/**
 * Pure layout for region labels.
 *
 * Picks one of six positions (TL/TR/BR/BL/TC/BC) inside the region's
 * bounding box, skipping any whose representative cell sits outside
 * the cell-union (so labels don't float in empty L-shape gaps).
 */
import type { RegionDef } from '../types.js';
import type { GridLayout } from '../geometry/grid.js';
import type { LabelRect, LineSeg, CanvasBounds, Circle } from '../geometry/collision.js';
import { type AttemptRecord } from '../geometry/label-placer.js';
import type { Blob } from '../geometry/blob.js';
export type RegionPosition = 'top-left' | 'top-right' | 'bottom-right' | 'bottom-left' | 'top-center' | 'bottom-center';
/** Fixed order: TL → TR → BR → BL → TC → BC */
export declare const POSITION_ORDER: RegionPosition[];
export interface LabelSlot {
    lx: number;
    ly: number;
    anchor: 'start' | 'middle' | 'end';
    rect: LabelRect;
}
/**
 * Place the label rect inside the bbox with `pad` clearance from the
 * inset rounded corner. Since the arc eats `~0.29 * radius` from the
 * corner, pad must account for inset + that arc bite + a small margin.
 */
export declare function computeRegionSlot(minX: number, maxX: number, minY: number, maxY: number, fontSize: number, estW: number, labelH: number, position: RegionPosition, pad: number): LabelSlot;
export declare function bboxInPixels(blob: Blob, layout: GridLayout): {
    minX: number;
    maxX: number;
    minY: number;
    maxY: number;
};
/**
 * Padding from bbox corner to label rect. The rounded corner eats
 * ~(1 − 1/√2) × radius ≈ 0.293 × radius into the bbox. Add inset and
 * a small extra margin so the label sits visibly clear of the arc.
 */
export declare function labelPadding(inset: number, radius: number, fontSize: number): number;
export interface RegionLabelMetrics {
    fs: number;
    estW: number;
    labelH: number;
    pad: number;
    inset: number;
    radius: number;
}
export declare function regionLabelMetrics(region: RegionDef, layout: GridLayout): RegionLabelMetrics;
export interface RegionLabelResult {
    rect: LabelRect;
    position: RegionPosition;
    error: boolean;
    /** Every position the placer tried, for diagnostic emission. */
    attempts: AttemptRecord[];
}
/** Pre-compute region label placement. Order: TL → TR → BR → BL → TC → BC */
export declare function computeRegionLabelRect(region: RegionDef, layout: GridLayout, placedLabels: LabelRect[], connLines: LineSeg[], bounds?: CanvasBounds, iconCircles?: Circle[]): RegionLabelResult | null;
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