Adds support for loading UIImage's from PDF files. I think it's a great way to add resolution-independent graphics to your apps, and also remove the "export to bitmap" step from your workflow. Just save directly from Illustrator!

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Adds support for loading UIImage's from PDF files. I think it's a great way to add resolution-independent graphics to your apps, and also remove the "export to bitmap" step from your workflow. Just save directly from Illustrator!

What it does:

- You can pass the name of a PDF file (with or without the '.pdf') to +[UIImage imageNamed:]
- You can use the name of a PDF file inside Interface Builder, in your UIImageView's
- Turn a multi-page PDF into an array of UIImage's... good for animation.

Feedback to gists @nielsbot.com. Thanks!

.n

UIImage+imageWithPDFNamed.h

//
//  UIImage+PDFSupport.h
//
//  Created by Niels Gabel on 1/11/11.
//  Copyright 2011 PlacePop Inc. All rights reserved.
//
//	Permission is hereby granted, free of charge, to any person obtaining a copy
//	of this software and associated documentation files (the "Software"), to deal
//	in the Software without restriction, including without limitation the rights
//	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//	copies of the Software, and to permit persons to whom the Software is
//	furnished to do so, subject to the following conditions:
//
//	The above copyright notice and this permission notice shall be included in
//	all copies or substantial portions of the Software.
//
//	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//	THE SOFTWARE.


#import <Foundation/Foundation.h>

// This option adds support for using PDFs in UIImageView's in NIB files.
// (You can specify PDF files for image views and they will load in your app,
// but interface builder won't display them)
// Use this option at your own risk; you could potentially fall afoul
// of Apple's SPI rules, but I think it's unlikely.
#define UIImage_PDFSupport_SupportNIBLoading 0

// n.b.: including this category in your project will patch +[ UIImage imageNamed: ] to also support PDF files automagically, like this:
//
//	UIImage * image = [ UIImage imageNamed:@"test.pdf" ] ;
//

@interface UIImage ( PDFSupport )

// returns an array containing images of the pages in a PDF
+(NSArray*)imagesWithPDFNamed:(NSString*)name scale:(CGFloat)scale ;

// returns an array containing images of the pages in a PDF, scaled by 'transform'
+(NSArray*)imagesWithPDFNamed:(NSString*)name scale:(CGFloat)scale transform:(CGAffineTransform)t ;

// returns an image of the first page in a PDF
+(UIImage*)imageWithPDFNamed:(NSString*)name scale:(CGFloat)scale ;

// returns an image of the first page in a PDF, scaled by 'transform'
+(UIImage*)imageWithPDFNamed:(NSString*)name scale:(CGFloat)scale transform:(CGAffineTransform)t ;

@end

UIImage+imageWithPDFNamed.m

//
//  UIImage+PDFSupport.m
//
//  Created by Niels Gabel on 1/11/11.
//  Copyright 2011 PlacePop Inc. All rights reserved.
//
//	Permission is hereby granted, free of charge, to any person obtaining a copy
//	of this software and associated documentation files (the "Software"), to deal
//	in the Software without restriction, including without limitation the rights
//	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//	copies of the Software, and to permit persons to whom the Software is
//	furnished to do so, subject to the following conditions:
//
//	The above copyright notice and this permission notice shall be included in
//	all copies or substantial portions of the Software.
//
//	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//	THE SOFTWARE.

#import "UIImage+UIImagePDFSupport.h"
#import <CoreGraphics/CoreGraphics.h>
#import <objc/runtime.h>

#undef DebugLog

#ifndef DebugAssert
#define DebugAssert(x) assert((x))
#endif


static UIImage * (*old_UIImage_imageNamed)(id target, SEL selector, NSString * name ) = NULL ;

#if UIImage_PDFSupport_SupportNIBLoading
static UIImage * (*oldUIImageNibPlaceholder_InitWithCoder)(id, SEL, NSKeyedUnarchiver*) = NULL ;
static UIImage * UIImageNibPlaceholder_InitWithCoder( id self, SEL _cmd, NSKeyedUnarchiver * unarchiver )
{
	NSString * resourceName = [ unarchiver decodeObjectForKey:@"UIResourceName" ] ;
	UIImage * result = [ UIImage imageNamed:resourceName ] ;
	if ( result )
	{
		[ self autorelease ] ;
		return [ result retain ] ;
	}
	
	return (*oldUIImageNibPlaceholder_InitWithCoder)( self, _cmd, unarchiver ) ;
}
#endif

static UIImage * UIImageWithPDF( id target, SEL selector, NSString * name )
{
	UIImage * result = (*old_UIImage_imageNamed)( target, selector, name ) ;
	if ( !result )
	{
		result = [ UIImage imageWithPDFNamed:name scale:[ UIScreen mainScreen ].scale ] ;
	}
	
	return result ;
}
static CGPDFDocumentRef CreatePDFDocumentWithName( CFStringRef nameCFString )
{
	if ( !nameCFString )
	{
		return NULL ;
	}
	
	NSString * name = (NSString*)nameCFString ;
	name = [ name stringByDeletingPathExtension ] ;
	
	NSString * path = [ [ NSBundle mainBundle ] pathForResource:name ofType:@"pdf" ] ;
	if ( !path )
	{
		return NULL ;
	}
	
	CFURLRef url = CFAutorelease( CFURLCreateWithFileSystemPath( kCFAllocatorDefault, (CFStringRef)path, kCFURLPOSIXPathStyle, false ) ) ;
	DebugAssert( url ) ;
	
	CGPDFDocumentRef doc = CGPDFDocumentCreateWithURL( url ) ;

	return doc ;
}

@implementation UIImage ( PDFSupport )

+(void)load
{	
	NSAutoreleasePool * pool = [[ NSAutoreleasePool alloc ] init ] ;
	
	Method m = class_getClassMethod( [ UIImage class ], @selector( imageNamed: )) ;
	old_UIImage_imageNamed = (UIImage *(*)(id, SEL, NSString*))method_setImplementation( m, (IMP)UIImageWithPDF ) ;
	DebugAssert( old_UIImage_imageNamed ) ;	
	
#if UIImage_PDFSupport_SupportNIBLoading
	oldUIImageNibPlaceholder_InitWithCoder = (UIImage	* (*)(id, SEL, NSKeyedUnarchiver*))class_replaceMethod( NSClassFromString(@"UIImageNibPlaceholder"), @selector( initWithCoder: ), (IMP)UIImageNibPlaceholder_InitWithCoder, "@@:@" ) ;
#endif
	
	[ pool release ] ;
}

+(UIImage*)imageWithPDFPage:(CGPDFPageRef)page scale:(CGFloat)scale transform:(CGAffineTransform)t
{
	if ( !page )
	{
		return nil ;
	}
	
	CGRect box = CGPDFPageGetBoxRect( page, kCGPDFCropBox ) ;
	DebugAssert( box.size.width >= FLT_MIN && box.size.height >= FLT_MIN )
	
	t = CGAffineTransformConcat( CGAffineTransformMakeScale( scale, scale ), t ) ;
	box = CGRectApplyAffineTransform( box, t ) ;
	
	size_t pixelWidth = box.size.width ;
	CGColorSpaceRef cs = CGColorSpaceCreateDeviceRGB() ;
	DebugAssert( cs ) ;
	
	CGContextRef c = CGBitmapContextCreate( NULL, box.size.width, box.size.height, 8, 4 * pixelWidth, cs, kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedLast ) ;
	CGColorSpaceRelease( cs ) ;
	DebugAssert( c ) ;
	
	CGContextConcatCTM( c, t ) ;
	CGContextDrawPDFPage( c, page ) ;
	
	CGImageRef cgImage = CGBitmapContextCreateImage( c ) ;
	DebugAssert( cgImage ) ;
	
	CGContextRelease( c ) ;
	
	UIImage * image = image = [ UIImage imageWithCGImage:cgImage scale:scale orientation:UIImageOrientationUp ] ;
	CGImageRelease( cgImage ) ;
	
	return image ;
}

+(NSArray*)imagesWithPDFNamed:(NSString*)name scale:(CGFloat)scale transform:(CGAffineTransform)t
{
	CGPDFDocumentRef doc = CreatePDFDocumentWithName( (CFStringRef)name ) ;
	
	NSMutableArray * array = [ NSMutableArray array ] ;

	// PDF pages are numbered starting at page 1
	for( size_t pageIndex=1, numberOfPages = CGPDFDocumentGetNumberOfPages( doc ); pageIndex <= numberOfPages; ++pageIndex )
	{
		CGPDFPageRef page = CGPDFDocumentGetPage( doc, pageIndex ) ;
		UIImage * image = [ UIImage imageWithPDFPage:page scale:scale transform:t ] ;
		
		[ array addObject:image ? image : (UIImage*)[ NSNull null ] ] ;
	}
	
	return array ;
}

+(NSArray*)imagesWithPDFNamed:(NSString*)name scale:(CGFloat)scale
{
	return [ self imagesWithPDFNamed:name scale:scale transform:CGAffineTransformIdentity ] ;
}


+(UIImage*)imageWithPDFNamed:(NSString*)name scale:(CGFloat)scale transform:(CGAffineTransform)t
{
	CGPDFDocumentRef doc = CreatePDFDocumentWithName( (CFStringRef)name ) ;
	if ( !doc )
	{
		return NULL ;
	}
		
	// PDF pages are numbered starting at page 1
	CGPDFPageRef page = CGPDFDocumentGetPage( doc, 1 ) ;
	DebugAssert( page ) ;
	
	UIImage * result = [ UIImage imageWithPDFPage:page scale:scale transform:t ] ;
	CFRelease( doc ) ;
	
	return result ;
}

+(UIImage*)imageWithPDFNamed:(NSString*)name scale:(CGFloat)scale
{
	return [ self imageWithPDFNamed:name scale:scale transform:CGAffineTransformIdentity ] ;
}

@end

Also i needed to add

#define CFAutorelease(cf) ((__typeof(cf))[NSMakeCollectable(cf) autorelease])

is this normal?