Input: Add DeepestSpriteWin function

Does what it says on the box: returns the deepest child window in a
given sprite's trace.

Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: Chase Douglas <chase.douglas@canonical.com>
Reviewed-by: Keith Packard <keithp@keithp.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/inputstr.h b/include/inputstr.h
index bd7c78dec..bc0accc87 100644
--- a/include/inputstr.h
+++ b/include/inputstr.h
@@ -591,4 +591,14 @@ typedef struct _EventSyncInfo {
 
 extern EventSyncInfoRec syncEvents;
 
+/**
+ * Given a sprite, returns the window at the bottom of the trace (i.e. the
+ * furthest window from the root).
+ */
+static inline WindowPtr DeepestSpriteWin(SpritePtr sprite)
+{
+    assert(sprite->spriteTraceGood > 0);
+    return sprite->spriteTrace[sprite->spriteTraceGood - 1];
+}
+
 #endif /* INPUTSTRUCT_H */