import type { Satellites } from "../satellites/types.ts";
import { type LonLat } from "./math.ts";
export type PaintLength = "1d" | "1w" | "1m";
export type PaintSwath = "track" | "coverage";
export interface PaintSpec {
    /** A NORAD catalogue number, or `group:index` of a group set on the element. */
    id: string;
    /** How long the trail is kept, in simulated time. `1d` when left out. */
    length?: PaintLength;
    /** `track` paints the point under the satellite (the default). `coverage` paints where it is at least 10° above the horizon. */
    swath?: PaintSwath;
}
export declare const paintLengthOf: (length: PaintLength | undefined) => PaintLength;
export declare const paintSwathOf: (swath: PaintSwath | undefined) => PaintSwath;
/** Minutes since the epoch, in 16 bits: the trail is at most a month, and 16 bits hold 45 days. */
export declare const paintMinute: (ms: number) => number;
export interface PaintState {
    readonly data: Uint8Array;
    readonly width: number;
    readonly height: number;
    /** Stamps whose alpha is set. Clear puts it back to 0. */
    readonly pixels: number;
    readonly on: boolean;
    readonly length: PaintLength;
    readonly swath: PaintSwath;
    /** The id now painted, or "" when painting is off. */
    readonly id: string;
    /** Minutes of simulated time the shader keeps. */
    readonly spanMinutes: number;
    set(spec: PaintSpec | null): void;
    clear(): void;
    /**
     * Stamp the ground crossed since the last call. `sample` is the satellite at a moment, or null when it cannot be placed.
     * Returns true when `data` changed and the picture should upload it. At rest, or with painting off, it returns false.
     * `periodMs` is one trip of the satellite round the Earth: samples are taken often enough that the line between two follows the orbit, however fast the clock. A clock run backwards lays down the older end of the length that it uncovers.
     */
    step(ms: number, sample: (ms: number) => (LonLat & {
        heightKm: number;
    }) | null, periodMs?: number): boolean;
}
export declare function createPaintState(): PaintState;
/** The satellite `id` names, in the groups now set: a NORAD number, or `group:index`. */
export declare function findPainted(groups: Iterable<[string, {
    satellites: Satellites;
}]>, id: string): {
    satellites: Satellites;
    index: number;
} | null;
/** The ground under the painted satellite at `ms`, or null when it cannot be placed. */
export declare function paintedGround(groups: Iterable<[string, {
    satellites: Satellites;
}]>, id: string, ms: number): (LonLat & {
    heightKm: number;
}) | null;
/** One trip of the painted satellite round the Earth, in milliseconds, from its mean motion; undefined when it is not found. */
export declare function paintedPeriod(groups: Iterable<[string, {
    satellites: Satellites;
}]>, id: string): number | undefined;