Interface Visibility

The visibility API.

interface Visibility {
    ratio: number;
    visible: boolean;
    visibleThreshold: number;
    addObserver(
        step: number,
        callback: VisibilityObserverCallback,
    ): VisibilityObserver;
    removeObserver(observer: VisibilityObserver): void;
}

Index

Properties

ratio visible visibleThreshold

Methods

addObserver removeObserver

Properties

`Readonly`ratio

ratio: number

The ratio of pixels of the player that are within the viewport.

`Readonly`visible

visible: boolean

Whether the Visibility.ratio of visible pixels is exceeded.

visibleThreshold

visibleThreshold: number

The threshold that the ratio must exceed for the player to be visible.

Remarks

- This number is in the range of [0, 1].

Methods

addObserver

addObserver(
step: number,
callback: VisibilityObserverCallback,
): VisibilityObserver
Add a visibility observer to monitor the player.
Parameters
- step: number
  The step between every threshold. This number is in the range of ]0, 1].
- callback: VisibilityObserverCallback
  The callback to be triggered every time a threshold is crossed.
Returns VisibilityObserver
A new visibility observer.

Remarks

- The callback is triggered every time the ratio of visible pixels crosses a threshold, and receives the ratio of visible pixels as first argument.
- The list of thresholds is evenly distributed between 0 and 1, with the distance between every two consecutive thresholds determined by the given step.

removeObserver

removeObserver(observer: VisibilityObserver): void
Remove a visibility observer.

The observer will stop monitoring player visibility, and will no longer trigger its callback.
Parameters
- observer: VisibilityObserver
  The observer to remove.
Returns void