* hayro-interpret: ink colors, overprint and font bytes for the flattener
Local patches for craft-prepress's PDF-in adapter, labeled Craft patch
(flatten) and listed in vendor/README.craft-reader.md:
- Device::set_overprint and Device::set_isolated, called where the
blend mode is set and after an isolated group is pushed.
- Color::ink_paint, ColorSpace::ink_space and ink_values: colors and
image samples as the inks they print, without converting to RGB.
RasterImage::with_inks gives native samples with Decode and Matte.
- OutlineFontData::embedded and index, and the CFF bytes of Type1C
fonts, so text can be embedded again.
- The sh operator ignores /Background (ISO 32000-2 8.7.4.5.1).
* plate-test: flattened-page checks, image alpha and scenes F01, F02
- report::run_flattened separates each scene's page after a caller's
flattener as well as the original, and structure::transparency lists
what transparency a page still has. plate-test doesn't depend on the
flattener.
- Scene images take an alpha channel, written as /SMask.
- F01: a partly transparent image over a flat fill; where its alpha is
0 the fill keeps its exact inks (vectorcraft#2160).
- F02: art hidden under opaque fills leaves no trace after flattening
(vectorcraft#2161).
* prepress: transparency flattener (flatten feature)
craft_prepress::flatten turns PDF pages with transparency into pages
without it, keeping inks, overprint and live text, for PDF/X-1a and
other output that can't carry transparency.
- pdf: reads a page into a display list in inks through hayro-interpret:
paths, outlined strokes, clips, groups, soft masks, overprint, spot
and DeviceN colors, images in their own color space, gradients,
rasterized mesh shadings, tiling patterns and glyph runs.
- font: prepares the source fonts for embedding again (TrueType,
OpenType, CFF wrapped as OpenType); others fall back to outlines with
ActualText.
- geom: planar regions with the shapes that cover each one (linesweeper).
- compose: composites each region per ink (separable and non-separable
blend modes, isolated and knockout groups, overprint per plate as ISO
32000 defines it); regions under images, gradients and soft masks are
marked complex.
- raster: complex regions as DeviceN images through plate mode, grid
snapped with a one-pixel outset; flatten_page.
- write: writes the result with the vendored krilla; flatten_document
writes every page into one PDF with the output intent, page boxes and
fonts shared across pages when their bytes match.
The regions and the compositor are ported from VectorCraft (commit
c2b15982, crates/pathops and crates/engine/src/cmd/flatten.rs), credited
in the crate README. scripts/plate-check.sh --flatten separates every
scene's flattened page with Ghostscript (local only). CI runs
craft-prepress with all features.
* krilla: DeviceN /Colorants from PDF 1.3, NChannel attributes from 1.6 (patch 11)
* prepress: flatten_document output PDF version and PDF/X version
* prepress: format the PDF/X-1a flatten test
* krilla, craft-prepress: write GTS_PDFXConformance next to GTS_PDFXVersion
PDF/X-1a:2003 files carry GTS_PDFXVersion (PDF/X-1:2003) and
GTS_PDFXConformance (PDF/X-1a:2003). Krilla patch 12 adds
SerializeSettings::pdfx_conformance, and FlattenDocumentOptions passes it
through.
* krilla, craft-pdf, craft-prepress: carry the modification date over
Krilla patch 13 adds Metadata::modification_date, written as /ModDate and
xmp:ModifyDate in place of the creation date. craft-pdf's Metadata gains
modified, and flatten_document takes it from the source's ModDate.
* craft-prepress: count the print annotations a read leaves out
ReadReport::dropped_annotations counts the annotations a printer would
paint (Print flag, not Hidden, with a normal appearance) when
ReadOptions::annotations is false; FlattenTotals sums it.
* craft-prepress: degenerate groups rasterize without a soft mask
A group the region sweep fails on is clipped to its members' boxes, which
no other group's items reach, so the paper is its only backdrop. Its
image is written opaque, as the plates of the items over paper, and the
page keeps no transparency for PDF/X-1a.
* craft-prepress: write untouched JPEG images as they are
A DCT-encoded DeviceGray or DeviceCMYK image that krilla's JPEG
passthrough writes with the same meaning (8 bits, no decode parameters,
the default gray Decode or the inverted Adobe CMYK one) keeps its data
in ImageItem::jpeg, and the writer embeds it unchanged when the image
has no soft mask. Other images are still 8-bit Flate samples.
* craft-prepress: keep group members with no transparency above them
Groups are transitive by bounding box, so a background frame put all the
body text on it under a transparent object far away, and the text came
back as outlined fills. A member is now drawn as it is when it is opaque
and, in every region its shapes are in, only members kept this way are
above it. The region fills under it are the composite of the other
members, and it is drawn over them in paint order.
* prepress: keep the backdrop under elements of a knockout group
* prepress: rasterize complex regions thinner than a point
* prepress: mark flatten errors, reasons and reports non_exhaustive
* prepress: bound the items a tiling pattern fill expands into
Each of up to MAX_TILING_CELLS cells copied the whole cell content, and a
cell can hold many items or an expanded pattern of its own. A fill whose
cells would hold more than MAX_TILING_ITEMS items in all, counting groups,
masks and nested patterns, is read as an image.
* prepress: stroke solid past the dash budget
A dash pattern that cuts a stroke into more than 250,000 pieces is outlined
solid, with the estimate hayro's renderer uses.
* prepress: bound the sampling and memory of rasterized tiling patterns
Each pixel sampled every cell over it, which for a BBox far larger than
its step is millions of cells per pixel; past MAX_TILING_CELLS cells per
pixel the fill paints nothing, and below it the image resolution drops to
keep the samples within MAX_TILING_SAMPLES. The canvases also hold a value
per page ink, so their pixel limits shrink with the ink count to keep the
memory of CMYK canvases, and the canvas size uses checked arithmetic.
* prepress: mark the page reader's error and report non_exhaustive
* prepress: format the tiling tests
* prepress: CodeRabbit fixes: no nonzero overprint mode for images and shadings, count dropped tilings, widen the hhea ascender
* prepress: refuse DeviceN spaces past the output's colorant limit and regions past the separated spot inks
* craft-pdf: write URI links only for http(s) with a host and mailto
A document from someone else can carry any link target, and an export
that turns every hyperlink into a PDF URI action hands those targets to
whoever opens the file: script and data URIs, OS protocol handlers,
UNC paths, //host/share, file:// and smb:// links to a host, and
Windows Search links naming a share.
safe_url allows only http and https URLs with a host and mailto with an
address, after trimming whitespace and comparing the scheme
case-insensitively. It is the rule DeckCraft uses for its slide show
and export, and is available without any feature.
write::uri_target returns the Krilla link target for an allowed URL and
None otherwise, so an app that builds its URI links with it writes no
link annotation for a refused target and leaves the page content as
drawn.
* craft-pdf: safe_url needs a real http(s) host and a mailto recipient
Document::add_optional_content_group writes an OCG; Surface::start_optional_content and
end_optional_content mark content with /OC BDC/EMC, registering the group under the stream's
/Properties resources. Marks nest independently of tagging, and misuse returns or records a
KrillaError instead of panicking. The catalog gets /OCProperties (hidden groups in /OFF) and,
opt-in, /PageMode /UseOC. PDF/A-1 reports ValidationError::OptionalContent; below PDF 1.5 the
version requirement is registered too.
print::cmyk_blending(profile) blends transparency in CMYK and writes no
output intent or /Trapped, as a non-PDF/X print PDF does. print::settings
builds on it and adds the GTS_PDFX output intent and /Trapped /False.
Print PDFs written through krilla separated wrongly: transparency groups blended in RGB
(K 50% over C100 separated as C84 M34 Y32 K37 instead of C50 K50), and there was no
overprint, knockout, DeviceN, soft-mask backdrop or print output intent.
Patches in vendor/krilla/patches/, recorded in README.craft.md and SOURCE.json:
- 02 blending color space: GroupColorSpace { Rgb (default, unchanged output), Cmyk }
- 03 overprint: Surface::push_overprint (/op /OP /OPM)
- 04 knockout groups: Surface::push_group(GroupOptions { isolated, knockout })
- 05 soft-mask backdrop and transfer function (/BC /TR)
- 06 DeviceN and NChannel colors for fills and strokes
- 07 DeviceN images and shadings
- 08 print output intent (GTS_PDFX), /Trapped, PDF/X version markers
craft_pdf::write::print::settings(PrintColor) turns them on for print export.
Bring storytold/pdfcraft#2974 (source commit
bae69819594a6385a027fec1f67e6b3c36c259b4) onto the vendored
hayro-interpret and hayro. Knockout transparency groups (/K true) knock
out: while one is innermost, fills, strokes, glyph outlines and shadings
are drawn with Compose::Copy, weighted by coverage. An unmasked image's
rectangle and a nested group's shape are cleared before their layer
composites; the nested group's shape comes from an erase pass over its
content. Masked images and stencils composite as before.
Code comments label the change "Knockout patch (pdfcraft #2974)": the
pull request numbers it hayro-interpret patch 39 and hayro patch 19,
which pdfcraft may renumber. The erase pass resolves resources with
Resources::from_scope, as this tree's form drawing does.
crates/pdf/tests/knockout.rs adapts the pull request's test to the
raster path (without its preview case: craft-pdf has no preview mode).
A plate-mode test checks that a knockout group of two 50% squares
separates with only the top square in the overlap. Options documents
that color_replacement also maps plate films. Ledger, NOTICE and the
source manifests are updated.
Co-authored-by: mtlcl410 <2368091+mtlcl410@users.noreply.github.com>
aiongg
aiongg
skylar taylor-barrick