import imageop
error = 'imgconv.error'
LOSSY = 1
NOT_LOSSY = 0
def null(img, x, y):
return img
def mono2grey(img, x, y):
return imageop.mono2grey(img, x, y, 0, 255)
def grey2jpeggrey(img, x, y):
import jpeg
return jpeg.compress(img, x, y, 1)
def rgb2jpeg(img, x, y):
import jpeg
return jpeg.compress(img, x, y, 4)
def jpeggrey2grey(img, width, height):
import jpeg
data, width, height, bytesperpixel = jpeg.decompress(img)
if bytesperpixel <> 1: raise RuntimeError, 'not greyscale jpeg'
return data
def jpeg2rgb(img, width, height):
import jpeg
data, width, height, bytesperpixel = jpeg.decompress(img)
if bytesperpixel <> 4: raise RuntimeError, 'not rgb jpeg'
return data
converters = [ \
('grey', 'grey4', imageop.grey2grey4, LOSSY), \
('grey', 'grey2', imageop.dither2grey2, LOSSY), \
('grey', 'mono', imageop.dither2mono, LOSSY), \
('mono', 'grey', mono2grey, NOT_LOSSY), \
('grey2', 'grey', imageop.grey22grey, NOT_LOSSY), \
('grey4', 'grey', imageop.grey42grey, NOT_LOSSY), \
('rgb', 'rgb8', imageop.rgb2rgb8, LOSSY), \
('rgb8', 'rgb', imageop.rgb82rgb, NOT_LOSSY), \
('rgb', 'grey', imageop.rgb2grey, LOSSY), \
('grey', 'rgb', imageop.grey2rgb, NOT_LOSSY), \
('jpeggrey','grey',jpeggrey2grey, NOT_LOSSY), \
('grey', 'jpeggrey',grey2jpeggrey, LOSSY), \
('jpeg', 'rgb', jpeg2rgb, NOT_LOSSY), \
('rgb', 'jpeg', rgb2jpeg, LOSSY), \
]
built = {}
def addconverter(fcs, tcs, lossy, func):
for i in range(len(converters)):
ifcs, itcs, irtn, ilossy = converters[i]
if (fcs, tcs) == (ifcs, itcs):
converters[i] = (fcs, tcs, func, lossy)
return
converters.append((fcs,tcs,lossy,func))
def getconverter(fcs, tcs):
#
# If formats are the same return the dummy converter
#
if fcs == tcs: return null
#
# Otherwise, if we have a converter return that one
#
for ifcs, itcs, irtn, ilossy in converters:
if (fcs, tcs) == (ifcs, itcs):
return irtn
#
# Finally, we try to create a converter
#
if not built.has_key(fcs):
built[fcs] = enumerate_converters(fcs)
if not built[fcs].has_key(tcs):
raise error, 'Sorry, conversion from '+fcs+' to '+tcs+ \
' is not implemented'
if len(built[fcs][tcs]) == 3:
#
# Converter not instantiated yet
#
built[fcs][tcs].append(instantiate_converter(built[fcs][tcs]))
cf = built[fcs][tcs][3]
return cf
def enumerate_converters(fcs):
cvs = {}
formats = [fcs]
steps = 0
while 1:
workdone = 0
for ifcs, itcs, irtn, ilossy in converters:
if ifcs == fcs:
template = [ilossy, 1, [irtn]]
elif cvs.has_key(ifcs):
template = cvs[ifcs][:]
template[2] = template[2][:]
if ilossy:
template[0] = ilossy
template[1] = template[1] + 1
template[2].append(irtn)
else:
continue
if not cvs.has_key(itcs):
cvs[itcs] = template
workdone = 1
else:
previous = cvs[itcs]
if template < previous:
cvs[itcs] = template
workdone = 1
if not workdone:
break
steps = steps + 1
if steps > len(converters):
print '------------------loop in emunerate_converters--------'
print 'CONVERTERS:'
print converters
print 'RESULTS:'
print cvs
raise error, 'Internal error - loop'
return cvs
def instantiate_converter(args):
list = args[2]
cl = RtConverters(list)
args.append(cl.convert)
return args
class RtConverters:
def __init__(self, list):
self.list = list
def convert(self, img, w, h):
for cv in self.list:
img = cv(img, w, h)
return img
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