Commit b69e6563 authored by Jonathan Kew's avatar Jonathan Kew
Browse files

Bug 1823644 - Optimize textrun initialization by merging SanitizeGlyphRuns and... 

Bug 1823644 - Optimize textrun initialization by merging SanitizeGlyphRuns and SortGlyphRuns. r=gfx-reviewers,lsalzman

No change in behavior, just a marginal optimization when creating large/complex textruns.

Differential Revision: https://phabricator.services.mozilla.com/D173140
parent b2e13b6c

gfx/thebes/gfxTextRun.cpp

+48 −46
Original line number Diff line number Diff line
@@ -1368,75 +1368,79 @@ void gfxTextRun::AddGlyphRun(gfxFont* aFont, FontMatchType aMatchType, 
      GlyphRun{aFont, aUTF16Offset, aOrientation, aMatchType, aIsCJK});

}



void gfxTextRun::SortGlyphRuns() {

void gfxTextRun::SanitizeGlyphRuns() {

  if (mGlyphRuns.Length() < 2) {

    return;

  }



  auto& runs = mGlyphRuns.Array();



  // The runs are almost certain to be already sorted, so it's worth avoiding

  // the Sort() call if possible.

  bool isSorted = true;

  uint32_t prevOffset = 0;

  for (const auto& r : runs) {

    if (r.mCharacterOffset < prevOffset) {

      isSorted = false;

      break;

    }

    prevOffset = r.mCharacterOffset;

  }

  if (!isSorted) {

    runs.Sort(GlyphRunOffsetComparator());

  }



  // Coalesce adjacent glyph runs that have the same properties.

  // Coalesce adjacent glyph runs that have the same properties, and eliminate

  // any empty runs.

  GlyphRun* prevRun = nullptr;

  runs.RemoveElementsBy([&prevRun](GlyphRun& aRun) -> bool {

  const CompressedGlyph* charGlyphs = mCharacterGlyphs;



  runs.RemoveElementsBy([&](GlyphRun& aRun) -> bool {

    // First run is always retained.

    if (!prevRun) {

      prevRun = &aRun;

      return false;

    }

    // Remove any run whose properties match its predecessor.



    // Merge any run whose properties match its predecessor.

    if (prevRun->Matches(aRun.mFont, aRun.mOrientation, aRun.mIsCJK,

                         aRun.mMatchType)) {

      return true;

    }

    MOZ_ASSERT(prevRun->mCharacterOffset < aRun.mCharacterOffset,

               "Two fonts for the same run, glyph indices unreliable");



    if (prevRun->mCharacterOffset >= aRun.mCharacterOffset) {

      // Preceding run is empty (or has become so due to the adjusting for

      // ligature boundaries), so we will overwrite it with this one, which

      // will then be discarded.

      *prevRun = aRun;

      return true;

    }



    // If any glyph run starts with ligature-continuation characters, we need to

    // advance it to the first "real" character to avoid drawing partial

    // ligature glyphs from wrong font (seen with U+FEFF in reftest 474417-1, as

    // Core Text eliminates the glyph, which makes it appear as if a ligature

    // has been formed)

    while (charGlyphs[aRun.mCharacterOffset].IsLigatureContinuation() &&

           aRun.mCharacterOffset < GetLength()) {

      aRun.mCharacterOffset++;

    }



    // We're keeping another run, so update prevRun pointer to refer to it (in

    // its new position).

    ++prevRun;

    return false;

  });

  MOZ_ASSERT(prevRun == &runs.LastElement(), "lost track of prevRun!");



  MOZ_ASSERT(!runs.IsEmpty());

  if (runs.Length() == 1) {

    mGlyphRuns.ConvertToElement();

  }

}



// Note that SanitizeGlyphRuns scans all glyph runs in the textrun;

// therefore we only call it once, at the end of textrun construction,

// NOT incrementally as each glyph run is added (bug 680402).

void gfxTextRun::SanitizeGlyphRuns() {

  if (mGlyphRuns.Length() < 2) {

    return;

  }

  MOZ_ASSERT(prevRun == &runs.LastElement(), "lost track of prevRun!");



  // If any glyph run starts with ligature-continuation characters, we need to

  // advance it to the first "real" character to avoid drawing partial ligature

  // glyphs from wrong font (seen with U+FEFF in reftest 474417-1, as Core Text

  // eliminates the glyph, which makes it appear as if a ligature has been

  // formed)

  auto& glyphRuns = mGlyphRuns.Array();

  int32_t i, lastRunIndex = glyphRuns.Length() - 1;

  const CompressedGlyph* charGlyphs = mCharacterGlyphs;

  for (i = lastRunIndex; i >= 0; --i) {

    GlyphRun& run = glyphRuns[i];

    while (charGlyphs[run.mCharacterOffset].IsLigatureContinuation() &&

           run.mCharacterOffset < GetLength()) {

      run.mCharacterOffset++;

    }

    // if the run has become empty, eliminate it

    if ((i < lastRunIndex &&

         run.mCharacterOffset >= glyphRuns[i + 1].mCharacterOffset) ||

        (i == lastRunIndex && run.mCharacterOffset == GetLength())) {

      glyphRuns.RemoveElementAt(i);

      --lastRunIndex;

    }

  // Drop any trailing empty run.

  if (runs.Length() > 1 && prevRun->mCharacterOffset == GetLength()) {

    runs.RemoveLastElement();

  }



  MOZ_ASSERT(!glyphRuns.IsEmpty());

  if (glyphRuns.Length() == 1) {

  MOZ_ASSERT(!runs.IsEmpty());

  if (runs.Length() == 1) {

    mGlyphRuns.ConvertToElement();

  }

}
@@ -2670,8 +2674,6 @@ void gfxFontGroup::InitTextRun(DrawTarget* aDrawTarget, gfxTextRun* aTextRun, 
  // changes (see bug 680402) - we'd end up re-sanitizing all the earlier runs

  // every time a new script subrun is processed.

  aTextRun->SanitizeGlyphRuns();



  aTextRun->SortGlyphRuns();

}



static inline bool IsPUA(uint32_t aUSV) {

gfx/thebes/gfxTextRun.h

+0 −1
Original line number Diff line number Diff line
@@ -615,7 +615,6 @@ class gfxTextRun : public gfxShapedText { 
                   uint32_t aUTF16Offset, bool aForceNewRun,

                   mozilla::gfx::ShapedTextFlags aOrientation, bool aIsCJK);

  void ResetGlyphRuns() { mGlyphRuns.Clear(); }

  void SortGlyphRuns();

  void SanitizeGlyphRuns();



  const CompressedGlyph* GetCharacterGlyphs() const final {