/**
 * A sparse character grid for drawing the workflow graph. Box-drawing
 * characters merge by connectivity (│ crossing ─ becomes ┼) so overlapping
 * edge polylines join instead of overwriting each other.
 */
export type CanvasStyle = "plain" | "dim" | "taken" | "active" | "back" | "ok" | "fail" | "warn" | "branch" | "agent" | "compute" | "action" | "checkpoint";
export declare const UP = 1;
export declare const DOWN = 2;
export declare const LEFT = 4;
export declare const RIGHT = 8;
/** Which sides each box-drawing character connects to (exported for tests). */
export declare const CHAR_TO_MASK: Record<string, number>;
export declare class CharCanvas {
    private readonly cells;
    private maxX;
    private maxY;
    private row;
    /** Place a single character, merging box-drawing connectivity. */
    put(x: number, y: number, char: string, style?: CanvasStyle): void;
    /** Write a text run left to right (labels, node lines). */
    text(x: number, y: number, value: string, style?: CanvasStyle): void;
    /**
     * Write text only when every target cell is empty. Returns whether the
     * text was written. Used for optional decorations (edge labels) that must
     * never corrupt lines or nodes already on the canvas.
     */
    textIfEmpty(x: number, y: number, value: string, style?: CanvasStyle): boolean;
    /**
     * Write text over a plain horizontal run, replacing `─` cells only.
     * Refuses (returns false) unless every target cell and both flanking
     * cells are exactly `─`, so a label can never overwrite or sit against
     * corners, crossings, or other labels. Spaces in `value` become real
     * blanks, visually breaking the run around the label on purpose.
     */
    textOverRun(x: number, y: number, value: string, style?: CanvasStyle): boolean;
    hline(y: number, x1: number, x2: number, style?: CanvasStyle): void;
    vline(x: number, y1: number, y2: number, style?: CanvasStyle): void;
    /** Render to lines; `paint` applies terminal styling per character run. */
    render(paint: (text: string, style: CanvasStyle) => string): string[];
}