Case-insensitive matching of family names for custom fonts

ci/licenses_golden/licenses_flutter

@@ -1001,6 +1001,7 @@ FILE: ../../../flutter/third_party/txt/src/minikin/WordBreaker.cpp
 FILE: ../../../flutter/third_party/txt/src/minikin/WordBreaker.h
 FILE: ../../../flutter/third_party/txt/src/txt/asset_font_manager.cc
 FILE: ../../../flutter/third_party/txt/src/txt/asset_font_manager.h
+FILE: ../../../flutter/third_party/txt/src/txt/font_asset_provider.cc
 FILE: ../../../flutter/third_party/txt/src/txt/font_asset_provider.h
 FILE: ../../../flutter/third_party/txt/src/txt/font_collection.cc
 FILE: ../../../flutter/third_party/txt/src/txt/font_collection.h

lib/ui/text/asset_manager_font_provider.cc

@@ -40,7 +40,7 @@ std::string AssetManagerFontProvider::GetFamilyName(int index) const {
 // |FontAssetProvider|
 SkFontStyleSet* AssetManagerFontProvider::MatchFamily(
     const std::string& family_name) {
-  auto found = registered_families_.find(family_name);
+  auto found = registered_families_.find(CanonicalFamilyName(family_name));
   if (found == registered_families_.end()) {
     return nullptr;
   }
@@ -49,13 +49,14 @@ SkFontStyleSet* AssetManagerFontProvider::MatchFamily(
 
 void AssetManagerFontProvider::RegisterAsset(std::string family_name,
                                              std::string asset) {
-  auto family_it = registered_families_.find(family_name);
+  std::string canonical_name = CanonicalFamilyName(family_name);
+  auto family_it = registered_families_.find(canonical_name);
 
   if (family_it == registered_families_.end()) {
     family_names_.push_back(family_name);
     family_it = registered_families_
                     .emplace(std::piecewise_construct,
-                             std::forward_as_tuple(family_name),
+                             std::forward_as_tuple(canonical_name),
                              std::forward_as_tuple(asset_manager_))
                     .first;
   }

third_party/txt/BUILD.gn

@@ -66,6 +66,7 @@ source_set("txt") {
     "src/minikin/WordBreaker.h",
     "src/txt/asset_font_manager.cc",
     "src/txt/asset_font_manager.h",
+    "src/txt/font_asset_provider.cc",
     "src/txt/font_asset_provider.h",
     "src/txt/font_collection.cc",
     "src/txt/font_collection.h",

third_party/txt/src/txt/font_asset_provider.cc

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <algorithm>
+#include <string>
+
+#include "txt/font_asset_provider.h"
+
+namespace txt {
+
+// Return a canonicalized version of a family name that is suitable for
+// matching.
+std::string FontAssetProvider::CanonicalFamilyName(std::string family_name) {
+  std::string result(family_name.length(), 0);
+
+  // Convert ASCII characters to lower case.
+  std::transform(family_name.begin(), family_name.end(), result.begin(),
+                 [](char c) { return (c & 0x80) ? c : ::tolower(c); });
+
+  return result;
+}
+
+}  // namespace txt

third_party/txt/src/txt/font_asset_provider.h

@@ -28,6 +28,9 @@ class FontAssetProvider {
   virtual size_t GetFamilyCount() const = 0;
   virtual std::string GetFamilyName(int index) const = 0;
   virtual SkFontStyleSet* MatchFamily(const std::string& family_name) = 0;
+
+ protected:
+  static std::string CanonicalFamilyName(std::string family_name);
 };
 
 }  // namespace txt

third_party/txt/src/txt/typeface_font_asset_provider.cc

@@ -39,7 +39,7 @@ std::string TypefaceFontAssetProvider::GetFamilyName(int index) const {
 // |FontAssetProvider|
 SkFontStyleSet* TypefaceFontAssetProvider::MatchFamily(
     const std::string& family_name) {
-  auto found = registered_families_.find(family_name);
+  auto found = registered_families_.find(CanonicalFamilyName(family_name));
   if (found == registered_families_.end()) {
     return nullptr;
   }
@@ -65,12 +65,13 @@ void TypefaceFontAssetProvider::RegisterTypeface(
     return;
   }
 
-  auto family_it = registered_families_.find(family_name_alias);
+  std::string canonical_name = CanonicalFamilyName(family_name_alias);
+  auto family_it = registered_families_.find(canonical_name);
   if (family_it == registered_families_.end()) {
     family_names_.push_back(family_name_alias);
     family_it = registered_families_
                     .emplace(std::piecewise_construct,
-                             std::forward_as_tuple(family_name_alias),
+                             std::forward_as_tuple(canonical_name),
                              std::forward_as_tuple())
                     .first;
   }