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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"
#import <Foundation/Foundation.h>
#include <dlfcn.h>
#include <string>
#include <vector>
#import "base/strings/sys_string_conversions.h"
#include "base/mac/foundation_util.h"
#import "base/mac/mac_util.h"
// CTFontCopyDefaultCascadeListForLanguages() doesn't exist in the 10.6 SDK.
// There is only the following. It doesn't exist in the public header files,
// but is an exported symbol so should always link.
extern "C" CFArrayRef CTFontCopyDefaultCascadeList(CTFontRef font_ref);
namespace {
// Wrapper for CTFontCopyDefaultCascadeListForLanguages() which should appear in
// CoreText.h from 10.8 onwards.
// TODO(tapted): Delete this wrapper when only 10.8+ is supported.
CFArrayRef CTFontCopyDefaultCascadeListForLanguagesWrapper(
CTFontRef font_ref,
CFArrayRef language_pref_list) {
typedef CFArrayRef (*MountainLionPrototype)(CTFontRef, CFArrayRef);
static const MountainLionPrototype cascade_with_languages_function =
reinterpret_cast<MountainLionPrototype>(
dlsym(RTLD_DEFAULT, "CTFontCopyDefaultCascadeListForLanguages"));
if (cascade_with_languages_function)
return cascade_with_languages_function(font_ref, language_pref_list);
// Fallback to the 10.6 Private API.
DCHECK(base::mac::IsOSLionOrEarlier());
return CTFontCopyDefaultCascadeList(font_ref);
}
} // namespace
namespace gfx {
std::vector<std::string> GetFallbackFontFamilies(
const std::string& font_family) {
// 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.
// The CoreText APIs provide CTFontCreateForString(font, string, range), but
// it requires a text string "hint", and the returned font can't be
// represented by name for easy retrieval later.
// In 10.8, CTFontCopyDefaultCascadeListForLanguages(font, language_list)
// showed up which is a good fit GetFallbackFontFamilies().
// Size doesn't matter for querying the cascade list.
const CGFloat font_size = 10.0;
base::ScopedCFTypeRef<CFStringRef> cfname(
base::SysUTF8ToCFStringRef(font_family));
// Using CTFontCreateWithName here works, but CoreText emits stderr spam along
// the lines of `CTFontCreateWithName() using name "Arial" and got font with
// PostScript name "ArialMT".` Instead, create a descriptor.
const void* attribute_keys[] = {kCTFontFamilyNameAttribute};
const void* attribute_values[] = {cfname.get()};
base::ScopedCFTypeRef<CFDictionaryRef> attributes(CFDictionaryCreate(
kCFAllocatorDefault, attribute_keys, attribute_values, 1,
&kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks));
base::ScopedCFTypeRef<CTFontDescriptorRef> descriptor(
CTFontDescriptorCreateWithAttributes(attributes));
base::ScopedCFTypeRef<CTFontRef> base_font(
CTFontCreateWithFontDescriptor(descriptor, font_size, nullptr));
if (!base_font)
return std::vector<std::string>(1, font_family);
NSArray* languages = [[NSUserDefaults standardUserDefaults]
stringArrayForKey:@"AppleLanguages"];
CFArrayRef languages_cf = base::mac::NSToCFCast(languages);
base::ScopedCFTypeRef<CFArrayRef> cascade_list(
CTFontCopyDefaultCascadeListForLanguagesWrapper(base_font, languages_cf));
std::vector<std::string> fallback_fonts;
const CFIndex fallback_count = CFArrayGetCount(cascade_list);
for (CFIndex i = 0; i < fallback_count; ++i) {
CTFontDescriptorRef descriptor =
base::mac::CFCastStrict<CTFontDescriptorRef>(
CFArrayGetValueAtIndex(cascade_list, i));
base::ScopedCFTypeRef<CFStringRef> font_name(
base::mac::CFCastStrict<CFStringRef>(CTFontDescriptorCopyAttribute(
descriptor, kCTFontFamilyNameAttribute)));
fallback_fonts.push_back(base::SysCFStringRefToUTF8(font_name));
}
if (fallback_fonts.empty())
return std::vector<std::string>(1, font_family);
return fallback_fonts;
}
} // namespace gfx
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