Source Code for Module fabio.pnmimage

  1  ## Automatically adapted for numpy.oldnumeric Oct 05, 2007 by alter_code1.py 
  2   
  3  #!/usr/bin/env python 
  4  """ 
  5   
  6  Authors: Henning O. Sorensen & Erik Knudsen 
  7           Center for Fundamental Research: Metal Structures in Four Dimensions 
  8           Risoe National Laboratory 
  9           Frederiksborgvej 399 
 10           DK-4000 Roskilde 
 11           email:henning.sorensen@risoe.dk 
 12   
 13  """ 
 14   
 15  import Image 
 16  import numpy as N 
 17  from fabioimage import fabioimage 
 18   
 19  SUBFORMATS = ['P1', 'P2', 'P3', 'P4', 'P5', 'P6', 'P7'] 
 20   
 21  HEADERITEMS = ['SUBFORMAT', 'DIMENSIONS', 'MAXVAL'] 
 22  P7HEADERITEMS = ['WIDTH', 'HEIGHT', 'DEPTH', 'MAXVAL', 'TUPLTYPE', 'ENDHDR'] 
 23   
 24 -class pnmimage(fabioimage): 
 25 -    def __init__(self): 
 26          fun = getattr(fabioimage, '__init__', lambda x: None) 
 27          fun(self) 
 28          self.data = None 
 29          self.header = {'Subformat':'P5'} 
 30          self.dim1 = self.dim2 = 0 
 31          self.m = self.maxval = self.stddev = self.minval = None 
 32          self.header_keys = self.header.keys() 
 33          self.bytecode = None 
 34   
 35 -    def _readheader(self, f): 
 36          #pnm images have a 3-line header but ignore lines starting with '#' 
 37          #1st line contains the pnm image sub format 
 38          #2nd line contains the image pixel dimension 
 39          #3rd line contains the maximum pixel value (at least for grayscale - check this) 
 40          self.header_keys = ['SUBFORMAT', 'DIMENSIONS', 'MAXVAL'] 
 41   
 42          l = f.readline().strip() 
 43          if l not in SUBFORMATS: 
 44              raise IOError, ('unknown subformat of pnm: %s' % l) 
 45          else: 
 46              self.header['SUBFORMAT'] = l 
 47   
 48          if self.header['SUBFORMAT'] == 'P7': 
 49              self.header_keys = P7HEADERITEMS 
 50              #this one has a special header 
 51              while 'ENDHDR' not in l: 
 52                  l = f.readline() 
 53                  while(l[0] == '#'): l = f.readline() 
 54                  s = l.lsplit(' ', 1) 
 55                  if s[0] not in P7HEADERITEMS: 
 56                      raise IOError, ('Illegal pam (netpnm p7) headeritem %s' % s[0]) 
 57                  self.self.header[s[0]] = s[1] 
 58          else: 
 59              self.header_keys = HEADERITEMS 
 60              for k in self.header_keys[1:]: 
 61                  l = f.readline() 
 62                  while(l[0] == '#'): l = f.readline() 
 63                  self.header[k] = l.strip() 
 64   
 65          #set the dimensions 
 66          dims = (self.header['DIMENSIONS'].split()) 
 67          self.dim1, self.dim2 = int(dims[0]), int(dims[1]) 
 68          #figure out how many bytes are used to store the data 
 69          #case construct here! 
 70          m = int(self.header['MAXVAL']) 
 71          if m < 256: 
 72              self.bytecode = N.uint8 
 73          elif m < 65536: 
 74              self.bytecode = N.uint16 
 75          elif m < 2147483648L: 
 76              self.bytecode = N.uint32 
 77              warn('32-bit pixels are not really supported by the netpgm standard') 
 78          else: 
 79              raise IOError, 'could not figure out what kind of pixels you have' 
 80   
 81 -    def read(self, fname, verbose=0): 
 82          self.header = {} 
 83          self.resetvals() 
 84          infile = self._open(fname) 
 85          self._readheader(infile) 
 86   
 87          #read the image data 
 88          try: 
 89              #let the Subformat header field pick the right decoder 
 90              self.data = eval('self.' + self.header['SUBFORMAT'] + 'dec(infile,self.bytecode)') 
 91          except ValueError: 
 92              raise IOError 
 93          self.resetvals() 
 94          return self 
 95   
 96 -    def P1dec(self, buf, bytecode): 
 97          data = N.zeros((self.dim2, self.dim1)) 
 98          i = 0 
 99          for l in buf.readlines(): 
100              try: 
101                  data[i, :] = N.array(l.split()).astype(bytecode) 
102              except ValueError: 
103                  raise IOError, 'Size spec in pnm-header does not match size of image data field' 
104          return data 
105   
106 -    def P4dec(self, buf, bytecode): 
107          warn('single bit (pbm) images are not supported - yet') 
108   
109 -    def P2dec(self, buf, bytecode): 
110          data = N.zeros((self.dim2, self.dim1)) 
111          i = 0 
112          for l in buf.readlines(): 
113              try: 
114                  data[i, :] = N.array(l.split()).astype(bytecode) 
115              except ValueError: 
116                  raise IOError, 'Size spec in pnm-header does not match size of image data field' 
117          return data 
118   
119 -    def P5dec(self, buf, bytecode): 
120          l = buf.read() 
121          try: 
122              data = N.reshape(N.fromstring(l, bytecode), [self.dim2, self.dim1]).byteswap() 
123          except ValueError: 
124              raise IOError, 'Size spec in pnm-header does not match size of image data field' 
125          return data 
126   
127 -    def P3dec(self, buf, bytecode): 
128          #decode (plain-ppm) rgb image 
129          pass 
130   
131 -    def P6dec(self, buf, bytecode): 
132          #decode (ppm) rgb image 
133          pass 
134   
135 -    def P7dec(self, buf, bytecode): 
136          #decode pam images, i.e. call one of the other decoders 
137          pass 
138   
139 -    def write(filename): 
140          warn('write pnm images is not implemented yet.') 
141