README.html

<h2>Installation</h2>

<p>
  Drag and drop the following link to your bookmarks bar:<br>
  <a href="javascript:(function() { var elem=document.createElement('script'); elem.setAttribute('src', 'https://gist.github.com/philippbosch/5018940/raw/pinterest-slideshow.js?t='+(new Date().getTime())); document.body.appendChild(elem); }())">Slideshow</a>
</p>

pinterest-slideshow.js

(function() {
  if (location.host != 'pinterest.com' || location.pathname.split('/').length != 4) {
    alert('Please use this bookmarklet on a Pinterest user\'s board page.');
    return;
  }
  
  if (!jQuery || !$) {
    // No jQuery!
    return;
  } 
  
  var $style = $('<style/>');
  var css = '#the-pinterest-slideshow-overlay { position: fixed; top: 0; left: 0; right: 0; bottom: 0; z-index: 99999999; background: #000; }';
  css += '#the-pinterest-slideshow-overlay img { position: absolute; top: 50%; left: 50%; }';
  $style.text(css);
  $style.appendTo('body');

  var $pins = $('.pin[data-closeup-url]');
  var urls = $pins.map(function(i, p) { return $(p).data('closeup-url'); });

  var $overlay = $('<div id="the-pinterest-slideshow-overlay"/>');
  var $img = $('<img>');
  $img.appendTo($overlay);
  $overlay.hide().appendTo('body');
  
  var currentPinNum = -1;
  
  function previousPin() {
    if (currentPinNum == 0) return;
    currentPinNum--;
    displayPin($pins.eq(currentPinNum));
  }
  
  function nextPin() {
    if (currentPinNum == $pins.length-1) return;
    currentPinNum++;
    displayPin($pins.eq(currentPinNum));
  }
  
  function displayPin($pin) {
    $img.fadeOut($img.attr('src') == '' ? 0 : 250, function() {
      $img.one('load', function() {
        $img.css('margin-left', '-' + ($pin.data('width')/2) + 'px');
        $img.css('margin-top', '-' + ($pin.data('height')/2) + 'px');
        $img.fadeIn(250);
      });
      $img.attr('src', $pin.data('closeup-url'));
      $img.data('$pin', $pin);
    });
    
  }
  
  function showSlideshow(callback) {
    $overlay.css('opacity',0).show().animate({'opacity': 1}, 500, callback);
  }
  
  function hideSlideshow(callback) {
    $overlay.animate({'opacity': 0}, 500, function() {
      $overlay.hide();
      if (callback) callback();
    });
  }
  
  $img.on('click', function(e) {
    var $pin = $pins.eq(currentPinNum);
    console.log($pin, $pin.data(), currentPinNum);
    hideSlideshow(function() {
      // location.href = '/pin/' + $pin.data('id') + '/';
    });
  });
  
  $(document).on('keydown', function(e) {
    switch(e.keyCode) {
      case 37: // previous
        previousPin();
        break;
      case 39: // next
        nextPin();
        break;
      case 27: // exit
        hideSlideshow();
        break;
    }
  });
  
  showSlideshow(nextPin);
})();