/**
 * SVG document construction utilities — XML escape, defs, gradients, clipPaths.
 */
export declare function escapeXml(text: string): string;
export declare function fmt(n: number, decimals?: number): string;
export declare class SVGDocumentBuilder {
    private width;
    private height;
    private fontFamily;
    private defs;
    private layers;
    constructor(width: number, height: number, fontFamily: string);
    resetGradientCounter(): void;
    addDef(content: string): string;
    registerLinearGradient(x1: number, y1: number, x2: number, y2: number, stops: Array<{
        offset: string;
        color: string;
        opacity?: number;
    }>): string;
    registerClipPath(id: string, content: string): void;
    registerArrowMarker(id: string, color: string): void;
    push(layer: string, element: string): void;
    pushRaw(element: string): void;
    openGroup(layer: string, transform?: string, attrs?: Record<string, string>): string;
    closeGroup(layer: string): void;
    build(backgroundColor: string, ariaLabel?: string): string;
}