/**
 * ImageStoreHelper - Cross-axis image storage
 *
 * Extracted from DrawToolCore.ts:
 * - syncLayerSliceData
 *
 * Phase 3: MaskVolume is the sole storage backend. All IPaintImages params removed.
 */
import { BaseTool } from "./BaseTool";
import type { ToolContext } from "./BaseTool";
import type { ImageStoreHostDeps } from "./ToolHost";
export declare class ImageStoreHelper extends BaseTool {
    private callbacks;
    constructor(ctx: ToolContext, callbacks: ImageStoreHostDeps);
    /**
     * Get MaskVolume for a specific layer.
     * Delegates to the volumes stored in protectedData.maskData.
     *
     * @param layer - "layer1", "layer2", or "layer3"
     * @returns MaskVolume for the given layer, or layer1 as fallback
     */
    private getVolumeForLayer;
    /**
     * Get the canvas element for a specific layer.
     */
    private getCanvasForLayer;
    /**
     * Vertically flip an ImageData buffer in-place (swap rows top↔bottom).
     *
     * Used to compensate for the Z-axis direction reversal between sagittal
     * and coronal views. On coronal, Z runs along the canvas j-axis (vertical),
     * and the display flip (scale(1,-1)) reverses Z relative to sagittal's
     * horizontal Z mapping. This row-swap aligns the Z ordering so that
     * MaskVolume stores data in a consistent coordinate system.
     */
    private flipImageDataVertically;
    /**
     * Sync the current layer canvas to its MaskVolume slice and notify the parent
     * via getMask. This is the primary write path after any draw/erase operation.
     */
    syncLayerSliceData(index: number, layer: string): void;
}