Since #733 a flat export from the CLI keeps the document's whole XMP
packet and free-form text, as Save As does; only Export As starts at
Metadata: None. Batch exports of Photoshop masters therefore carry the
full DocumentAncestors list (and the text of every type layer), which
can be many times larger than the image, with no way to leave it out.
`--metadata` is a new export option shared by `convert`, `run --out`
and `batch`. `none` sets ExportOptions::xmp to XmpEmbed::None, the same
path Export As's Metadata: None and Quick Export use, so the XMP packet
and free-form text are dropped while the ICC profile, EXIF and
resolution are written as before; PSD, PSB and .pcraft keep the XMP
either way. `all` is the default, so existing scripts write the same
files. Any other value is a usage error (exit 2) naming the flag,
before anything is read or written.
Tested through the binary for PNG, WebP, JPEG and TIFF from all three
subcommands (packet present by default and with `all`, absent with
`none`; pixels, ICC and resolution unchanged), layered saves, and bad
values. Documented in the CLI book page and file-format parity doc.
ljkx
b5770e4283