import type { Spread } from '../engine/spread';
import { type FlipDirection, type LayoutMetrics, type Renderer, type RenderOptions, type SpreadContent } from './types';
/**
 * GPU renderer (WebGL2, hand-written). The turning leaf is a dense grid deformed on
 * the CPU by the selected curl model (see geometry/curls) and
 * uploaded each frame, lit from real normals; the static pages are flat quads with a
 * gutter shadow. Restores
 * GL state on context loss; signals onFatal (→ CSS fallback) when unrecoverable.
 */
export declare class WebglRenderer implements Renderer {
    #private;
    mount(container: HTMLElement): Promise<void>;
    destroy(): void;
    onFatal(handler: () => void): void;
    get maxTextureSize(): number | undefined;
    renderSpread(_spread: Spread, content: SpreadContent, options?: RenderOptions): void;
    beginFlip(from: SpreadContent, to: SpreadContent, direction: FlipDirection, options?: RenderOptions): void;
    setFlipProgress(t: number, _direction: FlipDirection): void;
    setViewTransform(scale: number, x: number, y: number): void;
    measure(): LayoutMetrics;
}