A trace whose kept colors were traced and produced no paths gave no
warning, or, with Ignore Color on, said that Ignore Color left those
colors out. The Ignore Color warning now shows only when no kept color
was traced at all, and otherwise the first warning says that the colors
that match keepColors produce no paths. The new message has a row in
each complete-message catalog.
Whether Ignore Color or keepColors leaves a palette entry out is now
decided once per entry, so tracing a layer no longer scans the
keepColors list for each pixel.
Docs: docs/image-trace-adjustments.md.
Image Trace had no way to trace some of an image's colors and leave the
rest out. Ignore Color drops one color, so tracing only the line work of
a multi-color image took a full trace and then deleting the other
colors' paths by hand.
With "keepColors": ["#rrggbb", ...] in the params of imageTrace.make and
imageTrace.makeAndExpand, only the palette colors within about 30 levels
of a listed color are traced, the distance Ignore Color matches by. With
Method Abutting, the kept colors' paths are the same as in a trace of
every color. With Method Overlapping, a kept color's paths do not reach
under the colors left out, as with Ignore Color. An empty list traces
every color, and a value that is not a six-digit hex color is refused.
Flat Logo mode does not use the list.
The reply's warnings name each listed color that matches none of the
colors the trace found, and say when nothing was traced; the status bar
shows the first. The warnings are translated in every complete catalog.
The params help of imageTrace.make lists keepColors and the new
warnings, and the help of imageTrace.makeAndExpand lists the warnings
it returns.
The Automatic palette counts flat art's colours by area (a colour needs
about 1% of the picture, 0.5% at Colors 100) and fits that count with
median cut and area-weighted k-means. A stem, a highlight, or a near
white beside a pale background (within 24 levels, so in one box) was
averaged into a large neighbour; mixed-colour merging and Noise could
then remove what was left.
On the flat route only, after the count is fitted, rare_colours finds
the colours too rare or too close for it and keeps those that are
distinct (at least 2.5 in Oklab x 100 from every palette colour and from
the main colour each stands for), flat (mostly one histogram bin) and
drawn (a 4-connected region of their own unblended pixels of at least 8
pixels, or three of at least 4); a colour lying between two others, as
anti-aliasing mixes them, must also have an inside. At most six, largest
region first. They stay fixed while the other colours are refitted
around them; merge_mixed leaves them alone; denoise_keeping keeps their
regions of 4 pixels or more whatever Noise is (smaller specks still go).
Full Tone, Limited and Automatic's continuous-tone route are unchanged,
and denoise without kept labels is as before.
Methods cited in the code: median cut (Heckbert 1982), k-means (Lloyd
1982), Oklab (Ottosson 2020), salient-colour preservation (Fukuda et al.
2019, doi:10.1117/12.2521607). The rule and its numbers are VectorCraft's
own; Adobe does not document how its palettes are chosen.
Tests (code-drawn): a rare stem or patch over 2-8 flat colours, hard
and anti-aliased at 1x and 2x; near-white highlights on #FFF4E0 kept and
still paths at Noise 16; a 3 px #909090 stem on #808080; scattered
single pixels of the same areas add no colour; denoise_keeping at Noise
0-32.
Measured on 66 synthetic flat logos (22 designs x hard 1x, anti-aliased
1x and 2x; local inputs): every key colour and no spurious one in 66
(was 39); missing key colours 0 (was 43), spurious 0 (was 2), merged
pairs 0 (was 46); rendered dE00 0.348 -> 0.138. Four public-domain scan
crops take the continuous-tone route and are unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018tBcdwNhptqtmX32JCGFzB
The public documentation says Image Trace warns about images larger
than 1500 pixels on a side but traces them, only more slowly. VectorCraft
traced them silently, and refused any trace of more than 2,000,000
anchors, which a 4000 x 3000 photo at High Fidelity Photo nearly reaches
(1.9 million on a code-drawn photo) and a noisier one passes.
- imageTrace.make and makeAndExpand return `warnings`: one for an image
over 1500 px on a side (traced, but more slowly; a lower-fidelity
preset or a smaller copy is quicker), one for an image over 64 MP
that was traced from a scaled-down copy. The app shows the first in
the status bar.
- MAX_TRACE_ANCHORS is 8,000,000 natively (2,000,000 on wasm, where a
page has at most 4 GB). Measured through imageTrace.make on
code-drawn photos: about 90 bytes an anchor kept in the document;
7.9 million anchors kept 685 MB with an 876 MB peak (4000 x 3000,
Full Tone at Colors 100, Paths 100, Noise 1, 37 s).
- The refusal keeps its translated advice: raise Noise, lower Paths or
Colors, or pick a lower-fidelity preset.
Tests: a_large_image_traces_with_a_warning (1600 x 40 and 1500 x 8
code-drawn images, make and make-and-expand),
trace_warnings_name_a_large_or_scaled_down_image, a compile-time check
of the limit's range, and a UI test that the status bar shows the note.
Source:
https://helpx.adobe.com/illustrator/using/image-trace-results-optimization.html
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018tBcdwNhptqtmX32JCGFzB
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