I have been developing with Java for several years and last six months I have been building GWT based application. But I have almost no Flash or Action Script experience and I would like to try out some hobby programming with Flex. Especially 2D graphics and image manipulation would be interesting topics.
Adobe’s tutorials for Java developers are naturally the starting point but I would need some pointers for graphics. Something like drawing 2D graphics based on data from the server or modifying image uploaded by user. How much can be done on the Flex and what must be done on the server side?
For drawing you don’t need the ‘full’ flex library, flex will mostly provide you with a nice set of GUI components and some ways to integrate with your back-end server easily.
If you just want to draw something check out the Graphics object http://livedocs.adobe.com/flex/3/langref/flash/display/Graphics.html – it works similar to the java Graphics object.
If you want to modify an image uploaded by the user you are of course already at the server (because the image was uploaded) – however the new flash player (version 10) allows some manipulations of local data as well, so it might even be possible to show a modified image that was not even uploaded, see http://www.mikechambers.com/blog/2008/08/20/reading-and-writing-local-files-in-flash-player-10/ for example.
Flex/AS3 will feel a bit weird to a java programmer – parts of it are very easy and other parts will be frustrating, tooling support is worse, slow compiler, no support for running unittests without jumping through lots of hoops (don’t get me started…). But as a deployment platform I must say I like it a lot.