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, import_module 8 9 imgfile = import_module('imgfile', deprecated=True) 10 import uu 11 12 13 def 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) 102 103 104 def 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') 117 118 if __name__ == '__main__': 119 test_main() 120
