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//usr/lib/python2.4/test/test_imgfile.py
#! /usr/bin/env python2.4 """Simple test script for imgfile.c Roger E. Masse """ from test.test_support import verbose, unlink, findfile import imgfile, uu, os def main(): uu.decode(findfile('testrgb.uue'), 'test.rgb') uu.decode(findfile('greyrgb.uue'), 'greytest.rgb') # Test a 3 byte color image testimage('test.rgb') # Test a 1 byte greyscale image testimage('greytest.rgb') unlink('test.rgb') unlink('greytest.rgb') def testimage(name): """Run through the imgfile's battery of possible methods on the image passed in name. """ import sys import os outputfile = '/tmp/deleteme' # try opening the name directly try: # This function returns a tuple (x, y, z) where x and y are the size # of the image in pixels and z is the number of bytes per pixel. Only # 3 byte RGB pixels and 1 byte greyscale pixels are supported. sizes = imgfile.getsizes(name) except imgfile.error: # get a more qualified path component of the script... if __name__ == '__main__': ourname = sys.argv[0] else: # ...or the full path of the module ourname = sys.modules[__name__].__file__ parts = ourname.split(os.sep) parts[-1] = name name = os.sep.join(parts) sizes = imgfile.getsizes(name) if verbose: print 'Opening test image: %s, sizes: %s' % (name, str(sizes)) # This function reads and decodes the image on the specified file, # and returns it as a python string. The string has either 1 byte # greyscale pixels or 4 byte RGBA pixels. The bottom left pixel # is the first in the string. This format is suitable to pass # to gl.lrectwrite, for instance. image = imgfile.read(name) # This function writes the RGB or greyscale data in data to # image file file. x and y give the size of the image, z is # 1 for 1 byte greyscale images or 3 for RGB images (which # are stored as 4 byte values of which only the lower three # bytes are used). These are the formats returned by gl.lrectread. if verbose: print 'Writing output file' imgfile.write (outputfile, image, sizes[0], sizes[1], sizes[2]) if verbose: print 'Opening scaled test image: %s, sizes: %s' % (name, str(sizes)) # This function is identical to read but it returns an image that # is scaled to the given x and y sizes. If the filter and blur # parameters are omitted scaling is done by simply dropping # or duplicating pixels, so the result will be less than perfect, # especially for computer-generated images. Alternatively, # you can specify a filter to use to smoothen the image after # scaling. The filter forms supported are 'impulse', 'box', # 'triangle', 'quadratic' and 'gaussian'. If a filter is # specified blur is an optional parameter specifying the # blurriness of the filter. It defaults to 1.0. readscaled # makes no attempt to keep the aspect ratio correct, so that # is the users' responsibility. if verbose: print 'Filtering with "impulse"' simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'impulse', 2.0) # This function sets a global flag which defines whether the # scan lines of the image are read or written from bottom to # top (flag is zero, compatible with SGI GL) or from top to # bottom(flag is one, compatible with X). The default is zero. if verbose: print 'Switching to X compatibility' imgfile.ttob (1) if verbose: print 'Filtering with "triangle"' simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'triangle', 3.0) if verbose: print 'Switching back to SGI compatibility' imgfile.ttob (0) if verbose: print 'Filtering with "quadratic"' simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'quadratic') if verbose: print 'Filtering with "gaussian"' simage = imgfile.readscaled (name, sizes[0]/2, sizes[1]/2, 'gaussian', 1.0) if verbose: print 'Writing output file' imgfile.write (outputfile, simage, sizes[0]/2, sizes[1]/2, sizes[2]) os.unlink(outputfile) main()