[Qemu-devel] [PATCH] gtk: Implement grab-on-click behavior in relative mode

[Takashi Iwai]

This patch changes the behavior in the relative mode to be compatible
with other UIs, namely, grabbing the input at the first left click.
It improves the usability a lot; otherwise you have to press ctl-alt-G
or select from menu at each time you want to move the pointer.  Also,
the input grab is cleared when the current mode is switched to the
absolute mode.

The automatic reset of the implicit grabbing is needed since the
switching to the absolute mode happens always after the click even on
Gtk.  That is, we cannot check whether the absolute mode is already
available at the first click time even though it should have been
switched in X11 input driver side.

Signed-off-by: Takashi Iwai <address@hidden>
---

I tested a version with the internal implicit grab flag, but this
simpler behavior is less-confusing in the end (and of course the code
is simpler), so I took this version.

 ui/gtk.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/ui/gtk.c b/ui/gtk.c
index 6668bd8226d5..00fbbccb34b9 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -476,8 +476,15 @@ static void gd_change_runstate(void *opaque, int running, 
RunState state)
 
 static void gd_mouse_mode_change(Notifier *notify, void *data)
 {
-    gd_update_cursor(container_of(notify, GtkDisplayState, 
mouse_mode_notifier),
-                     FALSE);
+    GtkDisplayState *s;
+
+    s = container_of(notify, GtkDisplayState, mouse_mode_notifier);
+    /* release the grab at switching to absolute mode */
+    if (qemu_input_is_absolute() && gd_is_grab_active(s)) {
+        gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(s->grab_item),
+                                       FALSE);
+    }
+    gd_update_cursor(s, FALSE);
 }
 
 /** GTK Events **/
@@ -685,6 +692,14 @@ static gboolean gd_button_event(GtkWidget *widget, 
GdkEventButton *button,
     GtkDisplayState *s = opaque;
     InputButton btn;
 
+    /* implicitly grab the input at the first click in the relative mode */
+    if (button->button == 1 && button->type == GDK_BUTTON_PRESS &&
+        !qemu_input_is_absolute() && !gd_is_grab_active(s)) {
+        gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(s->grab_item),
+                                       TRUE);
+        return TRUE;
+    }
+
     if (button->button == 1) {
         btn = INPUT_BUTTON_LEFT;
     } else if (button->button == 2) {
-- 
1.9.1