Add a function to find a screen matching a given XWindowAttributes

It allows to find the screen associated to a Window, using it's x and y
position.

2 files changed, 20 insertions, 0 deletions

diff --git a/src/screen.c b/src/screen.c
index b9bb696..7bbc133 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -165,6 +165,24 @@ find_screen (Window w)
   return NULL;
 }
 
+/* Given a window attr, return the rp_screen struct */
+rp_screen *
+find_screen_by_attr (XWindowAttributes attr)
+{
+  rp_screen *cur;
+
+  list_for_each_entry (cur, &rp_screens, node)
+    {
+      if (attr.x >= cur->left &&
+          attr.x <= cur->left + cur->width &&
+          attr.y >= cur->top &&
+          attr.y <= cur->top + cur->height)
+        return cur;
+    }
+
+  return NULL;
+}
+
 /* Return 1 if w is a root window of any of the screens. */
 int
 is_a_root_window (unsigned int w)
diff --git a/src/screen.h b/src/screen.h
index 67d8ab4..69bc032 100644
--- a/src/screen.h
+++ b/src/screen.h
@@ -36,6 +36,8 @@ rp_frame *screen_get_frame (rp_screen *s, int frame_num);
 rp_frame *screen_find_frame_by_frame (rp_screen *s, rp_frame *f);
 
 rp_screen *find_screen (Window w);
+rp_screen *find_screen_by_attr (XWindowAttributes w);
+
 void init_screens (void);
 void activate_screen (rp_screen *s);
 void deactivate_screen (rp_screen *s);