[Image-SIG] transparency issues

[Joerg Baumann]

On Fri, 6 Oct 2000, Jeff Simpson wrote:

> I'm using PIL 1.1 to create some simple images, with lines and
> rectangles.  I am having a problem making the background for the image
> transparent.  I was wondering if anyone knows if these features work
> (i.e. do transparency masks work in 1.1?).  If so, can someone post a
> small example snippet for making a region transparent?
> 
> Thanks

This works for me (PIL 1.1 Linux)
import Image

#new image
img=Image.new("RGB",(100,100),(0,100,200))
#add alpah channel
img=img.convert("RGBA")
#draw violet background
img.paste((100,0,200,255),(0,0,100,100))
#make center transparent
img.paste((0,0,0,0),(20,20,80,80))
# save as png (png works, tif and gif not, tga?)
img.save("alpha.png")

bye
joerg

  Joerg Baumann       joerg.baumann@stud.informatik.uni-erlangen.de
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  
  Beware of bugs in the above code; I have only proved it correct, 
  not tried it.
                  Don Knuth