Included in the Flex 4.0 SDK and the, just released, Flash Professional CS5 lies a new hidden little gem of a class: flashx.undo.UndoManager (although the Flex 4.0 SDK’s been out for awhile, I have to admit I didn’t even notice this until I installed Flash CS5 and started poking around the documentation looking for new stuff to play with). Now, actually, the UndoManager is a part of the brand new shiny TextLayout framework, but, because it follows a basic Command design pattern, it’s very easy to adopt it to other aspects of your applications and allow functionality that users expect/demand. But since an example is worth a thousand words, check out the below to get an idea of what I’m talking about. First, let’s start off by creating just a real simple drawing application. [crayon-610bcb2f712c2776881908/] Now, if you compile that, you’ll see you can mouse down (with your ancient and anachronistic mouse that apparently no Mac users require anymore – don’t even get me started on Steve Jobs’ blatantly lying drivel) on the black area and draw white lines around (told you it was real simple). But what if you wanted to get rid of the last line you drew? […]
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