PNG, PDF, EPS, legacy `.ai`, packaged zips and saved `.vectorcraft` files
record the wall-clock time they were made in, so the same commands run twice
gave different bytes although the pixels matched (#2880):
PDF /CreationDate and /ModDate D:20261018155816 vs D:20261018155817
PNG the `Creation Time` tEXt entry
.vectorcraft one byte of the stored date
SVG carries no time, and already repeated
`metadata::output_time` is the time a file records: `SOURCE_DATE_EPOCH` when it
holds a non-negative whole number of seconds, else the clock, as the
reproducible-builds specification defines it. A date a command is given
(`file.new {created}`, a save's `modified`) still wins over the variable, and a
blank, negative or non-numeric value is ignored so that an export is never
refused over the environment.
`metadata::now_unix` keeps the real clock and now has exactly two callers, both
of which must not be pinnable from the environment: the recovery heartbeat, and
the seed PDF encryption draws on.
A PDF or PDF-compatible .ai saved with Preserve Editing carries the
native document as an embedded file, with a hash of its pages at the
end of the file's /Desc. The import read /Desc with from_utf8_lossy and
looked for "hash ". /Desc is a PDF text string, which may be written as
UTF-16BE with a byte order mark (ISO 32000-1 7.9.2.2). Written that
way it holds no UTF-8 "hash ", so the import found no hash, took the
editing data as intact and reopened the native document with no
warning, even after another app had changed the pages.
/Desc is now read with text_string, the importer's decoder for text
strings, so the hash is found in UTF-16BE, UTF-8 and PDFDocEncoding.
Changed pages open as artwork with the "changed in another app"
warning. The embedded file's /UF and /F names are decoded the same
way, so editing data named only in UTF-16BE is found.
A /Desc without a hash is still trusted, as before.
The engine built the PDF options without a creation date, so the
writer dated every PDF and PDF-compatible .ai file with the time it
was written. A document created on 2020-01-01 (File › File Info
shows the date) exported as a PDF with today's date in /CreationDate
and xmp:CreateDate. SVG export with the metadata option already
writes the document's own date.
The options now carry the document's File Info created date and the
time of writing as the modification date. A document without a
creation date is dated with the time of writing, as before, so PDF/X
files still get their required date. The PDF writer writes one date
for both, so the export then sets /ModDate, xmp:ModifyDate and the
PDF/A history dates to the time of writing; /CreationDate and
xmp:CreateDate keep the document's date. The page information mark
and the embedded editing data's modification date keep the time of
writing.
Docs: docs/mcp.md (File Info), docs/target-app-parity.md.
Preserve Editing (on in the VectorCraft Default preset) embeds the
native document in the PDF as an embedded file with a hash of the pages
it was written with. document.open of a PDF, .ai or .ait restores it
exactly (restored: true) and falls back to importing the artwork, with a
first warning saying why, when the pages were changed elsewhere or the
data can't be read; SVG and PDF share that fallback and its warnings.
The legacy drawcraft payload name is read too. vectorcraft_pdf gains
editing(), ImportReport.native and PdfOptions.native.
document.save / file.saveAs / Save a Copy write .ai (format "ai" or an
.ai path): every artboard as a PDF that always carries the document and
takes the PDF options; a restored .ai keeps its path so Save writes .ai
again, and .ait templates open their document untitled. The desktop
save dialog lists the formats Save writes. Choosing a standard turns
Preserve Editing off (PDF/A refuses it), Export for Screens and PDFs of
some artboards leave it out with a warning.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Hamza