Re: Placement of popup ( CellRendererDate from examples )

[muppet <scott asofyet org>]

On Sep 5, 2005, at 11:28 PM, Daniel Kasak wrote:

> muppet wrote:
>
> > > I know ( or I think I know anyway ... I haven't tried it yet ) I   
> > > can do $popup->allocation to get the size of the popup.
> >
> > There's also get_size_request(), which will ask the widget to   
> > calculate the size it wants (which propagates to children); you  
> > can  use this before the widget is onscreen to avoid flicker.
>
> This is returning -1 for x and y sizes.

I told you wrong; gtk_widget_get_size_request() merely fetches the  
existing size request, which is -1,-1 before the widget goes  
onscreen.  gtk_widget_size_request() asks the widget to calculate and  
populate the requisition.  I can never remember which is which  
without going to the docs...

But in this case, it doesn't matter, because the widget it fully  
realized offscreen.

But now that i look at it, this is pretty hackish, and can actually  
result in obnoxious flicker if you have another screen configured to  
the left and above the main one, and even worse if the screen at  
-500,-500 has a different font size.  Unlikely, but hey, it's a  
chance to learn how to use size_request() properly.

    # ensure that you've already called show() on all children of  
$popup
    $popup->realize();
    my $requisition = $popup->size_request();
    my $popup_width = $requisition->width;
    my $popup_height = $requisition->height;
    ...
    $popup->move (...);
    $popup->show;


This leaves you open the the possibility that the allocation is not  
the same as the requisition, but doesn't map-then-move the window.



> Not to worry - allocation() is working fine, and I've got a working  
> solution now.
> I've attached a patch, against the cellrenderer_date.pl from  
> Gtk2-1.081, to fix the issue ... it's a damned useful example ...  
> maybe even a candidate for Gtk2::Ex::CoolStuff or something?
>
> Is this the right place to send patches for the example apps?

Yep.


> --- cellrenderer_date.pl.original    2005-09-06 12:26:08.000000000  
> +1000
> +++ cellrenderer_date.pl    2005-09-06 12:27:47.000000000 +1000
> @@ -212,14 +212,26 @@
>    $popup -> move(-500, -500);
>    $popup -> show_all();
>
> -  # Align the top right edge of the popup with the the bottom  
> right edge of the
> -  # cell.
> +  # Figure out where to put the popup - ie don't put it offscreen,
> +  # as it's not movable ( by the user )
> +  my $screen_height = $popup->get_screen->get_height;
> +  my $popup_height = $popup->allocation->height;
> +
>    my ($x_origin, $y_origin) =  $view -> get_bin_window() ->  
> get_origin();
> -
> -  $popup -> move(
> -    $x_origin + $cell_area -> x() + $cell_area -> width() - $popup  
> -> allocation() -> width(),
> -    $y_origin + $cell_area -> y() + $cell_area -> height()
> -  );
> +
> +  my ($popup_x, $popup_y);
> +
> +  if ($x_origin + $cell_area -> x() + $cell_area -> width() -  
> $popup -> allocation() -> width() < 0) {
> +    $popup_x = 0;
> +  } else {
> +    $popup_x = $x_origin + $cell_area -> x() + $cell_area -> width 
> () - $popup -> allocation() -> width();
> +  }

For brevity and to avoid repeating yourself,

   $popup_x = big hairy calculation;
   $popup_x = 0 if $popup_x < 0;

> +  if ($y_origin + $cell_area->y + $cell_area->height +  
> $popup_height > $screen_height) {
> +    $popup_y = $screen_height - $popup_height;

That just anchors it at the bottom of the screen.  Less surprising,  
and somewhat more useful, is to hang the popup off the top edge of  
the cell instead of the bottom edge, like so:

  my $popup_y = $y_origin + $cell_area -> y() + $cell_area -> height();
  if ($popup_y + $popup_height > $screen_height) {
    $popup_y = $y_origin + $cell_area -> y() - $popup_height;
  }

That way, the user can still click the arrow to pop down easily,  
e.g., if it was an accident to pop it up in the first place.  ;-)

> +  } else {
> +    $popup_y = $y_origin + $cell_area -> y() + $cell_area -> height 
> ();
> +  }

And don't forget to add back the

  $popup->move ($popup_x, $popup_y);


>    # Grab the focus and the pointer.
>    Gtk2 -> grab_add($popup);


It's handy; i'll commit that.  You still get credit.  :-)


--
Without treatment, a common cold will last about seven days.
With treatment, it will last about a week.
  -- conventional wisdom