Thomas' Tidbits: A few tidbits from Thomas about a variety of topics like programming, gaming, sports and other things.

Desire2Learn / Javascript Picture Library

By: Thomas Hawkins     Published Date: 2009-02-09 18:31:00

d2l javascript html

Introduction

The picture library built into Desire2Learn doesn’t allow for instructors to create their own libraries. Rather, all images are shared across all courses. I wrote this bit of javascript to simulate and extend the idea of a picture library in D2L (this code can also be used for any HTML page). There are two parts to the library:

The Widget Code (or HTML code for any page)

This code is the skeleton of the library. The javascript code modifies this code in order to display the images.

The Javascript Code

This is the brain of the library. It must be installed somewhere locally and linked to the widget/HTML page. There is a configuration section at the top of the file where you can configure the library.

Here is the widget/HTML code that must be displayed on the pages.
You should not edit this code as it will cause the library to malfunction.

 

Here is the javascript code: picturelibrary.js
You will need to right click this link and save the file to your computer before you can upload it to your D2L shell/website.

Notes About The Code

Not all the variables need to be set a certain way in order for the code to function. However, it is a good idea to set up any variables that you don’t want to use to be false. Some variables require others, so read the comments in the code carefully. I’ve also included them below:

/**
	This script presents a picture library to the user.  It has several configurable
	options which are outlined below.
	With this script, you can:
		1) Present a slide show to users
		2) Present a navigatable interface for users to scroll through the library
		3) Release an image to them based on a set date/time
		4) Release a random image from the library
**/
/**
	=== CONFIG START ===
	Here you need to specify the path to this script.  To do this you must go to the
	Edit Course section of the site, and go to Manage Files.  Then, copy the URL for
	this javascript file.  Paste the URL into the variable below.  Then remove the
	filename at the end of the URL "picturelibrary.js".  Replace the file name with
	"piclibimages/" (no quotes)
*/
var path = "http://online.mun.ca/content/Sandbox/TT/Sp07/piclibimages/";

/**
	List your images here.  By default, it will look under the piclibimages folder
	in your course files.  Change the path above if you want to load from a different
	location.

	Place the file names in the array below.  A comma must be placed after each entry
	except for the last entry in the list.
*/

var images = new Array(
	"dataspace-code.gif",
	"MedSchoolCrestSmall.gif",
	"crest-toothpaste.png"
);

/**
	List your captions here.  

	If you enable captions below, you must have at least as many captions as you have images
	above or you will probably get a javascript error when the script scrolls through the
	images.  You can have blank captions, denoted with "" in the array below.
*/
var captions = new Array(
	"The icon I created for the phpLive -> Dataspace integration.",
	"Medicine School Crest",
	"Crest Toothpaste"
);

/**
	This array contains dates for the date release function of this script.  If you do not
	want to use date release, you can leave this blank.

	Each entry goes with an entry in the images array and should be formatted with
	the startdate-enddate for the image.  Only one image can be displayed at a time
	with this method.
	A sample entry is: 200809190000-200809222359
		This will allow the	image to be viewed on Friday the 19th until Monday the 22nd.

	If you want your images	to rotate through a day, you can place a * for the date and
	just include the time.
	A sample entry is: *0000-*1200
		This will allow your image to appear on the site between midnight and noon every
		day.
*/

var releasedates = new Array(
	"*0000-*1230",
	"*1231-*1300",
	"*1301-*2359"
);
//var releasedates = new Array(
//	"200809170000-200809182359",
//	"200809190000-200809202359",
//	"200809210000-200809222359"
//);

/**
	Here you can set your options for the script.
	resize = controls if images are automatically resized.  If true, width and
			 height must be set.  These are measured in pixels.  Be careful using this
			 as it will likely distort your pictures horribly.  It is much better to
			 resize your pictures before uploading them to the system.
	navigation = controls if users can navigate through images, or if they see
				 a loop of images.
	imagepause = the amount of time in milliseconds that an image appears before
				 changing.  Only used if navigation is false. 4000 = 4 seconds
	captionsdisplay = if this is set to true, the caption is pulled from the above array
			   		  and displayed with the picture.
	daterelease = Shows an image on a specific date/for a specific time.  The datearray
			      must store the dates in the format yearmonthday-yearmonthday or *time-*time.
			      the first date/time being when the image is displayed, and the second
			      when it ends.
	imagestyle = This is a CSS style tag that will be added to the image tag.
	captionstyle = This is a CSS style take that will be added to the caption.
	widgetsytle = This is a CSS style tag that well be added to the div around the image
				  and caption.
	randomstart = This variable controls whether or not the script begins on a random image.
	singlerandom = If true, this displays a single random image when the page is loaded.
*/			      

var resize = false;
var width = "";
var height = "";
var navigation = true;
var imagepause = "5000";
var captionsdisplay = true;
var daterelease = true;
var imagestyle = "margin: 0 auto; display: block; padding: 2px;";
var captionstyle = "margin: 1px; text-size: 10px; text-align: center; border: 1px dashed gray;";
var widgetstyle = "border: 2px solid black;";
var randomstart = true;
var singlerandom = false;

/**
	=== CONFIG END ===
	This is the end of configurable items for this script.  Do not edit the code below.
*/

Also of note is the use of CSS styles. I cannot figure out how to apply an arbitrary CSS style string to an HTML element. I can change specific things, but I cannot allow any style tags. If anyone knows how, please contact me.

Because of this limitation, the CSS code will only recognize:

• border
• text-align
• font-size
• margin
• display
• padding

You can add in your own code to the bottom by editing the doStyle function, or you can apply your own styles to the raw widget/HTML code. You must leave the style variables blank in this script.

Final Thoughts

I hope you find this useful, either for your D2L course, or for your personal homepage. I’ll probably post updates from time to time on this script depending on the feedback I receive. If you have any comments, you can leave them below. Take a look at some of the variable configurations below to see examples of how the code can be used.

Examples