// Image slideshow
// Author: Douglas Greiman
// Written: July 28, 2009
// Released to the public domain.
//
// To get a random slideshow, add code like this to your page:
//
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// ...
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// ...
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// ...
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// Other examples:
// 8 seconds per image, 5 images chosen, from entire Waterhouse collection
// duggelz.slideshow.start(8, 5, duggelz.slideshow.waterhouse_urls())
//
// 8 seconds per image, hand picked list
// duggelz.slideshow.startlist(8, [ "http://...", "url..", "url.."])
if (!this.duggelz) {
var duggelz = {};
if (!this.duggelz.slideshow) {
duggelz.slideshow = function() {
var urls;
var cur_idx = 0;
var images;
// Preload images
function _preload() {
images = new Array(urls.length);
for (var i = 0; i < urls.length; i++) {
images[i] = new Image();
images[i].src = urls[i];
}
}
// Advance to next slideshow image
function _next_image() {
cur_idx = (cur_idx + 1) % urls.length;
if (images[cur_idx].width) {
var slideshow = document.getElementById("slideshow_img_tag");
slideshow.src = urls[cur_idx];
}
}
// Advance to random slideshow index
function _random_image() {
cur_idx = _randn(urls.length);
if (images[cur_idx].width) {
var slideshow = document.getElementById("slideshow_img_tag");
slideshow.src = urls[cur_idx];
}
}
// Choose random number between 0 and maxn
function _randn(maxn) {
return Math.floor(Math.random()*maxn);
}
return {
// Public entry point
start : function(interval_in_s, num_images, all_urls) {
urls = new Array(num_images);
for (var i = 0; i < num_images; i++) {
urls[i] = all_urls[_randn(all_urls.length)];
}
_preload();
window.setInterval(_next_image, interval_in_s * 1000);
},
// Public entry point
startlist : function(interval_in_s, all_urls) {
// Copy array
urls = all_urls.slice();
_preload();
window.setInterval(_next_image, interval_in_s * 1000);
},
// Return an array of urls to all Waterhouse photos
waterhouse_urls : function() {
// Compute url for photo number i
function u(i) {
var ones = i % 10;
var tens = Math.floor(i/10) % 10;
var hundreds = Math.floor(i/100) % 10;
var thousands = Math.floor(i/1000) % 10;
return ("http://www.sourisseauacademy.org/" +
"Edith_Smith_Collections/Images/" +
thousands + "000/"
+ thousands + hundreds + "00/JPGs/" +
"ecs" + thousands + hundreds + tens + ones + ".jpg");
}
var all_urls = new Array(305);
for (var i=1; i<306; i++) {
all_urls[i-1] = u(i);
}
return all_urls;
}
}
} ();
} // if (!this.duggelz.slideshow)
} // if (!this.duggelz)