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[web] allow customizing Ahem URL using FontManifest.json (flutter/engine#30719)

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This commit is contained in:
Yegor
2022-01-06 15:47:07 -08:00
committed by GitHub
parent 68548f30e9
commit fbf0cd4e31
2 changed files with 129 additions and 44 deletions
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120
engine/src/flutter/lib/web_ui/lib/src/engine/canvaskit/fonts.dart
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@@ -24,12 +24,29 @@ const String _ahemUrl = '/assets/fonts/ahem.ttf';
/// Manages the fonts used in the Skia-based backend.
class SkiaFontCollection {
/// Fonts that have been registered but haven't been loaded yet.
final List<Future<RegisteredFont?>> _unloadedFonts =
<Future<RegisteredFont?>>[];
final Set<String> _registeredFontFamilies = <String>{};
/// Fonts which have been registered and loaded.
final List<RegisteredFont> _registeredFonts = <RegisteredFont>[];
/// Fonts that started the download process.
///
/// Once downloaded successfully, this map is cleared and the resulting
/// [RegisteredFont]s are added to [_downloadedFonts].
final List<Future<RegisteredFont?>> _pendingFonts = <Future<RegisteredFont?>>[];
/// Fonts that have been downloaded and parsed into [SkTypeface].
///
/// These fonts may not yet have been registered with the [fontProvider]. This
/// happens after [ensureFontsLoaded] completes.
final List<RegisteredFont> _downloadedFonts = <RegisteredFont>[];
/// Returns fonts that have been downloaded and parsed.
///
/// This should only be used in tests.
List<RegisteredFont>? get debugDownloadedFonts {
if (!assertionsEnabled) {
return null;
}
return _downloadedFonts;
}
final Map<String, List<SkFont>> familyToFontMap = <String, List<SkFont>>{};
@@ -43,7 +60,7 @@ class SkiaFontCollection {
fontProvider = canvasKit.TypefaceFontProvider.Make();
familyToFontMap.clear();
for (final RegisteredFont font in _registeredFonts) {
for (final RegisteredFont font in _downloadedFonts) {
fontProvider!.registerFont(font.bytes, font.family);
familyToFontMap
.putIfAbsent(font.family, () => <SkFont>[])
@@ -59,19 +76,19 @@ class SkiaFontCollection {
}
}
/// Loads all of the unloaded fonts in [_unloadedFonts] and adds them
/// to [_registeredFonts].
/// Loads all of the unloaded fonts in [_pendingFonts] and adds them
/// to [_downloadedFonts].
Future<void> _loadFonts() async {
if (_unloadedFonts.isEmpty) {
if (_pendingFonts.isEmpty) {
return;
}
final List<RegisteredFont?> loadedFonts = await Future.wait(_unloadedFonts);
final List<RegisteredFont?> loadedFonts = await Future.wait(_pendingFonts);
for (final RegisteredFont? font in loadedFonts) {
if (font != null) {
_registeredFonts.add(font);
_downloadedFonts.add(font);
}
}
_unloadedFonts.clear();
_pendingFonts.clear();
}
Future<void> loadFontFromList(Uint8List list, {String? fontFamily}) async {
@@ -86,7 +103,7 @@ class SkiaFontCollection {
final SkTypeface? typeface =
canvasKit.Typeface.MakeFreeTypeFaceFromData(list.buffer);
if (typeface != null) {
_registeredFonts.add(RegisteredFont(list, fontFamily, typeface));
_downloadedFonts.add(RegisteredFont(list, fontFamily, typeface));
await ensureFontsLoaded();
} else {
printWarning('Failed to parse font family "$fontFamily"');
@@ -94,6 +111,7 @@ class SkiaFontCollection {
}
}
/// Loads fonts from `FontManifest.json`.
Future<void> registerFonts(AssetManager assetManager) async {
ByteData byteData;
@@ -115,61 +133,75 @@ class SkiaFontCollection {
'There was a problem trying to load FontManifest.json');
}
bool registeredRoboto = false;
for (final Map<String, dynamic> fontFamily
in fontManifest.cast<Map<String, dynamic>>()) {
final String family = fontFamily.readString('family');
final List<dynamic> fontAssets = fontFamily.readList('fonts');
if (family == 'Roboto') {
registeredRoboto = true;
}
for (final dynamic fontAssetItem in fontAssets) {
final Map<String, dynamic> fontAsset = fontAssetItem as Map<String, dynamic>;
final String asset = fontAsset.readString('asset');
_unloadedFonts
.add(_registerFont(assetManager.getAssetUrl(asset), family));
_registerFont(assetManager.getAssetUrl(asset), family);
}
}
/// We need a default fallback font for CanvasKit, in order to
/// avoid crashing while laying out text with an unregistered font. We chose
/// Roboto to match Android.
if (!registeredRoboto) {
if (!_isFontFamilyRegistered('Roboto')) {
// Download Roboto and add it to the font buffers.
_unloadedFonts.add(_registerFont(_robotoUrl, 'Roboto'));
_registerFont(_robotoUrl, 'Roboto');
}
}
Future<void> debugRegisterTestFonts() async {
_unloadedFonts.add(_registerFont(_ahemUrl, 'Ahem'));
/// Whether the [fontFamily] was registered and/or loaded.
bool _isFontFamilyRegistered(String fontFamily) {
return _registeredFontFamilies.contains(fontFamily);
}
/// Loads the Ahem font, unless it's already been loaded using
/// `FontManifest.json` (see [registerFonts]).
///
/// `FontManifest.json` has higher priority than the default test font URLs.
/// This allows customizing test environments where fonts are loaded from
/// different URLs.
void debugRegisterTestFonts() {
if (!_isFontFamilyRegistered('Ahem')) {
_registerFont(_ahemUrl, 'Ahem');
}
// Ahem must be added to font fallbacks list regardless of where it was
// downloaded from.
FontFallbackData.instance.globalFontFallbacks.add('Ahem');
}
Future<RegisteredFont?> _registerFont(String url, String family) async {
ByteBuffer buffer;
try {
buffer = await httpFetch(url).then(_getArrayBuffer);
} catch (e) {
printWarning('Failed to load font $family at $url');
printWarning(e.toString());
return null;
void _registerFont(String url, String family) {
Future<RegisteredFont?> _downloadFont() async {
ByteBuffer buffer;
try {
buffer = await httpFetch(url).then(_getArrayBuffer);
} catch (e) {
printWarning('Failed to load font $family at $url');
printWarning(e.toString());
return null;
}
final Uint8List bytes = buffer.asUint8List();
final SkTypeface? typeface =
canvasKit.Typeface.MakeFreeTypeFaceFromData(bytes.buffer);
if (typeface != null) {
return RegisteredFont(bytes, family, typeface);
} else {
printWarning('Failed to load font $family at $url');
printWarning('Verify that $url contains a valid font.');
return null;
}
}
final Uint8List bytes = buffer.asUint8List();
final SkTypeface? typeface =
canvasKit.Typeface.MakeFreeTypeFaceFromData(bytes.buffer);
if (typeface != null) {
return RegisteredFont(bytes, family, typeface);
} else {
printWarning('Failed to load font $family at $url');
printWarning('Verify that $url contains a valid font.');
return null;
}
_registeredFontFamilies.add(family);
_pendingFonts.add(_downloadFont());
}
String? _readActualFamilyName(Uint8List bytes) {
final SkFontMgr tmpFontMgr =
canvasKit.FontMgr.FromData(<Uint8List>[bytes])!;

53
engine/src/flutter/lib/web_ui/test/canvaskit/skia_font_collection_test.dart
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@@ -2,6 +2,8 @@
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:typed_data';
import 'package:test/bootstrap/browser.dart';
import 'package:test/test.dart';
@@ -72,6 +74,57 @@ void testMain() {
),
);
});
test('prioritizes Ahem loaded via FontManifest.json', () async {
final SkiaFontCollection fontCollection = SkiaFontCollection();
final WebOnlyMockAssetManager mockAssetManager =
WebOnlyMockAssetManager();
mockAssetManager.defaultFontManifest = '''
[
{
"family":"Ahem",
"fonts":[{"asset":"/assets/fonts/Roboto-Regular.ttf"}]
}
]
'''.trim();
final ByteBuffer robotoData = (await (await httpFetch('/assets/fonts/Roboto-Regular.ttf')).arrayBuffer())! as ByteBuffer;
await fontCollection.registerFonts(mockAssetManager);
fontCollection.debugRegisterTestFonts();
await fontCollection.ensureFontsLoaded();
expect(warnings, isEmpty);
// Use `singleWhere` to make sure only one version of 'Ahem' is loaded.
final RegisteredFont ahem = fontCollection.debugDownloadedFonts!
.singleWhere((RegisteredFont font) => font.family == 'Ahem');
// Check that the contents of 'Ahem' is actually Roboto, because that's
// what's specified in the manifest, and the manifest takes precedence.
expect(ahem.bytes.length, robotoData.lengthInBytes);
});
test('falls back to default Ahem URL', () async {
final SkiaFontCollection fontCollection = SkiaFontCollection();
final WebOnlyMockAssetManager mockAssetManager =
WebOnlyMockAssetManager();
mockAssetManager.defaultFontManifest = '[]';
final ByteBuffer ahemData = (await (await httpFetch('/assets/fonts/ahem.ttf')).arrayBuffer())! as ByteBuffer;
await fontCollection.registerFonts(mockAssetManager);
fontCollection.debugRegisterTestFonts();
await fontCollection.ensureFontsLoaded();
expect(warnings, isEmpty);
// Use `singleWhere` to make sure only one version of 'Ahem' is loaded.
final RegisteredFont ahem = fontCollection.debugDownloadedFonts!
.singleWhere((RegisteredFont font) => font.family == 'Ahem');
// Check that the contents of 'Ahem' is actually Roboto, because that's
// what's specified in the manifest, and the manifest takes precedence.
expect(ahem.bytes.length, ahemData.lengthInBytes);
});
// TODO(hterkelsen): https://github.com/flutter/flutter/issues/60040
}, skip: isIosSafari);
}