gistfile1.m

// UIFont+Utility.h
// UIFont+Utility.[h|m] is (C) Kerri Shotts 2013, and released under an MIT license.

#import <UIKit/UIKit.h>

/**
 *
 * PKFontNormal = no modifications to the font; i.e., -Regular, -Roman, -Book, etc.
 * PKFontBold   = bold font desired (if possible); i.e., -Bold, -Black, -Heavy, etc.
 * PKFontItalic = italic font desired (if possible); i.e., -Italic, -Oblique, etc.
 *
 */
typedef enum {
  PKFontNormal = 0,
  PKFontBold   = 1 << 0,
  PKFontItalic = 1 << 1
} PKFontAttribute;

@interface UIFont (Utility)

/**
 *
 * Returns a string usable for [UIFont fontWithName:size:] based upon the supplied fontName
 * and attributes. 
 *
 * For example:
 *
 *     [UIFont fontForFamilyName: @"Helvetica" withAttributes: PKFontBold] ==> "Helvetica-Bold"
 *
 * In addition, if the font name has the word "Bold" or "Italic" (or both), the attributes will
 * be used as well, so:
 *
 *     [UIFont fontForFamilyName: @"Helvetica Bold" withAttributes: PKFontNormal] ==> "Helvetica-Bold"
 *
 * If a font does not support the desired attributes, the nearest rendition is used. In this
 * case if a font supports bold but not italic, and we request a bold, italic font, the result
 * will be a bold font instead. Likewise, the reverse is true -- if a font only supports italic,
 * and we request a bold, italic font, we'll get italic back instead. 
 *
 * For fonts not supported by the mapping matrix, the original font name is returned (minus the
 * "Bold" and "Italic" attributes). This is used to support "Symbol" and other fonts with only
 * one style. 
 *
 */
+(NSString *)fontForFamilyName: (NSString *)fontName withAttributes: (PKFontAttribute)attributes;

/**
 *
 * Convenience method if you're not going to use the attributes parameter above.
 *
 */
+(NSString *)fontForFamilyName: (NSString *)fontName;

/**
 *
 * Returns a font with the specified fontName (using the above fontForFamilyName:withAttributes method)
 * and if the font is not found, uses the altFontName (using the same method above). If no font is yet
 * found, Helvetica is returned.
 *
 * THIS MEANS THAT YOU WILL NEVER BE PRINTING TEXT WITH A NIL FONT! :-)
 *
 */
+(UIFont *)fontWithName:(NSString *)fontName andSize:(CGFloat)fontSize usingFallback: (NSString *)altFontName;

/**
 *
 * If you have no desire to specify a fallback font, use this method instead.
 * It's also nearly able to drop-in to your code -- just replace "size:" with "andSize:". 
 *
 * For example:
 *
 *     [UIFont fontWithName:@"Helvetica" size:20]
 *
 * becomes
 *
 *     [UIFont fontWithName:@"Helvetica" andSize:20]
 *
 */
+(UIFont *)fontWithName:(NSString *)fontName andSize:(CGFloat)fontSize;

/**
 *
 * Takes the family name of a font instance and tweaks it a bit
 * to return a family name that is semi-orthogonal to the mapping
 * table. Not quite, though, so expect some weirdness.
 *
 */
-(NSString *)mappableFamilyName;

/**
 *
 * Returns YES if the font is italicized.
 *
 */
-(BOOL) isItalicized;

/**
 *
 * Returns YES if the font is bolded.
 *
 */
-(BOOL) isBolded;

/**
 *
 * Returns the bold equivalent of the font instance.
 *
 */
-(UIFont *)boldFont;

/**
 *
 * Returns the italicized equivalent of the font instance.
 *
 */
-(UIFont *)italicFont;

/**
 *
 * Returns the bolded and italicized equivalent of the font instance.
 *
 */
-(UIFont *)boldItalicFont;

/**
 *
 * Returns a font with a new size that is larger or smaller than
 * the original. For example a delta of 6 would return a font 6pts
 * larger than the original.
 *
 */
-(UIFont *)fontWithSizeDelta:(CGFloat)theDelta;

/**
 *
 * Returns a font with the size multiplied by the Delta Percent.
 * For example, if the value is 1.25, the font will be 1.25 times
 * larger than the original.
 *
 */
-(UIFont *)fontWithSizeDeltaPercent:(CGFloat)theDeltaPercent;

@end

gistfile2.m

// UIFont+Utility.m
// UIFont+Utility.[h|m] is (C) Kerri Shotts 2013, and released under an MIT license.

#import "UIFont+Utility.h"

@implementation UIFont (Utility)

+(NSString *)fontForFamilyName: (NSString *)fontName
                withAttributes: (PKFontAttribute)attributes
{
  PKFontAttribute fuzzyAttributes = attributes;
  if ( [fontName rangeOfString:@"Bold"].location != NSNotFound ) fuzzyAttributes |= PKFontBold;
  if ( [fontName rangeOfString:@"Italic"].location != NSNotFound ) fuzzyAttributes |= PKFontItalic;
  NSString *theNewFontName = [[fontName stringByReplacingOccurrencesOfString:@"Bold" withString:@""]
                                        stringByReplacingOccurrencesOfString:@"Italic" withString:@""];
  theNewFontName = [theNewFontName stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
  
  static NSDictionary *fontMap;
  if (!fontMap)
  {
    fontMap = @{ //family                      //substitutionary string       //normal  //bold  //italic  //bold-italic
                 @"American Typewriter Light": @[ @"AmericanTypewriter%@",    @"-Light", @"", @"-Light", @""],
                 @"American Typewriter":       @[ @"AmericanTypewriter%@",    @"", @"-Bold", @"", @"-Bold" ],
                 @"Arial":                     @[ @"Arial%@MT",               @"", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Avenir Light":              @[ @"Avenir%@",                @"-Light", @"-Roman", @"-LightOblique", @"-Oblique" ],
                 @"Avenir":                    @[ @"Avenir%@",                @"-Roman", @"-Heavy", @"-Oblique", @"-HeavyOblique" ],
                 @"Avenir Heavy":              @[ @"Avenir%@",                @"-Heavy", @"-Black", @"-HeavyOblique", @"-BlackOblique" ],
                 @"Avenir Next Light":         @[ @"AvenirNext%@",            @"-UltraLight", @"-Regular", @"-UltraLightItalic", @"-Italic" ],
                 @"Avenir Next":               @[ @"AvenirNext%@",            @"-Regular", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Avenir Next Heavy":         @[ @"AvenirNext%@",            @"-Bold", @"-Heavy", @"-BoldItalic", @"-HeavyItalic" ],
                 @"Baskerville":               @[ @"Baskerville%@",           @"", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Bodoni 72":                 @[ @"BodoniSvtyTwoITCTT%@",    @"-Book", @"-Bold", @"-BookIta", @"-Bold" ],
                 @"Bodoni 72 Oldstyle":        @[ @"BodoniSvtyTwoOSITCTT%@",  @"-Book", @"-Bold", @"-BookIt", @"-Bold" ],
                 @"Chalkboard Light":          @[ @"ChalkboardSE%@",          @"-Light", @"-Regular", @"-Light", @"-Regular" ],
                 @"Chalkboard":                @[ @"ChalkboardSE%@",          @"-Regular", @"-Bold", @"-Regular", @"-Bold" ],
                 @"Cochin":                    @[ @"Cochin%@",                @"", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Copperplate Light":         @[ @"Copperplate%@",           @"-Light", @"", @"-Light", @"" ],
                 @"Copperplate":               @[ @"Copperplate%@",           @"", @"-Bold", @"", @"-Bold" ],
                 @"Courier":                   @[ @"Courier%@",               @"", @"-Bold", @"-Oblique", @"-BoldOblique" ],
                 @"Courier New":               @[ @"CourierNewPS%@MT",        @"", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Didot":                     @[ @"Didot%@",                 @"", @"-Bold", @"-Italic", @"-Bold" ],
                 @"Euphemia UCAS":             @[ @"EuphemiaUCAS%@",          @"", @"-Bold", @"-Italic", @"-Bold" ],
                 @"Futura Medium":             @[ @"Futura-Medium%@",         @"", @"", @"Italic", @"Italic" ],
                 @"Geeza Pro":                 @[ @"GeezaPro%@",              @"", @"-Bold", @"", @"-Bold" ],
                 @"Georgia":                   @[ @"Georgia%@",               @"", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Gill Sans Light":           @[ @"GillSans%@",              @"-Light", @"", @"-LightItalic", @"-Italic" ],
                 @"Gill Sans":                 @[ @"GillSans%@",              @"", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Helvetica Light":           @[ @"Helvetica%@",             @"-Light", @"", @"-LightOblique", @"-Oblique" ],
                 @"Helvetica":                 @[ @"Helvetica%@",             @"", @"-Bold", @"-Oblique", @"-BoldOblique" ],
                 @"Helvetica Neue Light":      @[ @"HelveticaNeue%@",         @"-Light", @"", @"-LightItalic", @"-Italic" ],
                 @"Helvetica Neue":            @[ @"HelveticaNeue%@",         @"", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Hoefler Text":              @[ @"HoeflerText%@",           @"-Regular", @"-Black", @"-Italic", @"-BlackItalic" ],
                 @"Marion":                    @[ @"Marion%@",                @"-Regular", @"-Bold", @"-Italic", @"-Bold" ],
                 @"Marker Felt":               @[ @"MarkerFelt%@",            @"-Thin", @"-Wide", @"-Thin", @"-Wide" ],
                 @"Noteworthy":                @[ @"Noteworthy%@",            @"-Light", @"-Bold", @"-Light", @"-Bold" ],
                 @"Open Dyslexic":             @[ @"OpenDyslexic%@",          @"-Regular", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Optima":                    @[ @"Optima%@",                @"-Regular", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Palatino":                  @[ @"Palatino%@",              @"-Roman", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Snell Roundhand":           @[ @"SnellRoundhand%@",        @"", @"-Bold", @"", @"-Bold" ],
                 @"Times New Roman":           @[ @"TimesNewRomanPS%@MT",     @"", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Trebuchet MS":              @[ @"TrebuchetMS%@",           @"", @"-Bold", @"-Italic", @"-BoldItalic" ],
                 @"Verdana":                   @[ @"Verdana%@",               @"", @"-Bold", @"-Italic", @"-BoldItalic" ]
               };
  }
  
  NSArray *theFont = [fontMap objectForKey:theNewFontName];
  if (theFont)
  {
    NSString *theSubstitutionary = theFont[0];
    NSString *theSubstitionText = theFont[ (NSUInteger)fuzzyAttributes + 1 ];
    return [NSString stringWithFormat:theSubstitutionary, theSubstitionText];
  }
  else
  {
    // return the original -- just in case (for things like Symbol)
    return fontName;
  }
}

+(NSString *)fontForFamilyName: (NSString *)fontName
{
  return [UIFont fontForFamilyName:fontName withAttributes:PKFontNormal];
}

+(UIFont *)fontWithName:(NSString *)fontName andSize:(CGFloat)fontSize usingFallback: (NSString *)altFontName
{
  UIFont *theFont = [UIFont fontWithName: [UIFont fontForFamilyName:fontName] size:fontSize];
  if (!theFont)
  {
    theFont = [UIFont fontWithName: [UIFont fontForFamilyName:altFontName] size:fontSize];
  }
  if (!theFont)
  {
    theFont = [UIFont fontWithName: [UIFont fontForFamilyName:@"Helvetica"] size:fontSize];
  }
  return theFont;
}

+(UIFont *)fontWithName:(NSString *)fontName andSize:(CGFloat)fontSize
{
  return [UIFont fontWithName:fontName andSize:fontSize usingFallback:@"Helvetica"];
}

-(NSString *)mappableFamilyName
{
  NSString *theFamilyName = self.familyName;
  if ([self.fontName rangeOfString:@"Light"].location != NSNotFound)
  {
    theFamilyName = [theFamilyName stringByAppendingString: @" Light"];
  }
  return theFamilyName;
}

-(BOOL) isItalicized
{
  return [self.fontName rangeOfString:@"Italic"].location != NSNotFound ||
         [self.fontName rangeOfString:@"Oblique"].location != NSNotFound ||
         [self.fontName rangeOfString:@"BookIt"].location != NSNotFound; // Bodoni.
}

-(BOOL) isBolded
{
  return [self.fontName rangeOfString:@"Bold"].location != NSNotFound ||
         [self.fontName rangeOfString:@"Heavy"].location != NSNotFound ||
         [self.fontName rangeOfString:@"Black"].location != NSNotFound;
}

-(UIFont *)boldFont
{
  if (self.isItalicized)
  {
    return [UIFont fontWithName:[ self.mappableFamilyName stringByAppendingString: @" Bold Italic" ] andSize:self.pointSize
                   usingFallback: self.fontName];
  }
  else
  {
    return [UIFont fontWithName:[ self.mappableFamilyName stringByAppendingString: @" Bold" ] andSize:self.pointSize                   usingFallback: self.fontName];
  }
}

-(UIFont *)italicFont
{
  if (self.isBolded)
  {
    return [UIFont fontWithName:[ self.mappableFamilyName stringByAppendingString: @" Bold Italic" ] andSize:self.pointSize                   usingFallback: self.fontName];
  }
  else
  {
    return [UIFont fontWithName:[ self.mappableFamilyName stringByAppendingString: @" Italic" ] andSize:self.pointSize                   usingFallback: self.fontName];
  }
}

-(UIFont *)boldItalicFont
{
  return [UIFont fontWithName:[ self.mappableFamilyName stringByAppendingString: @" Bold Italic" ] andSize:self.pointSize                   usingFallback: self.fontName];
}

-(UIFont *)fontWithSizeDelta:(CGFloat)theDelta
{
  return [self fontWithSize:self.pointSize + theDelta];
}

-(UIFont *)fontWithSizeDeltaPercent:(CGFloat)theDeltaPercent
{
  return [self fontWithSize:self.pointSize * theDeltaPercent];
}

@end