ximagesrc: Fix the destination coordinates of the cursor

XFixes provides the cursor coordinates relative to the root window, this
is not taken into account when using the xid property to capture
a specific window, the result is that the cursor gets drawn at the wrong
position.

In order to fix this consider the window location when calculating the
cursor position in the destination image.

https://bugzilla.gnome.org/show_bug.cgi?id=690646

2 files changed, 26 insertions, 6 deletions

diff --git a/sys/ximage/gstximagesrc.c b/sys/ximage/gstximagesrc.c
index 8058a953b..e8b276b14 100644
--- a/sys/ximage/gstximagesrc.c
+++ b/sys/ximage/gstximagesrc.c
@@ -169,6 +169,9 @@ gst_ximage_src_open_display (GstXImageSrc * s, const gchar * name)
     int status;
     XWindowAttributes attrs;
     Window window;
+    int x, y;
+    Window child;
+    Bool coord_translated;
 
     if (s->xid != 0) {
       status = XGetWindowAttributes (s->xcontext->disp, s->xid, &attrs);
@@ -205,8 +208,19 @@ gst_ximage_src_open_display (GstXImageSrc * s, const gchar * name)
     g_assert (s->xwindow != 0);
     s->width = attrs.width;
     s->height = attrs.height;
-    GST_INFO_OBJECT (s, "Using default window size of %dx%d",
-        s->width, s->height);
+
+    coord_translated = XTranslateCoordinates (s->xcontext->disp, s->xwindow,
+        s->xcontext->root, 0, 0, &x, &y, &child);
+    if (coord_translated) {
+      s->x = x;
+      s->y = y;
+    } else {
+      s->x = 0;
+      s->y = 0;
+    }
+
+    GST_INFO_OBJECT (s, "Using default window size of %dx%d at location %d,%d",
+        s->width, s->height, s->x, s->y);
   }
 use_root_window:
 
@@ -601,8 +615,10 @@ gst_ximage_src_ximage_get (GstXImageSrc * ximagesrc)
     if (ximagesrc->cursor_image) {
       gint x, y, width, height;
 
-      x = ximagesrc->cursor_image->x - ximagesrc->cursor_image->xhot;
-      y = ximagesrc->cursor_image->y - ximagesrc->cursor_image->yhot;
+      x = ximagesrc->cursor_image->x - ximagesrc->cursor_image->xhot -
+          ximagesrc->x;
+      y = ximagesrc->cursor_image->y - ximagesrc->cursor_image->yhot -
+          ximagesrc->y;
       width = ximagesrc->cursor_image->width;
       height = ximagesrc->cursor_image->height;
 
@@ -696,10 +712,12 @@ gst_ximage_src_ximage_get (GstXImageSrc * ximagesrc)
       int startx, starty, iwidth, iheight;
       gboolean cursor_in_image = TRUE;
 
-      cx = ximagesrc->cursor_image->x - ximagesrc->cursor_image->xhot;
+      cx = ximagesrc->cursor_image->x - ximagesrc->cursor_image->xhot -
+          ximagesrc->x;
       if (cx < 0)
         cx = 0;
-      cy = ximagesrc->cursor_image->y - ximagesrc->cursor_image->yhot;
+      cy = ximagesrc->cursor_image->y - ximagesrc->cursor_image->yhot -
+          ximagesrc->y;
       if (cy < 0)
         cy = 0;
       count = ximagesrc->cursor_image->width * ximagesrc->cursor_image->height;
diff --git a/sys/ximage/gstximagesrc.h b/sys/ximage/gstximagesrc.h
index 76506bffc..efaff750a 100644
--- a/sys/ximage/gstximagesrc.h
+++ b/sys/ximage/gstximagesrc.h
@@ -49,6 +49,8 @@ struct _GstXImageSrc
 
   /* Information on display */
   GstXContext *xcontext;
+  gint x;
+  gint y;
   gint width;
   gint height;