The import read each form's /Group /I and /K from the file in order and
matched them to the transparency groups the interpreter pushed. The
interpreter draws a group that adds nothing (full opacity, Normal, no
mask, neither flag) straight onto its parent without pushing it, so every
group after one took another group's flags. Blend steps written as a
knockout group of falling opacity then painted over each other and drew
as solid dark shapes instead of light rings.
The interpreter already reports the flags right after pushing a group
(set_knockout, set_isolated); the import now uses those and drops the
file-order list. That list was capped at 10,000 entries, past which a page
failed to import; that limit goes with it.
Patch and triangle mesh shadings of more than 4,096 patches, and strokes
painted with a mesh shading, came in as a flat grey. Illustrator writes
meshes of up to 14,355 patches, and writes a freeform gradient on a
stroke as a stroke painted with a type 7 shading.
- MAX_PATCHES is 16,384, as in the .ai editing-data reader.
- A stroke painted with a mesh shading is the meshes clipped to the area
the stroke paints (stroke_outline: width, caps, joins, miter limit and
dashes, built in the path's space and then transformed); draw_meshes
always clips a stroke's meshes.
PDF export (and the PDF-compatible .ai it writes) cut each gradient mesh
patch into 8 x 8 flat-coloured quads. Viewers showed colour bands and
hairline seams between them, and files with many meshes became very
large and slow to write.
An opaque mesh is now written as one Type 6 (Coons patch) shading
(ISO 32000-1, 8.7.4.5.7) filling its outline, through the PDF writer's
MeshGradient: each patch blends its corner colours bilinearly, as the
canvas draws it. Colours go through page_color as other fills do, and a
mesh mixing RGB with other models goes through RGB. A mesh with
see-through points, an invalid one, or one past the coordinate range
keeps the quads.
A page drawing one form over and over made its art again for every drawing
with no limit (a 1 KB file took 877 MB), and a form decoding to 64 MiB drawn
a thousand times hung. The import now makes at most half the objects a saved
document may hold (2M, 256K on the web), leaving the rest out with a warning,
and the scan reads at most 2 GiB of form content per page before refusing it
as past the reader's limits.
PDF export writes a CMYK image whose opacity mask is a gray image on its
own pixel grid with the mask as the image's soft mask. That path always
asked viewers to smooth the image, so a pixelated piece of an envelope
with Anti-Alias off was still written with /Interpolate when it had such
a mask. It now takes the pixelated flag as images without a mask do, and
caches the smoothed and pixelated versions apart.
An axial or radial shading's stops are the samples that linear
interpolation does not reproduce. An ink that changes nothing in RGB,
such as a varnish, could paint at dropped samples only, and its spot
swatch was then missing. Every sample now marks the inks it paints with
as used; the stops are unchanged.
A DeviceN color with a spot ink at a tint above 0 together with a process
plate or a second ink imports as RGB. The importer returned before marking
those inks as used, and only used inks become spot swatches, so the spot
ink was missing from the document and from every later export. Shading
stops take the same path, so a DeviceN gradient lost its ink the same way.
The art still imports as RGB with the existing warning; each ink it paints
with now becomes a spot swatch with its 100% color.
Don Omondi