Re: Pointer/screen problems, part two

[Tim Janik <timj gtk org>]

On Mon, 30 Sep 2002, Owen Taylor wrote:

> Turns out there is another problem as well - when a pointer
> grab is in effect, you can get pointer events where
> x_root/y_root are relative to a different screen than
> event->window, but there is no way to detect it.

whoo, messy.

> My possibly crazy idea for fixing this:
> 
> Add:
>   
>  gboolean g_mem_chunk_owns (GMemChunk *mem_chunk,
>                             gpointer   mem);

nono, don't rely on mem chunk implementations one way
or the other. for certain machines/systems they are already
nothing more than a new/free wrapper (DISABLE_MEM_POOLS),
and g_mem_chunk_destroy() is basically broken there.
mem chunks _have_ to be replaced in a future memory system
rewrite, ading something like g_mem_chunk_owns() simply
adds up to the compatibility maintenance nightmare mem chunks
already introduce.
gosh, why wasn't the mem chunk API correctly deprecated
before 2.0? i could swear i sent an email out on this.

> [ This is cheap to implement currently, could get a little
>   more expensive if we reimplement GMemChunk not to have an
>   area tree, but should always be possible ]
> 
> Then we can have a:
> 
>  void gdk_event_set_screen (GdkEvent *event);

if this is only going to work on events that are allocated
via _gdk_event_new() and thusly freed with gdk_event_free(),
i don't see why you couldn't simply use g_datalist_id_set_data_full().

> That works for events allocated with _gdk_event_new()
> but not for stack allocated evens.

not that i particularly like the idea of gdk_event_set_screen() not
working on stack located events, but then that's due to the
brokeness of allowing events not allocated through _gdk_event_new()
in the first place. so if you do implement gdk_event_set_screen()
based on datasets, you should deprecate event allocations
other than through _gdk_event_new() on the way, so for 3.0, we
have at least the ability to put a screen fields into GdkEvent.

> And a:
> 
>  GdkScreen *gdk_event_get_screen (GdkEvent *event);
> 
> That returns the value from gdk_event_set_screen() if 
> applicable, and otherwise works from event->window.
> 
> Reactions?

shudder ;)

>                                         Owen

---
ciaoTJ