phash-imagemagick/test/test.js

get and compare perceptual hashes (as computed by imagemagick)

var util = require('util');
var fs = require('fs');
var path = require('path');
var assert = require('assert');
var async = require('async');
var pHash = require('..');

var root = path.dirname(__filename);

var absPaths = fs
  .readdirSync(path.join(root, 'fixtures'))
  .filter(function(p) {
    return path.extname(p) === '.png' || path.extname(p) === '.jpg';
  })
  .map(function(p) {
    return path.join(root, 'fixtures', p);
  });

var color = absPaths.filter(function(p) {
  return path.extname(p) === '.png' && path.basename(p).indexOf('_gray') === -1;
});
var colorLow = absPaths.filter(function(p) {
  return path.extname(p) === '.jpg' && path.basename(p).indexOf('_gray') === -1;
});
var gray = absPaths.filter(function(p) {
  return path.extname(p) === '.png' && path.basename(p).indexOf('_gray') !== -1;
});
var grayLow = absPaths.filter(function(p) {
  return path.extname(p) === '.jpg' && path.basename(p).indexOf('_gray') !== -1;
});

describe('pHash-imagemagick', function() {
  this.timeout(40000);

  describe('pHash', function() {
    it('should get perceptual hash values', function(done) {
      pHash.get(color[0], function(err, data) {
        assert(data.pHash.length === 42 * 4);
        assert.equal(
          data.pHash,
          '006100520470037004230398044704220885087406860629092808360061-030043101600421-0100430004008700058064801210870010600640061047804480499042904930441102708880745066609930896'
        );
        done();
      });
    });
  });

  // compare -metric phash figure1.png figure2.png NULL:
  describe('pHash comparison', function() {
    var hashes;

    before(function(done) {
      async.parallel(
        {
          color: function(cb) {
            async.mapSeries(color, pHash.get, cb);
          },
          colorLow: function(cb) {
            async.mapSeries(colorLow, pHash.get, cb);
          },
          gray: function(cb) {
            async.mapSeries(gray, pHash.get, cb);
          },
          grayLow: function(cb) {
            async.mapSeries(grayLow, pHash.get, cb);
          }
        },
        function(err, res) {
          hashes = res;
          done();
        }
      );
    });

    it('should compare hashes for color images of different resolutions', function() {
      for (var i = 0; i < hashes.color.length; i++) {
        for (var j = 0; j < hashes.colorLow.length; j++) {
          assert.equal(i === j, pHash.eq(hashes.color[i], hashes.colorLow[j]));
        }
      }
    });

    it('should compare hashes for gray images of different resolutions', function() {
      for (var i = 0; i < hashes.gray.length; i++) {
        for (var j = 0; j < hashes.grayLow.length; j++) {
          assert.equal(i === j, pHash.eq(hashes.gray[i], hashes.grayLow[j]));
        }
      }
    });

    it('should test if more than 2 images are similar', function() {
      Object.keys(hashes).forEach(function(key) {
        assert(!pHash.eq.apply(pHash, hashes[key]));
      });
    });
  });
});