Class AcEdPreviewJig<T>Abstract

Description

A generic, TypeScript-based version of AutoCAD’s AcEdJig system for interactive previews during editor input.

This class manages a transient preview entity that updates dynamically as the user moves the cursor or provides other incremental input.

Why Generic?

AutoCAD’s jig can sample different types of values:

• a 3D point → during acquirePoint()
• a distance → during acquireDistance()
• an angle → during acquireAngle()

Using a generic type parameter T allows the jig to update entities based on different input types while sharing the same structure.

Method Mapping vs AutoCAD AcEdJig

AutoCAD AcEdJig Method	Purpose	This Class
sampler()	Sample new input	update(value: T)
worldDraw()	Draw geometry	render()
startJig()	Begin preview	setEntity()
drag()	Main loop	Controlled externally via JS events

Entity Integration

The preview entity may optionally implement:

onJigUpdate(value: T): void
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When present, the jig will call it whenever the input changes.

Example Use Cases

• Point acquisition (T = AcGePoint3d)
• Distance jig (T = number)
• Angle jig (T = number)

Example:

const jig = new AcEdPreviewJig<AcGePoint3d>(view)
jig.setEntity(circleEntity)
await editor.getPoint("Specify center:", { jig })
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