/// <reference types="web" />
/// <reference types="d3-shape" />
export declare function getCanvasContext(): CanvasRenderingContext2D;
export declare function getOpacityGradientFn(color: string, opacity: number): (self: uPlot, seriesIdx: number) => CanvasGradient;
export declare function alpha(color: string, value: number): string;
interface DecomposeColor {
    type: string;
    values: any;
    colorSpace?: string;
}
/**
 * Converts a color object with type and values to a string.
 * @param {object} color - Decomposed color
 * @param color.type - One of: 'rgb', 'rgba', 'hsl', 'hsla'
 * @param {array} color.values - [n,n,n] or [n,n,n,n]
 * @returns A CSS color string
 * @beta
 */
export declare function recomposeColor(color: DecomposeColor): string;
export declare enum GradientDirection {
    Right = 0,
    Up = 1,
    Left = 2,
    Down = 3
}
export declare enum ScaleOrientation {
    Horizontal = 0,
    Vertical = 1
}
export declare function decomposeColor(color: string | DecomposeColor): DecomposeColor;
export declare function hexToRgb(color: string): string;
export {};