With only ruler guides selected, X is the position of the vertical ones and Y
that of the horizontal ones; typing a value moves them (guide.move), together
when several are selected.
A point placed by the Pen, the shape tools and the other drawing tools, and a
dragged anchor, lands where two paths cross, where a path crosses a ruler guide
and where two ruler guides cross, with the Smart Guides label "intersect".
A scan's paper is a tenth darker in one corner than in another. Flat Logo found
each tone of it as a colour of its own and traced the bands and the specks
between them: on the scanned inputs 470 paths, 21 px from the art on average.
Two palette colours are now one when the pixels between them are no fewer than
a third of those at the lesser of the two: flat colours leave only their shared
edge between them, tones of one colour fill the gap. Whether the image is flat
art at all is still asked of the tones as found.
Flat Logo on its inputs, all sizes and variants: 3.106 -> 0.090 px off on
average, 88.5 -> 0.82 px at most, 69.9 -> 3.9 paths; clean, aliased, blurred
and noisy art as before.
A flyout's rows were 250 pt wide whatever they held, so in Spanish (and
other languages with long tool names) a name ran into its shortcut. The
rows are now as wide as the longest name and shortcut need, and never
narrower than before.
A save writes a temporary file beside the document and renames it over
it. Some network shares refuse one of those steps although the document
itself can be written. The save now falls back, without giving up what
the rename is for:
- the temporary file can't be created beside the document: it is made
in the system's temporary folder (for its owner only);
- the rename is refused: the content, whole and flushed in the
temporary file, is copied into the document itself;
- when that copy fails, the temporary file stays and the error names
it; when the document can't be opened for writing, it is untouched
and the first error is returned;
- permissions that can't be copied to the temporary file (SMB, FAT) no
longer fail the save.
A folder that isn't there and a full volume fail as before.
Snap Curves To Lines made every straight piece within 2.5 degrees of level or
upright exactly so, whatever its length: a 200 px line 2 degrees off had each end
moved 3.5 px. Now a piece is levelled only when neither end moves more than
1.6 px; a longer line that far off is left as the image has it.
Technical Drawing (the preset with the option on) on its inputs: largest
distance from the art 4.21 -> 1.46 px (1.43 before levelling existed), mean
0.178 -> 0.126 px; on the askew inputs 98% -> 70% of the outline comes out level
or upright.
Gradients (params `gradients`, a checkbox in the panel for Grayscale and Color;
off unless asked for): an area whose colour changes evenly along one direction
is traced as one path filled with a linear gradient, not as bands of flat colour.
Gradients are found before the palette is made, so no colour is spent on their
bands: a connected run of smoothly changing pixels is a gradient when a plane
fits each colour channel with all three sloping the same way, the colours along
that way are at most six stops with ramps between them, and painting them back
gives the area's own pixels. Flat colour, soft edges between flat colours and
shading that goes two ways are left as they were.
The harness gains two linear-gradient inputs with known lines and stops, and
measures whether each is found, the angle of its line and the colours of its ramp.
Auto Grouping (params `autoGrouping`, a checkbox in the panel; off unless asked
for): each traced path that has others inside its outer contour comes out in a
group with them, the path first, nested as deep as the picture is. The path that
covers the whole image is nobody's group.
The grouped result paints the same picture: where paths can overlap (stacked
layers, Flat Logo, strokes) a path only joins a path below it, and only if that
moves it under nothing that shares any of its box.
The harness measures three presets with the option on ("grouped %"), painting
them in the grouped order.
Shapes (params `shapes`, a checkbox in the panel; off unless asked for): a filled
outline that is a circle, an ellipse, a rectangle or a regular polygon comes out
as that live shape. A shape is only made when every point of the traced outline
lies within 0.5 px (0.2% of the shape's size, if more) of it; an ellipse whose
radii differ by less than twice that is a circle of its area.
The outline before fitting: a corner's own pixel no longer pulls the two edges
that meet there, and a one-pixel step between two long edges is the corner where
they meet. Sharp corners kept: Default 69% -> 76%, the colour presets 86% -> 91%.
The harness gains plain-shape inputs and "shapes %".
Create: Strokes (the Outline preset, or the option) traced lines along the pixel skeleton: right to a pixel,
with a width counted in pixels, and fitted by a separate, older fitter.
- Each skeleton point is moved to the middle of the line's ink, read from the image across the line: every
pixel counts as much ink as its colour is the line's rather than the paper's, the ink's centroid is the
middle and its sum the width (an anti-aliased or blurred line says both to a fraction of a pixel).
- The stroke width is the median of those widths, no longer a whole number of pixels.
- Each end goes where the ink ends, less the half width a round cap adds.
- Centre lines are fitted as outlines are: a straight line is two anchors, corners stay corners, Snap Curves To
Lines levels them. The old Douglas-Peucker and simplify fitter, and the crate's pathops dependency, go.
Outline on the thin-line inputs, all sizes and variants (docs/image-trace-quality.md), before -> after:
- painted outline 0.310 -> 0.055 px off on average; 81 -> 14 anchors for five lines
- centre line 0.295 -> 0.052 px from the true centre line; stroke width 0.13 -> 0.02 px off; 18.4 -> 2.7
anchors a stroke (blurred, noisy and scanned lines: 2.0 each; aliased: 4.6)
- largest distance 1.84 -> 2.94 px: the square ends of a 10 px line under a round cap
Presets without Create: Strokes are unchanged.
The documented option "replaces slightly curved lines with straight lines and snaps lines near 0 or 90 degrees
to absolute 0 or 90 degrees" (helpx, Image Trace panel options); ours did the first half only.
- With Snap Curves To Lines, a straight piece at least 2 px long and within 2.5 degrees of level or upright is
made exactly so, by moving its ends across it to their mean (the page gives no angle: 2.5 degrees is our
choice). The pieces next to a moved end follow it.
- A junction other regions share stays where it is, so abutting regions still have one curve along their edge;
a line between a junction and a free end is levelled to the junction.
- The harness gains askew inputs (a rectangle, a plus sign and two lines, 1 to 2 degrees off level and upright)
and an "upright %" column: the share of the outline length that is exactly level or upright.
On the clean askew inputs (docs/image-trace-quality.md): Black and White Logo and Technical Drawing, the presets
with the option on, go from 0% to 91% and 95% of their outline exactly level or upright. Their outlines are then
0.49 and 0.59 px from the art as drawn where they were 0.05 (4.2 px at the far end of a 300 px side turned 1.5
degrees): that distance is what the option is for. Presets without the option are unchanged.
Against the documented panel (https://helpx.adobe.com/illustrator/desktop/manage-objects/traces-mockups-symbols/image-trace-panel-options.html):
- Ignore Color: "Ignores a specific color while tracing. Use the color picker to selectively ignore a color."
The panel's Ignore White is now Ignore Color with a colour button beside it (white until another colour is
picked); `imageTrace.make` takes `ignoreColor: "#rrggbb"` beside `ignoreWhite`, and leaves out the palette
colours within about 30 levels of it. Documents saved before have no such setting and ignore white as they
did. Flat Logo mode leaves out white only.
- Auto Color ("Creates a posterized image from a photo or artwork"): Color mode with the Automatic palette.
- Outline ("Simplifies the image to black outlines"): Black and White with Create: Strokes and no fills.
- The Outline preset's name is translated as a preset's name, not as the Outline view's.
Measured (docs/image-trace-quality.md): Auto Color on flat art is 0.140 px off on average with 4.0 paths (16
Colors: 0.141, 4.2). Outline on the line inputs, the first measure of Create: Strokes: 0.310 px off on average,
1.84 at worst, 81 anchors for 5 lines (Line Art's filled outlines: 0.055, 0.96, 46).
Black and White read every pixel as a blend of "black" and "white", and took for those the mean luminance of
the image's black and white pixels. In blurred or scanned line art most black pixels are part paper, so the
mean black was a gray: the middle of every line counted as more than all ink, and by how much changed as the
line crossed the pixel rows, which put a ripple on its edges that the fit then followed with anchors.
- Black is the image's darkest black (the 2nd percentile of its black pixels' luminance).
- White is the lightest pixel within a few pixels of each crack: the paper as it is there. A scan's paper is
darker in one corner than in another, and read against the image's lightest white it counted as part ink.
On each preset's own inputs, all sizes and variants (docs/image-trace-quality.md), before -> after:
- Line Art: 78 -> 46 anchors, outlines 0.093 -> 0.055 px off on average (blurred lines 168 -> 53 anchors,
scanned 199 -> 70); before sub-pixel edges it was 25 anchors and 0.158 px off
- Technical Drawing: 56 -> 46 anchors, 0.092 -> 0.084 px off
- Sketched Art: 0.197 -> 0.186 px off; Default 0.092 -> 0.090; Black and White Logo 0.063 -> 0.059 with
27 -> 29 anchors
Not kept: reading lines up to six pixels deep by their ink's centroid and width, and a looser tolerance for
straight runs, neither of which measured better.
The font scan read /usr/share/fonts, /usr/local/share/fonts, ~/.fonts and the
XDG data folders. Packages add folders outside those to fontconfig's
configuration (TeX Gyre under /usr/share/texmf/fonts), so fc-list and other
apps showed fonts VectorCraft didn't have. The scan now also reads the <dir>
folders of /etc/fonts/fonts.conf and the files it includes (conf.d, the user's
own), as the fontconfig documentation describes them. The files are read as
they are: no library is linked and no program is run.
A drag near an anchor refitted the whole segments on either side of it, so a
short drag over a small bump on a long side turned the side into a curve from
end to end. The segments leading into the anchors under the drag are now split
where they enter the tool's reach, and only what is in reach is refitted.
Live Corners cut a corner between a curve and another side with the handles of
the arc between straight sides. The curve has turned by the time the cut meets
it, so those handles reached past where the tangents at the cut's ends cross,
and from a middling radius on the cut bulged out of the shape or looped. Each
handle is now the share an arc takes of its tangent up to that crossing.
Corners between straight sides are cut as before.
Every colour layer took a mask, component labels, a fill stack and an edge map the size of the whole image,
and as many layers were traced at once as the machine has cores.
- A layer is traced within the box its pixels lie in.
- The stack that fills components holds `u32` indices (a mask has at most 64 million pixels).
- Layers are traced as many at a time as fit in half a gigabyte (about ten bytes a pixel of the largest
layer's box each), on however many cores.
Peak memory above the image itself, photo-like image (docs/image-trace-quality.md), before -> after:
- 16 megapixels: High Fidelity Photo 3,856 -> 880 MB (2.85 -> 3.65 s), Low Fidelity Photo 1,972 -> 754 MB
(1.49 -> 1.80 s), 16 Colors 1,625 -> 298 MB, Shades of Gray 852 -> 407 MB, Default 256 -> 199 MB
- 4 megapixels: High Fidelity Photo 981 -> 643 MB, 16 Colors 408 -> 122 MB, times unchanged
The traces are the same, path for path.
BFlat