[Image-SIG] Bad antialias? (in Python Imaging Library 1.1.5)

[Laszlo Zsolt Nagy]

I create a fully transparent red image this way:

size = (400,400)
img = Image.new('RGBA',size,(255,0,0,0))

Then I draw an (antialiased) text on it:

drawer = ImageDraw.Draw(img)
font = ImageFont.truetype('arc.ttf',12)
drawer.text((0,0),"This text is 12pt",font=font,fill=(0,0,0,255))

This is what I get (image drawn on a gray background):

http://mess.hu/download/bad_antialias.png

Apparently, antialiasing will use a mixture of the background color and 
the text color on the edges.
I think this is good only if the background is fully opaque. Is there a 
workaround?

Is this a PIL bug or a feature?

Thanks,

  Les