import { Model } from "@singularsystems/neo-core";
import ObservableElement from "../React/ObservableElement";
export interface IHeaderContext {
    /** Indicates that the trigger element is obscured by the header, or has scrolled past the top of the viewport. */
    readonly isObscured: boolean;
    /** Indicates where the content will be placed in the header. */
    readonly placementInHeader: PlacementInHeader;
    /** State that can be passed by the view to the header. */
    state?: any;
}
export type PlacementInHeader = "inline" | "below";
/** Implemented by views that render content in the app header. */
export interface IHeaderPanelContributor {
    readonly placementInHeader?: PlacementInHeader;
    /** When this element is scrolled out of view, `renderInAppHeader()` will report that it is obscured. */
    headerTriggerElement?: ObservableElement<HTMLElement> | undefined;
    /**
     * Content to be rendered in the app header.
     * Return undefined instead of an empty element when there is no content. */
    renderInAppHeader(context: IHeaderContext): React.ReactNode | undefined;
}
export declare class HeaderContributorContext extends Model.ObservableStack<IHeaderPanelContributor> {
}
export interface IHeaderContributorContextHost {
    headerContext: HeaderContributorContext;
}