Flash Authoring is a huge application and part of its size is due to a plethora of useful bitmap manipulation tools. There aren't any built into Flex, maybe some third-parties have one. You will need to describe in vectors and curves (preferably just vectors) the outer border of the image.
________________________________ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of dodtsair Sent: Tuesday, October 02, 2007 10:19 AM To: [email protected] Subject: [flexcoders] Re: actionscript generation of mask/hitArea from bitmapdata... --- In [email protected] <mailto:flexcoders%40yahoogroups.com> , "unaflux" <[EMAIL PROTECTED]> wrote: > > How can I create an arbitrarily complex Shape > starting from alphachannel data of a dynamically loaded image? > > I'd like to use the shape mainly for two things: > - to set a complex hitArea of a Sprite > - to mask a DisplayObject that has MouseEvents on it > > The problem are somehow related: > 1) If I apply directly the loaded image > (wrapped in a Sprite) as the hitArea > mousevents gets triggered in the rect area > that has the dimension of the loaded image. > > 2) If I apply directly the loaded image as a mask > I've no problems to obtain the visual masking effect > but mousevents still gets triggered in the rect area > that has the dimension of the loaded image, not only > on the visible areas... > > > > In the authoring environment solution is simple... > - take the image > - do a trace bitmap > - use the traced bitmap non transparent areas > as hitArea in a SimpleButton. > > In Actionscript, if the masking/hitArea Shape is simple... > - draw the masking/hitArea Shape > - apply it as a mask > > > In ActionScript, if the masking/hitArea is complex > it starts becoming a problem. > I think that's because I'm still working > with the BitmapData of the image (that is rectangular). > Even in the authoring environment if you use a Bitmap, > instead of a Shape, you get a rectangular mouseSensible area. > But how can I obtain a Shape from the alphachannel data > of the image I loaded? > The idea is to use this arbitrarily complex Shape > (wrapped in a Sprite) as a dynamically generated mask/hitArea, > that gives me an arbitrarily complex mouseSensible area. > > Have you ever tried something like that? > Is that even possible? > Using Actionscript shouldn't I have access to all that > could be done in the authoring environment? > Stated in another way... > how can I actually do something similar to the > trace bitmap operation... > > Any suggestions > Thanks > Jo > I am trying to do the same thing. I wanted to build a widget that would allow the user to click on a world map to select his timezone. At this point like you I have failed to use the hitArea to filter the mouse events. The next thing I will try is grabing the x,y of the mouse event and trying to pull out the pixel data of the image at that point. We'll see if I succeed. If anyone knows a better more straight forward solution I think we would both appreciate it. Mike Power
