Test program for the SGI imageop module.
diff --git a/Lib/test/test_imageop.py b/Lib/test/test_imageop.py
new file mode 100755
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+++ b/Lib/test/test_imageop.py
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+#! /usr/bin/env python
+"""Test script for the imageop module. This has the side
+ effect of partially testing the imgfile module as well.
+ Roger E. Masse
+"""
+from test_support import verbose
+
+import imageop
+
+def main():
+
+ image, width, height = getimage('test.rgb')
+
+ # Return the selected part of image, which should by width by height
+ # in size and consist of pixels of psize bytes.
+ if verbose:
+ print 'crop'
+ newimage = imageop.crop (image, 4, width, height, 0, 0, 1, 1)
+
+ # Return image scaled to size newwidth by newheight. No interpolation
+ # is done, scaling is done by simple-minded pixel duplication or removal.
+ # Therefore, computer-generated images or dithered images will
+ # not look nice after scaling.
+ if verbose:
+ print 'scale'
+ scaleimage = imageop.scale(image, 4, width, height, 1, 1)
+
+ # Run a vertical low-pass filter over an image. It does so by computing
+ # each destination pixel as the average of two vertically-aligned source
+ # pixels. The main use of this routine is to forestall excessive flicker
+ # if the image two vertically-aligned source pixels, hence the name.
+ if verbose:
+ print 'tovideo'
+ videoimage = imageop.tovideo (image, 4, width, height)
+
+ image, width, height = getimage('greytest.rgb')
+ # Convert a 8-bit deep greyscale image to a 1-bit deep image by
+ # tresholding all the pixels. The resulting image is tightly packed
+ # and is probably only useful as an argument to mono2grey.
+ if verbose:
+ print 'grey2mono'
+ monoimage = imageop.grey2mono (image, width, height, 0)
+
+ #monoimage, width, height = getimage('monotest.rgb')
+
+ # Convert a 1-bit monochrome image to an 8 bit greyscale or color image.
+ # All pixels that are zero-valued on input get value p0 on output and
+ # all one-value input pixels get value p1 on output. To convert a
+ # monochrome black-and-white image to greyscale pass the values 0 and
+ # 255 respectively.
+ if verbose:
+ print 'mono2grey'
+ greyimage = imageop.mono2grey (monoimage, width, height, 0, 255)
+
+ # Convert an 8-bit greyscale image to a 1-bit monochrome image using a
+ # (simple-minded) dithering algorithm.
+ if verbose:
+ print 'dither2mono'
+ monoimage = imageop.dither2mono (greyimage, width, height)
+
+
+ # Convert an 8-bit greyscale image to a 4-bit greyscale image without
+ # dithering.
+ if verbose:
+ print 'grey2grey4'
+ grey4image = imageop.grey2grey4 (greyimage, width, height)
+
+ # Convert an 8-bit greyscale image to a 2-bit greyscale image without
+ # dithering.
+ if verbose:
+ print 'grey2grey2'
+ grey2image = imageop.grey2grey2 (greyimage, width, height)
+
+ # Convert an 8-bit greyscale image to a 2-bit greyscale image with
+ # dithering. As for dither2mono, the dithering algorithm is currently
+ # very simple.
+ if verbose:
+ print 'dither2grey2'
+ grey2image = imageop.dither2grey2 (greyimage, width, height)
+
+ # Convert a 4-bit greyscale image to an 8-bit greyscale image.
+ if verbose:
+ print 'grey42grey'
+ greyimage = imageop.grey42grey (grey4image, width, height)
+
+ # Convert a 2-bit greyscale image to an 8-bit greyscale image.
+ if verbose:
+ print 'grey22grey'
+ image = imageop.grey22grey (grey2image, width, height)
+
+def getimage(name):
+ """return a tuple consisting of
+ image (in 'imgfile' format) width and height
+ """
+
+ import sys
+ import os
+ import imgfile
+ import string
+
+ # try opening the name directly
+ try:
+ 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 = string.splitfields(ourname, os.sep)
+ parts[-1] = name
+ name = string.joinfields(parts, os.sep)
+ sizes = imgfile.getsizes(name)
+ if verbose:
+ print 'Opening test image: %s, sizes: %s' % (name, str(sizes))
+
+ image = imgfile.read(name)
+ return (image, sizes[0], sizes[1])
+
+main()