1 files changed, 85 insertions, 0 deletions
diff --git a/libs/minikin/FontCollection.cpp b/libs/minikin/FontCollection.cpp
index 0c1a173..84e5dd9 100644
--- a/libs/minikin/FontCollection.cpp
+++ b/libs/minikin/FontCollection.cpp
@@ -30,6 +30,8 @@
 #include "minikin/Characters.h"
 #include "minikin/Emoji.h"
 #include "minikin/FontFileParser.h"
+#include "minikin/MinikinExtent.h"
+#include "minikin/MinikinPaint.h"
 
 using std::vector;
 
@@ -606,6 +608,89 @@ 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);
+    for (uint8_t i = 0; i < mFamilyCount; ++i) {
+        const auto& family = getFamilyAt(i);
+        if (!family->isCustomFallback()) {
+            break;
+        }
+
+        // Use this family
+        MinikinExtent extent(0, 0);
+        FakedFont font = getFamilyAt(i)->getClosestMatch(paint.fontStyle);
+        font.typeface()->GetFontExtent(&extent, paint, font.fakery);
+        result.extendBy(extent);
+    }
+
+    if (localeId == LocaleListCache::kInvalidListId) {
+        return result;
+    }
+
+    // If default is requested, use compact one.
+    const FamilyVariant requestVariant = paint.familyVariant == FamilyVariant::DEFAULT
+                                                 ? FamilyVariant::COMPACT
+                                                 : paint.familyVariant;
+    const LocaleList& requestedLocaleList = LocaleListCache::getById(localeId);
+
+    bool familyFound = false;
+    filterFamilyByLocale(requestedLocaleList, [&](const FontFamily& family) {
+        const FamilyVariant familyVariant = family.variant() == FamilyVariant::DEFAULT
+                                                    ? FamilyVariant::COMPACT
+                                                    : family.variant();
+
+        if (familyVariant != requestVariant) {
+            return;
+        }
+
+        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 = 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);
+    }
+
+    return result;
+}
+
 std::vector<FontCollection::Run> FontCollection::itemize(U16StringPiece text, FontStyle,
                                                          uint32_t localeListId,
                                                          FamilyVariant familyVariant,