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# Implement 'jpeg' interface using SGI's compression library
# XXX Options 'smooth' and 'optimize' are ignored.
# XXX It appears that compressing grayscale images doesn't work right;
# XXX the resulting file causes weirdness.
class error(Exception):
pass
options = {'quality': 75, 'optimize': 0, 'smooth': 0, 'forcegray': 0}
comp = None
decomp = None
def compress(imgdata, width, height, bytesperpixel):
global comp
import cl
if comp is None: comp = cl.OpenCompressor(cl.JPEG)
if bytesperpixel == 1:
format = cl.GRAYSCALE
elif bytesperpixel == 4:
format = cl.RGBX
if options['forcegray']:
iformat = cl.GRAYSCALE
else:
iformat = cl.YUV
# XXX How to support 'optimize'?
params = [cl.IMAGE_WIDTH, width, cl.IMAGE_HEIGHT, height, \
cl.ORIGINAL_FORMAT, format, \
cl.ORIENTATION, cl.BOTTOM_UP, \
cl.QUALITY_FACTOR, options['quality'], \
cl.INTERNAL_FORMAT, iformat, \
]
comp.SetParams(params)
jpegdata = comp.Compress(1, imgdata)
return jpegdata
def decompress(jpegdata):
global decomp
import cl
if decomp is None: decomp = cl.OpenDecompressor(cl.JPEG)
headersize = decomp.ReadHeader(jpegdata)
params = [cl.IMAGE_WIDTH, 0, cl.IMAGE_HEIGHT, 0, cl.INTERNAL_FORMAT, 0]
decomp.GetParams(params)
width, height, format = params[1], params[3], params[5]
if format == cl.GRAYSCALE or options['forcegray']:
format = cl.GRAYSCALE
bytesperpixel = 1
else:
format = cl.RGBX
bytesperpixel = 4
# XXX How to support 'smooth'?
params = [cl.ORIGINAL_FORMAT, format, \
cl.ORIENTATION, cl.BOTTOM_UP, \
cl.FRAME_BUFFER_SIZE, width*height*bytesperpixel]
decomp.SetParams(params)
imgdata = decomp.Decompress(1, jpegdata)
return imgdata, width, height, bytesperpixel
def setoption(name, value):
if type(value) is not type(0):
raise TypeError, 'jpeg.setoption: numeric options only'
if name == 'forcegrey':
name = 'forcegray'
if not options.has_key(name):
raise KeyError, 'jpeg.setoption: unknown option name'
options[name] = int(value)
def test():
import sys
if sys.argv[1:2] == ['-g']:
del sys.argv[1]
setoption('forcegray', 1)
if not sys.argv[1:]:
sys.argv.append('/usr/local/images/data/jpg/asterix.jpg')
for file in sys.argv[1:]:
show(file)
def show(file):
import gl, GL, DEVICE
jpegdata = open(file, 'r').read()
imgdata, width, height, bytesperpixel = decompress(jpegdata)
gl.foreground()
gl.prefsize(width, height)
win = gl.winopen(file)
if bytesperpixel == 1:
gl.cmode()
gl.pixmode(GL.PM_SIZE, 8)
gl.gconfig()
for i in range(256):
gl.mapcolor(i, i, i, i)
else:
gl.RGBmode()
gl.pixmode(GL.PM_SIZE, 32)
gl.gconfig()
gl.qdevice(DEVICE.REDRAW)
gl.qdevice(DEVICE.ESCKEY)
gl.qdevice(DEVICE.WINQUIT)
gl.qdevice(DEVICE.WINSHUT)
gl.lrectwrite(0, 0, width-1, height-1, imgdata)
while 1:
dev, val = gl.qread()
if dev in (DEVICE.ESCKEY, DEVICE.WINSHUT, DEVICE.WINQUIT):
break
if dev == DEVICE.REDRAW:
gl.lrectwrite(0, 0, width-1, height-1, imgdata)
gl.winclose(win)
# Now test the compression and write the result to a fixed filename
newjpegdata = compress(imgdata, width, height, bytesperpixel)
open('/tmp/j.jpg', 'w').write(newjpegdata)
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