blend_equation_advanced.
          // For clipping we'll just skip any optimizations based on the bounds. This does, however,
          // hurt batching.
          SkRect bounds = SkRect::MakeIWH(pipelineBuilder->getRenderTarget()->width(),
                                          pipelineBuilder->getRenderTarget()->height());
  
          SkAutoTUnref<GrDrawPathBatchBase> batch(
              GrDrawPathRangeBatch::Create(viewMatrix, fTextRatio, fTextInverseRatio * x,
                                           fTextInverseRatio * y, color,
                                           GrPathRendering::kWinding_FillType, glyphs, fInstanceData,
                                           bounds));
  
          dc->drawPathBatch(*pipelineBuilder, batch);
      }
  
      if (fFallbackTextBlob) {
          SkPaint fallbackSkPaint(originalSkPaint);
          fStroke.applyToPaint(&fallbackSkPaint);
          if (!fStroke.isFillStyle()) {
              fallbackSkPaint.setStrokeWidth(fStroke.getWidth() * fTextRatio);
          }
  
          fallbackTextContext->drawTextBlob(dc, pipelineBuilder->clip(), fallbackSkPaint, viewMatrix,
                                            fFallbackTextBlob, x, y, nullptr, clipBounds);
      }
  }
  
  SkGlyphCache* GrStencilAndCoverTextContext::TextRun::getGlyphCache() const {
      if (!fDetachedGlyphCache) {
          fDetachedGlyphCache = fFont.detachCache(nullptr, nullptr, true /*ignoreGamma*/);
      }
      return fDetachedGlyphCache;
  }
  
  
  void GrStencilAndCoverTextContext::TextRun::releaseGlyphCache() const {
      if (fDetachedGlyphCache) {
          SkGlyphCache::AttachCache(fDetachedGlyphCache);
          fDetachedGlyphCache = nullptr;
      }
  }
  
  size_t GrStencilAndCoverTextContext::TextRun::computeSizeInCache() const {
      size_t size = sizeof(TextRun) + fGlyphPathsKey.size();
      // The instance data always reserves enough space for every glyph.
      size += (fTotalGlyphCount + fFallbackGlyphCount) * (sizeof(uint16_t) + 2 * sizeof(float));
      if (fInstanceData) {
          size += sizeof(InstanceData);
      }
      if (fFallbackTextBlob) {
          size += sizeof(SkTextBlob);
      }
      return size;
  }
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////
  
  void GrStencilAndCoverTextContext::FallbackBlobBuilder::init(const SkPaint& font,
                                                               SkScalar textRatio) {
      SkASSERT(!this->isInitialized());
      fBuilder.reset(new SkTextBlobBuilder);
      fFont = font;
      fFont.setTextAlign(SkPaint::kLeft_Align); // The glyph positions will already account for align.
      fFont.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
      // No need for subpixel positioning with bitmap glyphs. TODO: revisit if non-bitmap color glyphs
      // show up and https://code.google.com/p/skia/issues/detail?id=4408 gets resolved.
      fFont.setSubpixelText(false);
      fFont.setTextSize(fFont.getTextSize() * textRatio);
      fBuffIdx = 0;
  }
  
  void GrStencilAndCoverTextContext::FallbackBlobBuilder::appendGlyph(uint16_t glyphId,
                                                                      const SkPoint& pos) {
      SkASSERT(this->isInitialized());
      if (fBuffIdx >= kWriteBufferSize) {
          this->flush();
      }
      fGlyphIds[fBuffIdx] = glyphId;
      fPositions[fBuffIdx] = pos;
      fBuffIdx++;
      fCount++;
  }
  
  void GrStencilAndCoverTextContext::FallbackBlobBuilder::flush() {
      SkASSERT(this->isInitialized());
      SkASSERT(fBuffIdx <= kWriteBufferSize);
      if (!fBuffIdx) {
          return;
      }
      // This will automatically merge with previous runs since we use the same font.
      const SkTextBlobBuilder::RunBuffer& buff = fBuilder->allocRunPos(fFont, fBuffIdx);
      memcpy(buff.glyphs, fGlyphIds, fBuffIdx * sizeof(uint16_t));
      memcpy(buff.pos, fPositions[0].asScalars(), fBuffIdx * 2 * sizeof(SkScalar));
      fBuffIdx = 0;
  }
  
  const SkTextBlob* GrStencilAndCoverTextContext::FallbackBlobBuilder::buildIfNeeded(int *count) {
      *count = fCount;
      if (fCount) {
          this->flush();
          return fBuilder->build();
      }
      return nullptr;
  }
  