/**
 * Velo Plot - Debug Overlay Module
 *
 * Provides a visual debug overlay showing performance metrics,
 * rendering info, and chart state for development and debugging.
 *
 * @module debug
 */
export interface DebugStats {
    /** Current frames per second */
    fps: number;
    /** Average frame time in ms */
    frameTime: number;
    /** Total number of points being rendered */
    pointCount: number;
    /** Number of visible series */
    seriesCount: number;
    /** Current view bounds */
    viewBounds: {
        xMin: number;
        xMax: number;
        yMin: number;
        yMax: number;
    };
    /** WebGL/WebGPU renderer info */
    rendererInfo: {
        type: 'webgl' | 'webgpu' | 'unknown';
        vendor?: string;
        renderer?: string;
    };
    /** Memory usage estimate (bytes) */
    memoryEstimate: number;
    /** Number of draw calls per frame */
    drawCalls: number;
    /** Whether GPU downsampling is active */
    downsamplingActive: boolean;
    /** Device pixel ratio */
    devicePixelRatio: number;
    /** Canvas dimensions */
    canvasSize: {
        width: number;
        height: number;
    };
    /** Plot area dimensions */
    plotArea: {
        x: number;
        y: number;
        width: number;
        height: number;
    };
}
export interface DebugOverlayOptions {
    /** Show FPS counter (default: true) */
    showFps?: boolean;
    /** Show point count (default: true) */
    showPointCount?: boolean;
    /** Show view bounds (default: true) */
    showBounds?: boolean;
    /** Show renderer info (default: true) */
    showRendererInfo?: boolean;
    /** Show memory estimate (default: true) */
    showMemory?: boolean;
    /** Show draw calls (default: true) */
    showDrawCalls?: boolean;
    /** Position: 'top-left', 'top-right', 'bottom-left', 'bottom-right' */
    position?: 'top-left' | 'top-right' | 'bottom-left' | 'bottom-right';
    /** Background opacity (0-1, default: 0.8) */
    opacity?: number;
    /** Font size in pixels (default: 11) */
    fontSize?: number;
    /** Update interval in ms (default: 250) */
    updateInterval?: number;
    /** Custom CSS class name */
    className?: string;
}
export declare class DebugOverlay {
    private container;
    private element;
    private options;
    private visible;
    private updateIntervalId;
    private statsProvider;
    private lastStats;
    private frameCount;
    private lastFpsUpdate;
    private currentFps;
    private frameTimes;
    constructor(container: HTMLElement, options?: DebugOverlayOptions);
    /**
     * Set the stats provider function
     */
    setStatsProvider(provider: () => Partial<DebugStats>): void;
    /**
     * Record a frame for FPS calculation
     */
    recordFrame(frameTime?: number): void;
    /**
     * Show the debug overlay
     */
    show(): void;
    /**
     * Hide the debug overlay
     */
    hide(): void;
    /**
     * Toggle visibility
     */
    toggle(): void;
    /**
     * Check if visible
     */
    isVisible(): boolean;
    /**
     * Update the display with new stats
     */
    update(stats?: Partial<DebugStats>): void;
    /**
     * Get current stats
     */
    getStats(): Partial<DebugStats>;
    /**
     * Destroy the overlay
     */
    destroy(): void;
    private createElement;
    private destroyElement;
    private getPositionStyles;
    private startUpdates;
    private stopUpdates;
    private getAverageFrameTime;
    private renderStats;
    private formatNumber;
    private formatBytes;
    private formatValue;
}
/**
 * Create a debug overlay for a chart container
 */
export declare function createDebugOverlay(container: HTMLElement, options?: DebugOverlayOptions): DebugOverlay;
/**
 * Quick enable debug mode (attaches to first chart container found)
 */
export declare function enableDebugMode(options?: DebugOverlayOptions): DebugOverlay | null;