/**
 * Signed Distance Field (SDF) rasterizer
 *
 * For each pixel, compute the shortest distance to the outline.
 * Positive values are inside the outline, negative are outside.
 * This allows GPU text rendering at any scale.
 *
 * Algorithm:
 * 1. For each pixel center, find the minimum distance to all outline edges
 * 2. Determine sign based on whether point is inside or outside the outline
 * 3. Normalize and encode to 0-255 (128 = on the edge)
 */
import type { GlyphPath } from "../render/path.ts";
import { type Bitmap } from "./types.ts";
/**
 * Options for SDF rendering
 */
export interface SdfOptions {
    /** Width in pixels */
    width: number;
    /** Height in pixels */
    height: number;
    /** Scale factor (font units to pixels) */
    scale: number;
    /** X offset in pixels */
    offsetX?: number;
    /** Y offset in pixels */
    offsetY?: number;
    /** Flip Y axis (font coords are Y-up, bitmap is Y-down) */
    flipY?: boolean;
    /** Spread/radius - how far the distance field extends in pixels (default: 8) */
    spread?: number;
}
/**
 * Render a glyph path as a signed distance field
 * @param path Glyph path to render
 * @param options SDF rendering options (dimensions, scale, spread)
 * @returns Grayscale bitmap with signed distance field (128 = on edge, 255 = inside, 0 = outside)
 */
export declare function renderSdf(path: GlyphPath, options: SdfOptions): Bitmap;