Pil Transparency

[John Michelsen]

>I was wondering if anyone knows how to save an image in PIL
>with transparency.  Say changing all of the black pixels of an image
>to be transparent in gif, png format.  The documentation had a few
>references to pasting with transparency masks, but not enough
>that I could find to figure it out.  Here's what I came up with:

Figured it out with a bunch of trial and error.
Could put something like this in the documentation to
save the next person. :^)

John



from Tkinter import *
import Image, ImageTk
import tkFileDialog

class Transparency:
 def __init__(self, parent):
  self.canvas = Canvas(parent, bg='white')
  self.canvas.pack()
  b = Button(parent, command=self.open, text="Open")
  b.pack()

 def open(self):
  self.canvas.delete(ALL)
  filename = tkFileDialog.askopenfilename()
  if filename != '':
   im = Image.open(filename)
   if im.mode != "RGBA":
    im = Image.open(filename).convert("RGBA")
    source = im.split()
    R, G, B, A = 0, 1, 2, 3
    mask = im.point(lambda i: i > 0 and 255) # use black as transparent
    source[A].paste(mask)
    im = Image.merge(im.mode, source)  # build a new multiband image

   self.graphic = ImageTk.PhotoImage(image=im)
   self.canvas.create_image(100, 100, image=self.graphic)


if __name__ == "__main__":
 root = Tk()
 test = Transparency(root)
 root.mainloop()