Re: cursor warp [+PATCH]

[Jon TURNEY <jon dot turney at dronecode dot org dot uk>]

Jon TURNEY wrote:
> Tom George wrote:
> > Cursor warping does not work with the -multiwindow option. It works 
> > fine in the single window mode. I saw some vague references to this 
> > but nothing to indicate it will be fixed. Are there any plans to fix 
> > this?
>
> The first step towards fixing this is a description of the problem that 
> can be understood by someone who isn't in front of your computer :-)
>
> > Otherwise, Cygwin/X work great!

> Tom George wrote:
> I have an application that uses XWarpPointer to relocate the cursor on the screen. I recognize that this is not recommended protocol but it is very useful for this application.
>
> If cygwin X is started without the -multiwindow option, cursor warping works as expected. However, if the -multiwindow option is included, it seems that all calls to XWarpPointer are ignored. Maybe I am doing something wrong on startup or there is an alternate way to warp the cursor.
>
> I saw that there was some early references to this problem related to positioning the cursor on startup
> (http://sourceware.org/ml/cygwin-xfree/2003-05/msg00443.html) but no apparent resolution. If possible, I would like to see the XWarpPointer function work as documented for any windowing configuration.

Much better :-) Even I can understand what the problem is now.
(but for some reason your 2nd mail didn't appear on gmane, so I almost missed it)

The 'cursor positioning on startup' issue is subtly different: the X server 
internally generates a pointer warp at startup to move the pointer to the 
centre of the screen.  XWin takes special steps to ignore this warp, so that 
merely launching the X server doesn't disrupt what the user was doing.

Attached patch enables XWarpCursor to do something in -multiwindow and 
-rootless modes.

Also attached is a small application which functions as testcase for this.

Cygwin/X: Allow pointer warping to work in rootless modes

Mouse pointer warping in multiwindow/rootless mode was never implemented,
due to concerns that moving the  mouse pointer without asking might be rude

This patch allows X applications to move the mouse pointer in rootless modes,
Let's hope they don't abuse this privilege ;-)

---
 xserver/hw/xwin/wincursor.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Index: xorg-server-1.5.3/xserver/hw/xwin/wincursor.c
===================================================================
--- xorg-server-1.5.3.orig/xserver/hw/xwin/wincursor.c	2008-11-05 16:52:16.000000000 +0000
+++ xorg-server-1.5.3/xserver/hw/xwin/wincursor.c	2009-01-12 19:42:54.000000000 +0000
@@ -99,8 +99,16 @@
       return;
     }
 
-  /* Only update the Windows cursor position if we are active */
-  if (pScreenPriv->hwndScreen == GetForegroundWindow ())
+  /*
+     Only update the Windows cursor position if root window is active,
+     or we are in a rootless mode
+  */
+  if ((pScreenPriv->hwndScreen == GetForegroundWindow ())
+      || pScreenPriv->pScreenInfo->fRootless
+#ifdef XWIN_MULTIWINDOW
+      || pScreenPriv->pScreenInfo->fMultiWindow
+#endif
+      )
     {
       /* Get the client area coordinates */
       GetClientRect (pScreenPriv->hwndScreen, &rcClient);

/* 
   Testcase for: Cursor warping

  To compile: 
  gcc -Wall -o test-warp test-warp.c `pkg-config --cflags --libs gtk+-2.0 glib-2.0`

  To use:
  
  X -multiwindow &
  export DISPLAY=:0
  ./test-warp
  
  Press 'Warp' button, cursor should move elsewhere

*/

#include <glib/gprintf.h>
#include <gtk/gtk.h>
#include <gdk/gdkx.h>

GtkWidget *main_window;

static void warp_cursor( GtkWidget *widget,
                         gpointer   data )
{
  Display *dpy = GDK_DISPLAY();
  XWarpPointer(dpy, None, None, 0,0,0,0, +100,+100);
}

static void destroy( GtkWidget *widget,
                     gpointer   data )
{
  gtk_main_quit ();
}

int main( int   argc,
          char *argv[] )
{
    GtkWidget *button;
    gtk_init (&argc, &argv);

    main_window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_decorated (GTK_WINDOW(main_window), TRUE);

    g_signal_connect (G_OBJECT (main_window), "destroy",
		      G_CALLBACK (destroy), NULL);
    gtk_container_set_border_width (GTK_CONTAINER (main_window), 10);

    button = gtk_button_new_with_label ("Warp");
    g_signal_connect (G_OBJECT (button), "clicked",
		      G_CALLBACK (warp_cursor), NULL);

    gtk_container_add (GTK_CONTAINER (main_window), button);
    gtk_widget_show (button);
    gtk_widget_show (main_window);

    gtk_main ();
    return 0;
}

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