/**
 * Letters as rows of dots, for a child to trace (#1017): the dots a text
 * is painted with when its style sets `dotted` (a design text element, a
 * chip style).
 *
 * The browser shapes and draws the text, so a joined script keeps its
 * joins and an Arabic word its forms, and the dots are read off what it
 * drew. The run is painted alone on a small canvas, `RASTER_PITCH` pixels
 * to a dot spacing; the edge of its ink is traced (marching squares, at
 * the half-coverage level); each point of the edge is moved half the
 * stroke's width inward, onto the middle of the stroke; and the dots are
 * laid along each edge at the spacing, the longest edge first, a dot kept
 * only where no dot stands closer than `REJECT` spacings. The two edges of
 * a stroke meet on its middle, so the second one adds nothing: one row of
 * dots per stroke, whatever the weight (the thinnest weight of a face
 * gives the most even rows). An edge too short to carry two dots is a
 * mark of its own (the dot of an i, an accent): one dot at its middle, if
 * that is ink (the eye of a small loop is not).
 *
 * The dots are a function of the run, its font, its tracking, direction
 * and language, and of the spacing: cached under all of them. They are
 * paint, not layout: the run keeps the width it was measured at.
 */
import type { TextDotsStyle } from './types.js';
export interface TextDotsRequest {
    text: string;
    /** CSS font shorthand the run is painted in. */
    font: string;
    /** Distance between two dots along a stroke, px. */
    spacingPx: number;
    letterSpacingPx?: number;
    rtl?: boolean;
    /** The language the run is shaped in (`ctx.lang`). */
    lang?: string;
}
export interface TextDots {
    /** Dot centres, `x, y` pairs from the run's left edge and baseline, px. */
    points: Float32Array;
    /** The run's advance, px, as the raster's context measured it. */
    width: number;
}
/**
 * The dots `req.text` is traced with, or `null` where there is no canvas
 * to draw it on (the painter then fills the letters).
 */
export declare function textDots(req: TextDotsRequest): TextDots | null;
/** Forget every run's dots (a face loaded or replaced under a name). */
export declare function clearTextDots(): void;
/**
 * Dot centres (flat `x, y`, raster px) along the strokes of the ink in
 * `alpha` (coverage 0…1, `W × H`), `pitch` px apart. Exported for tests.
 */
export declare function dotsOnRaster(alpha: Float32Array, W: number, H: number, pitch: number): number[];
/**
 * The closed edges of the ink at coverage `level` (marching squares over
 * the pixel centres, each crossing placed by linear interpolation), as
 * flat `x, y` polylines, the ink on their right (y down). The raster's
 * border is taken as blank, so every edge closes.
 */
export declare function traceContours(alpha: Float32Array, W: number, H: number, level: number): number[][];
/** A `TextDotsStyle` in px, em being `fontSizePx`: `0.1em` apart, `0.05em`
 *  across by default; a spacing never under the dot. */
export declare function resolveTextDots(style: TextDotsStyle, dpi: number, fontSizePx: number): {
    spacingPx: number;
    sizePx: number;
};
//# sourceMappingURL=textDots.d.ts.map