1#! /usr/bin/env python
2
3"""Simple test script for imgfile.c
4   Roger E. Masse
5"""
6
7from test.test_support import verbose, unlink, findfile, import_module
8
9imgfile = import_module('imgfile', deprecated=True)
10import uu
11
12
13def testimage(name):
14    """Run through the imgfile's battery of possible methods
15       on the image passed in name.
16    """
17
18    import sys
19    import os
20
21    outputfile = '/tmp/deleteme'
22
23    # try opening the name directly
24    try:
25        # This function returns a tuple (x, y, z) where x and y are the size
26        # of the image in pixels and z is the number of bytes per pixel. Only
27        # 3 byte RGB pixels and 1 byte greyscale pixels are supported.
28        sizes = imgfile.getsizes(name)
29    except imgfile.error:
30        # get a more qualified path component of the script...
31        if __name__ == '__main__':
32            ourname = sys.argv[0]
33        else: # ...or the full path of the module
34            ourname = sys.modules[__name__].__file__
35
36        parts = ourname.split(os.sep)
37        parts[-1] = name
38        name = os.sep.join(parts)
39        sizes = imgfile.getsizes(name)
40    if verbose:
41        print 'Opening test image: %s, sizes: %s' % (name, str(sizes))
42    # This function reads and decodes the image on the specified file,
43    # and returns it as a python string. The string has either 1 byte
44    # greyscale pixels or 4 byte RGBA pixels. The bottom left pixel
45    # is the first in the string. This format is suitable to pass
46    # to gl.lrectwrite, for instance.
47    image = imgfile.read(name)
48
49    # This function writes the RGB or greyscale data in data to
50    # image file file. x and y give the size of the image, z is
51    # 1 for 1 byte greyscale images or 3 for RGB images (which
52    # are stored as 4 byte values of which only the lower three
53    # bytes are used). These are the formats returned by gl.lrectread.
54    if verbose:
55        print 'Writing output file'
56    imgfile.write (outputfile, image, sizes[0], sizes[1], sizes[2])
57
58
59    if verbose:
60        print 'Opening scaled test image: %s, sizes: %s' % (name, str(sizes))
61    # This function is identical to read but it returns an image that
62    # is scaled to the given x and y sizes. If the filter and blur
63    # parameters are omitted scaling is done by simply dropping
64    # or duplicating pixels, so the result will be less than perfect,
65    # especially for computer-generated images.  Alternatively,
66    # you can specify a filter to use to smoothen the image after
67    # scaling. The filter forms supported are 'impulse', 'box',
68    # 'triangle', 'quadratic' and 'gaussian'. If a filter is
69    # specified blur is an optional parameter specifying the
70    # blurriness of the filter. It defaults to 1.0.  readscaled
71    # makes no attempt to keep the aspect ratio correct, so that
72    # is the users' responsibility.
73    if verbose:
74        print 'Filtering with "impulse"'
75    simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'impulse', 2.0)
76
77    # This function sets a global flag which defines whether the
78    # scan lines of the image are read or written from bottom to
79    # top (flag is zero, compatible with SGI GL) or from top to
80    # bottom(flag is one, compatible with X). The default is zero.
81    if verbose:
82        print 'Switching to X compatibility'
83    imgfile.ttob (1)
84
85    if verbose:
86        print 'Filtering with "triangle"'
87    simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'triangle', 3.0)
88    if verbose:
89        print 'Switching back to SGI compatibility'
90    imgfile.ttob (0)
91
92    if verbose: print 'Filtering with "quadratic"'
93    simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'quadratic')
94    if verbose: print 'Filtering with "gaussian"'
95    simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'gaussian', 1.0)
96
97    if verbose:
98        print 'Writing output file'
99    imgfile.write (outputfile, simage, sizes[0]/2, sizes[1]/2, sizes[2])
100
101    os.unlink(outputfile)
102
103
104def test_main():
105
106    uu.decode(findfile('testrgb.uue'), 'test.rgb')
107    uu.decode(findfile('greyrgb.uue'), 'greytest.rgb')
108
109    # Test a 3 byte color image
110    testimage('test.rgb')
111
112    # Test a 1 byte greyscale image
113    testimage('greytest.rgb')
114
115    unlink('test.rgb')
116    unlink('greytest.rgb')
117
118if __name__ == '__main__':
119    test_main()
120