Move blobalizer implementation to ShapeResultBloberizer

third_party/WebKit/Source/platform/fonts/shaping/ShapeResultBloberizer.cpp

Index: third_party/WebKit/Source/platform/fonts/shaping/ShapeResultBloberizer.cpp
diff --git a/third_party/WebKit/Source/platform/fonts/shaping/ShapeResultBloberizer.cpp b/third_party/WebKit/Source/platform/fonts/shaping/ShapeResultBloberizer.cpp
index f04be8e616aa1197b0f8fbfb90b5e51654e4a262..ad1a6b7ebac3fafde8e619a96584abdffa9caa9a 100644
--- a/third_party/WebKit/Source/platform/fonts/shaping/ShapeResultBloberizer.cpp
+++ b/third_party/WebKit/Source/platform/fonts/shaping/ShapeResultBloberizer.cpp
@@ -4,8 +4,12 @@
 
 #include "platform/fonts/shaping/ShapeResultBloberizer.h"
 
+#include <hb.h>
 #include "platform/fonts/Font.h"
 #include "platform/fonts/shaping/CachingWordShaper.h"
+#include "platform/fonts/shaping/ShapeResult.h"
+#include "platform/fonts/shaping/ShapeResultInlineHeaders.h"
+#include "platform/text/TextBreakIterator.h"
 #include "platform/text/TextRun.h"
 
 namespace blink {
@@ -81,4 +85,285 @@ ShapeResultBloberizer::BlobRotation ShapeResultBloberizer::GetBlobRotation(
              : BlobRotation::kNoRotation;
 }
 
+float ShapeResultBloberizer::FillGlyphs(
+    const TextRunPaintInfo& run_info,
+    const ShapeResultBuffer& result_buffer) {
+  // Fast path: full run with no vertical offsets, no text intercepts.
+  if (!run_info.from && run_info.to == run_info.run.length() &&
+      !result_buffer.HasVerticalOffsets() &&
+      GetType() != ShapeResultBloberizer::Type::kTextIntercepts) {
+    return FillFastHorizontalGlyphs(result_buffer, run_info.run);
+  }
+
+  float advance = 0;
+  auto results = result_buffer.results_;
+
+  if (run_info.run.Rtl()) {
+    unsigned word_offset = run_info.run.length();
+    for (unsigned j = 0; j < results.size(); j++) {
+      unsigned resolved_index = results.size() - 1 - j;
+      const RefPtr<const ShapeResult>& word_result = results[resolved_index];
+      word_offset -= word_result->NumCharacters();
+      advance =
+          FillGlyphsForResult(*word_result, run_info, advance, word_offset);
+    }
+  } else {
+    unsigned word_offset = 0;
+    for (const auto& word_result : results) {
+      advance =
+          FillGlyphsForResult(*word_result, run_info, advance, word_offset);
+      word_offset += word_result->NumCharacters();
+    }
+  }
+
+  return advance;
+}
+
+void ShapeResultBloberizer::FillTextEmphasisGlyphs(
+    const TextRunPaintInfo& run_info,
+    const GlyphData& emphasis_data,
+    const ShapeResultBuffer& result_buffer) {
+  float advance = 0;
+  unsigned word_offset = run_info.run.Rtl() ? run_info.run.length() : 0;
+  auto results = result_buffer.results_;
+
+  for (unsigned j = 0; j < results.size(); j++) {
+    unsigned resolved_index = run_info.run.Rtl() ? results.size() - 1 - j : j;
+    const RefPtr<const ShapeResult>& word_result = results[resolved_index];
+    for (unsigned i = 0; i < word_result->runs_.size(); i++) {
+      unsigned resolved_offset =
+          word_offset - (run_info.run.Rtl() ? word_result->NumCharacters() : 0);
+      advance +=
+          FillTextEmphasisGlyphsForRun(word_result->runs_[i].get(), run_info,
+                                       emphasis_data, advance, resolved_offset);
+    }
+    word_offset += word_result->NumCharacters() * (run_info.run.Rtl() ? -1 : 1);
+  }
+}
+
+namespace {
+
+inline bool IsSkipInkException(const ShapeResultBloberizer& bloberizer,
+                               const TextRun& run,
+                               unsigned character_index) {
+  // We want to skip descenders in general, but it is undesirable renderings for
+  // CJK characters.
+  return bloberizer.GetType() == ShapeResultBloberizer::Type::kTextIntercepts &&
+         !run.Is8Bit() &&
+         Character::IsCJKIdeographOrSymbol(run.CodepointAt(character_index));
+}
+
+inline void AddGlyphToBloberizer(ShapeResultBloberizer& bloberizer,
+                                 float advance,
+                                 hb_direction_t direction,
+                                 const SimpleFontData* font_data,
+                                 const HarfBuzzRunGlyphData& glyph_data,
+                                 const TextRun& run,
+                                 unsigned character_index) {
+  FloatPoint start_offset = HB_DIRECTION_IS_HORIZONTAL(direction)
+                                ? FloatPoint(advance, 0)
+                                : FloatPoint(0, advance);
+  if (!IsSkipInkException(bloberizer, run, character_index)) {
+    bloberizer.Add(glyph_data.glyph, font_data,
+                   start_offset + glyph_data.offset);
+  }
+}
+
+inline void AddEmphasisMark(ShapeResultBloberizer& bloberizer,
+                            const GlyphData& emphasis_data,
+                            FloatPoint glyph_center,
+                            float mid_glyph_offset) {
+  const SimpleFontData* emphasis_font_data = emphasis_data.font_data;
+  DCHECK(emphasis_font_data);
+
+  bool is_vertical =
+      emphasis_font_data->PlatformData().IsVerticalAnyUpright() &&
+      emphasis_font_data->VerticalData();
+
+  if (!is_vertical) {
+    bloberizer.Add(emphasis_data.glyph, emphasis_font_data,
+                   mid_glyph_offset - glyph_center.X());
+  } else {
+    bloberizer.Add(
+        emphasis_data.glyph, emphasis_font_data,
+        FloatPoint(-glyph_center.X(), mid_glyph_offset - glyph_center.Y()));
+  }
+}
+
+inline unsigned CountGraphemesInCluster(const UChar* str,
+                                        unsigned str_length,
+                                        uint16_t start_index,
+                                        uint16_t end_index) {
+  if (start_index > end_index) {
+    uint16_t temp_index = start_index;
+    start_index = end_index;
+    end_index = temp_index;
+  }
+  uint16_t length = end_index - start_index;
+  DCHECK_LE(static_cast<unsigned>(start_index + length), str_length);
+  TextBreakIterator* cursor_pos_iterator =
+      CursorMovementIterator(&str[start_index], length);
+
+  int cursor_pos = cursor_pos_iterator->current();
+  int num_graphemes = -1;
+  while (0 <= cursor_pos) {
+    cursor_pos = cursor_pos_iterator->next();
+    num_graphemes++;
+  }
+  return std::max(0, num_graphemes);
+}
+
+}  // namespace
+
+float ShapeResultBloberizer::FillGlyphsForResult(
+    const ShapeResult& result,
+    const TextRunPaintInfo& run_info,
+    float initial_advance,
+    unsigned run_offset) {
+  auto total_advance = initial_advance;
+
+  for (const auto& run : result.runs_) {
+    total_advance = run->ForEachGlyphInRange(
+        total_advance, run_info.from, run_info.to, run_offset,
+        [&](const HarfBuzzRunGlyphData& glyph_data, float total_advance,
+            uint16_t character_index) -> bool {
+
+          AddGlyphToBloberizer(*this, total_advance, run->direction_,
+                               run->font_data_.Get(), glyph_data, run_info.run,
+                               character_index);
+          return true;
+        });
+  }
+
+  return total_advance;
+}
+
+float ShapeResultBloberizer::FillFastHorizontalGlyphs(
+    const ShapeResultBuffer& result_buffer,
+    const TextRun& text_run) {
+  DCHECK(!result_buffer.HasVerticalOffsets());
+  DCHECK_NE(GetType(), ShapeResultBloberizer::Type::kTextIntercepts);
+
+  float advance = 0;
+  auto results = result_buffer.results_;
+
+  for (unsigned i = 0; i < results.size(); ++i) {
+    const auto& word_result = IsLeftToRightDirection(text_run.Direction())
+                                  ? results[i]
+                                  : results[results.size() - 1 - i];
+    DCHECK(!word_result->HasVerticalOffsets());
+
+    for (const auto& run : word_result->runs_) {
+      DCHECK(run);
+      DCHECK(HB_DIRECTION_IS_HORIZONTAL(run->direction_));
+
+      advance =
+          run->ForEachGlyph(advance,
+                            [&](const HarfBuzzRunGlyphData& glyph_data,
+                                float total_advance) -> bool {
+                              DCHECK(!glyph_data.offset.Height());
+                              Add(glyph_data.glyph, run->font_data_.Get(),
+                                  total_advance + glyph_data.offset.Width());
+                              return true;
+                            });
+    }
+  }
+
+  return advance;
+}
+
+float ShapeResultBloberizer::FillTextEmphasisGlyphsForRun(
+    const ShapeResult::RunInfo* run,
+    const TextRunPaintInfo& run_info,
+    const GlyphData& emphasis_data,
+    float initial_advance,
+    unsigned run_offset) {
+  if (!run)
+    return 0;
+
+  unsigned graphemes_in_cluster = 1;
+  float cluster_advance = 0;
+
+  FloatPoint glyph_center =
+      emphasis_data.font_data->BoundsForGlyph(emphasis_data.glyph).Center();
+
+  const auto& text_run = run_info.run;
+  const auto from = run_info.from;
+  const auto to = run_info.to;
+
+  TextDirection direction = text_run.Direction();
+
+  // A "cluster" in this context means a cluster as it is used by HarfBuzz:
+  // The minimal group of characters and corresponding glyphs, that cannot be
+  // broken down further from a text shaping point of view.  A cluster can
+  // contain multiple glyphs and grapheme clusters, with mutually overlapping
+  // boundaries. Below we count grapheme clusters per HarfBuzz clusters, then
+  // linearly split the sum of corresponding glyph advances by the number of
+  // grapheme clusters in order to find positions for emphasis mark drawing.
+  uint16_t cluster_start = static_cast<uint16_t>(
+      direction == TextDirection::kRtl
+          ? run->start_index_ + run->num_characters_ + run_offset
+          : run->GlyphToCharacterIndex(0) + run_offset);
+
+  float advance_so_far = initial_advance;
+  const unsigned num_glyphs = run->glyph_data_.size();
+  for (unsigned i = 0; i < num_glyphs; ++i) {
+    const HarfBuzzRunGlyphData& glyph_data = run->glyph_data_[i];
+    uint16_t current_character_index =
+        run->start_index_ + glyph_data.character_index + run_offset;
+    bool is_run_end = (i + 1 == num_glyphs);
+    bool is_cluster_end =
+        is_run_end || (run->GlyphToCharacterIndex(i + 1) + run_offset !=
+                       current_character_index);
+
+    if ((direction == TextDirection::kRtl && current_character_index >= to) ||
+        (direction != TextDirection::kRtl && current_character_index < from)) {
+      advance_so_far += glyph_data.advance;
+      direction == TextDirection::kRtl ? --cluster_start : ++cluster_start;
+      continue;
+    }
+
+    cluster_advance += glyph_data.advance;
+
+    if (text_run.Is8Bit()) {
+      float glyph_advance_x = glyph_data.advance;
+      if (Character::CanReceiveTextEmphasis(
+              text_run[current_character_index])) {
+        AddEmphasisMark(*this, emphasis_data, glyph_center,
+                        advance_so_far + glyph_advance_x / 2);
+      }
+      advance_so_far += glyph_advance_x;
+    } else if (is_cluster_end) {
+      uint16_t cluster_end;
+      if (direction == TextDirection::kRtl) {
+        cluster_end = current_character_index;
+      } else {
+        cluster_end = static_cast<uint16_t>(
+            is_run_end ? run->start_index_ + run->num_characters_ + run_offset
+                       : run->GlyphToCharacterIndex(i + 1) + run_offset);
+      }
+      graphemes_in_cluster = CountGraphemesInCluster(
+          text_run.Characters16(), text_run.CharactersLength(), cluster_start,
+          cluster_end);
+      if (!graphemes_in_cluster || !cluster_advance)
+        continue;
+
+      float glyph_advance_x = cluster_advance / graphemes_in_cluster;
+      for (unsigned j = 0; j < graphemes_in_cluster; ++j) {
+        // Do not put emphasis marks on space, separator, and control
+        // characters.
+        if (Character::CanReceiveTextEmphasis(
+                text_run[current_character_index])) {
+          AddEmphasisMark(*this, emphasis_data, glyph_center,
+                          advance_so_far + glyph_advance_x / 2);
+        }
+        advance_so_far += glyph_advance_x;
+      }
+      cluster_start = cluster_end;
+      cluster_advance = 0;
+    }
+  }
+  return advance_so_far - initial_advance;
+}
+
 }  // namespace blink