summaryrefslogtreecommitdiffstats
path: root/Lib/test/test_imageop.py
blob: 77281ab52b246b63858f2427cf1f76dbcfdcdbc2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
#! /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, unlink

import imageop, uu

def main(use_rgbimg=1):

    # Create binary test files
    uu.decode(get_qualified_path('testrgb.uue'), 'test.rgb')

    if use_rgbimg:
	image, width, height = getrgbimage('test.rgb')
    else:
	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)

    # Convert an rgb image to an 8 bit rgb
    if verbose:
	print 'rgb2rgb8'
    greyimage = imageop.rgb2rgb8(image, width, height)

    # Convert an 8 bit rgb image to a 24 bit rgb image
    if verbose:
	print 'rgb82rgb'
    image = imageop.rgb82rgb(greyimage, width, height)
    
    # Convert an rgb image to an 8 bit greyscale image
    if verbose:
	print 'rgb2grey'
    greyimage = imageop.rgb2grey(image, width, height)

    # Convert an 8 bit greyscale image to a 24 bit rgb image
    if verbose:
	print 'grey2rgb'
    image = imageop.grey2rgb(greyimage, width, height)
    
    # 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 (greyimage, 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)

    # Cleanup
    unlink('test.rgb')

def getrgbimage(name):
    """return a tuple consisting of image (in 'imgfile' format but
    using rgbimg instead) width and height"""

    import rgbimg

    try:
	sizes = rgbimg.sizeofimage(name)
    except rgbimg.error:
	name = get_qualified_path(name)
	sizes = rgbimg.sizeofimage(name)
    if verbose:
	print 'rgbimg opening test image: %s, sizes: %s' % (name, str(sizes))

    image = rgbimg.longimagedata(name)
    return (image, sizes[0], sizes[1])
  
def getimage(name):
    """return a tuple consisting of
       image (in 'imgfile' format) width and height
    """

    import imgfile
  
    try:
	sizes = imgfile.getsizes(name)
    except imgfile.error:
	name = get_qualified_path(name)
	sizes = imgfile.getsizes(name)
    if verbose:
	print 'imgfile opening test image: %s, sizes: %s' % (name, str(sizes))

    image = imgfile.read(name)
    return (image, sizes[0], sizes[1])

def get_qualified_path(name):
    """ return a more qualified path to name"""
    import sys
    import os
    for dir in sys.path:
	fullname = os.path.join(dir, name)
	if os.path.exists(fullname):
	    return fullname
    return name

# rgbimg (unlike imgfile) is portable to platforms other than SGI.
# So we prefer to use it.
main(use_rgbimg=1)