LoadImage()

loadimage.cpp

#include "CoreGraphics/CGDataProvider.h"
#include "CoreGraphics/CGImage.h"
#include "CoreGraphics/CGBitmapContext.h"

void*	LoadImage( const char *path, int *width, int *height )
{
	CGDataProviderRef	dataProvider = CGDataProviderCreateWithFilename( path );
	UInt8				*pixels = nil;
	
	if( dataProvider )
	{
		CGImageRef			image = CGImageCreateWithPNGDataProvider( dataProvider, NULL, false, kCGRenderingIntentDefault );
		
		if( !image ) image = CGImageCreateWithJPEGDataProvider( dataProvider, NULL, false, kCGRenderingIntentDefault );
		
		if( image )
		{
			/*// this doesn't work because of a bug in CGImageRef that renders a PNG image incorrectly so that zero alpha pixels turn out white
			CFDataRef			data = CGDataProviderCopyData( CGImageGetDataProvider( image ) );
			
			if( data )
			{
				int		length = CFDataGetLength( data );
				
				pixels = (UInt8*) malloc( length );
				
				if( pixels )
				{
					CFDataGetBytes( data, CFRangeMake( 0, length ), pixels );
					
					*width = CGImageGetWidth( image );
					*height = CGImageGetHeight( image );
				}
				
				CFRelease( data );
			}*/
			
			// draw the image transparently onto a CGBitmapContext
			*width = CGImageGetWidth( image );
			*height = CGImageGetHeight( image );
			
			pixels = (UInt8*) malloc( (*width)*(*height)*4 );
			
			if( pixels )
			{
				CGContextRef	context = CGBitmapContextCreate( pixels, *width, *height, 8, *width*4, CGImageGetColorSpace( image ), kCGImageAlphaPremultipliedLast );
				
				if( context )
				{
					CGContextClearRect( context, CGRectMake( 0, 0, *width, *height ) );
					
					CGContextDrawImage( context, CGRectMake( 0, 0, *width, *height ), image );	// now pixels contains image pixels
					
					CGContextRelease( context );
				}
				else
				{
					free( pixels );
					pixels = nil;
				}
			}
			
			CFRelease( image );
		}
		
		CFRelease( dataProvider );
	}
	
	return( pixels );
}