Tutorials/LifeViewer JavaScript plug-in

The LifeViewer Javascript Plug-in lets you use LifeViewer in you own web pages.

Getting Started: Download the LifeViewer plug-in

• Use this link: download
• The javascript code will be displayed in your browser
• Do a "Save" or "Save as..." and save lv-plugin.js where you want it
• In this tutorial, we assume the plug-in is in the same folder as your html file

Lesson 1: Hello World--web page with glider in viewer

• A simple web page with a glider in a LifeViewer (run the example(dead link))
• Paste the code below in your text editor, save it and run it

<!DOCTYPE html>
<html>
<head>
<meta name="LifeViewer" content="viewer textarea"> <!--required tag-->
<script src="lv-plugin.js"></script> <!--assumes plug-in is in the same directory as html file-->
</head>
<body>
<!--viewer container-->
<div class="viewer"> <!--class=viewer is required-->
	<textarea>bo$2bo$3o!</textarea><br/> <!--textarea required in viewer container, with glider rle-->
	<canvas></canvas> <!--canvas required in viewer container-->
</div>
<!--end viewer container-->
</body>
</html>

Lesson 2: Add some style

• Size the textarea, change font, make it non-resizable
• Size viewer by sizing canvas using inline width and height attributes (not CSS)
• Align viewer and textarea
• Note the textarea needs to be a few pixels narrower to properly align
• Run the example

<!DOCTYPE html>
<html>
<head>
<meta name="LifeViewer" content="viewer textarea"> <!--required tag-->
<script src="lv-plugin.js"></script> <!--assumes plug-in is in the same directory as html file-->
<style>
body{
	margin:50px;
}
.lv-rle{
	font:12pt arial;
	resize:none;
	width:594px;
	min-height:120px;
	max-height:120px;
}
</style>
</head>
<body>
<!--viewer container-->
<div class="viewer"> 
	<textarea class="lv-rle">bo$2bo$3o!</textarea><br/> <!--added classname for styling-->
	<canvas height=400 width=600></canvas> <!--added width and height attributes for viewer-->
</div>
<!--end viewer container-->
</body>
</html>

Lesson 3: Update viewer with user input

• Add control buttons to clear the textarea and update the viewer with user-entered rle
• The rle may be entered manually or pasted into the textarea
• The element that calls the updateMe function (button, link, whatever) must be inside the viewer container
• Run the example

<!DOCTYPE html>
<html>
<head><meta name="LifeViewer" content="viewer textarea"> <!--required tag-->
<script src="lv-plugin.js"></script> <!--assumes plug-in is in the same directory as html file-->
<style>
body{
	margin:50px;
}
button{
	font:12pt arial;
}
.lv-rle{
	
	resize:none;
	width:594px;
	min-height:120px;
	max-height:120px;
	font:12pt arial;
}
.lv-buttons{
	margin-bottom:4px;
}
</style>
</head>
<body>
<!--viewer container-->
<div class="viewer"> 
	<div class="lv-buttons"> 
		<button onclick="document.getElementById('lv-text').innerHTML=''">Clear</button>
		<button onclick="updateMe(this)">Show in Viewer</button>
		<!--the element that calls updateMe must be in the viewer container-->
	</div>
	<textarea class="lv-rle" id="lv-text">o2bo3bo$o2bobobo$4o3bo$o2bobo$o2bobobo!</textarea><br/>
	<canvas height=400 width=600></canvas>
</div>
<!--end viewer container-->
</body>
</html>

Lesson 4: Hide the textarea

• Used when you only want to display a specific pattern in a LifeViewer
• This is done my moving the textarea containing the rle off the visible page using absolute positioning and setting the top to a negative number
• The textarea tag must remain inside the viewer container
• Run the example

<!DOCTYPE html>
<html>
<head><meta name="LifeViewer" content="viewer textarea"> <!--required tag-->
<script src="lv-plugin.js"></script> <!--assumes plug-in is in the same directory as html file-->
<style>
body{
	margin:50px;
}
.lv-rle{
	position:absolute;
	top:-1000px;
}
</style>
</head>
<body>
<!--viewer container-->
<div class="viewer"> 
	<textarea class="lv-rle">bo$2bo$3o!</textarea>
	<!--hide the textarea by moving it off the visible page with css-->
	<!--note the textarea element's tag must stay within the viewer container-->
	<canvas height=400 width=600></canvas>
</div>
<!--end viewer container-->
</body>
</html>

Lesson 5: Tips & Tricks

• To disable user input in a textarea, add the readonly attribute: <textarea readonly>whatever</textarea>
• RLEs can control the viewer using LifeViewer scripts
• You can put multiple LifeViewers on a single page; each must have its own <div> container with its own <textarea> and <canvas> inside, or use iframes like PatMan does
• For a full-featured web app illustrating the use of the LifeViewer plug-in, check out Pattern Manager (PatMan)
  • Shows how to use iframes to have a set of thumbnails on the same page that each open in a single viewer, like on LifeWiki pages
  • Downloadable source code and related files