A renderer's data window is its crop of the frame; the composition lives
on the whole display window (our MY27 renders: data 1782x1267 at
(1109,1100) inside a 4000x3000 stage). decode_deep now validates the
display window against the limits and reports it as stage + origin on
DeepImage; flatten pads the composed region to the stage at its offset
(transparent elsewhere) and tags the image with a DisplayWindowStage
warning. Files without a usable display window open as before.
Includes a cropped-deep generator and a stage/offset oracle test.
Elvis33LE
1bcb662828