UIFont from a CSS definition

FontRegistry.m

//
//  FontRegistry.h
//  Tabris
//
//  Created by Jordi Böhme López on 25.07.12.
//  Copyright (c) 2012 EclipseSource.
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  which accompanies this distribution, and is available at
//  http://www.eclipse.org/legal/epl-v10.html
//

#import <Foundation/Foundation.h>

@interface FontRegistry : NSObject {
    NSMutableDictionary *fonts;
}

+ (FontRegistry *)instance;
-(NSString *)fontForFamily:(NSString *)fontFamily forBold:(BOOL)isBold andItalic:(BOOL)isItalic;

@end

//
//  FontRegistry.m
//  Tabris
//
//  Created by Jordi Böhme López on 25.07.12.
//  Copyright (c) 2012 EclipseSource.
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  which accompanies this distribution, and is available at
//  http://www.eclipse.org/legal/epl-v10.html
//

#import "FontRegistry.h"

@implementation FontRegistry

- (id)init {
    self = [super init];
    if (self) {
        fonts = [[NSMutableDictionary alloc] init];
        [self initFonts];
    }
    return self;
}

#pragma mark - API Methods

+(FontRegistry *)instance {
    static FontRegistry *instance;
    @synchronized( self ) {
        if( !instance ) {
            instance = [[FontRegistry alloc] init];
        }
        return instance;
    }
}

-(NSString *)fontForFamily:(NSString *)fontFamily forBold:(BOOL)isBold andItalic:(BOOL)isItalic {
    NSString *key = [self computeKey:fontFamily forBold:isBold andItalic:isItalic];
    return [fonts objectForKey:key];
}

#pragma mark - Internal Methods

-(void)initFonts {
    NSArray *fontFamilies = [UIFont familyNames];
    for (NSString *fontFamily in fontFamilies) {
        [fonts setObject:[self computeFont:fontFamily forBold:NO andItalic:NO] forKey:[self computeKey:fontFamily forBold:NO andItalic:NO]];
        [fonts setObject:[self computeFont:fontFamily forBold:YES andItalic:NO] forKey:[self computeKey:fontFamily forBold:YES andItalic:NO]];
        [fonts setObject:[self computeFont:fontFamily forBold:NO andItalic:YES] forKey:[self computeKey:fontFamily forBold:NO andItalic:YES]];
        [fonts setObject:[self computeFont:fontFamily forBold:YES andItalic:YES] forKey:[self computeKey:fontFamily forBold:YES andItalic:YES]];
    }
}

-(NSString *)computeKey:(NSString *)fontFamily forBold:(BOOL)isBold andItalic:(BOOL)isItalic {
    return [NSString stringWithFormat:@"%@;%d;%d", fontFamily, isBold, isItalic];
}

-(NSString *)computeFont:(NSString *)family forBold:(BOOL)isBold andItalic:(BOOL)isItalic {
    NSString *result = nil;
    if( isBold && isItalic ) {
        result = [self findBoldItalicFontForFamily:family];
    }
    if( !result && isItalic ) {
        result = [self findItalicFontForFamily:family];
    }
    if( !result && isBold ) {
        result = [self findBoldFontForFamily:family];
    }
    if( !result ) {
        result = [self findRegularFontForFamily:family];
    }
    return result;
}

-(NSString *)findRegularFontForFamily:(NSString *)family {
    NSArray *fontNames = [UIFont fontNamesForFamilyName:family];
    NSArray *sortedFontNames = [self sortFontNames:fontNames];
    for (NSString *fontName in sortedFontNames) {
        if( ![self isItalic:fontName] && ![self isBold:fontName] ) {
            return fontName;
        }
    }
    return [sortedFontNames objectAtIndex:0];
}

-(NSString *)findBoldFontForFamily:(NSString *)family {
    NSString *result = nil;
    NSArray *fontNames = [UIFont fontNamesForFamilyName:family];
    NSArray *sortedFontNames = [self sortFontNames:fontNames];
    for (NSString *fontName in sortedFontNames) {
        if( [self isBold:fontName] && ![self isItalic:fontName] ) {
            return fontName;
        }
    }
    return result;
}

-(NSString *)findItalicFontForFamily:(NSString *)family {
    NSString *result = nil;
    NSArray *fontNames = [UIFont fontNamesForFamilyName:family];
    NSArray *sortedFontNames = [self sortFontNames:fontNames];
    for (NSString *fontName in sortedFontNames) {
        if( [self isItalic:fontName] && ![self isBold:fontName] ) {
            return fontName;
        }
    }
    return result;
}

-(NSString *)findBoldItalicFontForFamily:(NSString *)family {
    NSString *result = nil;
    NSArray *fontNames = [UIFont fontNamesForFamilyName:family];
    NSArray *sortedFontNames = [self sortFontNames:fontNames];
    for (NSString *fontName in sortedFontNames) {
        if( [self isItalic:fontName] && [self isBold:fontName] ) {
            return fontName;
        }
    }
    return result;
}

-(NSArray *)sortFontNames:(NSArray *)fontNames {
    NSArray *sortedFontNames = [fontNames sortedArrayUsingComparator:(NSComparator)^(id obj1, id obj2) {
        NSString *str1 = (NSString *)obj1;
        NSString *str2 = (NSString *)obj2;
        if( [str1 rangeOfString:@"Bold"].location != NSNotFound && [str2 rangeOfString:@"Black"].location != NSNotFound ) {
            return NSOrderedAscending;
        }
        if( [str1 rangeOfString:@"Light"].location != NSNotFound || [str1 rangeOfString:@"Condensed"].location != NSNotFound ) {
            return NSOrderedDescending;
        }
        if( [str2 rangeOfString:@"Light"].location != NSNotFound || [str2 rangeOfString:@"Condensed"].location != NSNotFound ) {
            return NSOrderedAscending;
        }
        return (NSInteger)[str1 caseInsensitiveCompare:str2];
    }];
    return sortedFontNames;
}

-(BOOL)isItalic:(NSString *)fontName {
    return (   [fontName rangeOfString:@"Italic"].location != NSNotFound
            || [fontName rangeOfString:@"Oblique"].location != NSNotFound
            || [fontName hasSuffix:@"It"]
            || [fontName hasSuffix:@"Ita"] );
}

-(BOOL)isBold:(NSString *)fontName {
    return (   [fontName rangeOfString:@"Bold"].location != NSNotFound
            || [fontName rangeOfString:@"Black"].location != NSNotFound
            || [fontName rangeOfString:@"Wide"].location != NSNotFound
            || [fontName hasSuffix:@"-W6"]
            || ([fontName hasSuffix:@"-Medium"] && [fontName rangeOfString:@"Heiti"].location != NSNotFound ));
}

- (void)dealloc {
    [fonts release];
    [super dealloc];
}

@end

FontRegistry_Test.m

//
//  FontRegistry_Test.h
//  Tabris
//
//  Created by Jordi Böhme López on 25.07.2012.
//  Copyright (c) 2012 EclipseSource.
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  which accompanies this distribution, and is available at
//  http://www.eclipse.org/legal/epl-v10.html
//

#import <SenTestingKit/SenTestingKit.h>

@interface FontRegistry_Test : SenTestCase

@end

//
//  FontRegistry_Test.m
//  Tabris
//
//  Created by Jordi Böhme López on 25.07.2012.
//  Copyright (c) 2012 EclipseSource.
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  which accompanies this distribution, and is available at
//  http://www.eclipse.org/legal/epl-v10.html
//
  
#import "FontRegistry_Test.h"
#import "FontRegistry.h"

@implementation FontRegistry_Test

-(void)testIsSingleton {
    FontRegistry *instance1 = [FontRegistry instance];
    FontRegistry *instance2 = [FontRegistry instance];
    
    STAssertEqualObjects(instance1, instance2, nil);
}

-(void)testInstance {
    FontRegistry *instance = [FontRegistry instance];
    
    STAssertNotNil(instance, nil);
}

-(void)testComputesFonts {
    NSArray *fontFamilies = [UIFont familyNames];
    FontRegistry *registry = [FontRegistry instance];
    for (NSString *fontFamily in fontFamilies) {
        STAssertNotNil([registry fontForFamily:fontFamily forBold:NO andItalic:NO], nil);
        STAssertNotNil([registry fontForFamily:fontFamily forBold:YES andItalic:NO], nil);
        STAssertNotNil([registry fontForFamily:fontFamily forBold:NO andItalic:YES], nil);
        STAssertNotNil([registry fontForFamily:fontFamily forBold:YES andItalic:YES], nil);
    }
}

@end

FontResolver.m

//
//  FontResolver.h
//  Tabris
//
//  Created by Jordi Böhme López on 23.07.12.
//  Copyright (c) 2012 EclipseSource.
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  which accompanies this distribution, and is available at
//  http://www.eclipse.org/legal/epl-v10.html
//

#import <Foundation/Foundation.h>

@interface FontResolver : NSObject

+(UIFont*)fontWithDescription:(NSString*)description;

@end

//
//  FontResolver.m
//  Tabris
//
//  Created by Jordi Böhme López on 23.07.12.
//  Copyright (c) 2012 EclipseSource.
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  which accompanies this distribution, and is available at
//  http://www.eclipse.org/legal/epl-v10.html
//

#import "FontResolver.h"
#import "FontRegistry.h"

@implementation FontResolver

NSString *const FONT_FAMILY = @"font-family";
NSString *const FONT_SIZE = @"font-size";
NSString *const FONT_WEIGHT = @"font-weight";
NSString *const FONT_STYLE = @"font-style";

NSString *const FAMILY_SANS_SERIF = @"Helvetica";
NSString *const FAMILY_SERIF = @"Times New Roman";
NSString *const FAMILY_MONOSPACE = @"Courier New";

CGFloat const DEFAULT_FONT_SIZE = 12;

#pragma mark - API Methods

+(UIFont*)fontWithDescription:(NSString*)description {
    UIFont *result = nil;
    CGFloat fontSize = [[self extractSize:description] floatValue];
    BOOL isBold = [[self extractWeight:description] boolValue];
    BOOL isItalic = [[self extractStyle:description] boolValue];
    result = [self computeFont:description forSize:fontSize andBold:isBold andItalic:isItalic];
    if( !result ) {
        result = [self computeFallbackFontForSize:fontSize andBold:isBold andItalic:isItalic];
    }
    return result;
}

#pragma mark - Internal Methods

+(UIFont *)computeFont:(NSString *)description forSize:(CGFloat)size andBold:(BOOL)isBold andItalic:(BOOL)isItalic {
    UIFont *result = nil;
    NSString *fontName = [self extractFontName:description forBold:isBold andItalic:isItalic];
    if( fontName ) {
        UIFont *foundFont = [UIFont fontWithName:fontName size:size];
        if( foundFont ) {
            result = foundFont;
        }
    }
    return result;
}

+(UIFont *)computeFallbackFontForSize:(CGFloat)size andBold:(BOOL)isBold andItalic:(BOOL)isItalic {
    UIFont *result = nil;
    if( isBold ) {
        result = [UIFont boldSystemFontOfSize:size];
    } else if( isItalic ) {
        result = [UIFont italicSystemFontOfSize:size];
    } else {
        result = [UIFont systemFontOfSize:size];
    }
    return result;
}

+(NSString *)extractFontName:(NSString *)description forBold:(BOOL)isBold andItalic:(BOOL)isItalic {
    NSString *result = nil;
    NSString *familyString = [self extractValue:FONT_FAMILY from:description];
    NSArray *families = [self splitFamilies:familyString];
    for (NSString *family in families) {
        NSString *foundFamily = [self findFamily:family];
        result = [[FontRegistry instance] fontForFamily:foundFamily forBold:isBold andItalic:isItalic]; //replace this with [UIFont fontWithMarkupDescription:] when it's public
        if( result ) {
            return result;
        }
    }
    return result;
}

+(NSArray *)splitFamilies:(NSString *)familiesString {
    NSMutableArray *result = [NSMutableArray array];
    NSArray *families = [familiesString componentsSeparatedByString:@","];
    for (NSString *family in families) {
        [result addObject:[self normalizeFamily:family]];
    }
    return result;
}

+(NSString *)normalizeFamily:(NSString *)family {
    NSString *result = trim(family);
    if( [[result lowercaseString] isEqualToString:@"sans-serif"] ) {
        result = FAMILY_SANS_SERIF;
    } else if( [[result lowercaseString] isEqualToString:@"serif"] ) {
        result = FAMILY_SERIF;
    } else if( [[result lowercaseString] isEqualToString:@"monospace"] ) {
        result = FAMILY_MONOSPACE;
    }
    return result;
}

+(NSString *)findFamily:(NSString *)definedFont {
    NSArray *familyNames = [UIFont familyNames];
    for (NSString *familyName in familyNames) {
        if( [familyName isEqualToString:definedFont] ) {
            return familyName;
        }
    }
    return nil;
}

+(NSNumber *)extractSize:(NSString *)description {
    CGFloat result = DEFAULT_FONT_SIZE;
    NSString *pixel = [self extractValue:FONT_SIZE from:description];
    if( pixel ) {
        CGFloat px = [pixel floatValue];
        result = px;
    }
    return [NSNumber numberWithFloat:result];
}

+(NSNumber *)extractWeight:(NSString *)description {
    BOOL result = NO;
    NSString *foundValue = [self extractValue:FONT_WEIGHT from:description];
    if( foundValue && [foundValue isEqualToString:@"bold"] ) {
        result = YES;
    }
    return [NSNumber numberWithBool:result];
}

+(NSNumber *)extractStyle:(NSString *)description {
    BOOL result = NO;
    NSString *foundValue = [self extractValue:FONT_STYLE from:description];
    if( foundValue && [foundValue isEqualToString:@"italic"] ) {
        result = YES;
    }
    return [NSNumber numberWithFloat:result];
}

+(NSString *)extractValue:(NSString *)key from:(NSString *)description {
    NSString *result = nil;
    NSArray *components = [description componentsSeparatedByString:@";"];
    for (NSString *component in components) {
        NSString *keyValue = trim(component);
        if( [keyValue hasPrefix:key] ) {
            result = [keyValue substringFromIndex:[key length]+1];
            result = trim(result);
        }
    }
    return result;
}

NSString * trim(NSString *string) {
    return [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}

@end

FontResolver_Test.m

//
//  FontResolver_Test.h
//  Tabris
//
//  Created by Jordi Böhme López on 23.07.2012.
//  Copyright (c) 2012 EclipseSource.
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  which accompanies this distribution, and is available at
//  http://www.eclipse.org/legal/epl-v10.html
//

#import <SenTestingKit/SenTestingKit.h>

@interface FontResolver_Test : SenTestCase

@end

//
//  FontResolver_Test.m
//  Tabris Client
//
//  Created by Jordi Böhme López on 23.07.2012.
//  Copyright (c) 2012 EclipseSource.
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  which accompanies this distribution, and is available at
//  http://www.eclipse.org/legal/epl-v10.html
//
  
#import "FontResolver_Test.h"
#import "FontResolver.h"

@implementation FontResolver_Test

-(void)assertFont:(UIFont *)actual equals:(UIFont *)expected for:(NSString *)description {
    STAssertEqualObjects([actual fontName], [expected fontName], description);
    STAssertEqualObjects([NSNumber numberWithFloat:[actual pointSize]], [NSNumber numberWithFloat:[expected pointSize]], description);
}

- (void)compareWithDefault:(NSString *)description {
    UIFont *expected = [UIFont performSelector:@selector(fontWithMarkupDescription:) withObject:description];
    UIFont *actual = [FontResolver fontWithDescription:description];
    
    [self assertFont:actual equals:expected for:description];
}

-(void)testExtractSize {
  NSString *description = @"font-size: 24px;";
  
  NSNumber *result = [FontResolver performSelector:@selector(extractSize:) withObject:description];
  
  STAssertEqualObjects([NSNumber numberWithFloat:24], result, nil);
}

-(void)testExtractWeight {
  NSString *description = @"font-weight: bold;";

  NSNumber *result = [FontResolver performSelector:@selector(extractWeight:) withObject:description];
  
  STAssertTrue([result boolValue], nil);
}

-(void)testExtractNoBoldWeight {
  NSString *description = @"font-weight: bla;";
  
  NSNumber *result = [FontResolver performSelector:@selector(extractWeight:) withObject:description];
  
  STAssertFalse([result boolValue], nil);
}

-(void)testExtractNoWeight {
  NSString *description = @"font-family: Arial; font-size: 24px;";

  NSNumber *result = [FontResolver performSelector:@selector(extractWeight:) withObject:description];
  
  STAssertFalse([result boolValue], nil);
}

-(void)testExtractStyle {
  NSString *description = @"font-style: italic;";
  
  NSNumber *result = [FontResolver performSelector:@selector(extractStyle:) withObject:description];
  
  STAssertTrue([result boolValue], nil);
}

-(void)testExtractNoItalicStyle {
  NSString *description = @"font-style: bla;";
  
  NSNumber *result = [FontResolver performSelector:@selector(extractStyle:) withObject:description];
  
  STAssertFalse([result boolValue], nil);
}

-(void)testExtractNoStyle {
  NSString *description = @"font-family: Arial; font-size: 24px;";
  
  NSNumber *result = [FontResolver performSelector:@selector(extractStyle:) withObject:description];
  
  STAssertFalse([result boolValue], nil);
}

-(void)testRegularFallbackFontWithDescription {
    NSString *description = @"font-family: NonExistent; font-size: 24px;";
    
    UIFont *actual = [FontResolver fontWithDescription:description];
    
    STAssertEqualObjects( [[UIFont systemFontOfSize:24] fontName], [actual fontName], nil);
    STAssertEqualObjects( [NSNumber numberWithFloat:[[UIFont systemFontOfSize:24] pointSize]], [NSNumber numberWithFloat:[actual pointSize]], nil);
}

-(void)testItalicFallbackFontWithDescription {
    NSString *description = @"font-family: NonExistent; font-size: 24px; font-style: italic;";
    
    UIFont *actual = [FontResolver fontWithDescription:description];
    
    STAssertEqualObjects( [[UIFont italicSystemFontOfSize:24] fontName], [actual fontName], nil);
    STAssertEqualObjects( [NSNumber numberWithFloat:[[UIFont italicSystemFontOfSize:24] pointSize]], [NSNumber numberWithFloat:[actual pointSize]], nil);
}

-(void)testBoldFallbackFontWithDescription {
    NSString *description = @"font-family: NonExistent; font-size: 24px; font-weight: bold;";
    
    UIFont *actual = [FontResolver fontWithDescription:description];
    
    STAssertEqualObjects( [[UIFont boldSystemFontOfSize:24] fontName], [actual fontName], nil);
    STAssertEqualObjects( [NSNumber numberWithFloat:[[UIFont boldSystemFontOfSize:24] pointSize]], [NSNumber numberWithFloat:[actual pointSize]], nil);
}

-(void)testBoldItalicFallbackFontWithDescription {
    NSString *description = @"font-family: NonExistent; font-size: 24px; font-weight: bold; font-style: italic;";
    
    UIFont *actual = [FontResolver fontWithDescription:description];
    
    STAssertEqualObjects( [[UIFont boldSystemFontOfSize:24] fontName], [actual fontName], nil);
    STAssertEqualObjects( [NSNumber numberWithFloat:[[UIFont boldSystemFontOfSize:24] pointSize]], [NSNumber numberWithFloat:[actual pointSize]], nil);
}

-(void)testSansSerifFontWithDescription {
    NSString *description = @"font-family: sans-serif; font-size: 24px;";
    UIFont *actual = [FontResolver fontWithDescription:description];
    
    STAssertEqualObjects( [[UIFont systemFontOfSize:24] fontName], [actual fontName], nil);
    STAssertEqualObjects( [NSNumber numberWithFloat:[[UIFont systemFontOfSize:24] pointSize]], [NSNumber numberWithFloat:[actual pointSize]], nil);
}

-(void)testSerifFontWithDescription {
    NSString *description = @"font-family: serif; font-size: 24px;";
    
    UIFont *actual = [FontResolver fontWithDescription:description];
    
    STAssertEqualObjects( [[UIFont fontWithName:@"Times New Roman" size:24] fontName], [actual fontName], nil);
    STAssertEqualObjects( [NSNumber numberWithFloat:[[UIFont fontWithName:@"Times New Roman" size:24] pointSize]], [NSNumber numberWithFloat:[actual pointSize]], nil);
}

-(void)testMonospaceFontWithDescription {
    NSString *description = @"font-family: monospace; font-size: 24px;";
    
    UIFont *actual = [FontResolver fontWithDescription:description];
    
    STAssertEqualObjects( [[UIFont fontWithName:@"Courier New" size:24] fontName], [actual fontName], nil);
    STAssertEqualObjects( [NSNumber numberWithFloat:[[UIFont fontWithName:@"Courier New" size:24] pointSize]], [NSNumber numberWithFloat:[actual pointSize]], nil);
}

-(void)testMultipleFontsWithDescription {
    NSString *description = @"font-family: blubb, monospace; font-size: 24px;";
    
    UIFont *actual = [FontResolver fontWithDescription:description];
    
    STAssertEqualObjects( [[UIFont fontWithName:@"Courier New" size:24] fontName], [actual fontName], nil);
    STAssertEqualObjects( [NSNumber numberWithFloat:[[UIFont fontWithName:@"Courier New" size:24] pointSize]], [NSNumber numberWithFloat:[actual pointSize]], nil);
}

-(void)testRegularFontWithDescription {
    [self compareWithDefault:@"font-family: Arial; font-size: 24px;"];
}

-(void)testBoldFontWithDescription {
    [self compareWithDefault:@"font-family: Arial; font-size: 24px; font-weight: bold;"];
}

-(void)testItalicFontWithDescription {
    [self compareWithDefault:@"font-family: Arial; font-size: 24px; font-style: italic;"];
}

-(void)testBoldItalicFontWithDescription {
    [self compareWithDefault:@"font-family: Arial; font-size: 24px; font-weight: bold; font-style: italic;"];
}

-(void)testFontThonburi {
    [self compareWithDefault:@"font-family: Thonburi; font-style: italic;"];
}

-(void)testFontAcademyEngravedLET {
    [self compareWithDefault:@"font-family: Academy Engraved LET; font-style: italic;"];
}

-(void)testFontMarkerFelt {
    [self compareWithDefault:@"font-family: Marker Felt;"];
}

-(void)testFontMarkerFeltBold {
    [self compareWithDefault:@"font-family: Marker Felt; font-weight: bold;"];
}

-(void)testFontBodoni {
    [self compareWithDefault:@"font-family: Bodoni 72 Oldstyle;"];
    [self compareWithDefault:@"font-family: Bodoni 72 Oldstyle; font-weight: bold;"];
    [self compareWithDefault:@"font-family: Bodoni 72 Oldstyle; font-style: italic;"];
    [self compareWithDefault:@"font-family: Bodoni 72 Oldstyle; font-weight: bold; font-style: italic;"];
}

-(void)testFontWithDescriptionComparedToFontWithMarkupDescription {
    NSArray *familyNames = [UIFont familyNames];
    for (NSString *familyName in familyNames) {
        if( [[UIFont fontNamesForFamilyName:familyName] count] == 1 ) {
            [self compareWithDefault:[NSString stringWithFormat:@"font-family: %@;", familyName]];
        } else {
            [self compareWithDefault:[NSString stringWithFormat:@"font-family: %@;", familyName]];
            [self compareWithDefault:[NSString stringWithFormat:@"font-family: %@; font-weight: bold;", familyName]];
            [self compareWithDefault:[NSString stringWithFormat:@"font-family: %@; font-style: italic;", familyName]];
            [self compareWithDefault:[NSString stringWithFormat:@"font-family: %@; font-weight: bold; font-style: italic;", familyName]];
        }
    }
}

@end

I updated the code. Better cast to NSComparisonResult which is an NSInteger (typedef NSInteger NSComparisonResult;)