// lightbox.js
// Sample JavaScript solution code for Lab 5: Lightbox
// INFO 343, Autumn 2012
// Morgan Doocy
// List of image filenames and captions to display in the gallery.
var IMAGES = [
{ file: 'http://info343.ischool.uw.edu/labs/5/avocado.jpg', caption: 'Avocado' },
{ file: 'http://info343.ischool.uw.edu/labs/5/beach.jpg', caption: 'Beach' },
{ file: 'http://info343.ischool.uw.edu/labs/5/biebs.jpg', caption: 'Biebs' },
{ file: 'http://info343.ischool.uw.edu/labs/5/bling.jpg', caption: 'Bling' },
{ file: 'http://info343.ischool.uw.edu/labs/5/cat.jpg', caption: 'Cat' },
{ file: 'http://info343.ischool.uw.edu/labs/5/dew.jpg', caption: 'Dew' },
{ file: 'http://info343.ischool.uw.edu/labs/5/fall.jpg', caption: 'Fall' },
{ file: 'http://info343.ischool.uw.edu/labs/5/freeway.jpg', caption: 'Freeway' },
{ file: 'http://info343.ischool.uw.edu/labs/5/hongkong.jpg', caption: 'Hong Kong' },
{ file: 'http://info343.ischool.uw.edu/labs/5/leaves.jpg', caption: 'Leaves' },
{ file: 'http://info343.ischool.uw.edu/labs/5/reflection.jpg', caption: 'Reflection' },
{ file: 'http://info343.ischool.uw.edu/labs/5/tuners.jpg', caption: 'Tuners' }
];
// Keep track of whether or not the lightbox is enabled, so we know whether to
// track key presses for keyboard navigation.
var enlarged = false;
// When the page is ready, create and inject images into #gallery and attach
// event handlers.
$(document).ready(function() {
// Create and inject images into #gallery.
$.each(IMAGES, function(i, image) {
// Create the image with appropriate attributes.
var $img = $('<img>').attr('src', image.file).attr('alt', image.caption);
// Create a link whose href is the image file itself - but attach a click
// handler to show the lightbox and prevent the browser from visiting the
// image's URL. (Here we introduce an anonymous intermediary function to
// pass i from here into the enlarge function.)
var $a = $('<a>').attr('href', image.file).click(function(event) { enlarge(event, i); });
// Inject the image into the link, and the link into the gallery.
$img.appendTo($a);
$a.appendTo('#gallery');
});
// Clear the lightbox when it’s clicked.
$('#lightbox').click(clear);
// Listen for all keypresses in the document for keyboard navigation.
$(document.body).keyup(keypress);
});
// Show the lightbox, enlarging the ith image in the list.
function enlarge(event, i) {
// Prevent the browser from visiting the clicked link.
event.preventDefault();
// Create and inject an image into the lightbox with the source and alt of the
// ith image in the list.
$('<img>').attr('src', IMAGES[i].file).attr('alt', IMAGES[i].caption).appendTo('#container');
// Set the previous and next links to go to the appropriate images.
setNavigation(i);
// Special effect: make the lightbox fade in using a jQuery effect.
$('#lightbox').fadeIn(200).focus();
// Remember that the lightbox is enabled for keyboard navigation.
enlarged = true;
}
// Set the lightbox navigation links to go to the next/previous images.
function setNavigation(index) {
var prev = index > 0 ? index - 1 : IMAGES.length - 1;
var next = (index + 1) % IMAGES.length;
// Set the next/prev links to new hrefs, and attach new click handlers (making
// sure to unbind the previous one).
$('#prev').attr('href', IMAGES[prev].file).unbind('click').click(function(event) { load(event, prev) });
$('#next').attr('href', IMAGES[next].file).unbind('click').click(function(event) { load(event, next) });
}
// Load the image at the given index into the lightbox.
function load(event, index) {
// Prevent the browser from viewing the clicked link.
event.preventDefault();
// Create and inject a new image into the lightbox, initially hidden. Make it
// fade in, then remove the previous image.
var $oldimg = $('#container img');
var $newimg = $('<img>').attr('src', IMAGES[index].file).attr('alt', IMAGES[index].caption);
$newimg.hide().appendTo('#container').fadeIn(200, function() {
$oldimg.remove();
});
// Reset the navigation links.
setNavigation(index);
}
// Clear the lightbox (fading out) if it was clicked.
function clear(event) {
if (event.target == document.getElementById('lightbox')) {
$('#lightbox').fadeOut(200, function() {
$('#lightbox img').remove();
enlarged = false;
});
}
}
// If the lightbox is being shown, make left/right arrow keys navigate through
// lightbox, and ESC dismiss it.
function keypress(event) {
if (enlarged) {
// console.log('keyCode: ' + event.which);
switch (event.which) {
case 27: // ESC
$('#lightbox').click(); // simulate a click on the lightbox
break;
case 37: // left arrow
$('#prev').click(); // simulate a click on #prev
break;
case 39: // right arrow
$('#next').click(); // simulate a click on #next
break;
}
}
}