[#1] add tiff support

Author: Quramy

README.md

@@ -72,6 +72,7 @@ The following codecs are available for input image files.
 
 - [x] png
 - [x] jpeg
+- [x] tiff (limited. See https://github.com/Quramy/decode-tiff#compatibility )
 - [ ] bmp
 
 `imgDiff` detects the input image format from it's extension name. For example, if the input file name ends with ".jpeg", `imgDiff` attempts to decode in JPEG way regardless of the actual file format.

lib/decode-tiff.js

@@ -0,0 +1,14 @@
+const fs = require("fs");
+const { decode } = require("decode-tiff");
+
+function decodeTiff(filename) {
+  return new Promise((resolve, reject) => {
+    fs.readFile(filename, (err, rawBuffer) => {
+      if (err) return reject(err);
+      const tiffData = decode(rawBuffer);
+      resolve(tiffData);
+    });
+  });
+}
+
+module.exports = decodeTiff;

lib/index.js

@@ -4,6 +4,7 @@ const pixelmatch = require("pixelmatch");
 const { PNG } = require("pngjs");
 const decodePng = require("./decode-png");
 const decodeJpeg = require("./decode-jpeg");
+const decodeTiff = require("./decode-tiff");
 const expand = require("./expand");
 
 const extensionDecoderMap = { };
@@ -28,6 +29,7 @@ function decode(filename) {
 
 registerDecoder(["png"], decodePng);
 registerDecoder(["jpg", "jpeg"], decodeJpeg);
+registerDecoder(["tiff"], decodeTiff);
 
 function compare(img1, img2, diffFilename, options) {
   const { dataList, width, height } = expand(img1, img2);

package.json

@@ -23,6 +23,7 @@
   },
   "homepage": "https://github.com/reg-viz/img-diff-js#readme",
   "dependencies": {
+    "decode-tiff": "^0.2.0",
     "jpeg-js": "^0.3.3",
     "pixelmatch": "^4.0.2",
     "pngjs": "^3.2.0"

test/decode-tiff.test.js

@@ -0,0 +1,11 @@
+import test from "ava";
+import path from "path";
+const decodeTiff = require("../lib/decode-tiff");
+
+test("decode tiff file", async t => {
+  const file = path.resolve(__dirname, "images/actual.tiff");
+  const jpeg = await decodeTiff(file);
+  t.is(typeof jpeg.width, "number");
+  t.is(typeof jpeg.height, "number");
+  t.is(jpeg.data.length, jpeg.width * jpeg.height * 4);
+});

test/images/actual.tiff

@@ -40,6 +40,17 @@ test("compare with 2 files whose dimension are different", async t => {
   t.truthy(fs.statSync(path.resolve(__dirname, "images/diff_generated.wide.png")));
 });
 
+test("compare with 2 jpeg files", async t => {
+  const diffFilename = path.resolve(__dirname, "images/diff_generated.tiff.png");
+  rimraf.sync(diffFilename);
+  const { width, height } = await imgDiff({
+    diffFilename,
+    actualFilename: path.resolve(__dirname, "images/actual.tiff"),
+    expectedFilename: path.resolve(__dirname, "images/expected.tiff"),
+  });
+  t.truthy(fs.statSync(path.resolve(__dirname, "images/diff_generated.tiff.png")));
+});
+
 test("compare with 2 jpeg files", async t => {
   const diffFilename = path.resolve(__dirname, "images/diff_generated.jpg.png");
   rimraf.sync(diffFilename);

test/images/expected.tiff

@@ -969,6 +969,10 @@ decamelize@^1.1.2:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/decamelize/-/decamelize-1.2.0.tgz#f6534d15148269b20352e7bee26f501f9a191290"
 
+decode-tiff@^0.2.0:
+  version "0.2.0"
+  resolved "https://registry.yarnpkg.com/decode-tiff/-/decode-tiff-0.2.0.tgz#540b2949efedee689e3e20224cc04af6b82ad88a"
+
 deep-equal@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/deep-equal/-/deep-equal-1.0.1.tgz#f5d260292b660e084eff4cdbc9f08ad3247448b5"