Compute the page size and world->paper-mm transform for exporting
bounds (metres) at an exact scaleFactor (the "100" in "1:100"),
with marginMm of blank paper around the drawing on every side.
Throws on a non-finite/non-positive scale factor, a non-finite/negative
margin, or degenerate bounds — silently producing a mis-scaled or
zero-size PDF would look plausible and be wrong, which is the failure
that matters most for a document someone measures from.
Compute the page size and world->paper-mm transform for exporting
bounds(metres) at an exactscaleFactor(the "100" in "1:100"), withmarginMmof blank paper around the drawing on every side.Throws on a non-finite/non-positive scale factor, a non-finite/negative margin, or degenerate bounds — silently producing a mis-scaled or zero-size PDF would look plausible and be wrong, which is the failure that matters most for a document someone measures from.