Class Image

The Image class is the spiritual equivalent of the HTMLImageElement class in web browsers. You can use it to load image data from the filesytem or remote source over the network. Once loaded, the image may be drawn onto the screen context or an offscreen canvas content using ctx.drawImage().

Supported Image Formats

Example

const ctx = Switch.screen.getContext('2d');

const img = new Image();
img.addEventListener('load', () => {
  ctx.drawImage(img);
});
img.src = 'romfs:/logo.png';

Hierarchy

Constructors

constructor

Properties

decoding isMap loading onerror onload

Accessors

complete height naturalHeight naturalWidth src width

Methods

addEventListener dispatchEvent removeEventListener

Constructors

constructor

  • Returns Image

Properties

decoding

decoding: "async" | "sync" | "auto"

isMap

isMap: boolean

loading

loading: "eager" | "lazy"

onerror

onerror: null | ((this, ev) => any)

Type declaration

onload

onload: null | ((this, ev) => any)

Type declaration

    • (this, ev): any

    • Parameters

      Returns any

Accessors

complete

  • get complete(): boolean

  • Returns boolean

height

  • get height(): number

  • Returns number

naturalHeight

  • get naturalHeight(): number

  • Returns number

naturalWidth

  • get naturalWidth(): number

  • Returns number

src

  • get src(): string

  • Returns string

  • set src(val): void

  • Parameters

    • val: string

    Returns void

width

  • get width(): number

  • Returns number

Methods

addEventListener

  • 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.

    MDN Reference

    Parameters

    • type: string
    • callback: null | EventListenerOrEventListenerObject
    • Optional options: boolean | AddEventListenerOptions

    Returns void

dispatchEvent

  • Parameters

    Returns boolean

removeEventListener

  • Removes the event listener in target's event listener list with the same type, callback, and options.

    MDN Reference

    Parameters

    • type: string
    • callback: null | EventListenerOrEventListenerObject
    • Optional options: boolean | EventListenerOptions

    Returns void

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