On 02/12/2016 09:15 PM, Chris Feng wrote:
> I think the relevant part in 'x_create_tip_frame' is actually:
> 
>   attrs.override_redirect = True;
> 
> What you want to do is to remove the decoration added by the window
> manager.  So you need to set the override-redirect flag on that X
> window.

You're right; thanks! I was navigating the C sources and reached that conclusion as your email came :)

It doesn't seem that there's any Elisp level facility to customize this flag, unfortunately. This means in particular that unless we patch the C sources, there won't be a cross platform solution to this issue, right?

I've started thinking at what a patch would look like; presumably the idea would be to expose the functionality of x_create_tip_frame to Elisp, moving parts of x_show_tip into that function. I could try coming up with a patch, if this is deemed useful.

There's one thing that confuses me, however: some code related to tooltips seems to be duplicated between xfns.c, w32fns.c, etc; are these files auto-generated? Or should I prepare a patch that adjusts all copies of that code?

>> Is there a way to create a borderless frame from Elisp?
> 
> You may have a look at XELB (available on ELPA).  The following code
> should create a frame without decoration.
> 
>   (require 'xcb)
> 
>   (setq frame (make-frame '((visibility . nil))))
> 
>   (let ((window (string-to-number (frame-parameter frame 'outer-window-id)))
>         (connection (xcb:connect-to-socket)))
>     (xcb:+request connection
>         (make-instance 'xcb:ChangeWindowAttributes
>                        :window window
>                        :value-mask xcb:CW:OverrideRedirect
>                        :override-redirect 1))
>     (xcb:flush connection)
>     (xcb:disconnect connection))
> 
>   (make-frame-visible frame)

This is really neat, actually :) Thanks a lot! It works great on my machine.
I'd still like to find a cross-platform solution, though; company isn't X-specific. Am I right to think that this will only work on GNU/Linux?

Clément.