osd: add change timestamp and screen size to struct sub_bitmap_list

Should be somewhat helpful. (All VOs are full of code trying to
compensate for this, more or less, and this will allow simplifying
some code later. Maybe.)

The screen size is mostly for robustness checks.

1 files changed, 1 insertions, 0 deletions

diff --git a/sub/osd_state.h b/sub/osd_state.h
index 054a98775b..056e54b1a8 100644
--- a/sub/osd_state.h
+++ b/sub/osd_state.h
@@ -49,6 +49,7 @@ struct osd_object {
     // VO cache state
     int vo_change_id;
     struct mp_osd_res vo_res;
+    bool vo_had_output;
 
     // Internally used by osd_libass.c
     bool changed;