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Merge branch 'issue210' into devel

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This commit is contained in:
John Evans 2014-04-02 11:29:03 -04:00
commit d2ba8a14b6
1 changed files with 41 additions and 29 deletions
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70
glymur/jp2box.py
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@ -1882,21 +1882,14 @@ class PaletteBox(Jp2kBox):
fptr.write(write_buffer)
bps = self.bits_per_component
if any(b != bps[0] for b in bps):
if all(b == bps[0] for b in bps):
# All components are the same. Writing is straightforward.
if self.bits_per_component[0] <= 8:
code = 'B'
dtype = np.uint8
write_buffer = np.getbuffer(self.palette.astype(np.uint8))
elif self.bits_per_component[0] <= 16:
code = 'H'
dtype = np.uint16
write_buffer = np.getbuffer(self.palette.astype(np.uint16))
elif self.bits_per_component[0] <= 32:
code = 'I'
dtype = np.uint32
nelts = self.palette.shape[0] * self.palette.shape[1]
fmt = '>{0}{1}'.format(nelts, code)
write_buffer = struct.pack(fmt,
self.palette.astype(dtype).flatten())
write_buffer = np.getbuffer(self.palette.astype(np.uint32))
fptr.write(write_buffer)
else:
# Not all the components are the same. More general, but much rarer
@ -1933,27 +1926,46 @@ class PaletteBox(Jp2kBox):
# Need to determine bps and signed or not
read_buffer = fptr.read(num_columns)
data = struct.unpack('>' + 'B' * num_columns, read_buffer)
bps = [((x & 0x7f) + 1) for x in data]
signed = [((x & 0x80) > 1) for x in data]
bps_signed = struct.unpack('>' + 'B' * num_columns, read_buffer)
bps = [((x & 0x7f) + 1) for x in bps_signed]
signed = [((x & 0x80) > 1) for x in bps_signed]
fmt = '>'
for bits in bps:
if bits <= 8:
fmt += 'B'
elif bits <= 16:
fmt += 'H'
elif bits <= 32:
fmt += 'I'
if all(b == bps_signed[0] for b in bps_signed):
# Ok the palette has the same datatype for all columns. We should
# be able to efficiently read it.
if bps[0] <= 8:
nbytes_per_row = num_columns
dtype = np.uint8
elif bps[0] <= 16:
nbytes_per_row = 2 * num_columns
dtype = np.uint16
elif bps[0] <= 32:
nbytes_per_row = 3 * num_columns
dtype = np.uint32
read_buffer = fptr.read(num_entries * nbytes_per_row)
palette = np.frombuffer(read_buffer, dtype=dtype)
palette = np.reshape(palette, (num_entries, num_columns))
# Each palette component is padded out to the next largest byte.
# That means a list comprehension does this in one shot.
row_nbytes = sum([int(math.ceil(x/8.0)) for x in bps])
else:
# General case where the columns may not be the same width.
fmt = '>'
for bits in bps:
if bits <= 8:
fmt += 'B'
elif bits <= 16:
fmt += 'H'
elif bits <= 32:
fmt += 'I'
read_buffer = fptr.read(num_entries * row_nbytes)
palette = np.zeros((num_entries, num_columns), dtype=np.int32)
for j in range(num_entries):
palette[j] = struct.unpack_from(fmt, read_buffer,
# Each palette component is padded out to the next largest byte.
# That means a list comprehension does this in one shot.
row_nbytes = sum([int(math.ceil(x/8.0)) for x in bps])
read_buffer = fptr.read(num_entries * row_nbytes)
palette = np.zeros((num_entries, num_columns), dtype=np.int32)
for j in range(num_entries):
palette[j] = struct.unpack_from(fmt, read_buffer,
offset=j * row_nbytes)
return cls(palette, bps, signed, length=length, offset=offset)