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1# Implement 'jpeg' interface using SGI's compression library
2
3# XXX Options 'smooth' and 'optimize' are ignored.
4
5# XXX It appears that compressing grayscale images doesn't work right;
6# XXX the resulting file causes weirdness.
7from warnings import warnpy3k
8warnpy3k("the jpeg module has been removed in Python 3.0", stacklevel=2)
9del warnpy3k
10
11class error(Exception):
12    pass
13
14options = {'quality': 75, 'optimize': 0, 'smooth': 0, 'forcegray': 0}
15
16comp = None
17decomp = None
18
19def compress(imgdata, width, height, bytesperpixel):
20    global comp
21    import cl
22    if comp is None: comp = cl.OpenCompressor(cl.JPEG)
23    if bytesperpixel == 1:
24        format = cl.GRAYSCALE
25    elif bytesperpixel == 4:
26        format = cl.RGBX
27    if options['forcegray']:
28        iformat = cl.GRAYSCALE
29    else:
30        iformat = cl.YUV
31    # XXX How to support 'optimize'?
32    params = [cl.IMAGE_WIDTH, width, cl.IMAGE_HEIGHT, height,
33              cl.ORIGINAL_FORMAT, format,
34              cl.ORIENTATION, cl.BOTTOM_UP,
35              cl.QUALITY_FACTOR, options['quality'],
36              cl.INTERNAL_FORMAT, iformat,
37             ]
38    comp.SetParams(params)
39    jpegdata = comp.Compress(1, imgdata)
40    return jpegdata
41
42def decompress(jpegdata):
43    global decomp
44    import cl
45    if decomp is None: decomp = cl.OpenDecompressor(cl.JPEG)
46    headersize = decomp.ReadHeader(jpegdata)
47    params = [cl.IMAGE_WIDTH, 0, cl.IMAGE_HEIGHT, 0, cl.INTERNAL_FORMAT, 0]
48    decomp.GetParams(params)
49    width, height, format = params[1], params[3], params[5]
50    if format == cl.GRAYSCALE or options['forcegray']:
51        format = cl.GRAYSCALE
52        bytesperpixel = 1
53    else:
54        format = cl.RGBX
55        bytesperpixel = 4
56    # XXX How to support 'smooth'?
57    params = [cl.ORIGINAL_FORMAT, format,
58              cl.ORIENTATION, cl.BOTTOM_UP,
59              cl.FRAME_BUFFER_SIZE, width*height*bytesperpixel]
60    decomp.SetParams(params)
61    imgdata = decomp.Decompress(1, jpegdata)
62    return imgdata, width, height, bytesperpixel
63
64def setoption(name, value):
65    if type(value) is not type(0):
66        raise TypeError, 'jpeg.setoption: numeric options only'
67    if name == 'forcegrey':
68        name = 'forcegray'
69    if not options.has_key(name):
70        raise KeyError, 'jpeg.setoption: unknown option name'
71    options[name] = int(value)
72
73def test():
74    import sys
75    if sys.argv[1:2] == ['-g']:
76        del sys.argv[1]
77        setoption('forcegray', 1)
78    if not sys.argv[1:]:
79        sys.argv.append('/usr/local/images/data/jpg/asterix.jpg')
80    for file in sys.argv[1:]:
81        show(file)
82
83def show(file):
84    import gl, GL, DEVICE
85    jpegdata = open(file, 'r').read()
86    imgdata, width, height, bytesperpixel = decompress(jpegdata)
87    gl.foreground()
88    gl.prefsize(width, height)
89    win = gl.winopen(file)
90    if bytesperpixel == 1:
91        gl.cmode()
92        gl.pixmode(GL.PM_SIZE, 8)
93        gl.gconfig()
94        for i in range(256):
95            gl.mapcolor(i, i, i, i)
96    else:
97        gl.RGBmode()
98        gl.pixmode(GL.PM_SIZE, 32)
99        gl.gconfig()
100    gl.qdevice(DEVICE.REDRAW)
101    gl.qdevice(DEVICE.ESCKEY)
102    gl.qdevice(DEVICE.WINQUIT)
103    gl.qdevice(DEVICE.WINSHUT)
104    gl.lrectwrite(0, 0, width-1, height-1, imgdata)
105    while 1:
106        dev, val = gl.qread()
107        if dev in (DEVICE.ESCKEY, DEVICE.WINSHUT, DEVICE.WINQUIT):
108            break
109        if dev == DEVICE.REDRAW:
110            gl.lrectwrite(0, 0, width-1, height-1, imgdata)
111    gl.winclose(win)
112    # Now test the compression and write the result to a fixed filename
113    newjpegdata = compress(imgdata, width, height, bytesperpixel)
114    open('/tmp/j.jpg', 'w').write(newjpegdata)
115