import type { PillCSSPlacement, TipPoint } from "../geometry/stickPositioning";
/**
 * Pure geometry snapshot consumed by the per-frame interpolators. Any time
 * the underlying layout changes (size tier, stick angle, label content), the
 * caller computes a fresh `StickFrameGeometry` and the next animation frame
 * naturally reflects it.
 */
export type StickFrameGeometry = Readonly<{
    /** Tip position in anchor-relative coordinates (anchor = origin). */
    tip: TipPoint;
    /** CSS placement for the surface's expanded (pill-at-tip) state. */
    pillCSS: PillCSSPlacement;
    /**
     * Half-extents of the SVG that draws the line/dot. The SVG sits centered on
     * the anchor; its internal origin is `(svgHalfExtentX, svgHalfExtentY)`,
     * which is also the anchor in the SVG's own coordinate space.
     */
    svgHalfExtentX: number;
    svgHalfExtentY: number;
    /** Visible circle diameter in collapsed/circle form. */
    circleDiameterPx: number;
    /** Outer pill height — also the diameter of the cap circle. */
    pillHeightPx: number;
    /** Stick anchor dot radius in pixels. */
    dotRadiusPx: number;
}>;
export type SurfacePlacement = Readonly<{
    /** Constant pixel `left` for the surface (top-left of the pill envelope at t=1). */
    leftPx: number;
    /** Constant pixel `top` for the surface (top-left of the pill envelope at t=1). */
    topPx: number;
    /** Animated transform components, ready to write into `style.transform`. */
    translateXPct: number;
    translateXPx: number;
    translateYPx: number;
}>;
export type LineEndpoint = Readonly<{
    x2: number;
    y2: number;
}>;
export type DotAppearance = Readonly<{
    opacity: number;
    scale: number;
}>;
/**
 * The constant pixel `left`/`top` for the surface — these never change during
 * the animation. The outer container is anchor-zero (positioned exactly at
 * the geographic anchor), so the surface's `left`/`top` are simply the
 * pill's anchor-relative placement (`pillCSS`) with no extra offset adapter.
 */
export declare const computeSurfaceFixedOrigin: (geometry: StickFrameGeometry) => {
    leftPx: number;
    topPx: number;
};
/**
 * Interpolates surface transform between the resting circle-at-anchor pose
 * and the expanded pill-at-tip pose.
 *
 * - At `t = 0`: the visible circle sits centered on the anchor. Implemented
 *   by translating the surface's top-left back from its expanded `left`/`top`
 *   so the circle of diameter `circleDiameterPx` aligns with the anchor.
 * - At `t = 1`: the surface is at its expanded pose with `pillCSS.translateXPct`
 *   placing the appropriate pill cap at the tip.
 */
export declare const interpolateSurfacePlacement: (t: number, geometry: StickFrameGeometry) => SurfacePlacement;
/**
 * Format a transform string in the same three-function shape used previously.
 * Centralized so the spring loop and React renders agree byte-for-byte.
 */
export declare const formatSurfaceTransform: (placement: SurfacePlacement) => string;
/**
 * Interpolates the SVG line endpoint between the anchor (zero-length line) and
 * the tip. Coordinates are in the SVG's own coordinate space — the SVG's
 * internal origin `(svgHalfExtentX, svgHalfExtentY)` is the anchor, so the tip
 * lands at `(svgHalfExtentX + tip.x, svgHalfExtentY + tip.y)` at `t=1`.
 */
export declare const interpolateLineEndpoint: (t: number, geometry: StickFrameGeometry) => LineEndpoint;
/**
 * Interpolates the anchor dot's opacity and scale. Linear blend keeps the dot
 * visually tied to the same progress value as the surface and line.
 */
export declare const interpolateDot: (t: number) => DotAppearance;