VSE preview transform autokeying improvements

NOTE: this patch originated in T98015 which was split into multiple
reports. While it could be split into multiple patches these are very
much related so keeping as one for now

This patch fixes the following issues:

[1] autokeying transforms in preview only creates keyframes if there is
an FCurve already
[2] autokeying transforms in preview only creates keyframes for
rotation/scale if rotating/scaling around cursor (should keyframe
position as well)
[3] autokeying transforms in preview does not work during animation
playback

For [1], a param was added to `ED_autokeyframe_property` which can tweak
its default behavior of only creating keyframes on already keyed
properties (which was fine because this is mostly called from buttons
where this behavior is desired). Callers such as gizmos (or the VSE in
our case) can use this additional param so that keyframes are also
created on "not-yet-keyframed" properties.

For [2], the pivot is checked and position properties also keyed if
necessary (which is also consistent with the way objects are keyed in
the 3DView)

For [3], `animrecord_check_state` was changed to be able to work on
scenes as well and the transform system in the VSE preview was made
aware of the screen's `animtimer`.

NOTE: there are still things to be improved for keyframing in the VSE,
the most obvious is probably a `keyframe_insert` operator (with
keyingsets)

Fixes T98429, T98430, T98431

Maniphest Tasks: T98015, T98431, T98430, T98429

Differential Revision: https://developer.blender.org/D15047

1 files changed, 4 insertions, 0 deletions

diff --git a/source/blender/editors/transform/transform_generics.c b/source/blender/editors/transform/transform_generics.c
index 975dbc2e986..e45cac36736 100644
--- a/source/blender/editors/transform/transform_generics.c
+++ b/source/blender/editors/transform/transform_generics.c
@@ -358,6 +358,10 @@ void initTransInfo(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *eve
   }
   else if (t->spacetype == SPACE_SEQ && region->regiontype == RGN_TYPE_PREVIEW) {
     t->options |= CTX_SEQUENCER_IMAGE;
+
+    /* Needed for autokeying transforms in preview during playback. */
+    bScreen *animscreen = ED_screen_animation_playing(CTX_wm_manager(C));
+    t->animtimer = (animscreen) ? animscreen->animtimer : NULL;
   }
 
   setTransformViewAspect(t, t->aspect);