export declare function cartesianToPolar(x: number, y: number): readonly [number, number];
export declare function thetaRangesOverlap(r1start: number, r1length: number, r2start: number, r2length: number): boolean;
export declare function viewportVisibleSection(viewSides: [number, number, number, number], circleCenter: [number, number], circleRadius: number): {
    rho: [number, number];
    theta: [number, number];
};