For sliding doors, custom borders, and other stretchy effects, I’d like a ‘background -extend’ effect. This would stretch an image only at the specified x-y points, preserving the four corners of that image.
123
456
789
would become:
122223
455556
455556
455556
455556
788889
with ‘background-extend: 2px 2px’ and,
111123
444456
444456
444456
444456
777789
with ‘background-extend: 1px 2px’ instead of:
112233
112233
445566
445566
778899
778899
With a regular stretch routine. More useful than first appears.