Getting Image Data in iOS

gistfile1.m

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

size_t numberOfComponents = CGColorSpaceGetNumberOfComponents(colorSpace) + 1; // Add 1 for the alpha channel
size_t bitsPerComponent = 8;
size_t bytesPerPixel = (bitsPerComponent * numberOfComponents) / 8;
size_t bytesPerRow = bytesPerPixel * width;

uint8_t *rawData = (uint8_t*)calloc(width * height * numberOfComponents, sizeof(uint8_t));

CGContextRef context = CGBitmapContextCreate(rawData,
                                             width,
                                             height,
                                             bitsPerComponent,
                                             bytesPerRow,
                                             colorSpace,
                                             kCGImageAlphaPremultipliedLast);

CGColorSpaceRelease(colorSpace);

CGContextDrawImage(context, CGRectMake(0, 0, width, height), [anImage CGImage]);

CGContextRelease(context);