Changing Alpha of a bitmapData

Hi,

I’m blitting a map onto the screen with tiles… and the source of these tiles are BitmapData objects.

I know you can change the alpha of a bitmap… but I’m not too sure if it can be done on the BitmapData object itself.

I want some tiles to have less alpha than others. Applying the alpha to the Bitmap… makes everything on the current screen have an alpha… but I only need one tile of it…

Does anyone have any ideas how I could accomplish this?

Thanks.