Validate and repair the page-boundary boxes (MediaBox, CropBox, TrimBox,
ArtBox, BleedBox) of input PDFs in triage(), following PDF 2.0:
- Coerce coordinates written in invalid exponential notation, stored by
qpdf/pikepdf as strings (#1398).
- Normalize rectangles whose corners are given in reversed order, which
previously crashed with NegativeDimensionError (#1526).
- Clamp a crop/trim/art/bleed box that extends outside the MediaBox to
their intersection, or discard it when the intersection is empty, which
previously produced a zero-height effective page some viewers rejected
(#1400).
When a box is discarded, clamped, or reinterpreted, a warning recommends
visual inspection of the output. pdfinfo box reading shares the same
coercion helper so PdfInfo no longer crashes on malformed boxes.
Supersedes PR #1691. Thanks @ajdlinux.
Closes#1398, #1526, #1400
James R. Barlow
df84945773