# Convert "arbitrary" image files to rgb files (SGI's image format).
# Input may be compressed.
# The uncompressed file type may be PBM, PGM, PPM, GIF, TIFF, or Sun raster.
# An exception is raised if the file is not of a recognized type.
# Returned filename is either the input filename or a temporary filename;
# in the latter case the caller must ensure that it is removed.
# Other temporary files used are removed by the function.
import os
import tempfile
import pipes
import imghdr
table = {}
t = pipes.Template()
t.append('fromppm $IN $OUT', 'ff')
table['ppm'] = t
t = pipes.Template()
t.append('(PATH=$PATH:/ufs/guido/bin/sgi; exec pnmtoppm)', '--')
t.append('fromppm $IN $OUT', 'ff')
table['pnm'] = t
table['pgm'] = t
table['pbm'] = t
t = pipes.Template()
t.append('fromgif $IN $OUT', 'ff')
table['gif'] = t
t = pipes.Template()
t.append('tifftopnm', '--')
t.append('(PATH=$PATH:/ufs/guido/bin/sgi; exec pnmtoppm)', '--')
t.append('fromppm $IN $OUT', 'ff')
table['tiff'] = t
t = pipes.Template()
t.append('rasttopnm', '--')
t.append('(PATH=$PATH:/ufs/guido/bin/sgi; exec pnmtoppm)', '--')
t.append('fromppm $IN $OUT', 'ff')
table['rast'] = t
t = pipes.Template()
t.append('djpeg', '--')
t.append('(PATH=$PATH:/ufs/guido/bin/sgi; exec pnmtoppm)', '--')
t.append('fromppm $IN $OUT', 'ff')
table['jpeg'] = t
uncompress = pipes.Template()
uncompress.append('uncompress', '--')
class error(Exception):
pass
def torgb(filename):
temps = []
ret = None
try:
ret = _torgb(filename, temps)
finally:
for temp in temps[:]:
if temp != ret:
try:
os.unlink(temp)
except os.error:
pass
temps.remove(temp)
return ret
def _torgb(filename, temps):
if filename[-2:] == '.Z':
fname = tempfile.mktemp()
temps.append(fname)
sts = uncompress.copy(filename, fname)
if sts:
raise error, filename + ': uncompress failed'
else:
fname = filename
try:
ftype = imghdr.what(fname)
except IOError, msg:
if type(msg) == type(()) and len(msg) == 2 and \
type(msg[0]) == type(0) and type(msg[1]) == type(''):
msg = msg[1]
if type(msg) is not type(''):
msg = `msg`
raise error, filename + ': ' + msg
if ftype == 'rgb':
return fname
if ftype is None or not table.has_key(ftype):
raise error, \
filename + ': unsupported image file type ' + `ftype`
temp = tempfile.mktemp()
sts = table[ftype].copy(fname, temp)
if sts:
raise error, filename + ': conversion to rgb failed'
return temp
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