/**
 * Camera-fit policy: pick a target / distance / view direction appropriate
 * to the scene's bounding-box shape.
 *
 * Compact models (typical buildings, aspect <= LINEAR_ASPECT_THRESHOLD) keep
 * the historical south-east isometric pose with `maxSize * 2` distance — the
 * established BIM convention and the only thing the existing test suite has
 * pinned. Long-thin models (railway alignments, road corridors, anything
 * with bbox aspect > 50:1) get a "linear" policy: camera positioned at the
 * bbox centre, looking down-and-along the longest axis, distance chosen so
 * sub-metre features (signals, referents, kerbs) project to several pixels
 * rather than vanishing into a single pixel of the auto-fit frustum.
 *
 * The module is intentionally pure (no GPU / Camera / Renderer dependency)
 * so it can be unit-tested for every aspect ratio that matters and reused
 * by both the post-load auto-fit and the Home-view button without
 * duplicating the heuristic at each call site.
 *
 * iTwin.js civil viewers solve this same problem with a stationing
 * navigation mode that tracks the alignment direction. We approximate the
 * starting pose iTwin uses for the first frame.
 */
import type { Vec3 } from './raycaster.js';
export interface Bounds3 {
    min: Vec3;
    max: Vec3;
}
export type FitPolicyKind = 'compact' | 'linear';
export interface FitPolicy {
    /** Which heuristic produced this pose — for telemetry / UI hints. */
    kind: FitPolicyKind;
    /** Bbox aspect ratio (longest / shortest, clamped). Surfaced for tests. */
    aspect: number;
    /** Where the camera should look. */
    target: Vec3;
    /** Where the camera should sit. */
    position: Vec3;
    /** World up vector. Always (0, 1, 0) — both policies are Y-up. */
    up: Vec3;
    /** Distance from position to target. Convenience copy for callers. */
    distance: number;
}
export interface PickFitPolicyOptions {
    /** Vertical field-of-view in radians. */
    fovY: number;
    /** Shortest viewport dimension in pixels (height for landscape). */
    viewportShortPx?: number;
    /**
     * Override the linear-detection threshold. Production should leave this
     * at the default; exposed for tests that pin the threshold behaviour.
     */
    linearAspectThreshold?: number;
    /**
     * Override the minimum longest-axis extent (world units) at/above which the
     * linear policy is allowed to apply. Production should leave this at the
     * default; exposed for tests that pin the size-floor behaviour.
     */
    linearMinLongest?: number;
}
/**
 * Compute the fit pose for a scene's bounding box. Pure function — no
 * side-effects; returns the pose the caller should apply to the camera.
 *
 * The compact branch reproduces the legacy `fitToBounds()` pose exactly
 * (south-east isometric at `maxSize * 2`) so a model that scored "compact"
 * frames identically to today's build. The linear branch only kicks in
 * once the bbox aspect ratio crosses the threshold, so building / room /
 * piece geometry never sees a behaviour change.
 */
export declare function pickFitPolicy(bounds: Bounds3, options: PickFitPolicyOptions): FitPolicy;
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