/** True when the runner image declares the desktop tier present (BOARDWALK_DESKTOP_TIER=1). */
export declare function desktopTierEnabled(env: NodeJS.ProcessEnv): boolean;
export interface GuestDesktopConfig {
    /** Which OS driver backs this session (`makeDesktopDriver` selects on it). */
    platform: "linux" | "darwin";
    /** X display — Linux only; meaningless on macOS (the real screen is the target). */
    display: string;
    screenWidth: number;
    screenHeight: number;
}
/** Read the guest desktop config from env, or null when the tier is disabled or unsupported here.
 *  Linux drives XTEST/x11grab; macOS drives CGEvent/screencapture (desktop_driver_darwin.ts). */
export declare function loadGuestDesktopConfig(env: NodeJS.ProcessEnv, platform?: NodeJS.Platform): GuestDesktopConfig | null;
export interface DesktopScreenshotCapture {
    png: Buffer;
    width: number;
    height: number;
}
export interface DesktopClick {
    x: number;
    y: number;
    button?: "left" | "right" | "middle";
    clicks?: 1 | 2;
}
export interface DesktopScroll {
    dx: number;
    dy: number;
    x?: number;
    y?: number;
}
/** One screen's input + capture surface. Coordinates are screen pixels, origin top-left; every
 *  implementation clamps into the screen bounds rather than erroring on an off-by-a-few click. */
export interface DesktopDriver {
    screenshot(): Promise<DesktopScreenshotCapture>;
    click(input: DesktopClick): Promise<void>;
    type(input: {
        text: string;
        submit?: boolean;
    }): Promise<void>;
    key(chord: string): Promise<void>;
    scroll(input: DesktopScroll): Promise<void>;
    drag(input: {
        from: {
            x: number;
            y: number;
        };
        to: {
            x: number;
            y: number;
        };
    }): Promise<void>;
}
/** Exec seam for tests: run a binary to completion, resolve stdout, reject on non-zero exit. */
export type DriverExec = (cmd: string, args: readonly string[]) => Promise<Buffer>;
/** A `+`-joined SDK chord ("Control+Shift+t", "Meta+a") in xdotool syntax ("ctrl+shift+t"). */
export declare function chordToXdotool(chord: string): string;
/** A scroll delta in wheel notches: at least 1 for any non-zero delta, capped. */
export declare function scrollNotches(delta: number): number;
/** Build the OS driver for a resolved desktop config (the composition root's one entry point). */
export declare function makeDesktopDriver(cfg: GuestDesktopConfig): DesktopDriver;
/**
 * The Linux driver: xdotool (XTEST) for input, the image's ffmpeg (one-frame x11grab) for
 * screenshots — both already in the hosted guest image. `exec` is injectable for tests.
 */
export declare function makeXdotoolDriver(cfg: GuestDesktopConfig, exec?: DriverExec): DesktopDriver;