122 lines
4.0 KiB
Python
Executable File
122 lines
4.0 KiB
Python
Executable File
#! /usr/bin/env python
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"""Test script for the imageop module. This has the side
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effect of partially testing the imgfile module as well.
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Roger E. Masse
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"""
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from test_support import verbose
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import imageop
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def main():
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image, width, height = getimage('test.rgb')
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# Return the selected part of image, which should by width by height
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# in size and consist of pixels of psize bytes.
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if verbose:
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print 'crop'
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newimage = imageop.crop (image, 4, width, height, 0, 0, 1, 1)
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# Return image scaled to size newwidth by newheight. No interpolation
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# is done, scaling is done by simple-minded pixel duplication or removal.
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# Therefore, computer-generated images or dithered images will
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# not look nice after scaling.
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if verbose:
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print 'scale'
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scaleimage = imageop.scale(image, 4, width, height, 1, 1)
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# Run a vertical low-pass filter over an image. It does so by computing
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# each destination pixel as the average of two vertically-aligned source
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# pixels. The main use of this routine is to forestall excessive flicker
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# if the image two vertically-aligned source pixels, hence the name.
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if verbose:
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print 'tovideo'
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videoimage = imageop.tovideo (image, 4, width, height)
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image, width, height = getimage('greytest.rgb')
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# Convert a 8-bit deep greyscale image to a 1-bit deep image by
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# tresholding all the pixels. The resulting image is tightly packed
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# and is probably only useful as an argument to mono2grey.
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if verbose:
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print 'grey2mono'
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monoimage = imageop.grey2mono (image, width, height, 0)
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#monoimage, width, height = getimage('monotest.rgb')
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# Convert a 1-bit monochrome image to an 8 bit greyscale or color image.
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# All pixels that are zero-valued on input get value p0 on output and
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# all one-value input pixels get value p1 on output. To convert a
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# monochrome black-and-white image to greyscale pass the values 0 and
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# 255 respectively.
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if verbose:
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print 'mono2grey'
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greyimage = imageop.mono2grey (monoimage, width, height, 0, 255)
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# Convert an 8-bit greyscale image to a 1-bit monochrome image using a
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# (simple-minded) dithering algorithm.
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if verbose:
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print 'dither2mono'
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monoimage = imageop.dither2mono (greyimage, width, height)
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# Convert an 8-bit greyscale image to a 4-bit greyscale image without
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# dithering.
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if verbose:
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print 'grey2grey4'
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grey4image = imageop.grey2grey4 (greyimage, width, height)
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# Convert an 8-bit greyscale image to a 2-bit greyscale image without
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# dithering.
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if verbose:
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print 'grey2grey2'
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grey2image = imageop.grey2grey2 (greyimage, width, height)
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# Convert an 8-bit greyscale image to a 2-bit greyscale image with
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# dithering. As for dither2mono, the dithering algorithm is currently
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# very simple.
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if verbose:
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print 'dither2grey2'
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grey2image = imageop.dither2grey2 (greyimage, width, height)
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# Convert a 4-bit greyscale image to an 8-bit greyscale image.
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if verbose:
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print 'grey42grey'
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greyimage = imageop.grey42grey (grey4image, width, height)
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# Convert a 2-bit greyscale image to an 8-bit greyscale image.
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if verbose:
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print 'grey22grey'
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image = imageop.grey22grey (grey2image, width, height)
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def getimage(name):
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"""return a tuple consisting of
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image (in 'imgfile' format) width and height
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"""
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import sys
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import os
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import imgfile
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import string
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# try opening the name directly
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try:
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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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image = imgfile.read(name)
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return (image, sizes[0], sizes[1])
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main()
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