import { LayoutRect, ThemeContext } from '../../shared/kernel';
import { FontOptions, PaddingValue, Pixels, Switchable } from '../../shared/options';
import { Group } from '../../shared/scene';
export interface CaptionOptions extends Switchable, FontOptions {
    text?: string;
    /** Horizontal alignment within the chart width ('center' by default). */
    textAlign?: 'left' | 'center' | 'right';
    /** Vertical placement: above ('top', default) or below ('bottom') the plot. */
    position?: 'top' | 'bottom';
    /**
     * Padding around the caption text in any CSS-like shorthand — `8`, `[8, 12]`,
     * `[8, 12, 4, 0]` or `{ top, right, bottom, left }`. By default only the
     * plot-facing side is padded (8 px): below the caption in the 'top' zone,
     * above it in the 'bottom' zone. When both captions share a zone, the padding
     * of the outer one separates the two captions, and the padding of the one
     * closest to the plot separates it from the plot. Horizontal padding narrows
     * the width the text is wrapped within.
     */
    padding?: PaddingValue;
    /**
     * Gap on the plot-facing side of the caption (8 by default).
     *
     * @deprecated Use `padding` — it covers the same gap and the other three
     * sides. Kept as the default for the plot-facing side of `padding`.
     */
    spacing?: Pixels;
    /**
     * Break the text onto several lines when it does not fit the available width
     * (true by default). Line breaks written as '\n' always apply.
     */
    wrap?: boolean;
}
export interface CaptionLayoutContext {
    measureText: (text: string, font: string) => number;
    /**
     * Box the captions flow around — a floating legend, in scene coordinates.
     * Lines overlapping it vertically are laid out in the wider side gap. Asked
     * again with a width cap when a line has nowhere to go beside the box: the
     * legend gives up width rather than have the caption land on it. Undefined
     * (or a callback returning it) — there is nothing to flow around.
     */
    obstacle?: (widthCap?: number) => LayoutRect | undefined;
}
interface CaptionLine {
    text: string;
    /** Anchor point of the line, matching `align`. */
    x: number;
    y: number;
    align: 'left' | 'center' | 'right';
}
interface CaptionPlacement {
    role: 'title' | 'subtitle';
    options: CaptionOptions;
    fontSize: number;
    /** Height of the whole block: the lines plus the vertical padding. */
    height: number;
    lines: CaptionLine[];
    /** Width the widest line is missing in the gap the obstacle left it (0 — everything fits). */
    shortfall: number;
}
/** Whether anything will be drawn at all — lets callers skip preparing the layout context. */
export declare function hasCaptions(title: CaptionOptions | undefined, subtitle: CaptionOptions | undefined): boolean;
/**
 * Places the title and subtitle around the plot: 'top' captions stack below
 * `padding.top`, 'bottom' ones sit above `padding.bottom` (the title stays
 * above the subtitle in both zones, the caption padding faces the plot). Long
 * text wraps within the available width, flowing around `context.obstacle`.
 * Returns the placements plus the space consumed from each edge, chart padding
 * excluded.
 *
 * When a line has nowhere to go beside the obstacle, the obstacle is asked to
 * fit into a narrower width and the whole layout is taken again — a floating
 * legend gives up the room the caption is missing instead of being written
 * over. It gives up no more than half the width: past that its own labels
 * would be the ones with nowhere to go.
 */
export declare function layoutCaptions(title: CaptionOptions | undefined, subtitle: CaptionOptions | undefined, theme: ThemeContext, width: number, height: number, padding: {
    top: number;
    right: number;
    bottom: number;
    left: number;
}, context: CaptionLayoutContext): {
    placements: CaptionPlacement[];
    top: number;
    bottom: number;
};
/**
 * Renders the title and subtitle around the plot (see {@link layoutCaptions})
 * and returns the space consumed from each edge, padding excluded.
 */
export declare function renderCaptions(layer: Group, title: CaptionOptions | undefined, subtitle: CaptionOptions | undefined, theme: ThemeContext, width: number, height: number, padding: {
    top: number;
    right: number;
    bottom: number;
    left: number;
}, context: CaptionLayoutContext): {
    top: number;
    bottom: number;
};
export {};