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