Merge pull request #1301: Add associative viewport dimensions

Refresh associations after complete SpaceMouse camera updates and recognize imported paper-space owners without Layout objects. Use kernel containment, intersection, perpendicular and spline tangent solving; pin cadkernel 7ce27f2 and add regressions.
2026-09-16 09:56:33 +03:00
commit d10a0cf798
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+<svg xmlns="http://www.w3.org/2000/svg" width="900" height="350" viewBox="0 0 900 350">
+<style>text{font-family:Arial,sans-serif;fill:#263238} .title{font-size:22px;font-weight:600} .label{font-size:16px} .small{font-size:13px;fill:#54616a} .model{stroke:#1479b8;stroke-width:4;fill:none} .paper{stroke:#a94610;stroke-width:2;stroke-dasharray:9 5} .dim{stroke:#263238;stroke-width:1.5;fill:none}</style>
+<defs><marker id="arrow" viewBox="0 0 8 8" refX="4" refY="4" markerWidth="6" markerHeight="6" orient="auto-start-reverse"><path d="M8 0L0 4L8 8" fill="#263238"/></marker></defs>
+<rect width="900" height="350" rx="10" fill="white"/>
+<text class="title" x="30" y="38">The dimension follows its paper-space centerline</text>
+<rect x="30" y="65" width="400" height="220" fill="#f5f8fa" stroke="#c3ced5"/>
+<rect x="470" y="65" width="400" height="220" fill="#f5f8fa" stroke="#c3ced5"/>
+<text class="label" x="48" y="93">Before</text><text class="label" x="488" y="93">Centerline moved 1 paper unit right</text>
+<path class="model" d="M85 160H385M525 160H825"/>
+<circle cx="385" cy="160" r="5" fill="#1479b8"/><circle cx="825" cy="160" r="5" fill="#1479b8"/>
+<path class="paper" d="M235 113V257M705 113V257"/>
+<path class="dim" d="M385 171V244M825 171V244"/>
+<path class="dim" d="M235 232H385" marker-start="url(#arrow)" marker-end="url(#arrow)"/>
+<path class="dim" d="M705 232H825" marker-start="url(#arrow)" marker-end="url(#arrow)"/>
+<rect x="291" y="217" width="38" height="28" fill="#f5f8fa"/><rect x="746" y="217" width="38" height="28" fill="#f5f8fa"/>
+<text class="label" x="310" y="237" text-anchor="middle">50</text><text class="label" x="765" y="237" text-anchor="middle">40</text>
+<text class="label" x="30" y="316">The model endpoint stays fixed. The dimension updates from 50 to 40.</text>
+<text class="small" x="30" y="340">Association schematic; viewport 1:10, dimension style unit factor = 1, DIMASSOC = 2.</text>
+</svg>
@@ -0,0 +1,22 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="900" height="350" viewBox="0 0 900 350">
+<style>text{font-family:Arial,sans-serif;fill:#263238} .title{font-size:22px;font-weight:600} .label{font-size:16px} .small{font-size:13px;fill:#54616a} .model{stroke:#1479b8;stroke-width:4;fill:none} .paper{stroke:#a94610;stroke-width:2;stroke-dasharray:9 5} .dim{stroke:#263238;stroke-width:1.5;fill:none}</style>
+<defs><marker id="arrow" viewBox="0 0 8 8" refX="4" refY="4" markerWidth="6" markerHeight="6" orient="auto-start-reverse"><path d="M8 0L0 4L8 8" fill="#263238"/></marker></defs>
+<rect width="900" height="350" rx="10" fill="white"/>
+<text class="title" x="30" y="38">Dimension from a paper centerline to a model endpoint</text>
+<rect x="30" y="65" width="430" height="245" fill="#f5f8fa" stroke="#c3ced5"/>
+<text class="small" x="45" y="89">Viewport 1:10</text>
+<path class="model" d="M100 160H400"/>
+<circle cx="400" cy="160" r="5" fill="#1479b8"/>
+<path class="paper" d="M250 110V260"/>
+<text class="small" x="100" y="144">Model geometry</text>
+<path class="dim" d="M400 171V244"/>
+<path class="dim" d="M250 232H400" marker-start="url(#arrow)" marker-end="url(#arrow)"/>
+<rect x="306" y="217" width="38" height="28" fill="#f5f8fa"/>
+<text class="label" x="325" y="237" text-anchor="middle">50</text>
+<text class="small" x="45" y="290">Brown dashed line: paper-space centerline</text>
+<text class="label" x="500" y="116">5 paper units between the picked points</text>
+<text class="label" x="500" y="155">5 × 10 = 50 model units</text>
+<text class="label" x="500" y="206">The viewport supplies the length scale.</text>
+<text class="label" x="500" y="240">Either pick order gives the same value.</text>
+<text class="small" x="30" y="336">Measurement schematic; dimension style unit factor = 1.</text>
+</svg>
@@ -0,0 +1,74 @@
+# Dimensions through layout viewports
+
+In paper space, snap to model geometry displayed through a planar, orthographic
+viewport. `DIMLINEAR`, `DIMALIGNED`, `DIMANGULAR`, `DIMRADIUS`, and `DIMDIAMETER`
+also support their usual object-pick modes through these viewports.
+
+## Measurement
+
+- Model geometry supplies the viewport scale. A 100-unit model length displayed
+  at 1:10 measures 100, although it occupies 10 paper units.
+- A paper-space centerline or free sheet point can be combined with model
+  geometry through one viewport, in either pick order. The paper-space span is
+  measured using that viewport's scale.
+- Sheet-only dimensions measure paper units, even inside a viewport rectangle.
+- Model picks from a second viewport are rejected without advancing the command.
+  Dimension-line and text placement do not change the measurement scale.
+- The current dimension style's unit conversion is preserved. Angular dimensions
+  do not use length compensation. `DIMASSOC=0` explodes the compensated dimension.
+
+Snapping and object picking respect visibility, clipping, and viewport draw order.
+Paper geometry has priority in object picks. Ordinary selection uses the active
+drawing space. Object picks reuse the resident interaction index and resolve
+nested block transforms.
+
+![Measurement schematic: a five-unit sheet span measures 50 through a 1:10 viewport.](viewport-dimension-creation.svg)
+
+## Saved scale
+
+Length dimensions store paper-space definition points and a negative `DIMLFAC`
+override: user unit factor multiplied by `1 / viewport scale`.
+`OCS_VIEWPORT_MEASUREMENT` XData stores version `1` (integer16), the positive user
+factor (real), and viewport compensation (real). Keeping the factors separate
+allows compensation to change without losing the user's unit conversion.
+Both the override and XData survive DXF/DWG saves and undo/redo.
+
+## Associations
+
+With `DIMASSOC=2`, acquired features retain their viewport, block-instance path,
+source entity, and snap feature. Intersections retain both source chains.
+Source edits and viewport changes update the dimension and its compensation,
+preserving style overrides and user-positioned text on the sheet.
+
+A sheet centerline stays on the sheet; a model endpoint follows its viewport.
+Moving the viewport therefore changes the distance between them. Undo/redo and
+DXF/DWG saves preserve the references.
+
+Properties shows association status. If a required reference is broken or cannot
+be resolved, the entire dimension keeps its last valid geometry and reference
+records. A successful refresh regenerates its displayed and exported geometry.
+
+![Association schematic: moving the sheet centerline changes the dimension from 50 to 40.](viewport-dimension-association.svg)
+
+## Limits
+
+Unsupported cases preserve saved dimensions:
+
+- Perspective or oblique views; missing or malformed reference chains.
+- Array instances without an addressable instance index, nesting beyond eight
+  levels, and radial measurements of nonuniformly scaled circles or arcs.
+- Intersections without two identifiable source chains inside a batched block.
+- Ambiguous imported endpoint, midpoint, or quadrant markers. A stored point can
+  validate a feature; it cannot establish an otherwise unknown identity.
+- Tangency without a verified solution, or two perpendicular/tangent references
+  requiring a coupled solve.
+- Imported viewport scaling without OCS scale metadata or
+  `ACAD_DIMASSOC_CALC_DIMLFAC` identifying the saved compensation.
+
+## Tests
+
+Run `cargo test --locked --lib viewport_dimension`. Tests cover the five commands,
+mixed sheet/model input, styles, clipping, object picks, source/viewport edits,
+snap features, nested paths, intersections, preserved overrides, undo/redo, and
+DXF/DWG persistence. The synthetic association fixture is in
+`tests/fixtures/dim_assoc/`.