VistaImageEvent Class

The VistaImageEvent class manages pointer events and translates them into image manipulation actions like zooming, panning, and navigation.

Overview

VistaImageEvent coordinates:

• Single and multi-touch gestures
• Pinch-to-zoom detection
• Pan/drag interactions when zoomed
• Momentum scrolling
• External pointer event listeners

Use Case: Created internally by VistaView. Extensions can register listeners through registerPointerListener().

Public Properties

None - all properties are private.

Public Methods

constructor()

constructor(vvw: VistaView)

Creates a new event handling system for a VistaView instance.

registerPointerListener()

registerPointerListener(listener: (e: VistaExternalPointerListenerArgs) => void): void

Registers an external pointer event listener. Same as calling viewer.registerPointerListener().

Parameters:

• listener - Function receiving pointer event data

Example:

const eventSystem = new VistaImageEvent(viewer);

eventSystem.registerPointerListener((e) => {
  console.log('Event:', e.event);
  console.log('Pointers:', e.pointers.length);
  console.log('State:', e.state.zoomedIn);
});

start()

start(imageContainer: HTMLElement): void

Starts listening to pointer events on the specified container. Called automatically by VistaView when opening.

Parameters:

• imageContainer - The element to attach event listeners to

stop()

stop(): void

Removes all event listeners and cleans up resources. Called automatically by VistaView when closing.

Related

• VistaView - Main controller that uses VistaImageEvent
• VistaPointers - Underlying pointer tracking system
• VistaExternalPointerListenerArgs - Event data type