While selecting and transforming multiple grease pencil frames in the
timeline, frames would sometimes disappear. This happened when the
transformation overlapped, meaning when a frame replaced another moving
one in the timeline. The frames transformation was happening in place
and in series, and thus leaded to the initial position of the frame to
be removed, even if it was occupied by a freshly transformed framed.
This commit fixes the issue by storing two separate maps in the
transform data structure instead of one, one map to store the static
data, meaning the frames that are not affected by the transform, and
another one for the moving data, meaning the frames that are affected by
the transform.
Some changes were made to account for the potential duplication of the
frames (move + duplicate):
* the map of the duplicated frames was renamed to a more explicit name,
* when a duplication occurs, the original frame is stored in the static
frames map, and the duplicate is stored in the moving frames map,
* thus the check for the duplicate flag of the operator is now done at
the init step of the transform, instead of the update step, so that
the maps are initialized accordingly.
Co-authored-by: Lukas Tönne <lukas@blender.org>
Pull Request: https://projects.blender.org/blender/blender/pulls/119337
d0d4bf2068