/**
 * HDRBlitCanvas - an on-screen WebGL2 canvas that displays a decoded frame
 * with the same HDR colorspace handling as the main CanvasRenderer.
 *
 * Why this exists: poster + hover-preview frames are HDR (rec2100-pq). The old
 * path encoded them to an 8-bit SDR JPEG via canvas.toBlob and showed an <img>,
 * which clamps PQ highlights → the picture looked dull next to the live video.
 * A 2D canvas cannot carry a rec2100-pq tag (only srgb/display-p3), so to keep
 * full HDR peak brightness the display surface must be a WebGL canvas tagged
 * rec2100-pq — exactly what CanvasRenderer does to composite to screen.
 *
 * This class is a thin passthrough blitter: it uploads a source (another canvas,
 * a VideoFrame, or raw RGBA) as a texture and draws it 1:1 onto its own canvas,
 * which is tagged with the appropriate colorspace. The heavy decode + (for
 * non-Chromium) PQ tone-mapping already happened in ThumbnailRenderer; here we
 * only transport the pixels to screen without an SDR round-trip.
 */
export interface HDRBlitOptions {
    /** Source color primaries (e.g. "bt2020"). Drives colorspace selection. */
    colorPrimaries?: string;
    /** Source transfer characteristics (e.g. "pq", "hlg"). */
    colorTransfer?: string;
    /** Whether HDR upgrade is allowed; false forces srgb. Default true. */
    hdrEnabled?: boolean;
}
export declare class HDRBlitCanvas {
    readonly canvas: HTMLCanvasElement;
    private gl;
    private program;
    private texture;
    private vao;
    private appliedColorSpace;
    constructor(canvas?: HTMLCanvasElement);
    private detectChromium;
    /**
     * Choose the wide-gamut SDR colorspace for a source. HDR upgrade to
     * rec2100-pq/hlg is attempted separately at apply time (it can throw when the
     * Chromium experimental flag is off), so this only ever returns a value the
     * 2D/WebGL spec guarantees: srgb or display-p3.
     */
    private detectColorSpace;
    /**
     * Lazily create the WebGL2 context + passthrough program and apply the
     * colorspace tag. Safe to call repeatedly; only the first call builds GL
     * state, later calls just re-apply the colorspace for the current source.
     */
    private ensureGL;
    /** Mirror of ThumbnailRenderer/CanvasRenderer colorspace setup. */
    private applyColorSpace;
    private buildProgram;
    /**
     * Blit a source (a canvas, VideoFrame, ImageBitmap, etc. — anything
     * texImage2D accepts) onto the display canvas at the given size.
     */
    blit(source: TexImageSource, width: number, height: number, opts?: HDRBlitOptions): boolean;
    get colorSpace(): string;
    destroy(): void;
}
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