/**
 * @file
 *
 * Fits a screenshot onto a canvas of a different aspect ratio without cropping
 * it or distorting it, filling the leftover margins with a blurred, enlarged
 * copy of the same image (the "pillarbox" treatment used by store listings).
 *
 * The motivating case is a mobile store screenshot. The Android emulator's
 * framebuffer is whatever the AVD's screen is — a Pixel 10 Pro XL is 1344x2992,
 * roughly 9:20 — while the community store asks for 900x1600 (9:16). Cropping
 * to 9:16 throws away a fifth of the frame, and stretching distorts the UI, so
 * the image is scaled to fit the HEIGHT and the two side margins are filled.
 *
 * The geometry is a pure function so it can be unit-tested; the pixel work needs
 * `sharp`, which is an OPTIONAL peer dependency — declared rather than bundled
 * because only screenshot capture needs it, and it ships platform-specific
 * native binaries that every other consumer would pay for.
 */
/**
 * Parameters for {@link computeFitToCanvas}.
 */
export interface ComputeFitToCanvasParams {
    /**
     * Height of the target canvas, in pixels.
     */
    readonly canvasHeightInPixels: number;
    /**
     * Width of the target canvas, in pixels.
     */
    readonly canvasWidthInPixels: number;
    /**
     * Height of the source image, in pixels.
     */
    readonly sourceHeightInPixels: number;
    /**
     * Width of the source image, in pixels.
     */
    readonly sourceWidthInPixels: number;
}
/**
 * Options for {@link fitScreenshotToCanvas}.
 */
export interface FitScreenshotToCanvasOptions {
    /**
     * Gaussian blur strength applied to the margin fill.
     *
     * @default `24`
     */
    readonly blurSigma?: number;
    /**
     * Height of the target canvas, in pixels.
     */
    readonly canvasHeightInPixels: number;
    /**
     * Width of the target canvas, in pixels.
     */
    readonly canvasWidthInPixels: number;
}
/**
 * Where the scaled source image sits on the canvas.
 */
export interface FitToCanvasGeometry {
    /**
     * Width of each side margin, in pixels. Both sides are equal by construction.
     */
    readonly marginInPixels: number;
    /**
     * Left offset of the scaled image on the canvas, in pixels.
     */
    readonly offsetXInPixels: number;
    /**
     * Top offset of the scaled image on the canvas, in pixels.
     */
    readonly offsetYInPixels: number;
    /**
     * Height the source is scaled to, in pixels.
     */
    readonly scaledHeightInPixels: number;
    /**
     * Width the source is scaled to, in pixels.
     */
    readonly scaledWidthInPixels: number;
}
/**
 * Computes how a source image is scaled and placed to fill a canvas's height,
 * with equal margins on the left and right.
 *
 * The scaled width is rounded to the nearest integer that leaves an EVEN
 * remainder, so the two margins are exactly equal — an asymmetric pillarbox is
 * visible at a glance and looks like a mistake. Where both neighbors qualify,
 * the one closer to the true scaled width wins, so the aspect error stays below
 * one part in a thousand.
 *
 * Worked example, the mobile store case: a 1344x2992 frame onto a 900x1600
 * canvas scales by `1600/2992` to 718.72 wide. 719 would leave a 181px
 * remainder, which cannot split evenly, so 718 is chosen (margin 91) over 720
 * (margin 90) because 718 is nearer 718.72.
 *
 * @param params - The source and canvas dimensions.
 * @returns The scaled size, the offsets, and the side margin.
 * @throws Error if any dimension is not a positive number.
 */
export declare function computeFitToCanvas(params: ComputeFitToCanvasParams): FitToCanvasGeometry;
/**
 * Scales a screenshot to fill a canvas's height and fills the side margins with
 * a blurred, enlarged copy of the same image.
 *
 * Nothing is cropped and nothing is stretched: the visible screenshot keeps its
 * aspect ratio to within a rounding pixel, and the margins are made of the
 * image itself rather than a flat color, so the result reads as one frame.
 *
 * @param bytes - The source PNG.
 * @param options - The target canvas size and blur strength.
 * @returns A {@link Promise} that resolves to the composed PNG, exactly the canvas size.
 * @throws Error if `sharp` is not installed, or the source dimensions cannot be read.
 */
export declare function fitScreenshotToCanvas(bytes: Uint8Array, options: FitScreenshotToCanvasOptions): Promise<Uint8Array>;