Class Screen

EventTarget is a DOM interface implemented by objects that can receive events and may have listeners for them.

Hierarchy

Implements

Properties

className: string = ''
height: number

The height of the screen in CSS pixels.

width: number

The width of the screen in CSS pixels.

Accessors

  • get availHeight(): number
  • Returns number

  • get availWidth(): number
  • Returns number

  • get colorDepth(): number
  • Returns number

  • get nodeName(): string
  • Returns string

  • get nodeType(): number
  • Returns number

  • get pixelDepth(): number
  • Returns number

Methods

  • Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

    The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

    When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

    When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in ยง 2.8 Observing event listeners.

    When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

    If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

    The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

    Parameters

    • type: "touchend" | "touchmove" | "touchstart"
    • listener: ((ev) => any)
    • Optional options: boolean | AddEventListenerOptions

    Returns void

  • Parameters

    • type: string
    • listener: EventListenerOrEventListenerObject
    • Optional options: boolean | AddEventListenerOptions

    Returns void

  • Parameters

    • name: string

    Returns null | string

  • Parameters

    • name: string
    • value: string | number

    Returns void

  • Creates a Blob object representing the image contained on the screen.

    Parameters

    • callback: ((blob) => void)

      A callback function with the resulting Blob object as a single argument. null may be passed if the image cannot be created for any reason.

        • (blob): void
        • Parameters

          Returns void

    • type: string = 'image/png'

      A string indicating the image format. The default type is image/png. This image format will be also used if the specified type is not supported.

    • quality: number = 0.8

      A number between 0 and 1 indicating the image quality to be used when creating images using file formats that support lossy compression (such as image/jpeg). A user agent will use its default quality value if this option is not specified, or if the number is outside the allowed range.

    Returns void

    Example

    screen.toBlob(blob => {
    blob.arrayBuffer().then(buffer => {
    Switch.writeFileSync('out.png', buffer);
    });
    });
  • Returns a data: URL containing a representation of the image in the format specified by the type parameter.

    Parameters

    • type: string = 'image/png'

      A string indicating the image format. The default type is image/png. This image format will be also used if the specified type is not supported.

    • quality: number = 0.8

      A number between 0 and 1 indicating the image quality to be used when creating images using file formats that support lossy compression (such as image/jpeg). The default quality value will be used if this option is not specified, or if the number is outside the allowed range.

    Returns void

    Example

    const url = screen.toDataURL();
    fetch(url)
    .then(res => res.arrayBuffer())
    .then(buffer => {
    Switch.writeFileSync('out.png', buffer);
    });

    See

    https://developer.mozilla.org/docs/Web/API/HTMLCanvasElement/toDataURL

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