1 #! /usr/bin/env python

     2 

     3 """Simple test script for imgfile.c

     4    Roger E. Masse

     5 """

     6 

     7 from test.test_support import verbose, unlink, findfile

     8 

     9 import imgfile, uu, os

    10 

    11 

    12 def main():

    13 

    14     uu.decode(findfile('testrgb.uue'), 'test.rgb')

    15     uu.decode(findfile('greyrgb.uue'), 'greytest.rgb')

    16 

    17     # Test a 3 byte color image

    18     testimage('test.rgb')

    19 

    20     # Test a 1 byte greyscale image

    21     testimage('greytest.rgb')

    22 

    23     unlink('test.rgb')

    24     unlink('greytest.rgb')

    25 

    26 def testimage(name):

    27     """Run through the imgfile's battery of possible methods

    28        on the image passed in name.

    29     """

    30 

    31     import sys

    32     import os

    33 

    34     outputfile = '/tmp/deleteme'

    35 

    36     # try opening the name directly

    37     try:

    38         # This function returns a tuple (x, y, z) where x and y are the size

    39         # of the image in pixels and z is the number of bytes per pixel. Only

    40         # 3 byte RGB pixels and 1 byte greyscale pixels are supported.

    41         sizes = imgfile.getsizes(name)

    42     except imgfile.error:

    43         # get a more qualified path component of the script...

    44         if __name__ == '__main__':

    45             ourname = sys.argv[0]

    46         else: # ...or the full path of the module

    47             ourname = sys.modules[__name__].__file__

    48 

    49         parts = ourname.split(os.sep)

    50         parts[-1] = name

    51         name = os.sep.join(parts)

    52         sizes = imgfile.getsizes(name)

    53     if verbose:

    54         print 'Opening test image: %s, sizes: %s' % (name, str(sizes))

    55     # This function reads and decodes the image on the specified file,

    56     # and returns it as a python string. The string has either 1 byte

    57     # greyscale pixels or 4 byte RGBA pixels. The bottom left pixel

    58     # is the first in the string. This format is suitable to pass

    59     # to gl.lrectwrite, for instance.

    60     image = imgfile.read(name)

    61 

    62     # This function writes the RGB or greyscale data in data to

    63     # image file file. x and y give the size of the image, z is

    64     # 1 for 1 byte greyscale images or 3 for RGB images (which

    65     # are stored as 4 byte values of which only the lower three

    66     # bytes are used). These are the formats returned by gl.lrectread.

    67     if verbose:

    68         print 'Writing output file'

    69     imgfile.write (outputfile, image, sizes[0], sizes[1], sizes[2])

    70 

    71 

    72     if verbose:

    73         print 'Opening scaled test image: %s, sizes: %s' % (name, str(sizes))

    74     # This function is identical to read but it returns an image that

    75     # is scaled to the given x and y sizes. If the filter and blur

    76     # parameters are omitted scaling is done by simply dropping

    77     # or duplicating pixels, so the result will be less than perfect,

    78     # especially for computer-generated images.  Alternatively,

    79     # you can specify a filter to use to smoothen the image after

    80     # scaling. The filter forms supported are 'impulse', 'box',

    81     # 'triangle', 'quadratic' and 'gaussian'. If a filter is

    82     # specified blur is an optional parameter specifying the

    83     # blurriness of the filter. It defaults to 1.0.  readscaled

    84     # makes no attempt to keep the aspect ratio correct, so that

    85     # is the users' responsibility.

    86     if verbose:

    87         print 'Filtering with "impulse"'

    88     simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'impulse', 2.0)

    89 

    90     # This function sets a global flag which defines whether the

    91     # scan lines of the image are read or written from bottom to

    92     # top (flag is zero, compatible with SGI GL) or from top to

    93     # bottom(flag is one, compatible with X). The default is zero.

    94     if verbose:

    95         print 'Switching to X compatibility'

    96     imgfile.ttob (1)

    97 

    98     if verbose:

    99         print 'Filtering with "triangle"'

   100     simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'triangle', 3.0)

   101     if verbose:

   102         print 'Switching back to SGI compatibility'

   103     imgfile.ttob (0)

   104 

   105     if verbose: print 'Filtering with "quadratic"'

   106     simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'quadratic')

   107     if verbose: print 'Filtering with "gaussian"'

   108     simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'gaussian', 1.0)

   109 

   110     if verbose:

   111         print 'Writing output file'

   112     imgfile.write (outputfile, simage, sizes[0]/2, sizes[1]/2, sizes[2])

   113 

   114     os.unlink(outputfile)

   115 

   116 main()