How to use nsview.layer?

[paulrouget]

I'm trying to animate a Cocoa nsview via its layer. But with no luck. What would it take to make it work?

I'm trying for example to set the opacity of a layer. All the conditions to enable core animation are met.

This code crashes:

let content_view: id = msg_send![nswindow, contentView];
let layer: id = msg_send![content_view, layer];
let transform: CGAffineTransform = msg_send![layer, affineTransform];
msg_send![layer, setAffineTransform:transform];

And this code behaves in a strange way:

let content_view: id = msg_send![nswindow, contentView];
let layer: id = msg_send![content_view, layer];
let opacity: CGFloat = msg_send![layer, opacity];
// opacity is equal to 0.
let opacity: CGFloat = 0.5;
msg_send![layer, setOpacity:opacity];
// view disappear
let opacity: CGFloat = msg_send![layer, opacity];
// opacity is still equal to 0.

[metajack]

cc @pcwalton

[oluseyi]

@paulrouget Did you call setWantLayer:YES on the NSView? Unlike on iOS, macOS views are not CALayer-backed by default.

[paulrouget]

Did you call setWantLayer:YES on the NSView? Unlike on iOS, macOS views are not CALayer-backed by default.

Yes.

[oluseyi]

For the first snippet, any chance you got a stack trace?

For the second snippet, did you call setNeedsDisplay:YES, or displayIfNeeded if you wanted to evaluate attributes in the same runloop?

Sorry if the questions seem obvious, just eliminating the low-hanging fruit.

[pcwalton]

You might have to do something special to the NSWindow in order to get Core Animation to work. I think Interface Builder does this for you if you use nibs, but if you're setting things up manually there may be something magic you have to invoke.

[paulrouget]

@pcwalton: Interface Builder does this for you if you use nibs

I use nibs.

@oluseyi: For the first snippet, any chance you got a stack trace?
For the second snippet, did you call setNeedsDisplay:YES, or displayIfNeeded if you wanted to evaluate attributes in the same runloop?

I'll try to get a backtrace and try these later.