DefinitelyTyped/types/looks-same/index.d.ts

// Type definitions for looks-same 4.0
// Project: https://github.com/gemini-testing/looks-same
// Definitions by: xcatliu <https://github.com/xcatliu>
// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped

/// <reference types="node"/>

type LooksSameCallback = (error: Error | null, equal: boolean) => any;

/**
 * The options passed to looksSame function
 */
interface LooksSameOptions {
    /**
     * By default, it will detect only noticeable differences. If you wish to detect any difference, use strict options.
     */
    strict?: boolean;
    /**
     * You can also adjust the ΔE value that will be treated as error in non-strict mode.
     */
    tolerance?: number;
    /**
     * Some devices can have different proportion between physical and logical screen resolutions also known as pixel ratio.
     * Default value for this proportion is 1.
     * This param also affects the comparison result, so it can be set manually with pixelRatio option.
     */
    pixelRatio?: number;
    /**
     * For visual regression tasks it may be useful to ignore text caret in text input elements. You can do it with ignoreCaret option.
     */
    ignoreCaret?: boolean;
    /**
     * Some images has difference while comparing because of antialiasing.
     * These diffs will be ignored by default. You can use ignoreAntialiasing option with false value to disable ignoring such diffs.
     * In that way antialiased pixels will be marked as diffs.
     */
    ignoreAntialiasing?: boolean;
    /**
     * Sometimes the antialiasing algorithm can work incorrectly due to some features of the browser rendering engine.
     * Use the option antialiasingTolerance to make the algorithm less strict.
     * With this option you can specify the minimum difference in brightness (zero by default)
     * between the darkest/lightest pixel (which is adjacent to the antialiasing pixel) and theirs adjacent pixels.
     *
     * We recommend that you don't increase this value above 10. If you need to increase more than 10 then this is definitely not antialiasing.
     */
    antialiasingTolerance?: number;
}

/**
 * The options passed to looksSame.createDiff function without diff
 */
interface CreateDiffAsBufferOptions {
    /**
     * The baseline image path
     */
    reference: string;
    /**
     * The current image path
     */
    current: string;
    /**
     * Color to highlight the differences
     * e.g. '#ff00ff'
     */
    highlightColor: string;
    /**
     * strict comparsion
     */
    strict: boolean;
    /**
     * ΔE value that will be treated as error in non-strict mode
     */
    tolerance: number;
}

/**
 * The options passed to looksSame.createDiff function
 */
interface CreateDiffOptions extends CreateDiffAsBufferOptions {
    /**
     * The diff image path to store
     */
    diff: string;
}

/**
 * Pass to looksSame.colors function
 */
interface LooksSameColor {
    /**
     * Red
     */
    R: number;
    /**
     * Green
     */
    G: number;
    /**
     * Blue
     */
    B: number;
}

/**
 * Compare two images with options
 * @param image1 The first image path
 * @param image2 The second image path
 * @param options The options passed to looksSame function
 * @param callback Call when finish compare
 */
declare function looksSame(image1: string, image2: string, options: LooksSameOptions, callback: LooksSameCallback): void;
/**
 * Compare two images
 * @param image1 The first image path
 * @param image2 The second image path
 * @param callback Call when finish compare
 */
declare function looksSame(image1: string, image2: string, callback: LooksSameCallback): void;

// https://stackoverflow.com/questions/44058101/typescript-declare-third-party-modules
declare namespace looksSame {
    function createDiff(options: CreateDiffOptions, callback: (error: Error | null) => any): void;
    function createDiff(options: CreateDiffAsBufferOptions, callback: (error: Error | null, buffer: Buffer) => any): void;

    /**
     * Compare two colors
     * @param color1 The first color
     * @param color2 The second color
     * @param options The options passed to looksSame.colors function
     */
    function colors(color1: LooksSameColor, color2: LooksSameColor, options: { tolerance: number }): void;
}

/**
 * Node.js library for comparing PNG-images, taking into account human color perception.
 * It is created specially for the needs of visual regression testing for gemini utility, but can be used for other purposes.
 */
export = looksSame;