import { vec2, vec3 } from 'gl-matrix';
import { Camera } from '../camera';
import { GLfloat2, GLfloat3 } from '../tuples';
import { FontFace } from './fontface';
import { GlyphVertices } from './glyphvertices';
import { Label } from './label';
import { Text } from './text';
/**
 * A Label that can be positioned in 3D space, but projected onto a 2D plane (a.k.a. screen).
 * The unit for positioning is world space, the unit for size is pixel (px).
 */
export declare class Projected3DLabel extends Label {
    private static readonly DEFAULT_FONTSIZE_PX;
    /** @see {@link position} */
    protected _position: vec3;
    /** @see {@link direction} */
    protected _direction: vec2;
    /** @see {@link camera} */
    protected _camera: Camera | undefined;
    /**
     * Constructs a pre-configured projected 3D-label with given text. Depending on the label type, transformations are
     * applied once when typesetting (static) or every frame during rendering (dynamic).
     * @param text - The text that is displayed by this label.
     * @param type - Either static or dynamic. If static is used, all transformations are baked and modifications to
     * on any of the label's transformations are expected to occur less often.
     * @param fontFace - The font face that should be used for that label, or undefined if set later.
     */
    constructor(text: Text, type: Label.Type, fontFace?: FontFace);
    /**
     * If altered, creates a position and direction-vector, then prepares the vertex storage and invokes
     * typesetting. Depending on the label's type (static or dynamic) the transform is stored and applied either during
     * typesetting (static) or passed as single transform to the vertex shader during rendering (dynamic).
     */
    typeset(force?: boolean): GlyphVertices | undefined;
    /**
     * The camera is used to retrieve (1) the view projection matrix, and (2) the width and height of targeted frame.
     * (1) is used to project the 3D label as a 2D label, (2) is used to calculate the font size in px units.
     * Setting the camera invalidates the transform.
     */
    set camera(camera: Camera | undefined);
    get camera(): Camera | undefined;
    /**
     * Sets the 3D position of the label's reference point.
     */
    set position(position: vec3 | GLfloat3);
    get position(): vec3 | GLfloat3;
    /**
     * Sets the 2D direction of the label, i.e., the direction of the baseline.
     */
    set direction(direction: vec2 | GLfloat2);
    get direction(): vec2 | GLfloat2;
    /**
     * This unit is used for the font size. This method overrides the super.fontSizeUnit, since `Projected3DLabel` only
     * supports Pixel, for now.
     * (@see {@link fontSize})
     * @param newUnit - Unit to be used, though, this label type only supports pixel units (px).
     */
    set fontSizeUnit(unit: Label.Unit);
    get fontSizeUnit(): Label.Unit;
}