Click through custom NSWindow

Question

I have custom NSWindow with custom NSView set as its contentView.

The window gets initialized with:

[window setOpaque:NO];
[window setBackgroundColor: [NSColor clearColor]];
[window setHasShadow: NO];

[window setAcceptsMouseMovedEvents: YES];
[window setLevel: NSFloatingWindowLevel];

Content view, in its drawRect draws simple circle filled by solid color.

All this works OK - the window appears on desktop and I see that circle.

The only thing that does not work: the whole window rectangle is not transparent for mouse clicks. If I will click outside the circle (but inside invisible window box) my view receives mouseDown events but I expect underlying windows (or desktop) to be activated instead.

It appears that I need something like hitTest method to be overridden on my NSWindow class but unfortunately there is no such menthod.

So is the question: is it possible to have NSWindow with custom click through areas in OS X. If "yes" then how?

UPDATE:

Looking on RoundTransparentWindow sample that works as expected - the window is click through in transparent areas. Seems like this piece:

- (void)drawRect:(NSRect)rect {
   ...
   // Reset the window shape and shadow.
    if (shouldDisplayWindow) {
        [[self window] display];
        [[self window] setHasShadow:NO];
        [[self window] setHasShadow:YES];
    }
}

in CustomView.m is related to the problem but even with it (in my case) I cannot achieve transparency for mouse clicks :(

Answer 1

Answering my own question:

On OS X, in order to have windows with custom shapes with click through on transparent areas following conditions must be met:

1. The window must be created with only NSBorderlessWindowMask set by [window setStyleMask: NSBorderlessWindowMask] for example.

2. You MUST NOT call [window setIgnoresMouseEvent: NO] on it. As that method clearly contains a bug on Apple's side.

3. contentView of the window MUST NOT use layers. So something like this [[window contentView] setWantsLayer: YES] effectively disables click through too.

Just in case: all this was about layered windows handling in Sciter on OS X

Answer 2

Thanks to the absolutely incredible answer of c-smile and the absolutely incredible comment of KenThomases,

Here's the basic and simple way to do a "full screen floating app thing" where clicks go through, and conversely you can click on "your" stuff.

You'll need this (for reasons I don't fully understand, the window won't expand fully without it),

and then ...

override func viewWillAppear() {
    super.viewWillAppear()
    guard let w = view.window else {
        print("what the?")
        return
    }
    w.styleMask = .borderless
    // note that you DO NOT do this: w.ignoresMouseEvents = true
    // see comments: https://stackoverflow.com/a/29451199/294884

    w.collectionBehavior = [.fullScreenPrimary]
    w.level = .floating
    w.isMovable = false
    w.titleVisibility = .hidden
    w.titlebarAppearsTransparent = true
    w.standardWindowButton(.closeButton)?.isHidden = true
    w.standardWindowButton(.miniaturizeButton)?.isHidden = true
    w.standardWindowButton(.zoomButton)?.isHidden = true
    w.hasShadow = false
    w.isOpaque = false
    w.backgroundColor = NSColor(red: 1, green: 1, blue: 1, alpha: 0)
    w.zoom(self)

    guard let screen = w.screen ?? NSScreen.main else {
        print("what the???")
        return
    }
    w.setFrame(screen.visibleFrame, display: true)
}