Engine API Reference - v2.7.1
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    Class ElementComponent

    ElementComponents are used to construct user interfaces. The ElementComponent#type property can be configured in 3 main ways: as a text element, as an image element or as a group element. If the ElementComponent has a ScreenComponent ancestor in the hierarchy, it will be transformed with respect to the coordinate system of the screen. If there is no ScreenComponent ancestor, the ElementComponent will be transformed like any other entity.

    You should never need to use the ElementComponent constructor directly. To add an ElementComponent to an Entity, use Entity#addComponent:

    const entity = pc.Entity();
    entity.addComponent('element'); // This defaults to a 'group' element

    To create a simple text-based element:

    entity.addComponent('element', {
        anchor: new pc.Vec4(0.5, 0.5, 0.5, 0.5), // centered anchor
        fontAsset: fontAsset,
        fontSize: 128,
        pivot: new pc.Vec2(0.5, 0.5),            // centered pivot
        text: 'Hello World!',
        type: pc.ELEMENTTYPE_TEXT
    });

    Once the ElementComponent is added to the entity, you can access it via the element property:

    entity.element.color = pc.Color.RED; // Set the element's color to red

    console.log(entity.element.color);   // Get the element's color and print it

    Relevant Engine API examples:

    Hierarchy (View Summary)

    Index

    Properties

    entity screen system

    Accessors

    aabb alignment anchor autoFitHeight autoFitWidth autoHeight autoWidth batchGroupId bottom calculatedHeight calculatedWidth canvasCorners color drawOrder enabled enableMarkup fitMode font fontAsset fontSize height key layers left lineHeight margin mask material materialAsset maxFontSize maxLines minFontSize opacity outlineColor outlineThickness pivot pixelsPerUnit rangeEnd rangeStart rect right rtlReorder screenCorners shadowColor shadowOffset spacing sprite spriteAsset spriteFrame text textHeight texture textureAsset textWidth top type unicodeConverter useInput width worldCorners wrapLines

    Methods

    fire hasEvent off on once

    Events

    EVENT_CLICK EVENT_MOUSEDOWN EVENT_MOUSEENTER EVENT_MOUSELEAVE EVENT_MOUSEMOVE EVENT_MOUSEUP EVENT_MOUSEWHEEL EVENT_TOUCHCANCEL EVENT_TOUCHEND EVENT_TOUCHMOVE EVENT_TOUCHSTART

    Properties

    entity: Entity

    The Entity that this Component is attached to.

    screen: null | Entity

    The Entity with a ScreenComponent that this component belongs to. This is automatically set when the component is a child of a ScreenComponent.

    system: ComponentSystem

    The ComponentSystem used to create this Component.

    Accessors

    • get anchor(): number[] | Vec4

      Gets the anchor for this element component.

      Returns number[] | Vec4

    • set anchor(value: number[] | Vec4): void

      Sets the anchor for this element component. Specifies where the left, bottom, right and top edges of the component are anchored relative to its parent. Each value ranges from 0 to 1. e.g. a value of [0, 0, 0, 0] means that the element will be anchored to the bottom left of its parent. A value of [1, 1, 1, 1] means it will be anchored to the top right. A split anchor is when the left-right or top-bottom pairs of the anchor are not equal. In that case, the component will be resized to cover that entire area. For example, a value of [0, 0, 1, 1] will make the component resize exactly as its parent.

      Parameters

      • value: number[] | Vec4

      Returns void

      this.entity.element.anchor = new pc.Vec4(Math.random() * 0.1, 0, 1, 0);

      this.entity.element.anchor = [Math.random() * 0.1, 0, 1, 0];
    • get calculatedHeight(): number

      Gets the height at which the element will be rendered.

      Returns number

    • set calculatedHeight(value: number): void

      Sets the height at which the element will be rendered. In most cases this will be the same as height. However, in some cases the engine may calculate a different height for the element, such as when the element is under the control of a LayoutGroupComponent. In these scenarios, calculatedHeight may be smaller or larger than the height that was set in the editor.

      Parameters

      • value: number

      Returns void

    • get calculatedWidth(): number

      Gets the width at which the element will be rendered.

      Returns number

    • set calculatedWidth(value: number): void

      Sets the width at which the element will be rendered. In most cases this will be the same as width. However, in some cases the engine may calculate a different width for the element, such as when the element is under the control of a LayoutGroupComponent. In these scenarios, calculatedWidth may be smaller or larger than the width that was set in the editor.

      Parameters

      • value: number

      Returns void

    • get maxLines(): null | number

      Gets the maximum number of lines that the Element can wrap to. Returns null for unlimited lines.

      Returns null | number

    • set maxLines(arg: null | number): void

      Sets the maximum number of lines that the Element can wrap to. Any leftover text will be appended to the last line. Set this to null to allow unlimited lines.

      Parameters

      • arg: null | number

      Returns void

    • get pivot(): number[] | Vec2

      Gets the position of the pivot of the component relative to its anchor.

      Returns number[] | Vec2

    • set pivot(value: number[] | Vec2): void

      Sets the position of the pivot of the component relative to its anchor. Each value ranges from 0 to 1 where [0, 0] is the bottom left and [1, 1] is the top right.

      Parameters

      • value: number[] | Vec2

      Returns void

      this.entity.element.pivot = [Math.random() * 0.1, Math.random() * 0.1];

      this.entity.element.pivot = new pc.Vec2(Math.random() * 0.1, Math.random() * 0.1);

    text

    • get text(): string

      Gets the text to render.

      Returns string

    • set text(arg: string): void

      Sets the text to render. Only works for ELEMENTTYPE_TEXT types. To override certain text styling properties on a per-character basis, the text can optionally include markup tags contained within square brackets. Supported tags are:

      1. color - override the element's color property. Examples:
        • [color="#ff0000"]red text[/color]
        • [color="#00ff00"]green text[/color]
        • [color="#0000ff"]blue text[/color]
      2. outline - override the element's outlineColor and outlineThickness properties. Example:
        • [outline color="#ffffff" thickness="0.5"]text[/outline]
      3. shadow - override the element's shadowColor and shadowOffset properties. Examples:
        • [shadow color="#ffffff" offset="0.5"]text[/shadow]
        • [shadow color="#000000" offsetX="0.1" offsetY="0.2"]text[/shadow]

      Note that markup tags are only processed if the text element's enableMarkup property is set to true.

      Parameters

      • arg: string

      Returns void

    Methods

    • Fire an event, all additional arguments are passed on to the event listener.

      Parameters

      • name: string

        Name of event to fire.

      • Optionalarg1: any

        First argument that is passed to the event handler.

      • Optionalarg2: any

        Second argument that is passed to the event handler.

      • Optionalarg3: any

        Third argument that is passed to the event handler.

      • Optionalarg4: any

        Fourth argument that is passed to the event handler.

      • Optionalarg5: any

        Fifth argument that is passed to the event handler.

      • Optionalarg6: any

        Sixth argument that is passed to the event handler.

      • Optionalarg7: any

        Seventh argument that is passed to the event handler.

      • Optionalarg8: any

        Eighth argument that is passed to the event handler.

      Returns EventHandler

      Self for chaining.

      obj.fire('test', 'This is the message');

    • Test if there are any handlers bound to an event name.

      Parameters

      • name: string

        The name of the event to test.

      Returns boolean

      True if the object has handlers bound to the specified event name.

      obj.on('test', () => {}); // bind an event to 'test'
      obj.hasEvent('test'); // returns true
      obj.hasEvent('hello'); // returns false

    • Detach an event handler from an event. If callback is not provided then all callbacks are unbound from the event, if scope is not provided then all events with the callback will be unbound.

      Parameters

      • Optionalname: string

        Name of the event to unbind.

      • Optionalcallback: HandleEventCallback

        Function to be unbound.

      • Optionalscope: any

        Scope that was used as the this when the event is fired.

      Returns EventHandler

      Self for chaining.

      const handler = () => {};
      obj.on('test', handler);

      obj.off(); // Removes all events
      obj.off('test'); // Removes all events called 'test'
      obj.off('test', handler); // Removes all handler functions, called 'test'
      obj.off('test', handler, this); // Removes all handler functions, called 'test' with scope this

    • Attach an event handler to an event.

      Parameters

      • name: string

        Name of the event to bind the callback to.

      • callback: HandleEventCallback

        Function that is called when event is fired. Note the callback is limited to 8 arguments.

      • Optionalscope: any = ...

        Object to use as 'this' when the event is fired, defaults to current this.

      Returns EventHandle

      Can be used for removing event in the future.

      obj.on('test', (a, b) => {
          console.log(a + b);
      });
      obj.fire('test', 1, 2); // prints 3 to the console

      const evt = obj.on('test', (a, b) => {
          console.log(a + b);
      });
      // some time later
      evt.off();

    • Attach an event handler to an event. This handler will be removed after being fired once.

      Parameters

      • name: string

        Name of the event to bind the callback to.

      • callback: HandleEventCallback

        Function that is called when event is fired. Note the callback is limited to 8 arguments.

      • Optionalscope: any = ...

        Object to use as 'this' when the event is fired, defaults to current this.

      Returns EventHandle

      • can be used for removing event in the future.
      obj.once('test', (a, b) => {
          console.log(a + b);
      });
      obj.fire('test', 1, 2); // prints 3 to the console
      obj.fire('test', 1, 2); // not going to get handled

    Events

    EVENT_CLICK: string = 'click'

    Fired when the mouse is pressed and released on the component or when a touch starts and ends on the component. Only fired when useInput is true. The handler is passed an ElementMouseEvent or ElementTouchEvent.

    entity.element.on('click', (event) => {
        console.log(`Click event on entity ${entity.name}`);
    });
    EVENT_MOUSEDOWN: string = 'mousedown'

    Fired when the mouse is pressed while the cursor is on the component. Only fired when useInput is true. The handler is passed an ElementMouseEvent.

    entity.element.on('mousedown', (event) => {
        console.log(`Mouse down event on entity ${entity.name}`);
    });
    EVENT_MOUSEENTER: string = 'mouseenter'

    Fired when the mouse cursor enters the component. Only fired when useInput is true. The handler is passed an ElementMouseEvent.

    entity.element.on('mouseenter', (event) => {
        console.log(`Mouse enter event on entity ${entity.name}`);
    });
    EVENT_MOUSELEAVE: string = 'mouseleave'

    Fired when the mouse cursor leaves the component. Only fired when useInput is true. The handler is passed an ElementMouseEvent.

    entity.element.on('mouseleave', (event) => {
        console.log(`Mouse leave event on entity ${entity.name}`);
    });
    EVENT_MOUSEMOVE: string = 'mousemove'

    Fired when the mouse cursor is moved on the component. Only fired when useInput is true. The handler is passed an ElementMouseEvent.

    entity.element.on('mousemove', (event) => {
        console.log(`Mouse move event on entity ${entity.name}`);
    });
    EVENT_MOUSEUP: string = 'mouseup'

    Fired when the mouse is released while the cursor is on the component. Only fired when useInput is true. The handler is passed an ElementMouseEvent.

    entity.element.on('mouseup', (event) => {
        console.log(`Mouse up event on entity ${entity.name}`);
    });
    EVENT_MOUSEWHEEL: string = 'mousewheel'

    Fired when the mouse wheel is scrolled on the component. Only fired when useInput is true. The handler is passed an ElementMouseEvent.

    entity.element.on('mousewheel', (event) => {
        console.log(`Mouse wheel event on entity ${entity.name}`);
    });
    EVENT_TOUCHCANCEL: string = 'touchcancel'

    Fired when a touch is canceled on the component. Only fired when useInput is true. The handler is passed an ElementTouchEvent.

    entity.element.on('touchcancel', (event) => {
        console.log(`Touch cancel event on entity ${entity.name}`);
    });
    EVENT_TOUCHEND: string = 'touchend'

    Fired when a touch ends on the component. Only fired when useInput is true. The handler is passed an ElementTouchEvent.

    entity.element.on('touchend', (event) => {
        console.log(`Touch end event on entity ${entity.name}`);
    });
    EVENT_TOUCHMOVE: string = 'touchmove'

    Fired when a touch moves after it started touching the component. Only fired when useInput is true. The handler is passed an ElementTouchEvent.

    entity.element.on('touchmove', (event) => {
        console.log(`Touch move event on entity ${entity.name}`);
    });
    EVENT_TOUCHSTART: string = 'touchstart'

    Fired when a touch starts on the component. Only fired when useInput is true. The handler is passed an ElementTouchEvent.

    entity.element.on('touchstart', (event) => {
        console.log(`Touch start event on entity ${entity.name}`);
    });

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