FRImageOperation.m

// Copyright (c) 2011-2012 Jonathan Dalrymple
// 
// 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.
//
//  FRImageOperation.m
//

#import "FRImageOperation.h"

@implementation FRImageOperation

#pragma mark - Object life cycle
- (id)init{
	
	if( !(self = [super init]) ) return nil;

	[self setCanvasSize:CGSizeZero];

	return self;
}

- (id)initWithSize:(CGSize) aSize{
	
	if( !(self = [self init]) ) return nil;
	
	[self setCanvasSize:aSize];
	
	return self;
}


#pragma mark - Methods to be overridden
/**
 *	This method is to overridden by subclasses
 */
- (void)renderInContext:(CGContextRef) aContext{
	//Go forth and draw!!
}

#pragma mark - boilerplate

- (void)main{

  CGContextRef		context;
  void				*bitmapData;
  CGColorSpaceRef		colorSpace;
  int					bitmapByteCount;
  int					bitmapBytesPerRow;
  
  @autoreleasepool {
    //////////////////////////////////////////
    
    bitmapBytesPerRow	= ([self canvasSize].width * 4);
    bitmapByteCount		= (bitmapBytesPerRow * [self canvasSize].height);
    
    //Create the color space
    colorSpace = CGColorSpaceCreateDeviceRGB();
    
    bitmapData = malloc( bitmapByteCount );
    
    //Check the the buffer is alloc'd
    if (bitmapData == NULL) {
      NSLog(@"Buffer could not be alloc'd");
    }
    
    //Create the context
    context = CGBitmapContextCreate(bitmapData, [self canvasSize].width, [self canvasSize].height, 8, bitmapBytesPerRow, colorSpace, kCGImageAlphaPremultipliedLast);
    
    if (context == NULL) {
      NSLog(@"Context could not be created");
    }
    
    //Render user data	
    [self renderInContext:context];
    
    //If they want a result we convert the context to a UIImage
    if ([self resultBlock]) {
      
      CGImageRef image;
      
      image = CGBitmapContextCreateImage(context);
      
      [self resultBlock]([UIImage imageWithCGImage:image]);
      
      CGImageRelease(image);
      
    }
    
    //Cleanup
    free(bitmapData);
    CGColorSpaceRelease(colorSpace);
      
    //////////////////////////////////////////
  }

}

@end