Cache the glyphs and fonts used when matching fonts

Signed-off-by: MuHong Byun <mh.byun@samsung.com>

Author: bwikbs

third_party/txt/src/minikin/FontCollection.cpp

@@ -510,7 +510,8 @@ void FontCollection::itemize(const uint16_t* string,
       const std::shared_ptr<FontFamily>& family = getFamilyForChar(
           ch, isVariationSelector(nextCh) ? nextCh : 0, langListId, variant);
 
-      if (utf16Pos == 0 || family.get() != lastFamily) {
+      if (utf16Pos == 0 || family.get() != lastFamily ||
+          family.get()->getLastMatchedCodePoint() != ch) {
         size_t start = utf16Pos;
         // Workaround for combining marks and emoji modifiers until we implement
         // per-cluster font selection: if a combining mark or an emoji modifier

third_party/txt/src/minikin/FontFamily.cpp

@@ -165,9 +165,18 @@ FakedFont FontFamily::getClosestMatch(FontStyle style) const {
 }
 
 FakedFont FontFamily::getClosestMatchWithChar(FontStyle style,
-                                              uint32_t codepoint) const {
+                                              uint32_t codepoint) {
+  int bestMatch = INT_MAX;
   const Font* bestFont = nullptr;
-  int bestMatch = 0;
+  if (mLastMatchedCodePoint == codepoint && style == mLastMatchedFontStyle) {
+    if (mFonts.size() > mLastMatchedFontIndex) {
+      printf("[MONG] Cache Hit!!\n");
+      bestFont = &mFonts[mLastMatchedFontIndex];
+      return FakedFont{bestFont->typeface.get(),
+                       computeFakery(style, bestFont->style)};
+    }
+  }
+
   for (size_t i = 0; i < mFonts.size(); i++) {
     const Font& font = mFonts[i];
     int match = computeMatch(font.style, style);
@@ -180,13 +189,16 @@ FakedFont FontFamily::getClosestMatchWithChar(FontStyle style,
     }
 
     if (result) {
-      if (i == 0 || match < bestMatch || bestMatch == 0) {
+      if (match < bestMatch) {
         bestFont = &font;
         bestMatch = match;
+        mLastMatchedFontIndex = i;
       }
     }
   }
   if (bestFont != nullptr) {
+    mLastMatchedFontStyle = style;
+    mLastMatchedCodePoint = codepoint;
     return FakedFont{bestFont->typeface.get(),
                      computeFakery(style, bestFont->style)};
   }

third_party/txt/src/minikin/FontFamily.h

@@ -141,7 +141,7 @@ class FontFamily {
                            int* weight,
                            bool* italic);
   FakedFont getClosestMatch(FontStyle style) const;
-  FakedFont getClosestMatchWithChar(FontStyle style, uint32_t codepoint) const;
+  FakedFont getClosestMatchWithChar(FontStyle style, uint32_t codepoint);
 
   uint32_t langId() const { return mLangId; }
   int variant() const { return mVariant; }
@@ -174,6 +174,8 @@ class FontFamily {
   std::shared_ptr<FontFamily> createFamilyWithVariation(
       const std::vector<FontVariation>& variations) const;
 
+  uint32_t getLastMatchedCodePoint() { return mLastMatchedCodePoint; }
+
  private:
   void computeCoverage();
 
@@ -185,6 +187,10 @@ class FontFamily {
   SparseBitSet mCoverage;
   bool mHasVSTable;
 
+  uint mLastMatchedFontIndex;
+  uint32_t mLastMatchedCodePoint;
+  FontStyle mLastMatchedFontStyle;
+
   // Forbid copying and assignment.
   FontFamily(const FontFamily&) = delete;
   void operator=(const FontFamily&) = delete;