0001 #! /usr/bin/env python 0002 0003 """Simple test script for imgfile.c 0004 Roger E. Masse 0005 """ 0006 0007 from test.test_support import verbose, unlink, findfile 0008 0009 import imgfile, uu, os 0010 0011 0012 def main(): 0013 0014 uu.decode(findfile('testrgb.uue'), 'test.rgb') 0015 uu.decode(findfile('greyrgb.uue'), 'greytest.rgb') 0016 0017 # Test a 3 byte color image 0018 testimage('test.rgb') 0019 0020 # Test a 1 byte greyscale image 0021 testimage('greytest.rgb') 0022 0023 unlink('test.rgb') 0024 unlink('greytest.rgb') 0025 0026 def testimage(name): 0027 """Run through the imgfile's battery of possible methods 0028 on the image passed in name. 0029 """ 0030 0031 import sys 0032 import os 0033 0034 outputfile = '/tmp/deleteme' 0035 0036 # try opening the name directly 0037 try: 0038 # This function returns a tuple (x, y, z) where x and y are the size 0039 # of the image in pixels and z is the number of bytes per pixel. Only 0040 # 3 byte RGB pixels and 1 byte greyscale pixels are supported. 0041 sizes = imgfile.getsizes(name) 0042 except imgfile.error: 0043 # get a more qualified path component of the script... 0044 if __name__ == '__main__': 0045 ourname = sys.argv[0] 0046 else: # ...or the full path of the module 0047 ourname = sys.modules[__name__].__file__ 0048 0049 parts = ourname.split(os.sep) 0050 parts[-1] = name 0051 name = os.sep.join(parts) 0052 sizes = imgfile.getsizes(name) 0053 if verbose: 0054 print 'Opening test image: %s, sizes: %s' % (name, str(sizes)) 0055 # This function reads and decodes the image on the specified file, 0056 # and returns it as a python string. The string has either 1 byte 0057 # greyscale pixels or 4 byte RGBA pixels. The bottom left pixel 0058 # is the first in the string. This format is suitable to pass 0059 # to gl.lrectwrite, for instance. 0060 image = imgfile.read(name) 0061 0062 # This function writes the RGB or greyscale data in data to 0063 # image file file. x and y give the size of the image, z is 0064 # 1 for 1 byte greyscale images or 3 for RGB images (which 0065 # are stored as 4 byte values of which only the lower three 0066 # bytes are used). These are the formats returned by gl.lrectread. 0067 if verbose: 0068 print 'Writing output file' 0069 imgfile.write (outputfile, image, sizes[0], sizes[1], sizes[2]) 0070 0071 0072 if verbose: 0073 print 'Opening scaled test image: %s, sizes: %s' % (name, str(sizes)) 0074 # This function is identical to read but it returns an image that 0075 # is scaled to the given x and y sizes. If the filter and blur 0076 # parameters are omitted scaling is done by simply dropping 0077 # or duplicating pixels, so the result will be less than perfect, 0078 # especially for computer-generated images. Alternatively, 0079 # you can specify a filter to use to smoothen the image after 0080 # scaling. The filter forms supported are 'impulse', 'box', 0081 # 'triangle', 'quadratic' and 'gaussian'. If a filter is 0082 # specified blur is an optional parameter specifying the 0083 # blurriness of the filter. It defaults to 1.0. readscaled 0084 # makes no attempt to keep the aspect ratio correct, so that 0085 # is the users' responsibility. 0086 if verbose: 0087 print 'Filtering with "impulse"' 0088 simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'impulse', 2.0) 0089 0090 # This function sets a global flag which defines whether the 0091 # scan lines of the image are read or written from bottom to 0092 # top (flag is zero, compatible with SGI GL) or from top to 0093 # bottom(flag is one, compatible with X). The default is zero. 0094 if verbose: 0095 print 'Switching to X compatibility' 0096 imgfile.ttob (1) 0097 0098 if verbose: 0099 print 'Filtering with "triangle"' 0100 simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'triangle', 3.0) 0101 if verbose: 0102 print 'Switching back to SGI compatibility' 0103 imgfile.ttob (0) 0104 0105 if verbose: print 'Filtering with "quadratic"' 0106 simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'quadratic') 0107 if verbose: print 'Filtering with "gaussian"' 0108 simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'gaussian', 1.0) 0109 0110 if verbose: 0111 print 'Writing output file' 0112 imgfile.write (outputfile, simage, sizes[0]/2, sizes[1]/2, sizes[2]) 0113 0114 os.unlink(outputfile) 0115 0116 main() 0117
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