import { RenderContext } from './RenderContext';
/**
 * Renders the multi-row column-group header band above the leaf column headers.
 * Each cell — a group span or a blank filler for an ungrouped/shallow column —
 * is a pooled element positioned from the layout: `left`/`width` from the column
 * geometry, `top`/`height` from its header row and row-span. Group cells show the
 * header and, when collapsible, a chevron that toggles the group.
 *
 * Only cells intersecting the visible column window are materialized, so the
 * node count tracks the viewport (times the small, fixed header depth), never the
 * total column count.
 */
export declare class ColumnGroupRenderer {
    private inner;
    private onToggle;
    private rowHeight;
    private active;
    private pool;
    constructor(inner: HTMLElement, onToggle: (key: string) => void, rowHeight: number);
    render(ctx: RenderContext): void;
    clear(): void;
    dispose(): void;
    private fill;
    private readonly onClick;
}