A linear dimension clicked from an anchor to a point that is not an
anchor (a point on a segment, or a point a Smart Guide gave) followed
the art at the anchor end only, so scaling the art turned it into a
long slanted dimension.
- A point on a segment is stored by its curve parameter on that
segment, and stays on it when the segment's anchors or handles are
edited.
- Any other point is stored against anchors (and, for a path whose
anchors lie on one line, handles) of the path under it, or of the
path at the other end, and moves, scales, turns and reflects with
that path. Beside a path whose anchors and handles all lie on one
line, such as a straight line, it keeps its distance along and
across the path: a reflection moves it as a half turn does, and a
scale that is not uniform moves it as a uniform scale does.
- When linked art is reflected, a linear dimension's line goes to the
reflected side, except for art whose anchors and handles lie on one
line.
- Deleting the art, changing its anchor count or whether it is closed,
turning an angle's arm into a curve, or making a measured circle or
arc no longer circular leaves the dimension where it was, no longer
linked, instead of removing it. Undo links it again.
Docs: docs/dimensions.md, docs/target-app-parity.md.
A linear dimension between two clicked points, or dragged out from a
segment, always measured the straight distance between its points and
drew its line parallel to them, so two points at different heights gave
only a slanted dimension. The linear dimensions help describes aligned,
horizontal and vertical linear dimensions: after the second click,
clicking again gives an aligned one and moving the pointer gives a
horizontal or vertical one.
https://helpx.adobe.com/illustrator/desktop/measure-and-align/plot-and-measure/plot-linear-dimensions-of-objects.html
While a linear dimension is being placed, the pointer's position sets
whether it is aligned, horizontal or vertical. The rule is VectorCraft's
own. With the pointer beside the two points (the nearest point of the
line through them lies between them) or on that line, the dimension is
aligned. Past either point, the line through the points and the
perpendicular through that point bound a quarter on each side of the
line. The quarter that holds the direction straight up or down gives
the horizontal distance, and the quarter that holds the direction
straight left or right gives the vertical distance. A click within
reach of the second point, or of where the pointer was for the second
click, places it aligned. Points on one horizontal or vertical line
give an aligned dimension. The dimension stays linked to the anchors it
measures.
- Dimension recipes carry an orientation (aligned by default; files
without it open as before). The line runs along the axis, and each
extension line runs from its point to it.
- dimension.create and dimension.update take orientation: aligned,
horizontal or vertical, for linear dimensions only. Any other value
is an error. A new orientation keeps the line on the side of the
points it was on, and an update that changes nothing records no
undo step.
- A horizontal or vertical dimension keeps its orientation when it or
the art it measures turns, and shows 0 when its points come into line
across its axis. A line that lay outside the points stays outside
them after a turn.
- The hint bar names the two-click placement.
Docs: docs/dimensions.md, the Evidence list in docs/target-app-parity.md.
With the Linear mode, two problems kept a click on an anchor from
taking it:
- A press on an anchor that moved more than 3 pixels before the release
dragged out the dimension of the segment under the pointer and
committed it almost on top of the art. A press on an anchor now picks
it unless the pointer moves past the anchor's 8-pixel reach; a longer
drag still dimensions the segment.
- A pick linked only an anchor of the segment nearest the pointer. An
anchor of another path near that segment, for example one inside a
group lying just inside another object's edge, was taken at most as a
Smart Guides point with no link, so the dimension did not follow it
when the art changed. A pick now links the nearest anchor of any
visible, unlocked path within reach, in groups and compound paths too.
Object > Expand left a dimension's recipe on its group, so the next move
redrew the live dimension and discarded the expanded art. Expand now ends
the live link of a dimension whose art it changes, in the same undo step.
Moving or scaling the group leaves its art as it is, the art no longer
follows what it measured, and undo gives the live dimension back.
Expand Appearance, Create Outlines and Outline Stroke had the same fault
and now do the same, also when they reach only a part of a dimension. A
dimension whose art a command leaves as it was stays live. A dimension
selected with the art it measures becomes a plain group when Expand,
Expand Appearance or Outline Stroke replaces only that art.
Picking the two points of a Linear dimension snapped to anchors and to the
line under the pointer, but showed no guides and ignored the art around it.
The picks now go through the drawing tools' Smart Guides (DrawSnap), hovering
too, so the guides show before each click: a point slides into line with other
objects' anchors and centres, and the second onto the construction guides
through the first. An anchor of the line under the pointer still wins (it
links the dimension to that path), then a guide, then the closest point of the
line (#2432). The guides go once the dimension is being placed.
Test: linear_picks_show_and_snap_to_smart_guides (fails on the old tool, which
showed no overlays while hovering). docs/dimensions.md updated.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Drag out from a segment, corner, circle or arc to place a dimension; plain clicks pick two points or two lines. Radial dimensions on perfect arcs, picas, Away/Between and Left/Center/Right text placement. The Properties panel edits a selected dimension, with Apply to All (dimension.applyToAll) and Set as Default. Dimension Selected Paths, the Arc/R/Ø prefixes and the custom defaults are left out. The refresh returns at once in documents without dimensions (Document::dimensions); a linked dimension moved on its own keeps its place; modes, units, line types, arrows and text placement are enums; the tool has its own icon.
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