import type { ChannelNumber } from '../../types';
import type { VisualizerParams, GraphicsStyles, SpectrumScale } from './Visualizer';
import { Visualizer } from './Visualizer';
export type SpectrumParams = VisualizerParams & {
    scale?: SpectrumScale;
    logarithmicFrequencies?: number[];
    textInterval?: number;
    readonly minFrequency?: number;
    readonly maxFrequency?: number;
};
/**
 * This private class visualizes spectrum.
 */
export declare abstract class Spectrum extends Visualizer {
    protected scale: SpectrumScale;
    protected logarithmicFrequencies: number[];
    protected minFrequency: number;
    protected maxFrequency: number;
    protected ratio: number;
    protected log10Ratio: number;
    protected textInterval: number;
    /**
     * @param {number} sampleRate This argument is sample rate.
     * @param {ChannelNumber} channel This argument is channel number (Left: 0, Right: 1 ...).
     */
    constructor(sampleRate: number, channel: ChannelNumber);
    /**
     * This method gets or sets parameters for visualizing spectrum.
     * This method is overloaded for type interface and type check.
     * @param {keyof SpectrumParams|SpectrumParams} params This argument is string if getter. Otherwise, setter.
     * @return {SpectrumParams[keyof SpectrumParams]|Spectrum} Return value is parameter for visualizing spectrum if getter.
     *     Otherwise, return value is for method chain.
     * @override
     */
    param(params: 'interval'): number;
    param(params: 'styles'): GraphicsStyles;
    param(params: 'scale'): SpectrumScale;
    param(params: 'logarithmicFrequencies'): number[];
    param(params: 'minFrequency'): number;
    param(params: 'maxFrequency'): number;
    param(params: 'textInterval'): number;
    param(params: SpectrumParams): Spectrum;
}
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