leptonica: remove special PNM handling

We no longer use PNM as an intermediate format, so there's no need to
handle leptonica's PNM quirks.

ocrmypdf/leptonica.py

@@ -113,23 +113,11 @@ class Pix:
         jpeg_quality -- quality (iff JPEG; 1 - 100, 0 for default)
         jpeg_progressive -- (iff JPEG; 0 for baseline seq., 1 for progressive)
         """
-        fileroot, extension = os.path.splitext(filename)
-        fix_pnm = False
-        if extension.lower() in ('.pbm', '.pgm', '.ppm'):
-            # Leptonica does not process handle these extensions correctly, but
-            # does handle .pnm correctly.  Add another .pnm suffix.
-            filename += '.pnm'
-            fix_pnm = True
-
         with LeptonicaErrorTrap():
             lept.pixWriteImpliedFormat(
                 filename.encode(sys.getfilesystemencoding()),
                 self.cpix, jpeg_quality, jpeg_progressive)
 
-        if fix_pnm:
-            from shutil import move
-            move(filename, filename[:-4])   # Remove .pnm suffix
-
     def deskew(self, reduction_factor=0):
         """Returns the deskewed pix object.
 
@@ -254,33 +242,6 @@ if __name__ == '__main__':
     args.func(args)
 
 
-def _test_output(mode, extension, im_format):
-    from PIL import Image
-    from tempfile import NamedTemporaryFile
-
-    with NamedTemporaryFile(prefix='test-lept-pnm', suffix=extension, delete=True) as tmpfile:
-        im = Image.new(mode=mode, size=(100, 100))
-        im.save(tmpfile)
-
-        pix = pixRead(tmpfile.name)
-        pixWriteImpliedFormat(tmpfile.name, pix)
-        pixDestroy(pix)
-
-        im_roundtrip = Image.open(tmpfile.name)
-        assert im_roundtrip.mode == im.mode, "leptonica mode differs"
-        assert im_roundtrip.format == im_format, \
-            "{0}: leptonica produced a {1}".format(
-                extension,
-                im_roundtrip.format)
-
-
-def test_pnm_output():
-    params = [['1', '.pbm', 'PPM'], ['L', '.pgm', 'PPM'],
-              ['RGB', '.ppm', 'PPM']]
-    for param in params:
-        _test_output(*param)
-
-
 def test_skew_angle():
     from PIL import Image, ImageDraw
     from tempfile import NamedTemporaryFile