UILabelWithCGFont.h

//
//  UILabelWithCGFont.h
//
//  Created by Marcus Rohrmoser on 26.08.10.
//  Copyright 2010 Marcus Rohrmoser mobile Software. All rights reserved.
//

/** <a href="http://www.devx.com/tips/Tip/13829">Function pointer</a> for unicode -> glyph conversion.
 *
 * Example implementation:
 * \code
 * CGGlyph unicode2glyphDeutscheDruckschrift(UniChar c)
 * {
 *   if ( '0' <= c && c <= '9' )
 *     return c + (16 - '0');
 *   if ( 'A' <= c && c <= 'Z' )
 *     return c + (32 - 'A');
 *   if ( 'a' <= c && c <= 'z' )
 *     return c + (58 - 'a');
 *   return 0;
 * }
 * \endcode
 */
typedef CGGlyph (*t_UniChar2CGGlyph)(UniChar);

/** Overload UILabel::drawTextInRect: to render using a \c CGFont.
 *
 * Inspired by http://stackoverflow.com/questions/360751/can-i-embed-a-custom-font-in-an-iphone-application
 */
@interface UILabelWithCGFont : UILabel  {
	/// \c NULL falls back to normal \c UILabel behaviour. Set via UILabelWithCustomFont::setCGFont:mapping:
	CGFontRef _CGFont;
	/// <a href="http://www.devx.com/tips/Tip/13829">Function pointer</a> for unicode -> glyph conversion.
	t_UniChar2CGGlyph _mapping;
}

@property (readonly, getter = CGFont) CGFontRef _CGFont;
@property (readonly, getter = mapping) t_UniChar2CGGlyph _mapping;


/**
 * @param name The name of the resource file - see <tt>NSBundle::pathForResource:ofType:</tt>
 * @param extension If extension is an empty string or nil, the extension is assumed not to exist and the file is the first file encountered that exactly matches name. - see <tt>NSBundle::pathForResource:ofType:</tt>
 */
+(CGFontRef)createFontFromFile:(NSString *)name ofType:(NSString *)type;


/** Set UILabelWithCustomFont::customFont - usually a ttf or otf font.
 *
 * Uses <tt>[[NSBundle bundleForClass:self.class] pathForResource:... ofType:...]</tt>.
 *
 * Call with all parameters \c NULL to return to default behaviour.
 *
 * @param font
 * @param mapping C function - see t_UniChar2CGGlyph for an example implementation
 */
-(void)setCGFont:(CGFontRef)font mapping:(t_UniChar2CGGlyph)mapping;


/** Convenience wrapper for UILabelWithCustomFont::setCGFont:mapping:.
 *
 * Uses <tt>[[NSBundle bundleForClass:self.class] pathForResource:... ofType:...]</tt>.
 *
 * Call with all parameters \c nil / \c NULL to return to default behaviour.
 *
 * @param name The name of the resource file - see <tt>NSBundle::pathForResource:ofType:</tt>
 * @param extension If extension is an empty string or nil, the extension is assumed not to exist and the file is the first file encountered that exactly matches name. - see <tt>NSBundle::pathForResource:ofType:</tt>
 * @param mapping C function - see t_UniChar2CGGlyph for an example implementation
 */
-(void)setFontFromFile:(NSString *)name ofType:(NSString *)extension mapping:(t_UniChar2CGGlyph)mapping;

@end

UILabelWithCGFont.m

//
//  UILabelWithCGFont.m
//
//  Created by Marcus Rohrmoser on 26.08.10.
//  Copyright 2010 Marcus Rohrmoser mobile Software. All rights reserved.
//

#import "UILabelWithCGFont.h"


#ifndef MRLogD
#define MRLogD(x, ...) NSLog(@"%s " x, __FUNCTION__, ## __VA_ARGS__)
#endif
#ifndef DEBUG
#define DEBUG 1
#endif

#define DEBUG_LIST_FONT_GLYPH_NAMES 0

@implementation UILabelWithCGFont


+(CGFontRef)createFontFromFile:(NSString *)name ofType:(NSString *)type
{
	MRLogD();
	NSString *fontPath = [[NSBundle bundleForClass:self.class] pathForResource:name ofType:type];
	CGDataProviderRef fontDataProvider = CGDataProviderCreateWithFilename([fontPath UTF8String]);
	CGFontRef customFont = CGFontCreateWithDataProvider(fontDataProvider);
	CGDataProviderRelease(fontDataProvider);
	return customFont;
}


@synthesize _CGFont, _mapping;

-(void)dealloc
{
	MRLogD();
	if ( _CGFont != NULL )
		CGFontRelease(_CGFont);
	[super dealloc];
}


-(void)setFontFromFile:(NSString *)name ofType:(NSString *)type mapping:(t_UniChar2CGGlyph)mapping_
{
	CGFontRef fo = [UILabelWithCGFont createFontFromFile:name ofType:type];
	[self setCGFont:fo mapping:mapping_];
	if ( fo != NULL )
		CGFontRelease(fo);
}


-(void)setCGFont:(CGFontRef)font_ mapping:(t_UniChar2CGGlyph)mapping_;
{
	if ( _CGFont != NULL )
		CGFontRelease(_CGFont);
	_CGFont = font_;
	_mapping = mapping_;
	[self setNeedsDisplay];
	if ( _CGFont == NULL && _mapping == NULL )
		return;
	NSAssert(_CGFont != NULL, @"");
	NSAssert(_mapping != NULL, @"Mapping must be specified");
	CGFontRetain(_CGFont);

#if DEBUG
	{
		NSString *fontName = (NSString *)CGFontCopyFullName(_CGFont);
		NSAssert(fontName != nil, @"Font Name Nil.");
		NSAssert(fontName.length > 0, @"Font Name Empty.");
		MRLogD(@"'%@'", fontName);
		[fontName release];
	}
#endif

#if DEBUG_LIST_FONT_GLYPH_NAMES
	// list all glyph names within the font:
	size_t count = CGFontGetNumberOfGlyphs(_CGFont);
	NSMutableString *names = [NSMutableString stringWithCapacity:(count * 10)];
	for ( CGGlyph i = 0; i < count; i++ ) {
		NSString *name  = (NSString *)CGFontCopyGlyphNameForGlyph(_CGFont, i);
		// NSLog(@"\tglyph[%d] = '%@'", i, name);
		[names appendFormat:@"@\"%@\" /* %d */, ", name, i];
		[name release];
	}
	MRLogD(@"glyphs: %@", names);
#endif

#if !NS_BLOCK_ASSERTIONS
	// @".notdef", @"space", @"exclam", @"quotedbl", @"numbersign", @"dollar", @"percent", @"ampersand", @"quotesingle", @"parenleft", @"parenright", @"asterisk", @"plus", @"comma", @"minus", @"period", @"zero", @"one", @"two", @"three", @"four", @"five", @"six", @"seven", @"eight", @"nine", @"colon", @"semicolon", @"less", @"equal", @"greater", @"question", @"A", @"B", @"C", @"D", @"E", @"F", @"G", @"H", @"I", @"J", @"K", @"L", @"M", @"N", @"O", @"P", @"Q", @"R", @"S", @"T", @"U", @"V", @"W", @"X", @"Y", @"Z", @"a", @"b", @"c", @"d", @"e", @"f", @"g", @"h", @"i", @"j", @"k", @"l", @"m", @"n", @"o", @"p", @"q", @"r", @"s", @"t", @"u", @"v", @"w", @"x", @"y", @"z", @"bar", @"braceright", @"asciitilde", @"quotesinglbase", @"quotedblbase", @"ellipsis", @"dagger", @"quoteleft", @"quoteright", @"quotedblleft", @"quotedblright", @"Adieresis", @"Odieresis", @"Udieresis", @"germandbls", @"adieresis", @"odieresis", @"udieresis"

	// check basic glyphs
	NSArray *numbers = [NSArray arrayWithObjects:@"zero", @"one", @"two", @"three", @"four", @"five", @"six", @"seven", @"eight", @"nine", nil];
	for ( int i = numbers.count - 1; i >= 0; i-- ) {
		UniChar uc = '0' + i;
		NSString *name  = (NSString *)CGFontCopyGlyphNameForGlyph( _CGFont, _mapping(uc) );
		NSString *msg = [NSString stringWithFormat:@"mismatch for UniChar %d", uc];
		NSAssert([[numbers objectAtIndex:i] isEqualToString:name], msg);
		[name release];
	}

	for ( UniChar uc = 'a'; uc <= 'z'; uc++ ) {
		NSString *name  = (NSString *)CGFontCopyGlyphNameForGlyph( _CGFont, _mapping(uc) );
		NSString *msg = [NSString stringWithFormat:@"mismatch for UniChar %d", uc];
		NSAssert(name.length == 1 && uc == [name characterAtIndex:0], msg);
		[name release];
	}

	for ( UniChar uc = 'A'; uc <= 'Z'; uc++ ) {
		NSString *name  = (NSString *)CGFontCopyGlyphNameForGlyph( _CGFont, _mapping(uc) );
		NSString *msg = [NSString stringWithFormat:@"mismatch for UniChar %d", uc];
		NSAssert(name.length == 1 && uc == [name characterAtIndex:0], msg);
		[name release];
	}
#endif
}


-(void)drawTextInRect:(CGRect)rect
{
	MRLogD(@"(%f,%f) (%f,%f)", rect.origin.x, rect.origin.y, rect.size.width, rect.size.height);
	if ( _CGFont == NULL ) {
		[super drawTextInRect:rect];
		return;
	}
	NSAssert(_mapping != NULL, @"Mapping function pointer not set.");

	// prepare the target graphics context.
	const CGContextRef ctx = UIGraphicsGetCurrentContext();
	CGContextSaveGState(ctx);
	{
		// prepare the glyphs array to draw
		const NSString *txt = self.text;
		const size_t glyphCount = txt.length;
		CGGlyph glyphs[glyphCount];
		{
			// turn the string txt into glyphs (indices into the font):
			// give non-allocating unicode character retrieval a try:
			const UniChar *raw_unichars = CFStringGetCharactersPtr( (CFStringRef)txt );
			const UniChar *unichars = raw_unichars == NULL ? malloc( glyphCount * sizeof(UniChar) ) : raw_unichars;
			NSAssert(unichars != NULL, @"unichars not allocated");
			if ( raw_unichars == NULL )
				CFStringGetCharacters( (CFStringRef)txt, CFRangeMake(0, txt.length), (UniChar *)unichars );
			for ( int i = glyphCount - 1; i >= 0; i-- )
				glyphs[i] = _mapping(unichars[i]);
			if ( raw_unichars == NULL )
				free( (void *)unichars );
		}

		CGContextSetFont(ctx, _CGFont);
		CGContextSetFontSize(ctx, self.font.pointSize);
		CGContextSetTextMatrix( ctx, CGAffineTransformMake(1.0, 0.0, 0.0, -1.0, 0.0, 0.0) );

		// first print 'invisible' to measure size:
		CGContextSetTextDrawingMode(ctx, kCGTextInvisible);
		const CGPoint pre = CGContextGetTextPosition(ctx);
		CGContextShowGlyphs(ctx, glyphs, glyphCount);
		const CGPoint post = CGContextGetTextPosition(ctx);
		// restore text position
		CGContextSetTextPosition(ctx, pre.x, pre.y);

		// centered horizontal + vertical:
		NSAssert( (int)rect.origin.x == 0, @"origin.x not zero" );
		NSAssert( (int)rect.origin.y == 0, @"origin.y not zero" );
		NSAssert(self.baselineAdjustment == UIBaselineAdjustmentAlignCenters, @"vertical alignment not 'center'");
		NSAssert(self.textAlignment == UITextAlignmentCenter, @"horizontal alignment not 'center'");
		const CGPoint p = CGPointMake( ( rect.size.width - (post.x - pre.x) ) / 2, (rect.size.height + self.font.pointSize + pre.y) / 2 );

		// finally render it to the graphics context:
		CGContextSetTextDrawingMode(ctx, kCGTextFill);
		CGContextSetFillColorWithColor(ctx, self.textColor.CGColor);
		CGContextShowGlyphsAtPoint(ctx, p.x, p.y, glyphs, glyphCount);
	}
	CGContextRestoreGState(ctx);
}


@end