Can I draw a line (or better any polygon) directly on screen?

[Cubist at aol.com]

sez ken norris:
>>I couildn't get any of my paint programs, or even Photoshop, to make a
>> transparent PNG image of nothing.
   My experience does not match yours...
   I'm using Photoshop 6.0 for Mac. I opened up an old .PSD file I had lying 
around, made some bits of it transparent, selected SAVE AS from the FILE MENU, 
and in the SAVE AS dialogue box, selected PNG as the file format. When I 
opened up the resulting PNG file, the transparent bits remained transparent. What 
are you doing differently than I did?

sez scott rossi:
>In Photoshop, create a new file of the dimensions you want with a single
>empty layer.  If the file has a background layer, delete it.  You should now
>see the checkerboard pattern in the document window.  Choose "Save for
>Web..." from the File menu as GIF with transparency enabled.
   This will work perfectly well. I used to do it myself, until I discovered 
another option which will also work *and* saves a bit of effort on the user's 
part...
   First: Make sure the background is the active layer. If the background is 
the *only* layer, you're covered.
   Second: Go to the LAYER menu, select the NEW submenu, select LAYER FROM 
BACKGROUND from the LAYER:NEW submenu.