How do I iterate on EACH PIXEL in a bitmap context? I found some source that seems to be attempting to do this but it is somehow flawed. Can someone tell me how to fix this code so that I can iterate on the RGBA of each pixel?
-(UIImage*)modifyPixels:(UIImage*)originalImage
{
NSData* pixelData = (NSData*)CGDataProviderCopyData(CGImageGetDataProvider(originalImage.CGImage));
void* pixelBytes = [pixelData bytes];
// Take away the red pixel, assuming 32-bit RGBA
for(int i = 0; i < [pixelData length]; i += 4) {
bytes[i] = 0; // red
bytes[i+1] = bytes[i+1]; // green
bytes[i+2] = bytes[i+2]; // blue
bytes[i+3] = bytes[i+3]; // alpha
}
NSData* newPixelData = [NSData dataWithBytes:pixelBytes length:[pixelData length]];
UIImage* newImage = [UIImage imageWithData:newPixelData];
return newImage;
}