How to change these UIs in iOS to Mac OS X

Question

I want change some codes from iOS to Mac OS X, can anyone give me some tips

UIGraphicsBeginImageContext(CGSizeMake( width , height ));
[image drawInRect:CGRectMake(0, 0,width, height)];
image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

and

UIGraphicsGetImageFromCurrentImageContext();

and

UIImageJPEGRepresentation(newImage, 0.75);

thank you.

Answer 1

请参见NSGraphicsContext类参考 。