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