PIL Convert PNG or GIF with Transparency to JPG without

问题:

I'm prototyping an image processor in Python 2.7 using PIL1.1.7 and I would like all images to end up in JPG. Input file types will include tiff,gif,png both with transparency and without. I've been trying to combine two scripts that I found that 1. convert other file types to JPG and 2. removing transparency by creating a blank white image and pasting the original image over the white background. My searches are being spammed with people seeking to generate or preserve transparency rather than the opposite.

I'm currently working with this:

#!/usr/bin/python import os, glob import Image  images = glob.glob("*.png")+glob.glob("*.gif")  for infile in images:     f, e = os.path.splitext(infile)     outfile = f + ".jpg"     if infile != outfile:         #try:         im = Image.open(infile)         # Create a new image with a solid color         background = Image.new('RGBA', im.size, (255, 255, 255))         # Paste the image on top of the background         background.paste(im, im)         #I suspect that the problem is the line below         im = background.convert('RGB').convert('P', palette=Image.ADAPTIVE)         im.save(outfile)         #except IOError:            # print "cannot convert", infile 

Both scripts work in isolation, but as I have combined them I get a ValueError: Bad Transparency Mask.

Traceback (most recent call last): File "pilhello.py", line 17, in  background.paste(im, im) File "/usr/lib/python2.7/dist-packages/PIL/Image.py", line 1101, in paste self.im.paste(im, box, mask.im) ValueError: bad transparency mask 

I suspect that if I were to save a PNG without transparency I could then open that new file, and re-save it as a JPG, and delete the PNG that was written to disk, but I'm hoping that there is an elegant solution that I haven't found yet.

回答1:

Make your background RGB, not RGBA. And remove the later conversion of the background to RGB, of course, since it's already in that mode. This worked for me with a test image I created:

from PIL import Image im = Image.open(r"C:\jk.png") bg = Image.new("RGB", im.size, (255,255,255)) bg.paste(im,im) bg.save(r"C:\jk2.jpg") 

回答2:

image=Image.open('file.png') non_transparent=Image.new('RGBA',image.size,(255,255,255,255)) non_transparent.paste(image,(0,0),image) 

The key is to make the mask (for the paste) the image itself.

This should work on those images that have "soft edges" (where the alpha transparency is set to not be 0 or 255)

回答3:

The following works for me on this image

f, e = os.path.splitext(infile) print infile outfile = f + ".jpg" if infile != outfile:     im = Image.open(infile)     im.convert('RGB').save(outfile, 'JPEG') 

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