From WWDC 2012 Session 245 (translated to Swift): let viewToCapture = self.window!.contentView! let rep = viewToCapture.bitmapImageRepForCachingDisplay(in: viewToCapture.bounds)! viewToCapture.cacheDisplay(in: viewToCapture.bounds, to: rep) let img = NSImage(size: viewToCapture.bounds.size) img.addRepresentation(rep)
NSImage size method returns size information that is screen resolution dependent. To get the size represented in the actual file image you need to use an NSImageRep. You can get an NSImageRep from an NSImage using the representations method. Alternatively you can create a NSBitmapImageRep subclass instance directly like this: NSArray * imageReps = [NSBitmapImageRep … Read more
Edit: Since this answer is still the accepted answer, but was written without Retina screens in mind, I will straight up link to a better solution further down the thread: Objective-C Swift 4 Because the method of Paresh is totally correct but deprecated since 10.8 I’ll post the working 10.8 code below. All credit to … Read more
You could add a category to NSImage like this @interface NSImage(saveAsJpegWithName) – (void) saveAsJpegWithName:(NSString*) fileName; @end @implementation NSImage(saveAsJpegWithName) – (void) saveAsJpegWithName:(NSString*) fileName { // Cache the reduced image NSData *imageData = [self TIFFRepresentation]; NSBitmapImageRep *imageRep = [NSBitmapImageRep imageRepWithData:imageData]; NSDictionary *imageProps = [NSDictionary dictionaryWithObject:[NSNumber numberWithFloat:1.0] forKey:NSImageCompressionFactor]; imageData = [imageRep representationUsingType:NSJPEGFileType properties:imageProps]; [imageData writeToFile:fileName atomically:NO]; } @end … Read more
If you have an NSImage and want to save it as an image file to the filesystem, you should never use lockFocus! lockFocus creates a new image which is determined for getting shown an the screen and nothing else. Therefore lockFocus uses the properties of the screen: 72 dpi for normal screens and 144 dpi … Read more