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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/font_fallback.h"
#include <CoreText/CoreText.h>
#import <Foundation/Foundation.h>
#include "base/i18n/char_iterator.h"
#include "base/mac/foundation_util.h"
#import "base/mac/mac_util.h"
#include "base/mac/scoped_cftyperef.h"
#import "base/strings/sys_string_conversions.h"
#include "base/trace_event/trace_event.h"
#include "third_party/icu/source/common/unicode/uchar.h"
#include "ui/gfx/font.h"
#include "ui/gfx/font_fallback_skia_impl.h"
#include "ui/gfx/platform_font.h"
namespace gfx {
namespace {
bool TextSequenceHasEmoji(base::StringPiece16 text) {
for (base::i18n::UTF16CharIterator iter(text); !iter.end(); iter.Advance()) {
const UChar32 codepoint = iter.get();
if (u_hasBinaryProperty(codepoint, UCHAR_EMOJI))
return true;
return false;
} // namespace
std::vector<Font> GetFallbackFonts(const Font& font) {
// On Mac "There is a system default cascade list (which is polymorphic, based
// on the user's language setting and current font)" - CoreText Programming
// Guide.
NSArray* languages = [[NSUserDefaults standardUserDefaults]
CFArrayRef languages_cf = base::mac::NSToCFCast(languages);
base::ScopedCFTypeRef<CFArrayRef> cascade_list(
static_cast<CTFontRef>(font.GetNativeFont()), languages_cf));
std::vector<Font> fallback_fonts;
if (!cascade_list)
return fallback_fonts; // This should only happen for an invalid |font|.
const CFIndex fallback_count = CFArrayGetCount(cascade_list);
for (CFIndex i = 0; i < fallback_count; ++i) {
CTFontDescriptorRef descriptor =
CFArrayGetValueAtIndex(cascade_list, i));
base::ScopedCFTypeRef<CTFontRef> fallback_font(
CTFontCreateWithFontDescriptor(descriptor, 0.0, nullptr));
if (fallback_font.get())
if (fallback_fonts.empty())
return std::vector<Font>(1, font);
return fallback_fonts;
bool GetFallbackFont(const Font& font,
const std::string& locale,
base::StringPiece16 text,
Font* result) {
TRACE_EVENT0("fonts", "gfx::GetFallbackFont");
if (TextSequenceHasEmoji(text)) {
*result = Font("Apple Color Emoji", font.GetFontSize());
return true;
sk_sp<SkTypeface> fallback_typeface =
GetSkiaFallbackTypeface(font, locale, text);
if (!fallback_typeface)
return false;
// Fallback needs to keep the exact SkTypeface, as re-matching the font using
// family name and styling information loses access to the underlying platform
// font handles and is not guaranteed to result in the correct typeface, see
*result = Font(PlatformFont::CreateFromSkTypeface(
std::move(fallback_typeface), font.GetFontSize(), base::nullopt));
return true;
} // namespace gfx