I was digging through some old development and came across some flash slitscan experiments from ages ago. Slitscan is a special effects process of exposing film while moving the negative (or exposure) in a controlled manner, if you’ve seen a few early 80′s movies I can guarantee you’ve seen used it in credits or a special effects sequence. I’m surprised the technique hasn’t been utilized more within flash game development. In terms of a flash timeline, it is very easy to create – on one layer a graphic is either tweened or remains stationary while a layer mask (the slit) is tweened over it. The results are some really cool perspective tricks. The main constraint within flash is that creating the “exposure” requires many frames – and in interactive flash there’s not enough muscle to render a series of exposures in real time (e.g. 20 slit renders per exposure @ 20fps is like running 400 fps, at least using frame based rendering). What you can do with flash is present the actual exposure process, and with a bit of polish make some really neat effects. With pixel level control of bitmaps now available in AS3, there must be some possibility of overcoming the frame based rendering limitation using advanced filtering algorithms – though I wouldn’t say I’ll be experimenting with those any time soon..

Note: source fla files are experimental and way out of date (AS1 from many, many years ago).

“warp” source fla
“text effect” source fla

I’ve recently been working on an image viewer to display local restaurant menus. I looked around for an open source flash image viewer to modify for the development and came up empty handed… The flash community is a little odd in terms of open source. There’s a lot of components out there for sale/license without an open source parallel. This seems very odd after running with the python and jquery crowd where sharing code is a cultural norm. It is, of course, not all that  way with flash – the game developers and graphics tweakers are very active in releasing code, there are a number of fantastic 2d/3d and physics libraries which are extremely impressive. Hopefully the culture will shift with them.

In any case, with the development stable it seems only right to open it up some code for the next developer. I’ve profited immensely over the years from open source, and it feels good to give back – even if with just a tiny contribution as a zoomable image viewer. Take it, modify it, do whatever you need to do to make it work for you.

The source is available at google code, and I hope to have some documentation up before the week is out. In the mean time, here’s a simple example.

keenerview.swf?image_url=[uri or url with cross-domain privileges]

Apologies to the squeamish for the anatomy page, it was the first interesting public domain image I came across.