Re: Clipboard improvements

[Hans Breuer <Hans Breuer org>]

At 17:37 06.05.04, Matthias Clasen wrote:
> I have looked at wrapping the clipboard owner change notification
> provided by the XFIXES extension for gdk. Here is the api I'd like to
> propose for this:
>
> /**
>  * gdk_display_supports_selection_notification:
>  * @display: a #GdkDisplay
>  *
>  * Returns whether #GdkEventOwnerChange events will be
>  * sent when the owner of a selection changes.
>  *
>  * Return value: whether #GdkEventOwnerChange events will
>  *               be sent.
>  *
>  * Since: 2.6
>  **/
> gboolean
> gdk_display_supports_selection_notification (GdkDisplay *display)
>
>
> typedef enum
> {
>   GDK_OWNER_CHANGE_NEW_OWNER,
>   GDK_OWNER_CHANGE_DESTROY,
>   GDK_OWNER_CHANGE_CLOSE
> } GdkOwnerChange;

If I understand correctly this function would query the ability to
kind of register 'listeners' for the change of available clipboard
content (given that 'selection' is a very X centric concept and
from all I read about not that well understood, i.e. PRIMAY,
SECONDARY, ...)
It should be possible for gdk/win32 to generate events on
clipboard change with the windows API SetClipboardViewer()
and than map WM_DRAWCLIPBOARD to the event below.

> struct _GdkEventOwnerChange
> {
>   GdkEventType type;
>   GdkWindow *window;
>   gint8 send_event;
>   GdkNativeWindow owner;
>   GdkOwnerChange reason;
>   GdkAtom selection;
>   guint32 time;
>   guint32 selection_time;
> };
>
>   /**
>    * GtkClipboard::owner-change:
>    * @clipboard: the clipboard which received the signal
>    * @event: the #GtkEventOwnerChange event
>    *
>    * The ::owner-change signal is emitted if the owner of
>    * the clipboard changes. Applications can use this information
>    * to e.g. obtain the supported targets from the new owner and
>    * update the sensitivity of "Paste" menuitems based on that
>    * information.
>    *
>    * Note that not all displays support owner change notification
>    * for selections, see gdk_display_supports_selection_notification().
>    *
>    * Returns: %TRUE if the event was handled
>    *
>    * Since: 2.6
>    */
>
> I'd like to hear from our win32 hackers whether this kind of API can be
> supported on Windows. It would be unfortunate to have
> gdk_display_supports_selection_notification() simply return FALSE on
> Windows, since that information is definitively available in some form.

There are already some coments in gdkselection-win32.c about maybe
implementation problems, e.g. returning NULL for the owner of the
global clipboard, so the new functionality might finally not get a clear
and/or working implementation.
OTOH maybe it's just necessary to clarify the issues/expectations some
more like required in
http://bugzilla.gnome.org/show_bug.cgi?id=63820
http://bugzilla.gnome.org/show_bug.cgi?id=106507
http://bugzilla.gnome.org/show_bug.cgi?id=107320
http://bugzilla.gnome.org/show_bug.cgi?id=111865
http://bugzilla.gnome.org/show_bug.cgi?id=112404
http://bugzilla.gnome.org/show_bug.cgi?id=119290
http://bugzilla.gnome.org/show_bug.cgi?id=129043

not to mention ;(
http://bugzilla.gnome.org/show_bug.cgi?id=58541


Thanks,
        Hans
-------- Hans "at" Breuer "dot" Org -----------
Tell me what you need, and I'll tell you how to
get along without it.                -- Dilbert