Creating watermark with transparency on jpeg using PIL?

[tvmaly]

I have been trying to add a watermark to a jpeg using PIL, but the
watermark has a black box around it. I looked at

http://aspn.activestate.com/ASPN/Coo.../Recipe/362879

and

http://mail.python.org/pipermail/pyt...ay/003369.html

but I think these only refer to gif or png. I know jpegs really do not
support transparency, but is there some way to take a watermark in a
non jpeg format and add it to a jpeg without that box appearing around
it?

Best Regards

Ty

[Terry Hancock]

On Thursday 18 August 2005 10:07 am, tv****@gmail.co m wrote:

I have been trying to add a watermark to a jpeg using PIL, but the
watermark has a black box around it. I looked at [...] but I think these only refer to gif or png. I know jpegs really do not
support transparency, but is there some way to take a watermark in a
non jpeg format and add it to a jpeg without that box appearing around
it?

Jpeg is a lossy compression format. You shouldn't do image processing
in such a format at all. Convert the data to PNG, do your processing,
and convert back to JPG for delivery. PIL can do that.

--
Terry Hancock ( hancock at anansispacework s.com )
Anansi Spaceworks http://www.anansispaceworks.com

[Max Erickson]

You need to pass a mask in when you paste in the watermark.

see the documentation for the paste method at
http://effbot.org/imagingbook/image.htm
for more information

This should at least get you started...

import Image
import ImageDraw
import ImageFont
import ImageEnhance
im=Image.new('R GB',(300,300),( 0,0,0))
font=ImageFont. truetype('verda na.ttf',12)
wm=Image.new('R GBA',(100,50),( 255,255,255))
im=Image.new('R GB',(300,300),( 255,255,255))
draw=ImageDraw. Draw(wm)
draw.text((0,0) ,'Watermark',(0 ,0,0),font)
wm.show()
en=ImageEnhance .Brightness(wm)
mask=en.enhance (0.5)
im.paste(wm,(25 ,25),mask)
im.show()

Here, the alpha channel of 'mask' is used as the mask.

max