/**
 * ============================================================================
 * IMPORTS
 * ============================================================================
 * @hidden
 */
import { LinearGradient } from "./LinearGradient";
import { GradientModifier } from "./GradientModifier";
/**
 * ============================================================================
 * MAIN CLASS
 * ============================================================================
 * @hidden
 */
/**
 * This class can be used to modify linear gradient steps, changing visual
 * properties like lightness, brightness, opacity of each set.
 *
 * It can also set offsets for each gradient step.
 *
 * E.g. if I want to fill a columns in a column series to be a solid fill from
 * top to 80% of height, then gradually fades out, I can use the following
 * gradient modifier as a `fillModifier`:
 *
 * ```TypeScript
 * let fillModifier = new am4core.LinearGradientModifier();
 * fillModifier.opacities = [1, 1, 0];
 * fillModifier.offsets = [0, 0.8, 1];
 * columnSeries.columns.template.fillModifier = fillModifier;
 * ```
 * ```JavaScript
 * var fillModifier = new am4core.LinearGradientModifier();
 * fillModifier.opacities = [1, 1, 0];
 * fillModifier.offsets = [0, 0.8, 1];
 * columnSeries.columns.template.fillModifier = fillModifier;
 * ```
 * ```JSON
 * "series": [{
 *   "type": "ColumnSeries",
 *   "columns": {
 *     "fillModifier": {
 *       "type": "LinearGradientModifier",
 *       "opacities": [1, 1, 0],
 *       "offsets": [0, 0.8, 1]
 *     }
 *   }
 * }]
 * ```
 */
export declare class LinearGradientModifier extends GradientModifier {
    /**
     * A reference to the gradient instance that this modifier is used for.
     */
    gradient: LinearGradient;
    /**
     * Constructor.
     */
    constructor();
    copyFrom(source: this): void;
}