Fallback to non-variant match if nothing matches

Bug: 310117531
Test: atest CtsGraphicsTestCases CtsTextTestCases CtsWidgetTestCases
Change-Id: I574b641e50e8f2bc03c7490c0199697e79d81aa2

2 files changed, 40 insertions, 15 deletions

diff --git a/include/minikin/FontCollection.h b/include/minikin/FontCollection.h
index 7ad644a..ee0315e 100644
--- a/include/minikin/FontCollection.h
+++ b/include/minikin/FontCollection.h
@@ -34,6 +34,8 @@ namespace minikin {
 // The maximum number of font families.
 constexpr uint32_t MAX_FAMILY_COUNT = 254;
 
+class LocaleList;
+
 class FontCollection {
 public:
     static std::shared_ptr<FontCollection> create(
@@ -225,6 +227,9 @@ private:
 
     bool isPrimaryFamily(const std::shared_ptr<FontFamily>& fontFamily) const;
 
+    void filterFamilyByLocale(const LocaleList& localeList,
+                              const std::function<void(const FontFamily& family)>& callback) const;
+
     static uint32_t calcLocaleMatchingScore(uint32_t userLocaleListId,
                                             const FontFamily& fontFamily);
 
diff --git a/libs/minikin/FontCollection.cpp b/libs/minikin/FontCollection.cpp
index 440eab2..84e5dd9 100644
--- a/libs/minikin/FontCollection.cpp
+++ b/libs/minikin/FontCollection.cpp
@@ -608,6 +608,25 @@ FontCollection::FamilyMatchResult FontCollection::FamilyMatchResult::intersect(
     return b.build();
 }
 
+void FontCollection::filterFamilyByLocale(
+        const LocaleList& localeList,
+        const std::function<void(const FontFamily& family)>& callback) const {
+    for (uint8_t i = 0; i < mFamilyCount; ++i) {
+        const auto& family = getFamilyAt(i);
+
+        uint32_t fontLocaleId = family->localeListId();
+        if (fontLocaleId == LocaleListCache::kInvalidListId) {
+            continue;
+        }
+        const LocaleList& fontLocaleList = LocaleListCache::getById(fontLocaleId);
+        if (!localeList.atLeastOneScriptMatch(fontLocaleList)) {
+            continue;
+        }
+
+        callback(*family.get());
+    }
+}
+
 MinikinExtent FontCollection::getReferenceExtentForLocale(const MinikinPaint& paint) const {
     uint32_t localeId = paint.localeListId;
     MinikinExtent result(0, 0);
@@ -635,34 +654,35 @@ MinikinExtent FontCollection::getReferenceExtentForLocale(const MinikinPaint& pa
     const LocaleList& requestedLocaleList = LocaleListCache::getById(localeId);
 
     bool familyFound = false;
-    for (uint8_t i = 0; i < mFamilyCount; ++i) {
-        const auto& family = getFamilyAt(i);
-        const FamilyVariant familyVariant = family->variant() == FamilyVariant::DEFAULT
+    filterFamilyByLocale(requestedLocaleList, [&](const FontFamily& family) {
+        const FamilyVariant familyVariant = family.variant() == FamilyVariant::DEFAULT
                                                     ? FamilyVariant::COMPACT
-                                                    : family->variant();
+                                                    : family.variant();
 
         if (familyVariant != requestVariant) {
-            continue;
+            return;
         }
 
-        uint32_t fontLocaleId = family->localeListId();
-        if (fontLocaleId == LocaleListCache::kInvalidListId) {
-            continue;
-        }
-        const LocaleList& fontLocaleList = LocaleListCache::getById(fontLocaleId);
-        if (!requestedLocaleList.atLeastOneScriptMatch(fontLocaleList)) {
-            continue;
-        }
+        MinikinExtent extent(0, 0);
+        FakedFont font = family.getClosestMatch(paint.fontStyle);
+        font.typeface()->GetFontExtent(&extent, paint, font.fakery);
+        result.extendBy(extent);
 
+        familyFound = true;
+    });
+
+    // If nothing matches, try non-variant match cases since it is used for fallback.
+    filterFamilyByLocale(requestedLocaleList, [&](const FontFamily& family) {
         // Use this family
         MinikinExtent extent(0, 0);
-        FakedFont font = getFamilyAt(i)->getClosestMatch(paint.fontStyle);
+        FakedFont font = family.getClosestMatch(paint.fontStyle);
         font.typeface()->GetFontExtent(&extent, paint, font.fakery);
         result.extendBy(extent);
 
         familyFound = true;
-    }
+    });
 
+    // If nothing matches, use default font.
     if (!familyFound) {
         FakedFont font = getFamilyAt(0)->getClosestMatch(paint.fontStyle);
         font.typeface()->GetFontExtent(&result, paint, font.fakery);