From 3ee058afb0f214dee5054ffa002bd05c8df07fb8 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tom@procensus.com>
Date: Tue, 28 Nov 2017 16:13:30 +0000
Subject: [PATCH] add options to compareImages

---
 README.md        | 26 ++++++++++++++++++++++----
 compareImages.js | 36 +++++++++++++++++++++++++++++++++---
 2 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 0f3bda6..bba094b 100644
--- a/README.md
+++ b/README.md
@@ -121,17 +121,35 @@ The API under Node is the same as on the browser with one addition, a promise ba
 
 ``` js
 const compareImages = require('resemblejs/compareImages');
-const fs = require("fs");
+const fs = require("mz/fs");
 
 async function getDiff(){
+
+const options = {
+  output: {
+    errorColor: {
+      red: 255,
+      green: 0,
+      blue: 255
+    },
+    errorType: 'movement',
+    transparency: 0.3,
+    largeImageThreshold: 1200,
+    useCrossOrigin: false,
+    outputDiff: true
+  },
+  scaleToSameSize: true,
+  ignore: ['nothing', 'less', 'antialiasing', 'colors', 'alpha'],
+};
 // The parameters can be Node Buffers
 // data is the same as usual with an additional getBuffer() function
 const data = await compareImages(
-	fs.readFileSync('./demoassets/People.jpg'),
-	fs.readFileSync('./demoassets/People2.jpg')
+	await fs.readFile('./demoassets/People.jpg'),
+	await fs.readFile('./demoassets/People2.jpg'),
+	options,
 );
 
-fs.writeFileSync('./output.png', data.getBuffer());
+await fs.writeFile('./output.png', data.getBuffer());
 
 }
 
diff --git a/compareImages.js b/compareImages.js
index 42e5772..1884317 100644
--- a/compareImages.js
+++ b/compareImages.js
@@ -1,8 +1,38 @@
-const resemble = require('./resemble');
+var resemble = require('./resemble');
 
-module.exports = async function(image1, image2) {
+function applyIgnore(api, ignore) {
+  switch (ignore) {
+    case 'nothing': api.ignoreNothing();
+    case 'less': api.ignoreLess();
+    case 'antialiasing': api.ignoreAntialiasing();
+    case 'colors': api.ignoreColors();
+    case 'alpha': api.ignoreAlpha();
+    default: throw new Error('Invalid ignore: ' + ignore);
+  }
+}
+
+module.exports = function(image1, image2, options) {
   return new Promise(function(resolve, reject) {
-    resemble(image1).compareTo(image2).onComplete(function(data) {
+    var res = resemble(image1), opt = options || {}, compare;
+    if (opt.output) {
+      res.outputSettings(opt.output);
+    }
+
+    compare = res.compareTo(image2);
+
+    if (opt.scaleToSameSize) {
+      compare.scaleToSameSize();
+    }
+
+    if (typeof opt.ignore === 'string') {
+      applyIgnore(compare, opt.ignore);
+    } else if (opt.ignore && opt.ignore.forEach) {
+      opt.ignore.forEach(function (v) {
+        applyIgnore(compare, v);
+      });
+    }
+
+    compare.onComplete(function(data) {
       if (data.error) {
         reject(data.error);
       } else {