Open-source – Antti Kupila

Actionscript 2 utility class: Grid

I’ve been working on a project with fullscreen flash. Everybody who has worked with something like this, or even without working with something like this probably knows that a grid for checking positioning can be handy. Well, I know I thought so, so I wrote this simple utility class.

Below is an example, you can enable it with the SPACE key (click inside it first, to give it focus). Change resolution with the arrow keys.

It’s nothing special or new, I know, but still can be very helpful.

Download Grid.as with example

Update: Hehe, since my tilde key wasn’t working for anybody else, i changed the default key to SPACE. You can of course change the response key, just use Grid.key = keycode

Posted Apr 29, 2007
Posted in Actionscript 2, Development, Flash, Open-source
Comments (6)

Getting JPG dimensions with AS3 without loading the entire file

Does this sound familiar: You're loading a JPG file, and want to know what size it is before it has loaded? This can be useful if you're for example drawing a border/background, which will contain the image. If you don't know what size the image is, you don't know what size the box should be. I'm sure there are better & more common uses to this, but i know for sure it can be really useful.

Anyway, I decided to solve this problem. If you don't care about how it works, fine, i'll give you the short version first. After all the class i've created does all the heavy lifting for you, so if you just want to have it work, you can just use it without worrying about what's under the hood.

Here's the class: JPGSizeExtractor.as. Download it and put it in a folder com/anttikupila/utils in your classpath. Then you can just use it like this:

PLAIN TEXT

Actionscript:

var je : JPGSizeExtractor = new JPGSizeExtractor( );
je.addEventListener( JPGSizeExtractor.PARSE_COMPLETE, sizeHandler );
je.extractSize( your_jpg_file.jpg );
function sizeHandler( e : Event ) : void {
trace( "Dimensions: " + je.width + " x " + je.height );
}

To trace out debug information, you can say je.debug = true;

What it actually does is that it starts loading the JPG file and analyzes every byte that has loaded. When it find the jpg's JFIF headers (according to the JPEG specs), it will be able to determine the dimension of the file and close the stream. The dimensions in a jpg are before the actual image info, meaning that you can load a 10mb file and get it's dimensions in a fraction of a second, instead of waiting for the entire file to load.

Note: This doesn't work for all files. Some files i tried with were not according to the JPEG specs (or then i misunderstood something, which is more likely since other software showed the correct dimensions). Don't use this in mission critical projects, unless you have control over the JPG files. I don't take any responsibility of it working correctly.

Download the class, with an example

If you're not so much interested in “the what”, but more “the how”? Read on. Let's see what we can do about that ..

Posted Apr 08, 2007
Posted in Actionscript 3, Flash, Open-source, Tutorials, Web
Comments (21)

Tutorial: Most popular YouTube videos of the day in Actionscript 3

As you probably know, Flash CS3 is coming really soon. Actionscript has developed a lot with the years and just like Adobe's Flex, Flash CS3 will feature it's latest revision, actionscript 3.0. This tutorial is a pretty basic introduction to AS3, to give you a kickstart before the final release of Flash CS3. If you're familiar with AS3, this probably isn't anything for you, but if you've done some stuff in AS1 & 2, maybe had a look at 3, read it and tell me what you think This was originally a school assignment and written pretty quickly so please bear with me

Alrighty, let's start.

Before you build a house you need to get the tools so let's take a look at a couple approaches of working in AS3:

Currently there are three ways.

Flash 9 alpha
Flex
Flex SDK with third party application

Flash 9 alpha is basically Flash 8, but with support and a compiler for AS3. You can download it for free from Adobe labs, but you'll need a licenced Flash 8 to install it. Also it does not work on intel macs so if you have one, you can't compile your actionscript with it. This obviously is a problem

Flex is basically flash, but meant more for online applications. Supports the exact same actionscript 3 as Flash 9. If you have flex, you probably already know that you can compile AS3 with it, if you don't you can always get it. It's $499 though

The Flex SDK is a free download which you can use with a third party application. I myself use this one together with Eclipse, and am very happy with the combination. Free too

You'll find loads of info about these on google, and going thru all this isn't really in the scope of this tutorial, so please, help yourself

Very helpful links:
http://livedocs.adobe.com/flex/201/langref/index.html
http://livedocs.adobe.com/flex/2/langref/migration.html

Here's a small demonstration of what the app we're building today might look like (click it to see it in action):