import type { PPTImageElement, Slide } from '../types/slides';
import type { ImagePaintCache } from './textContrast';
interface CanvasRange {
    minX: number;
    maxX: number;
    minY: number;
    maxY: number;
}
interface Viewport {
    width: number;
    height: number;
}
/** Map a canvas overlap onto the image's natural pixels, honoring clip + flip. */
export declare const canvasRegionToImagePixels: (el: PPTImageElement, region: CanvasRange, naturalWidth: number, naturalHeight: number) => {
    left: number;
    top: number;
    width: number;
    height: number;
} | null;
/** Map a canvas overlap onto a cover-fitted slide background image. */
export declare const canvasRegionToCoverPixels: (region: CanvasRange, viewport: Viewport, naturalWidth: number, naturalHeight: number) => {
    left: number;
    top: number;
    width: number;
    height: number;
} | null;
/**
 * Sample average colors for image layers that actually sit under text.
 * Browser-only (`Image` + canvas). Returns `undefined` when there is nothing
 * to sample or the environment can't decode images — the contrast query then
 * keeps treating those layers as `unknown`.
 */
export declare const sampleImagePaintsForSlide: (slide: Slide, viewport: Viewport) => Promise<ImagePaintCache | undefined>;
export {};