import { Surface } from './Surface';
import { Color } from './Color';
import { Vec2D } from '../Math';
/**
 * Linear gradient parameters
 */
interface LinearGradient {
    type: 'linear';
    /**
     * Start position of the gradient
     */
    start: Vec2D;
    /**
     * End position of the gradient
     */
    end: Vec2D;
}
/**
 * Radial gradient parameters
 */
interface RadialGradient {
    type: 'radial';
    /**
     * Inner radial center
     */
    inPos: Vec2D;
    /**
     * Outer radial center
     */
    outPos: Vec2D;
    /**
     * Inner radius
     */
    inR: number;
    /**
     * Outer radius
     */
    outR: number;
}
declare class ColorGradient {
    readonly grad: CanvasGradient;
    /**
     * Alpha value between [0, 255]
     */
    a: number;
    /**
     * A wrapper for a canvas color gradient. It can
     * implement both LinearGradient and RadialGradient types.
     *
     * The parameters are dependent on gradient type:
     *     "linear" - {start (Vec2D), end (Vec2D)}
     *     "radial" - {inPos (Vec2D), inR (Number),
     *                 outPos (Vec2D), outR (Number)}
     *
     * @param surface    Target Surface object
     * @param parameters Gradient type-dependent parameters
     * @param alpha      Alpha value between [0, 255]
     * @return New ColorGradient object
     */
    constructor(surface: Surface, parameters: LinearGradient | RadialGradient, alpha?: number);
    /**
     * Set a color at a position in the gradient.
     *
     * @param color Target color value
     * @param t     Position in gradient between [0, 1]
     */
    addValue(color: Color, t: number): void;
    /**
     * Get the underlying canvas gradient object.
     *
     * @return Target CanvasGradient object
     */
    get(): CanvasGradient;
    /**
     * Get the normalized alpha value.
     *
     * @return Alpha value between [0, 1]
     */
    alpha(): number;
}
export { ColorGradient };
export type { LinearGradient, RadialGradient };