objective-ccocoacalayernsviewnsimage

Rendering NSView containing some CALayers to an NSImage

I have an NSView that contains an NSScrollView containing a CALayer-backed NSView. I've tried all the usual methods of capturing an NSView into an NSImage (using -dataWithPDFInsideRect, NSBitmapImageRep's -initWithFocusedViewRect, etc.) However, all these methods treat the CALayer-backed NSView as if it doesn't exist. I've already seen this StackOverflow post, but it was a question about rendering just a CALayer tree to an image, not an NSView containing both regular NSView's and layer-backed views.

Any help is appreciated, thanks :)

Solution

  • The only way I found to do this is to use the CGWindow API's, something like:

    CGImageRef cgimg = CGWindowListCreateImage(CGRectZero, kCGWindowListOptionIncludingWindow, [theWindow windowNumber], kCGWindowImageDefault);

    then clip out the part of that CGImage that corresponds to your view with

    -imageByCroppingToRect.

    Then make a NSImage from the cropped CGImage. Be aware this won't work well if parts of that window are offscreen.