/**
 * An instance of this class can be passed to an [[ICanvas]] to draw with an active filter.
 * Many effects / filter can be used parallel, simply add the ones you want with following functions.
 */
export declare class CanvasFilter {
    private filter;
    private filterArray;
    /**
     * Get the filter as string.
     */
    getFilter(): string;
    /**
     * Reset the filter to none.
     */
    reset(): void;
    /**
     * Add a custom filter to the filter query.
     */
    addCustomFilter(value: string): void;
    /**
     * Add blur effect with length in pixel.
     */
    addBlur(length: number): void;
    /**
     * Add a brightness with percentage.
     */
    addBrightness(percentage: number): void;
    /**
     * Add a contract filter with percentage.
     */
    addContrast(percentage: number): void;
    /**
     * Add a drop shadow, all parameter in pixel except color.
     */
    addDropShadow(offsetX: number, offsetY: number, radius: number, color: string): void;
    /**
     * Add a grayscale with percentage.
     */
    addGrayscale(percentage: number): void;
    /**
     * Add a hue rotation with degree.
     */
    hueRotation(degree: number): void;
    /**
     * Invert with percentage.
     */
    invert(percentage: number): void;
    /**
     * Add an opacity with percentage.
     */
    opacity(percentage: number): void;
    /**
     * Add saturation with percentage.
     */
    saturation(percentage: number): void;
    /**
     * Add a sepia effect with percentage.
     */
    sepia(percentage: number): void;
    private addFilter;
}