/**
 * Multi-channel Signed Distance Field (MSDF) rasterizer
 *
 * MSDF uses three channels (RGB) to encode distance information,
 * allowing sharp corners to be preserved when scaling.
 *
 * Algorithm:
 * 1. Decompose glyph outline into edges (lines, quadratics, cubics)
 * 2. Color edges so adjacent edges at sharp corners have different colors
 * 3. For each pixel, compute signed distance to nearest edge of each color
 * 4. Store R, G, B distances in output bitmap
 * 5. Shader reconstructs using: median(r, g, b)
 *
 * Reference: https://github.com/Chlumsky/msdfgen
 */
import type { Font } from "../font/font.ts";
import type { GlyphPath } from "../render/path.ts";
import { type Bitmap, type GlyphAtlas, type MsdfAtlasOptions } from "./types.ts";
/**
 * A 2D point
 */
export interface Point {
    x: number;
    y: number;
}
/**
 * Edge color channels for MSDF
 * 0 = red, 1 = green, 2 = blue
 */
export type EdgeColor = 0 | 1 | 2;
/**
 * Bounding box for edge culling
 */
interface EdgeBounds {
    minX: number;
    maxX: number;
    minY: number;
    maxY: number;
}
/**
 * An edge with color assignment and bounding box
 */
export type MsdfEdge = ({
    type: "line";
    p0: Point;
    p1: Point;
    color: EdgeColor;
} & EdgeBounds) | ({
    type: "quadratic";
    p0: Point;
    p1: Point;
    p2: Point;
    color: EdgeColor;
} & EdgeBounds) | ({
    type: "cubic";
    p0: Point;
    p1: Point;
    p2: Point;
    p3: Point;
    color: EdgeColor;
} & EdgeBounds);
/**
 * Signed distance result with parameter t
 */
export interface SignedDistanceResult {
    distance: number;
    t: number;
}
/**
 * Options for MSDF rendering
 */
export interface MsdfOptions {
    /** 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;
}
/**
 * Return the median of three numbers
 */
export declare function median(a: number, b: number, c: number): number;
/**
 * Compute signed distance from point to line segment
 */
export declare function signedDistanceToLine(px: number, py: number, p0: Point, p1: Point): SignedDistanceResult;
/**
 * Compute signed distance from point to quadratic bezier curve
 * Uses Newton-Raphson iteration to find closest point
 */
export declare function signedDistanceToQuadratic(px: number, py: number, p0: Point, p1: Point, p2: Point): SignedDistanceResult;
/**
 * Compute signed distance from point to cubic bezier curve
 * Uses Newton-Raphson iteration with multiple starting points
 */
export declare function signedDistanceToCubic(px: number, py: number, p0: Point, p1: Point, p2: Point, p3: Point): SignedDistanceResult;
/**
 * Assign colors to edges based on corner angles
 * At sharp corners, adjacent edges get different colors
 */
export declare function assignEdgeColors(contours: MsdfEdge[][]): void;
/**
 * Compute signed distance from point to edge
 */
export declare function signedDistanceToEdge(px: number, py: number, edge: MsdfEdge): SignedDistanceResult;
/**
 * Determine if a point is inside using ray casting (even-odd rule)
 */
export declare function isPointInside(px: number, py: number, contours: MsdfEdge[][]): boolean;
/**
 * Flatten an edge to points for inside testing
 */
export declare function flattenEdge(edge: MsdfEdge): Point[];
/**
 * Render a glyph path as a multi-channel signed distance field
 */
export declare function renderMsdf(path: GlyphPath, options: MsdfOptions): Bitmap;
/**
 * Build an MSDF texture atlas from a set of glyphs
 */
export declare function buildMsdfAtlas(font: Font, glyphIds: number[], options: MsdfAtlasOptions): GlyphAtlas;
/**
 * Build MSDF atlas for ASCII printable characters (32-126)
 */
export declare function buildMsdfAsciiAtlas(font: Font, options: MsdfAtlasOptions): GlyphAtlas;
/**
 * Build MSDF atlas for a specific string (including all unique glyphs)
 */
export declare function buildMsdfStringAtlas(font: Font, text: string, options: MsdfAtlasOptions): GlyphAtlas;
/**
 * Export MSDF atlas as RGB texture data
 */
export declare function msdfAtlasToRGB(atlas: GlyphAtlas): Uint8Array;
/**
 * Export MSDF atlas as RGBA texture data
 */
export declare function msdfAtlasToRGBA(atlas: GlyphAtlas): Uint8Array;
export {};