import type { GenericParent } from 'myst-common';
import type { VFileMessage } from 'vfile-message';
import type { PageFrontmatter } from 'myst-frontmatter';
import type { ISession } from '../session/types.js';
import { ImageExtensions } from '../utils/resolveExtension.js';
export declare const BASE64_HEADER_SPLIT = ";base64,";
export declare function downloadAndSaveImage(session: ISession, url: string, stem: string, fileFolder: string): Promise<string | undefined>;
export declare function resolveOutputPath(file: string, writeFolder: string, altOutputFolder?: string): string;
export declare function saveImageInStaticFolder(session: ISession, urlSource: string, sourceFile: string, writeFolder: string, opts?: {
    altOutputFolder?: string;
    position?: VFileMessage['position'];
}): Promise<{
    urlSource: string;
    url: string;
} | null>;
export declare function transformImagesToEmbed(mdast: GenericParent): void;
export declare function transformImagesWithoutExt(session: ISession, mdast: GenericParent, file: string, opts?: {
    imageExtensions?: ImageExtensions[];
}): void;
export declare function transformImagesToDisk(session: ISession, mdast: GenericParent, file: string, writeFolder: string, opts?: {
    altOutputFolder?: string;
    imageExtensions?: ImageExtensions[];
}): Promise<void>;
type ConversionOpts = {
    file: string;
    inkscapeAvailable: boolean;
    imagemagickAvailable: boolean;
    dwebpAvailable: boolean;
    ffmpegAvailable: boolean;
};
type ConversionFn = (session: ISession, source: string, writeFolder: string, conversionOpts: ConversionOpts) => Promise<string | null>;
/**
 * Returns a list of all available conversion functions from the input extension to valid extensions
 *
 * If multiple functions are available, they are ordered based on the order of validExts.
 * Therefore validExts should have preferred formats first.
 */
export declare function getConversionFns(imageExt: string, validExts: ImageExtensions[]): ConversionFn[];
/**
 * Transform to convert all images with known-but-unsupported extensions to supported extensions
 *
 * The `imageExtensions` option is a list of supported extensions, ordered by preference.
 * For example you may use `imageExtensions = ['.svg', '.png']` so the vector svg
 * format is preferred but fallback png is allowed.
 *
 * If an image extension is unknown or if there are no functions to covnert it to
 * a valid extension, the image will remain unchanged.
 */
export declare function transformImageFormats(session: ISession, mdast: GenericParent, file: string, writeFolder: string, opts?: {
    altOutputFolder?: string;
    imageExtensions?: ImageExtensions[];
}): Promise<void[] | undefined>;
export declare function transformThumbnail(session: ISession, mdast: GenericParent | null, file: string, frontmatter: PageFrontmatter, writeFolder: string, opts?: {
    altOutputFolder?: string;
    webp?: boolean;
    maxSizeWebp?: number;
}): Promise<{
    url: string;
    urlOptimized?: string;
} | undefined>;
export declare function transformBanner(session: ISession, file: string, frontmatter: {
    banner?: string | null;
    bannerOptimized?: string;
}, writeFolder: string, opts?: {
    altOutputFolder?: string;
    webp?: boolean;
    maxSizeWebp?: number;
}): Promise<{
    url: string;
    urlOptimized?: string;
} | undefined>;
export declare function transformWebp(session: ISession, opts: {
    file: string;
    imageWriteFolder: string;
    maxSizeWebp?: number;
}): Promise<void>;
/**
 * Handle placeholder image nodes in figures.
 *
 * This reduces figures to a single representation; it should only be used for static contexts
 * where you do not need to persist the multiple figure representations.
 *
 * If there is a valid image or code node in the figure, the placeholder image is removed.
 * If there is no other valid image or code node, the placeholder image is promoted to normal image.
 *
 * Elsewhere in the mdast tree, placeholder images are just left as-is; currently the only way to
 * author a placeholder image is using a figure directive.
 */
export declare function transformPlaceholderImages(mdast: GenericParent, opts?: {
    imageExtensions?: ImageExtensions[];
}): void;
/**
 * Trim base64 values for urlSource when they have been replaced by image urls
 */
export declare function transformDeleteBase64UrlSource(mdast: GenericParent): Promise<void[]>;
export {};
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