ImportProgressClosure

ImportProgressClosure is a closure-backed conformance to OCCTSwift’s ImportProgress protocol. It lets you pass progress: to ShapeLoader.load / loadRobust as a closure instead of writing a one-shot subclass. STEP and IGES imports fire the callbacks; other formats don’t surface progress.

Topics

• ImportProgressClosure.init(cancelCheck:progress:) · progress(fraction:step:) · shouldCancel()

ImportProgressClosure.init(cancelCheck:progress:)

Creates a progress observer from a progress closure and an optional cancellation closure.

public init(
    cancelCheck: @escaping @Sendable () -> Bool = { false },
    progress: @escaping @Sendable (Double, String) -> Void
)

• Parameters:
  • cancelCheck — return true to cooperatively cancel the import. Defaults to { false }. Common pattern: { Task.isCancelled } to wire upstream Swift-task cancellation.
  • progress — called with fraction in 0.0...1.0 and a human-readable step name (e.g. "Reading STEP file").
• Note: callbacks fire on whatever thread the importer runs on (typically background when launched via the async ShapeLoader.load). Hop to the main actor for UI updates.
• Example:

  let result = try await ShapeLoader.load(
      from: stepURL, format: .step,
      progress: ImportProgressClosure(
          cancelCheck: { Task.isCancelled },
          progress: { fraction, step in
              Task { @MainActor in progressBar.doubleValue = fraction }
          }
      )
  )
  

progress(fraction:step:)

ImportProgress protocol requirement; forwards to the stored progress closure.

public func progress(fraction: Double, step: String)

• Parameters: fraction — completion in 0.0...1.0; step — the current stage name.

shouldCancel()

ImportProgress protocol requirement; returns the result of the stored cancelCheck closure. When it returns true, the loader throws ImportError.cancelled.

public func shouldCancel() -> Bool