Test program for the SGI imageop module.

Lib/test/test_imageop.py

@@ -0,0 +1,121 @@
+#! /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()

Lib/test/testall.py

@@ -30,6 +30,7 @@
 	 'test_gdbm',
 	 'test_grp',
 	 'test_operator',
+	 'test_imageop',
 	 ]
 
 if __name__ == '__main__':