2ez4gcxandClaude Opus 5.5 beb6c48a59 AREA, PERIMETER and DISTANCE system variables, as AutoCAD sets them (#2552) ...

* feat(inquiry): AREA, PERIMETER and DISTANCE system variables, as AutoCAD sets them

AREA, DIST and MEASUREGEOM now leave AREA, PERIMETER and DISTANCE for
getvar, read-only and not saved: the area just measured (the running
total in Add and Subtract mode) with the last area's perimeter, and the
distance (the total of Multiple points). After DIST's two points
LASTPOINT stays at the first point, as measured. AREA's Object option
measures splines, closed by their chord like open polylines.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Address review: spline area over narrow spans, finite distances, list order

- AREA of a spline samples it span by span (Spline::tessellate_spans), so
  a narrow knot span no longer drops out of the area. The spread over the
  spans is one helper shared with Spline::bounds, whose boxes are
  unchanged.
- DIST refuses a distance that isn't finite on all three paths and leaves
  DISTANCE as it was.
- sysvars::list puts the session's values after the drawing's header, so
  it shows what get returns (AREA, ORTHOMODE, LWDISPLAY...).
- LASTPOINT after DIST's Multiple points is pinned to AutoCAD 2024's
  measured behaviour: the last point entered, also after Length and Undo.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Address review: measure every knot span of a spline in AREA

A spline with more knot spans than half the sample cap fell back to an
even grid over the domain, which can step over a narrow span and measure
the wrong area: a 100 x 100 square as a degree-1 spline, its right and
top edges two spans a millionth wide after 4,500 spans along the bottom,
measured 4,998.75.

Spread the samples over the spans at any span count: at least one
segment per span, within the cap up to MAX_SAMPLES spans and one each
past it, as Spline::length integrates every span. One evaluation per
span costs 85-285 ms on a million spans in a release build, against
32-52 s for the length AREA already takes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Address review: share AREA's spline samples by how much each span bends

Past the sample cap, tessellate_spans gave each knot span one segment, so
a bent span among many straight ones was measured by its chord. Example:
a quadratic spline along the x-axis, one control point 1000 above it,
past 4,500 spans. It measured 750; the area is 1750/3.

Each span now keeps one segment. A span whose control points are
collinear is straight, so its chord is exact. tessellate's count is
shared among the spans that bend, by the cube root of a measure of their
control points' convex hull, which holds the span and its chord. The
shares are rounded on the running total, so they use the whole count
however many spans share it. The example now measures 583.33343, below
the cap and past it.

The spreading by parameter width that this replaces goes, and
span_params with it: bounds is main's code again.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* DIST: a measurement refused as too large leaves LASTPOINT at the first point

Session::feed sets LASTPOINT to the second point before DIST checks the
distance, and the refusal returned before DIST put the first point back,
as it does after a measurement. It now does so before refusing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* AREA: a spline too long to measure is too large, not a perimeter of 0

Spline::length reads a length past f64's range as 0, and AREA took that
as the spline's perimeter. Spline::checked_length returns None there,
and AREA reports the perimeter too large, as it does a polyline's.

The overflow was hidden twice: in the sum, and before it in the
derivative, which read as zero speed once past f64's range. The length
integral now takes the derivative before that (Spline::velocity), so an
overflowing speed counts too. param_at_length keeps the speed it had,
and finite lengths are unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

2026-11-02 14:36:42 -07:00

..

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AREA, PERIMETER and DISTANCE system variables, as AutoCAD sets them (#2552)

2026-11-02 14:36:42 -07:00

Cargo.toml

M0: CADCraft skeleton and vertical slice

2026-10-05 23:22:25 -04:00