需要为jpg添加标题，python找不到图像

Question

I am trying to add a caption - the file name - under the bottom edge of a jpg.

I have the following Python code:

    import Image, ImageDraw, ImageFont, os, glob

list = glob.glob('*.jpg')

for infile in list:
    print infile
    file, ext = os.path.splitext(infile)
    outname = file + "_test.jpg"
    print outname
    im = Image.open(infile)
    d = ImageDraw.Draw(im)
    f = ImageFont.truetype("Arial.ttf", 16)
    d.text((4,0), file, font=f)
    im.save(outname)

It prints out the name of the file, so the file is there - so why can't it open it?

The file exists, but I get the following error:

Is there an easier way to add a caption to the bottom of the image?

Answer 1

That exception, Cannot identify image file , means that it was able to open the file, but then could not determine what type of image it is. PIL does this by reading the first 16 bytes and seeing if they match any of the well known magic numbers .

Could you verify that the file you're trying to read is actually a jpeg?

If so, how did you get the version of PIL? If it was compiled on a machine without libjpeg (or whatever the windows equivalent is), it might not support jpegs. See this other question for a possible solution to that issue, though I don't have a windows machine to test with.

Answer 2

"You can use either a string (representing the filename) or a file object as the file argument. In the latter case, the file object must implement read, seek, and tell methods, and be opened in binary mode."

Try this:

im = Image.open(open(infile, 'rb'))

or:

from StringIO import StringIO
im = Image.open(StringIO(infile))

Answer 3

Thanks to the help of Nick & Manu pointing me in the right dierction, I worked out a solution that works:

    import Image, ImageDraw, ImageFont
from PIL import Image
import glob, os
import Tkinter
import ImageTk
import fnmatch

list = glob.glob('*.jpg')

cnt = 0
for infile in list:
    cnt += 1
    print infile
    file, ext = os.path.splitext(infile)
    outname = file + "_test.jpg"
    print outname
    #im = Image.open(infile)
    im = Image.open(open(infile, 'rb'))
    d = ImageDraw.Draw(im)
    f = ImageFont.truetype("c:/windows/fonts/arial.ttf", 200)
    x = 10
    y = 550
    d.text((x, y), str(cnt), font=f)
    im.save(outname)
    print "==========="

Note that this uses the direct path to the font, and I set the x, y location on the image.

I also had to use a very large font size since the original file is a very large full image from the camera.

I used the cnt as a string for continuity - the originals have a number of names.

All I need to do now is locate the bottom of the image and place the string there...