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