Lib/plat-irix5/jpeg.py

   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.
   7 from warnings import warnpy3k
   8 warnpy3k("the jpeg module has been removed in Python 3.0", stacklevel=2)
   9 del warnpy3k
  10
  11 class error(Exception):
  12     pass
  13
  14 options = {'quality': 75, 'optimize': 0, 'smooth': 0, 'forcegray': 0}
  15
  16 comp = None
  17 decomp = None
  18
  19 def 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
  42 def 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
  64 def 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
  73 def 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
  83 def 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)