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[text_shaper] coretext_locator: Adds font fallback implementation
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Signed-off-by: Christian Parpart <[email protected]>
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@christianparpart
christianparpart committed Jun 22, 2024
1 parent 9c1a060 commit cb18dc8
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Showing 2 changed files with 82 additions and 49 deletions.
1 change: 1 addition & 0 deletions metainfo.xml
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Expand Up @@ -107,6 +107,7 @@
<release version="0.4.4" urgency="medium" type="development">
<description>
<ul>
<li>Add CoreText font fallback implementation for macOS (#1533)</li>
<li>Add Ubuntu-24.04 in github actions (#1460)</li>
<li>Add 'early_exit_threshold' config option (#1460)</li>
<li>Add AppImage package with Qt6 support (#586)</li>
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130 changes: 81 additions & 49 deletions src/text_shaper/coretext_locator.mm
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Expand Up @@ -6,26 +6,48 @@
#include <text_shaper/font_locator.h>

#import <AppKit/AppKit.h>
#import <CoreText/CTFont.h>
#import <CoreText/CTFontDescriptor.h>
#import <CoreText/CoreText.h>
#import <Foundation/Foundation.h>

namespace text
{
namespace
{
font_path ctFontPath(NSString const* _name)
font_path ctFontPath(NSString const* name)
{
auto const fontRef = CTFontDescriptorCreateWithNameAndSize((CFStringRef)_name, 16.0);
auto const fontRef = CTFontDescriptorCreateWithNameAndSize((CFStringRef)name, 16.0);

CFURLRef const url = (CFURLRef)CTFontDescriptorCopyAttribute(fontRef, kCTFontURLAttribute);
NSString const* fontPath = [NSString stringWithString: [(NSURL const*)CFBridgingRelease(url) path]];

return font_path{[fontPath cStringUsingEncoding: [NSString defaultCStringEncoding]]};
}

constexpr font_weight ctFontWeight(int _weight) noexcept
constexpr NSFontWeight makeFontWeight(font_weight value) noexcept
{
switch (_weight)
switch (value)
{
case font_weight::thin: return NSFontWeightThin;
case font_weight::extra_light: return NSFontWeightUltraLight;
case font_weight::light: return NSFontWeightLight;
case font_weight::demilight: return NSFontWeightLight; // does not exist on CoreText
case font_weight::book: return NSFontWeightRegular; // does not exist on CoreText
case font_weight::normal: return NSFontWeightRegular;
case font_weight::medium: return NSFontWeightMedium;
case font_weight::demibold: return NSFontWeightSemibold;
case font_weight::bold: return NSFontWeightBold;
case font_weight::extra_bold: return NSFontWeightHeavy;
case font_weight::black: return NSFontWeightBlack;
case font_weight::extra_black: return NSFontWeightBlack; // does not exist on CoreText
}
return NSFontWeightRegular;
}

[[maybe_unused]] constexpr font_weight ctFontWeight(int weight) noexcept
{
switch (weight)
{
case 2: return font_weight::thin;
case 3: return font_weight::extra_light;
Expand All @@ -40,12 +62,12 @@ constexpr font_weight ctFontWeight(int _weight) noexcept
}
}

constexpr font_slant ctFontSlant(int _slant) noexcept
[[maybe_unused]] constexpr font_slant ctFontSlant(int slant) noexcept
{
if (unsigned(_slant) & NSItalicFontMask)
if (unsigned(slant) & NSItalicFontMask)
return font_slant::italic;

if (unsigned(_slant) & (NSUnitalicFontMask | NSUnboldFontMask))
if (unsigned(slant) & (NSUnitalicFontMask | NSUnboldFontMask))
return font_slant::normal;

// Figure out how to get Oblique font, even though according to some docs.
Expand All @@ -65,70 +87,80 @@ constexpr font_slant ctFontSlant(int _slant) noexcept
}
};


coretext_locator::coretext_locator() :
_d{ new Private(), [](Private* p) { delete p; } }
{
}

font_source_list coretext_locator::locate(font_description const& _fd)
font_source_list coretext_locator::locate(font_description const& description)
{
locatorLog()("Locating font chain for: {}", _fd);
locatorLog()("Locating font chain for: {}", description);

font_source_list output;
font_source_list fonts;

// "Emoji"
auto const familyName = crispy::toLower(_fd.familyName) != "emoji"
? _fd.familyName.c_str()
: "Apple Color Emoji";
CFStringRef familyName = CFStringCreateWithCString(
kCFAllocatorDefault, description.familyName.c_str(), kCFStringEncodingUTF8);

NSArray<NSArray *>* fonts = [_d->fm
availableMembersOfFontFamily: [NSString
stringWithCString: familyName
encoding: [NSString defaultCStringEncoding]
]
];
bool const isItalic = description.slant == font_slant::italic;
auto const fontWeight = makeFontWeight(description.weight);
auto const fontSlant = isItalic ? NSFontItalicTrait : 0;

if (fonts == nil)
{
locatorLog()("No fonts found. Falling back to font family: Menlo.");
fonts = [_d->fm availableMembersOfFontFamily:@"Menlo"];
}
CTFontDescriptorRef descriptor = CTFontDescriptorCreateWithAttributes(
(__bridge CFDictionaryRef) @{
(id)kCTFontFamilyNameAttribute: (__bridge id)familyName,
(id)kCTFontWeightTrait: @(fontWeight),
(id)kCTFontSlantTrait: @(fontSlant)
});

for (bool const forceWeight: {true, false})
{
for ([[maybe_unused]] bool const forceSlant: {true, false})
{
for (NSArray* object in fonts)
{
auto path = ctFontPath([object objectAtIndex: 0]);
auto const weight = ctFontWeight([[object objectAtIndex: 2] intValue]);

if (forceWeight && weight != _fd.weight)
continue;

auto const slant = ctFontSlant([[object objectAtIndex: 3] intValue]);

if (slant != _fd.slant)
continue;
CTFontRef font = CTFontCreateWithFontDescriptor(descriptor, 0.0, nullptr);
if (font) {
auto* const fontURL = (NSURL const*) CTFontCopyAttribute(font, kCTFontURLAttribute);
fonts.emplace_back(font_path { fontURL.path.UTF8String } );
CFRelease(fontURL);
}

output.emplace_back(ctFontPath([object objectAtIndex: 0]));
// Get Fallback List
auto const* cascadeList = (CFArrayRef) CTFontCopyDefaultCascadeListForLanguages(
font,
(CFArrayRef) NSLocale.preferredLanguages
);

if (cascadeList) {
for (CFIndex i = 0; i < CFArrayGetCount(cascadeList); i++) {
const auto* fallbackFont = (CTFontDescriptorRef) CFArrayGetValueAtIndex(cascadeList, i);
if (fallbackFont) {
CTFontRef fallbackFontRef = CTFontCreateWithFontDescriptor(fallbackFont, 0.0, nullptr);
if (fallbackFontRef) {
auto const* const fontURL = (NSURL const*) CTFontCopyAttribute(fallbackFontRef, kCTFontURLAttribute);
if (fontURL)
{
fonts.emplace_back(font_path { fontURL.path.UTF8String });
CFRelease(fontURL);
}
else
locatorLog()("No URL found for fallback font at index {}", i);
CFRelease(fallbackFontRef);
}
}
if (!output.empty())
break;
else
locatorLog()("No fallback font found at index {}", i);
}
if (!output.empty())
break;
}
else
locatorLog()("No fallback fonts found");

return output;
CFRelease(cascadeList);
CFRelease(familyName);
CFBridgingRelease(familyName);

return fonts;
}

font_source_list coretext_locator::all()
{
font_source_list output;

NSArray<NSString *> const* fonts = [_d->fm availableFonts];
NSArray<NSString *> const* const fonts = [_d->fm availableFonts];

for (NSString const* fontName in fonts) {
output.emplace_back(ctFontPath(fontName));
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