1-bit TIFFs compressed with CCITT Group 3 did not open, place or
relink: the image decoder reads Group 4 only and refuses Compression 2
(modified Huffman) and Compression 3 (ITU-T T.4).
They are now decoded with hayro-ccitt, the CCITT decoder that EPS
import uses. Compression 2 rows start at a byte and have no EOL codes.
Compression 3 rows follow an EOL code and are one-dimensional, or, with
T4Options bit 0, one- or two-dimensional as each row's tag bit says.
Fill bits, FillOrder 2, either PhotometricInterpretation, strips and
tiles are read.
A file whose pixels would take more than the decoding allowance as
RGBA is refused as too large to draw. A strip or tile whose data ends
before its last row is refused as damaged, and so is a tile larger
than the allowance. The strips and tiles together are read from at
most as many bytes as the file holds.
Part of #1466.
Docs: docs/file-format-parity.md, docs/target-app-parity.md.
A PDF's DeviceCMYK image opened as RGB (the interpreter's pixels as a PNG),
so every export wrote it as DeviceRGB or ICC RGB, silently. Images now keep
their CMYK samples, as CMYK colours already did:
- Model: CMYK images are blobs holding CMYK samples, a four-component JPEG
(Adobe's inverted samples) or a Deflate CMYK TIFF. vectorcraft-doc's cmyk
module reads their ink amounts (ImageBlob::is_cmyk, ::cmyk, capped at 64
megapixels) and writes the TIFF (ImageBlob::cmyk_tiff).
- PDF import: DeviceCMYK, CalCMYK and four-component ICC images keep their
samples. A JPEG with Decode [1 0 1 0 1 0 1 0] is kept byte for byte; any
other is decoded (8 or 16 bits, its Decode array applied) and stored as a
CMYK TIFF. Masked CMYK images and 1/2/4-bit ones open in RGB with a warning.
Placing a CMYK TIFF keeps it CMYK too.
- PDF export: CMYK images are written in CMYK (DeviceCMYK, or ICC-based with
the CMYK profile when colours are tagged: PDF/X-3, PDF/X-4, PDF/A). A CMYK
JPEG neither resampled nor recompressed passes through unchanged; others are
resampled in CMYK and compressed as ZIP or as a CMYK JPEG (jpeg-encoder,
which also replaces the ZIP fallback and its warning for images converted to
CMYK). Output conversion treats them like CMYK colours: Preserve Numbers and
PDF/X-1a keep their numbers, Convert to Destination converts them to another
CMYK profile or to RGB through a 17^4 lookup table (cms::CmykLut, now also
behind the renderer's ink table). A CMYK image that can't be decoded is
reported in the warnings.
- Canvas: CMYK images show through the working CMYK profile, as CMYK fills
do, and paint their own inks in ink planes (CMYK raster exports, CMYK
blending). SVG export writes TIFF images as PNG.
Illustrator's Output › No Conversion keeps colour data as it is
(https://helpx.adobe.com/illustrator/using/pdf-options.html).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
One shared colour visitor (`colorcmds::Recolor`, used by Edit Colors, Recolor Artwork, the Blend
commands, the proxy Invert/Complement and Document Color Mode) maps solid colours, gradient stops
and text runs as before, and now also:
- gradient-mesh points (with fills); Blend grades meshes by their average and keeps their shading;
- embedded images' pixels (`includeImages?`, default on): the image becomes a recoloured copy under
a content key, the original stays for undo and other objects; linked images are left alone;
- the tiles of pattern fills and strokes (`includePatterns?`, default on): one recoloured copy per
pattern saved as a new pattern swatch ("Dots 2"), the original untouched.
Everything stays one undo step; only nodes that change are copied, in one walk of the tree.
- doc: `ImageBlob::map_rgb` (decode, map each distinct colour once, keep alpha, re-encode PNG),
`ImageBlob::content_key` (now also used by image import) and `ImageBlob::png`.
- `recolor.colors` lists mesh points and pattern tile colours too.
- patterncmds: `add_pattern` adds a pattern and its swatch (shared by Make Pattern and Save a Copy).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
dotCooCoo