Previews

[drewish]

I finally got the preview reading working correctly. Did some benchmarking and found that—as you'd guess—the performance was better when you did all the IO in the worker thread and copied the images across. It was about ~20% faster when reading 1.5MB JPEG previews from CR2 files. I want to see if there's a similar speed up loading the tags that way.

Anyway give this a look and let me know what you think.

[drewish]

Here's roughly the script I was using to do benchmarks (it's setup for testing getImageTags() right now):

#!/usr/bin/env node

var exiv = require('./exiv2')
  , async = require('async')
  , Benchmark = require('benchmark');

var files = [
  '/Users/amorton/Desktop/2012-02-11 16.43.21.cr2'
, '/Users/amorton/Desktop/2012-02-11 16.43.40.cr2'
, '/Users/amorton/Desktop/2012-02-11 16.43.30.cr2'
, '/Users/amorton/Desktop/2012-02-11 16.43.51.cr2'
];

var suite = new Benchmark.Suite;

suite.add('files', {
  'defer': true,
  'fn': function(deferred) {
    async.map(files, exiv.getImageTags, function(err, results) {
      deferred.resolve();
    });
  }
});

suite
  .on('cycle', function(event, bench) {
    console.log(String(bench));
  })
  .on('complete', function() {
    console.log('Fastest is ' + this.filter('fastest').pluck('name'));
    console.log(this);
  })
  .run({ 'async': true });