将大图裁剪成瓦片

#import int main(int argc, const char * argv[])
{
    @autoreleasepool{
        ?//handle incorrect arguments
        if (argc < 2) {
            NSLog(@"TileCutter arguments: inputfile");
            return 0;
        }
        //input file
        NSString *inputFile = [NSString stringWithCString:argv[1] encoding:NSUTF8StringEncoding];
        //tile size
        CGFloat tileSize = 256; //output path
        NSString *outputPath = [inputFile stringByDeletingPathExtension];
        //load image
        NSImage *image = [[NSImage alloc] initWithContentsOfFile:inputFile];
        NSSize size = [image size];
        NSArray *representations = [image representations];
        if ([representations count]){
            NSBitmapImageRep *representation = representations[0];
            size.width = [representation pixelsWide];
            size.height = [representation pixelsHigh];
        }
        NSRect rect = NSMakeRect(0.0, 0.0, size.width, size.height);
        CGImageRef imageRef = [image CGImageForProposedRect:&rect context:NULL hints:nil];
        //calculate rows and columns
        NSInteger rows = ceil(size.height / tileSize);
        NSInteger cols = ceil(size.width / tileSize);
        //generate tiles
        for (int y = 0; y < rows; ++y) {
            for (int x = 0; x < cols; ++x) {
            //extract tile image
            CGRect tileRect = CGRectMake(x*tileSize, y*tileSize, tileSize, tileSize);
            CGImageRef tileImage = CGImageCreateWithImageInRect(imageRef, tileRect);
            //convert to jpeg data
            NSBitmapImageRep *imageRep = [[NSBitmapImageRep alloc] initWithCGImage:tileImage];
            NSData *data = [imageRep representationUsingType: NSJPEGFileType properties:nil];
            CGImageRelease(tileImage);
            //save file
            NSString *path = [outputPath stringByAppendingFormat: @"_i_i.jpg", x, y];
            [data writeToFile:path atomically:NO];
            }
        }
    }
    return 0;
}