vectorcraft/docs/dimensions.md

Dimensions

Choose Dimension Tool in the Modify section of the toolbar. Its control strip offers Length, Angle, Radius, Diameter, Options… and All selected edges.

• Length: hover a path to highlight the segment between two anchors. Click it, move the pointer to place the dimension, then click again. Curved segments report their actual curve length, prefixed Arc, rather than the distance between their endpoints.
• Two points: Alt-click an anchor to start measuring individual points, click the second point, then click to place the dimension. Picked anchors remain linked to their original paths. Empty-space clicks also work; these fixed points have no source object to follow. Shift constrains a manually picked point to 45-degree increments.
• Angle: click two nonparallel straight segments, then click to place the angle. To choose three points instead, Alt-click the first arm, click the vertex, then the second arm; click once more to place the annotation. Angles use the smaller angle between the chosen arms.
• Radius / Diameter: click a circular path, then move and click to choose the direction of the annotation. Ellipses are rejected because they have no single radius.
• All selected edges: select paths or groups, then use this button or Object → Dimensions → Dimension Selected Paths. Adds up to 1,000 segment dimensions in one undo step. Existing dimension groups, hidden art and locked art are skipped.
• Escape or switching tools cancels a measurement being placed.

Double-click the tool or choose Options… for units, precision (0–6 decimal places), scale, line weight/type/colour, arrows and arrow size, extension-line gaps/overshoot/visibility, font family/style/size/colour, text position/orientation/offset. Reset restores defaults in the dialog; Cancel leaves settings unchanged. Save stores tool defaults, and optionally updates selected dimension groups. These changes are undoable; defaults persist in preferences.

Scale means drawing : real size, independent of zoom. At 1:10, a 1 cm line on the page is labelled 10 cm. At 10:1, it is labelled 0.1 cm. Presets and custom positive ratios are supported. Scale affects lengths, not angles or the physical size of text/arrows.

Measurements track source moves, scaling and anchor/handle edits, including undo/redo. Deleting a source or making it degenerate removes its linked annotations in the same undo step. Changing a path's anchor count/closedness invalidates indexed references and removes those annotations rather than attaching them to a different edge. Recreate them after such topology edits. A circle changed into an ellipse similarly loses its radius/diameter annotation.

Native .vectorcraft files retain recipes and links. SVG/PDF/bitmap output contains ordinary paths and text, so exported dimensions look the same; generic SVG/PDF round trips do not promise editable measurement links. Ungrouping exposes the generated paths/text as ordinary artwork. Copied/pasted dimensions retain their measured geometry but detach their original links, so source ids cannot accidentally bind to unrelated objects in another document.

Commands

• dimension.create: fixed points or linked segment/angle/circle/anchor sources, mode, offset, and style options; returns the group id and label.
• dimension.selection: all selected path segments, one undo step.
• dimension.update: change existing groups' options and/or placement offset.
• tool.select {"tool":"dimension"} and tool.setOption {"tool":"dimension","values":{"mode":"linear","style":{"units":"cm","scale":"1:10"}}}.
• tool.options {"tool":"dimension"} opens the agent-accessible dimensionOptions dialog.

Recipes live on normal document groups (Node.dimension); rendering and export use their generated children. Commands validate options and finite bounds before mutation. Source edits refresh annotations inside Session::edit, sharing history and cancellation with the source. The icon uses the project's existing original measurement artwork; no external assets are added.