Codec ░ RGBA

338Accessing RGBA Pixel Data

NSData* pixelData = (NSData*) 
    CGDataProviderCopyData(CGImageGetDataProvider(c.CGImage));
unsigned char* pixelBytes = (unsigned char *)[pixelData bytes];
for(int i = 0; i < [pixelData length]; i += 4) {
        NSLog(@"pixelBytes[i] R:%i G:%i B:%i A:%i ", 
        (int)pixelBytes[i], 
        (int)pixelBytes[i+1], 
        (int)pixelBytes[i+2],
        (int)pixelBytes[i+3]);
        /*
        pixelBytes[i] = pixelBytes[i+3];
        pixelBytes[i+1] = pixelBytes[i+3];
        pixelBytes[i+2] = pixelBytes[i+3];
        pixelBytes[i+3] = 0;
         */
    }
    NSData* newPixelData = [NSData dataWithBytes:pixelBytes length:[pixelData length]];
    UIImage* newImage = [UIImage imageWithData:newPixelData];