VSE: Implement the bounding box (xform) tool in the seq preview window

Make the "xform" tool/gizmo available for strip transformations in the
sequencer preview window.

Because of the amount of hacks needed to make the gizmo work nicely with
multiple strips at the same time, it was decided to only show the
translate gizmo when multiple strips are selected.

This is because the transforms with multiple strips would appear buggy
because of our lack of shearing support in the transform system.
There is also currently no way to properly sync the gizmo drawing with
the transform when using multiple strips.

Reviewed By: Richard Antalik, Campbell Barton

Differential Revision: http://developer.blender.org/D12729

1 files changed, 4 insertions, 0 deletions

diff --git a/source/blender/sequencer/SEQ_transform.h b/source/blender/sequencer/SEQ_transform.h
index 69db21d4c63..18437680731 100644
--- a/source/blender/sequencer/SEQ_transform.h
+++ b/source/blender/sequencer/SEQ_transform.h
@@ -66,6 +66,10 @@ void SEQ_image_transform_mirror_factor_get(const struct Sequence *seq, float r_m
 void SEQ_image_transform_origin_offset_pixelspace_get(const struct Scene *scene,
                                                       const struct Sequence *seq,
                                                       float r_origin[2]);
+void SEQ_image_transform_quad_get(const struct Scene *scene,
+                                  const struct Sequence *seq,
+                                  bool apply_rotation,
+                                  float r_quad[4][2]);
 void SEQ_image_transform_final_quad_get(const struct Scene *scene,
                                         const struct Sequence *seq,
                                         float r_quad[4][2]);