VSE: Image transform tools

Add tools for image manipulation in sequencer preview region.

This includes:
- Translate, rotate and resize operators, tools and gizmos
- Origin for image transformation
- Median point and individual origins pivot modes
- Select and Box select operator works in preview
- Image overlay drawing

ref T90156

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D12105

1 files changed, 7 insertions, 0 deletions

diff --git a/source/blender/editors/transform/transform_generics.c b/source/blender/editors/transform/transform_generics.c
index c493b9bd102..fa323f0c1f7 100644
--- a/source/blender/editors/transform/transform_generics.c
+++ b/source/blender/editors/transform/transform_generics.c
@@ -59,6 +59,8 @@
 #include "UI_resources.h"
 #include "UI_view2d.h"
 
+#include "SEQ_sequencer.h"
+
 #include "transform.h"
 #include "transform_convert.h"
 #include "transform_mode.h"
@@ -335,6 +337,11 @@ void initTransInfo(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *eve
       t->options |= CTX_MASK;
     }
   }
+  else if (t->spacetype == SPACE_SEQ && region->regiontype == RGN_TYPE_PREVIEW) {
+    t->view = &region->v2d;
+    t->around = SEQ_tool_settings_pivot_point_get(t->scene);
+    t->options |= CTX_SEQUENCER_IMAGE;
+  }
   else {
     if (region) {
       /* XXX: For now, get View2D from the active region. */