feat: add APNG support

README.md

@@ -5,17 +5,7 @@
 [![standard][standard-image]][standard-url]
 [![coverage][coveralls-image]][coveralls-url]
 
-[npm-image]: https://img.shields.io/npm/v/is-animated.svg
-[npm-url]: https://www.npmjs.com/package/is-animated
-[travis-image]: https://img.shields.io/travis/qzb/is-animated.svg
-[travis-url]: https://travis-ci.org/qzb/is-animated
-[standard-image]: https://img.shields.io/badge/code%20style-standard-brightgreen.svg
-[standard-url]: http://npm.im/standard
-[coveralls-image]: https://img.shields.io/coveralls/qzb/is-animated/master.svg
-[coveralls-url]: https://coveralls.io/r/qzb/is-animated?branch=master
-
-**is-animated** is a simple library for checking if specified GIF is animated.
-It doesn't care if gif is valid or not, invalid GIFs are treated as not-animated ones.
+**is-animated** is a simple library for detecting animated images, it supports not only GIFs, but also APNG images.
 
 ## Install
 
@@ -41,3 +31,15 @@ fs.readFile(filename, (err, buffer) => {
 ## License
 
 [MIT](LICENSE.md)
+
+
+[npm-image]: https://img.shields.io/npm/v/is-animated.svg
+[npm-url]: https://www.npmjs.com/package/is-animated
+[travis-image]: https://img.shields.io/travis/qzb/is-animated.svg
+[travis-url]: https://travis-ci.org/qzb/is-animated
+[standard-image]: https://img.shields.io/badge/code%20style-standard-brightgreen.svg
+[standard-url]: http://npm.im/standard
+[coveralls-image]: https://img.shields.io/coveralls/qzb/is-animated/master.svg
+[coveralls-url]: https://coveralls.io/r/qzb/is-animated?branch=master
+
+

lib/index.js

@@ -0,0 +1,24 @@
+'use strict'
+
+var gif = require('./types/gif')
+var png = require('./types/png')
+
+/**
+ * Checks if buffer contains animated image
+ *
+ * @param {Buffer} buffer
+ * @returns {boolean}
+ */
+function isAnimated (buffer) {
+  if (gif.isGIF(buffer)) {
+    return gif.isAnimated(buffer)
+  }
+
+  if (png.isPNG(buffer)) {
+    return png.isAnimated(buffer)
+  }
+
+  return false
+}
+
+module.exports = isAnimated

index.js → lib/types/gif.js

@@ -17,13 +17,24 @@ function getDataBlocksLength (buffer, offset) {
   return length + 1
 }
 
+/**
+ * Checks if buffer contains GIF image
+ *
+ * @param {Buffer} buffer
+ * @returns {boolean}
+ */
+exports.isGIF = function (buffer) {
+  var header = buffer.slice(0, 3).toString('ascii')
+  return (header === 'GIF')
+}
+
 /**
  * Checks if buffer contains animated GIF image
  *
  * @param {Buffer} buffer
  * @returns {boolean}
  */
-function isAnimated (buffer) {
+exports.isAnimated = function (buffer) {
   var hasColorTable, colorTableSize, header
   var offset = 0
   var imagesCount = 0
@@ -88,5 +99,3 @@ function isAnimated (buffer) {
 
   return (imagesCount > 1)
 }
-
-module.exports = isAnimated

lib/types/png.js

@@ -0,0 +1,52 @@
+exports.isPNG = function (buffer) {
+  var header = buffer.slice(0, 8).toString('hex')
+  return (header === '89504e470d0a1a0a') // \211 P N G \r \n \032 'n
+}
+
+exports.isAnimated = function (buffer) {
+  var hasACTL = false
+  var hasIDAT = false
+  var hasFDAT = false
+
+  var previousChunkType = null
+
+  var offset = 8
+
+  while (offset < buffer.length) {
+    var chunkLength = buffer.readUInt32BE(offset)
+    var chunkType = buffer.slice(offset + 4, offset + 8).toString('ascii')
+
+    switch (chunkType) {
+      case 'acTL':
+        hasACTL = true
+        break
+      case 'IDAT':
+        if (!hasACTL) {
+          return false
+        }
+
+        if (previousChunkType !== 'fcTL') {
+          return false
+        }
+
+        hasIDAT = true
+        break
+      case 'fdAT':
+        if (!hasIDAT) {
+          return false
+        }
+
+        if (previousChunkType !== 'fcTL') {
+          return false
+        }
+
+        hasFDAT = true
+        break
+    }
+
+    previousChunkType = chunkType
+    offset += 4 + 4 + chunkLength + 4
+  }
+
+  return (hasACTL && hasIDAT && hasFDAT)
+}

package.json

@@ -1,7 +1,7 @@
 {
   "name": "is-animated",
-  "description": "Checks if GIF image is animated",
-  "version": "1.0.0",
+  "description": "Detects animated GIF and APNG images",
+  "version": "1.1.0",
   "author": "Józef Sokołowski <j.k.sokolowski@gmail.com>",
   "bugs": {
     "url": "https://github.com/qzb/is-animated/issues"
@@ -20,7 +20,7 @@
     "image"
   ],
   "license": "MIT",
-  "main": "index.js",
+  "main": "lib/index.js",
   "repository": {
     "type": "git",
     "url": "https://github.com/qzb/is-animated.git"

test/index.js

@@ -1,38 +1,49 @@
 'use strict'
 
 var fs = require('fs')
+var path = require('path')
 var test = require('tape')
-var isAnimated = require('../index')
+var isAnimated = require('../lib')
 
-test('Test animated GIFs', function (t) {
-  var images = fs.readdirSync('./test/animated')
+var types = [ 'gif', 'png' ]
 
-  t.plan(images.length)
+types.forEach(function (type) {
+  test('Test animated ' + type.toUpperCase() + ' images', function (t) {
+    var images = fs.readdirSync('./test/animated').filter(function (name) {
+      return path.extname(name).slice(1) === type
+    })
 
-  images.forEach(function (imgName) {
-    var buffer = fs.readFileSync('./test/animated/' + imgName)
-    t.true(isAnimated(buffer), imgName)
+    t.plan(images.length)
+
+    images.forEach(function (imgName) {
+      var buffer = fs.readFileSync('./test/animated/' + imgName)
+      t.true(isAnimated(buffer), imgName)
+    })
   })
-})
 
-test('Test static GIFs', function (t) {
-  var images = fs.readdirSync('./test/static')
+  test('Test static ' + type.toUpperCase() + ' images', function (t) {
+    var images = fs.readdirSync('./test/static').filter(function (name) {
+      return path.extname(name).slice(1) === type
+    })
 
-  t.plan(images.length)
+    t.plan(images.length)
 
-  images.forEach(function (imgName) {
-    var buffer = fs.readFileSync('./test/static/' + imgName)
-    t.false(isAnimated(buffer), imgName)
+    images.forEach(function (imgName) {
+      var buffer = fs.readFileSync('./test/static/' + imgName)
+      t.false(isAnimated(buffer), imgName)
+    })
   })
-})
 
-test('Test invalid GIFs', function (t) {
-  var images = fs.readdirSync('./test/invalid')
+  test('Test invalid ' + type.toUpperCase() + ' images', function (t) {
+    var images = fs.readdirSync('./test/invalid').filter(function (name) {
+      return path.extname(name).slice(1) === type
+    })
 
-  t.plan(images.length)
+    t.plan(images.length)
 
-  images.forEach(function (imgName) {
-    var buffer = fs.readFileSync('./test/invalid/' + imgName)
-    t.false(isAnimated(buffer), imgName)
+    images.forEach(function (imgName) {
+      var buffer = fs.readFileSync('./test/invalid/' + imgName)
+      t.false(isAnimated(buffer), imgName)
+    })
   })
 })