33409f9f1c
This is only part of the experimental "Full Frame" mode (disabled
by default). See T88150.
Currently the viewer node uses buffer paddings to display image offset
in the backdrop as a temporal solution implemented for {D12466}.
This solution is inefficient memory and performance-wise. Another
issue is that the paddings are part the image when saved.
This patch instead sets the offset in the Viewer node image
as variables and makes the backdrop take it into account
when drawing the image or any related gizmo.
Reviewed By: jbakker
Differential Revision: https://developer.blender.org/D12750