Tag Archives: AS3

ActionScript 3.0

MouseWheelTrap – how to stop simultaneous Flash / browser scrolling

Update: This project is now hosted at GitHub. There are currently known issues with Chrome’s PPAPI plugin architecture. USE AT YOUR OWN RISK.

I recently stumbled over a new AS3 gotcha that seems to be bugging a lot of the Flash community. Apparently a new ‘feature’ of AS3, whereby using the mousewheel inside an embedded Flash movie still scrolls the surrounding browser window (if it has enough content, that is).

This didn’t happen in AS2. If a Flash movie had focus, mousewheel events weren’t sent to the browser window. It wasn’t a problem in FireFox either, until a recent update and adversely affects any AS3 Flash app embedded in an HTML page where you might want to scroll or zoom with the mousewheel while over the Flash, instead of the scrolling the browser window.

So, I decided to cook up some code to fix this. While it’s early version and isn’t perfect, it suits my purposes, is easy to set up and doesn’t require any external JavaScript – so I’d thought I’d share it with the world, in case Adobe never get around to addressing this ‘feature’.


 

Introducing MouseWheelTrap. A handy little utility class that traps mousewheel events while the mouse is over the Flash, so your app scrolls how it was intended to. I’ve tested it with SWFObject on PC IE and FireFox, but not with SWFMacMouseWheel on Mac (if someone could tell me if it works). I decided against using jQuery for trapping mouse events, partly out of laziness, partly because many people have no control over the HTML that embeds their Flash app and therefore can’t add custom JavaScript.

Setting up MouseWheelTrap is easy:

  • Download the MouseWheelTrap ZIP package, or just the AS file.
  • Unzip the package and have a look at the demo, or just take the MouseWheelTrap.as file and put it in the com.spikything.utils folder into your own project or classpath.
  • Import the utility and set it up somewhere in your main class like so:

Simple huh? Let me know how you get on…

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How to embed fonts in pure AS3

On my travels as a contractor, I’ve seen various methods used for embedding fonts in ActionScript 3 projects (code embedded, creating font SWFs, runtime loading, etc). Each of them has its own merits (and limitations), but generally you’re looking for something that’s easy to do, easy to maintain (for others, not just yourself) and of course that works!

So, here’s the method I use for pure AS3 projects I compile with the Flex SDK. I embed the TTF or OTF file in a ‘Style’ class and include those font files in the CVS/SVN repository too – it does my head in when fonts go missing, because a designer can’t remember which font they used:

Through experience, this seems to be the most robust and maintainable way of dealing with fonts (not to throw out more flexible, but perhaps less robust ways, such as runtime loading), especially when you need control of the unicode ranges you are embedding – which I have included for reference.

How to use ExternalInterface to integrate AS3 with JavaScript

Here’s a quick snippet of code for setting up intercommunication between a SWF and JavaScript, using ExternalInterface:

Head tracking in 3D

I started trying to find useful things to do with face detection, but with limited success. I tried using the Libspark Haar Cascades implementation of face detection with Papervision3D to create a sort of head tracking effect, but it’s a little flaky – partly because of poor tracking accuracy and partly because it’s too CPU intensive. You can view it on its own page here.