iOS RGBA Color Information of CGPoint

CFDataRef CopyImagePixels(CGImageRef inImage)
{
    return CGDataProviderCopyData(CGImageGetDataProvider(inImage));
}

#import "ColorPickerViewController.h"
#import <CoreGraphics/CoreGraphics.h>

@implementation ColorPickerViewController
@synthesize outputLabel, pictureView;


#pragma mark -
#pragma mark Launch Methods

- (void)viewWillAppear:(BOOL)animated
	{
	UIImage *colorWheelImage = [UIImage imageNamed:@"colorWheel1.png"];
	self.pictureView.image = colorWheelImage;
	[self createCGContextWithImage:colorWheelImage];
	
	[super viewWillAppear:animated];
	}

- (void)dealloc
	{
	[outputLabel release];
	[pictureView release];
	free(pixelData);
	[super dealloc];
	}


#pragma mark -
#pragma mark Touch Methods

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
	{
	self.view.backgroundColor = [self pixelColorAtLocation:[[touches anyObject] locationInView:self.pictureView]];
	}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
	{
	self.view.backgroundColor = [self pixelColorAtLocation:[[touches anyObject] locationInView:self.pictureView]];
	}	


#pragma mark -
#pragma mark Pixel Data Methods

- (void)createCGContextWithImage:(UIImage*)image
	{
	NSLog(@"CGContext Created Image");
	CGImageRef imageRef = [image CGImage];
	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();	
	NSUInteger imageRefHeight = CGImageGetHeight(imageRef);

	imageRefWidth = CGImageGetWidth(imageRef);
	pixelData = malloc(imageRefWidth * imageRefHeight * 4);

	NSUInteger bytesPerPixel = 4;
	NSUInteger bytesPerRow = (bytesPerPixel * imageRefWidth);
	NSUInteger bitsPerComponent = 8;

	CGContextRef context = CGBitmapContextCreate(pixelData, imageRefWidth, imageRefHeight, bitsPerComponent, bytesPerRow, colorSpace, kCGImageAlphaPremultipliedLast);
	CGContextDrawImage(context, CGRectMake(0, 0, imageRefWidth, imageRefHeight), imageRef);
	CGContextRelease(context);
	}

- (UIColor*)pixelColorAtLocation:(CGPoint)point
	{
	int offset	= 4 * ((imageRefWidth * round(point.y)) + round(point.x));

	int red		= pixelData[offset]; 
	int green	= pixelData[offset+1]; 
	int blue	= pixelData[offset+2]; 
	int alpha	= pixelData[offset+3];
	
	self.outputLabel.text = [NSString stringWithFormat:@"Red:%i\nGreen:%i\nBlue:%i\nAlpha:%i", red, green, blue, alpha];
	return [UIColor colorWithRed:(red/255.0f) green:(green/255.0f) blue:(blue/255.0f) alpha:(alpha/255.0f)];
	}
	
	
@end

CGImageRelease(imageRef);