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Migration guide additions

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Some information about plugs and sockets, and event filters.
This commit is contained in:
Matthias Clasen 2011-02-05 01:56:19 -05:00
parent 19092fe44f
commit ab66ac50cf
1 changed files with 78 additions and 0 deletions
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78
docs/reference/gtk/migrating-2to3.xml
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@ -779,6 +779,73 @@ on_alpha_screen_changed (GtkWindow *window,
</para>
</section>
<section>
<title>Event filtering</title>
<para>
If your application uses the low-level event filtering facilities in GDK,
there are some changes you need to be aware of.
</para>
<para>
The special-purpose GdkEventClient events and the gdk_add_client_message_filter() and gdk_display_add_client_message_filter() functions have been
removed. Receiving X11 ClientMessage events is still possible, using
the general gdk_window_add_filter() API. A client message filter like
<informalexample><programlisting>
static GdkFilterReturn
message_filter (GdkXEvent *xevent, GdkEvent *event, gpointer data)
{
XClientMessageEvent *evt = (XClientMessageEvent *)xevent;
/* do something with evt ... */
}
...
message_type = gdk_atom_intern ("MANAGER", FALSE);
gdk_display_add_client_message_filter (display, message_type, message_filter, NULL);
</programlisting></informalexample>
then looks like this:
<informalexample><programlisting>
static GdkFilterReturn
event_filter (GdkXEvent *xevent, GdkEvent *event, gpointer data)
{
XClientMessageEvent *evt;
GdkAtom message_type;
if (((XEvent *)xevent)->type != ClientMessage)
return GDK_FILTER_CONTINUE;
evt = (XClientMessageEvent *)xevent;
message_type = XInternAtom (evt->display, "MANAGER", FALSE);
if (evt->message_type != message_type)
return GDK_FILTER_CONTINUE;
/* do something with evt ... */
}
...
gdk_window_add_filter (NULL, message_filter, NULL);
</programlisting></informalexample>
One advantage of using an event filter is that you can actually
remove the filter when you don't need it anymore, using
gdk_window_remove_filter().
</para>
<para>
The other difference to be aware of when working with event filters
in GTK+ 3 is that GDK now uses XI2 by default when available. That
means that your application does not receive core X11 key or button
events. Instead, all input events are delivered as XIDeviceEvents.
As a short-term workaround for this, you can force your application
to not use XI2, with gdk_disable_multidevice(). In the long term,
you probably want to rewrite your event filter to deal with
XIDeviceEvents.
</para>
</section>
<section>
<title>Backend-specific code</title>
<para>
@ -822,6 +889,17 @@ on_alpha_screen_changed (GtkWindow *window,
</para>
</section>
<section>
<title>GtkPlug and GtkSocket</title>
<para>
The #GtkPlug and #GtkSocket widgets are now X11-specific, and you
have to include the <filename>&lt;gtk/gtkx.h&gt;</filename> header
to use them. The previous section about proper handling of
backend-specific code applies, if you care about other backends.
</para>
</section>
<section>
<title>The GtkWidget::draw signal</title>
<para>