A Perceptual linear or radial gradient that mixes spot colors with each
other or with CMYK or gray stops was written as an image in process
colors. It is now written as a DeviceN shading of its inks, with the
stops on its Perceptual curve: at each one, the inks of the two stops on
either side are mixed at the weight where the two colors mixed in
display RGB have the OKLab lightness of the color on the curve.
- Gradient::ink_mixes gives the curve's stops as weights between stops,
under the same 4,096-stop limit as ink_tints.
- Perceptual gradients that mix a spot color with RGB or Lab stops,
dithered fills and freeform gradients stay images, and the warning
now names those cases.
A Perceptual linear or radial gradient was always written as an image,
so a gradient of spot ink tints lost its plate, and no warning named the
spot ink.
PDF export now writes a Perceptual gradient whose stops are tints of one
spot color (and paper white) as a Separation shading in that ink. Its
tints follow the gradient's curve: at each stop the renderer places on
the curve, the tint with the OKLab lightness of the color there.
Dithered fills, freeform gradients and Perceptual gradients that mix a
spot color with other colors are still images, and the export now warns
when such a gradient has stops linked to a spot swatch that its spot
colors are written in process colors.
A linear or radial gradient whose stops mix a spot color with process
colors, or two spot colors, was written in process colors with a
warning. It is now written as a DeviceN shading of the process inks
its stops use and its spot inks, so each spot ink separates onto its
own plate. An off-center midpoint becomes a stop with the inks halfway
between its two stops. A gradient that mixes a spot color with RGB or
Lab colors is still written without the spot ink, with a warning that
says so.
An unclipped opacity mask is drawn on a white backdrop. When an image in
the mask art could not be written (a colorized image whose color channel
is over the size limit, an image that can't be decoded, or one placed
beyond the coordinates a file holds), the backdrop stayed white and the
masked object showed in full where the image should hide it.
The exporter now records an image left out while it writes mask art,
and leaves the masked object out instead of applying the incomplete
mask, with a warning. A failure in a nested mask makes the outer mask
incomplete too.
colorized_image returned before its cache insertion when the image was
missing, left out or undecodable, or when its color channel was larger
than MAX_RASTER_ALLOC. Every placement of such an image then decoded it
and computed its coverage again. Both cases now cache None for the key,
as load_image does.
A colorized image's color channel is the paint's samples repeated once a
pixel, and nothing bounded its size: an image colorized in Registration in
a document with many spot swatches could allocate without limit, and an
overflowing length panicked inside repeat. The length is now computed with
checked arithmetic and refused above MAX_RASTER_ALLOC, the image's own
decode budget, and the export leaves such an image out with the existing
"an image couldn't be decoded" warning instead of drawing it uncolored.
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.
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.
Envelope Options stored Anti-Alias and Preserve Shape Using, but nothing that
draws an image read them: a distorted image was always smoothed and always
cut into clip groups.
- With Anti-Alias off, each piece of a distorted image is marked pixelated
(saved as `pixelated`). The renderer draws it with nearest-neighbor
sampling and without mips, SVG export writes `image-rendering: pixelated`,
and PDF export writes it without /Interpolate.
- With Preserve Shape Using Transparency, each piece is the image with a
white opacity mask in the piece's shape instead of a clip group. The
renderer paints an image whose mask is one plain white path straight into
that path, as it does for an image in a clip group, when the path lies
inside the image's frame.
Docs: docs/mcp.md, docs/target-app-parity.md.
dotCooCoo