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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) fptr.write(write_buffer)
bps = self.bits_per_component 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. # All components are the same. Writing is straightforward.
if self.bits_per_component[0] <= 8: if self.bits_per_component[0] <= 8:
code = 'B' write_buffer = np.getbuffer(self.palette.astype(np.uint8))
dtype = np.uint8
elif self.bits_per_component[0] <= 16: elif self.bits_per_component[0] <= 16:
code = 'H' write_buffer = np.getbuffer(self.palette.astype(np.uint16))
dtype = np.uint16
elif self.bits_per_component[0] <= 32: elif self.bits_per_component[0] <= 32:
code = 'I' write_buffer = np.getbuffer(self.palette.astype(np.uint32))
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())
fptr.write(write_buffer) fptr.write(write_buffer)
else: else:
# Not all the components are the same. More general, but much rarer # 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 # Need to determine bps and signed or not
read_buffer = fptr.read(num_columns) read_buffer = fptr.read(num_columns)
data = struct.unpack('>' + 'B' * num_columns, read_buffer) bps_signed = struct.unpack('>' + 'B' * num_columns, read_buffer)
bps = [((x & 0x7f) + 1) for x in data] bps = [((x & 0x7f) + 1) for x in bps_signed]
signed = [((x & 0x80) > 1) for x in data] signed = [((x & 0x80) > 1) for x in bps_signed]
fmt = '>' if all(b == bps_signed[0] for b in bps_signed):
for bits in bps: # Ok the palette has the same datatype for all columns. We should
if bits <= 8: # be able to efficiently read it.
fmt += 'B' if bps[0] <= 8:
elif bits <= 16: nbytes_per_row = num_columns
fmt += 'H' dtype = np.uint8
elif bits <= 32: elif bps[0] <= 16:
fmt += 'I' nbytes_per_row = 2 * num_columns
dtype = np.uint16
elif bps[0] <= 32:
nbytes_per_row = 3 * num_columns
dtype = np.uint32
# Each palette component is padded out to the next largest byte. read_buffer = fptr.read(num_entries * nbytes_per_row)
# That means a list comprehension does this in one shot. palette = np.frombuffer(read_buffer, dtype=dtype)
row_nbytes = sum([int(math.ceil(x/8.0)) for x in bps]) palette = np.reshape(palette, (num_entries, num_columns))
read_buffer = fptr.read(num_entries * row_nbytes) else:
palette = np.zeros((num_entries, num_columns), dtype=np.int32) # General case where the columns may not be the same width.
for j in range(num_entries): fmt = '>'
palette[j] = struct.unpack_from(fmt, read_buffer, for bits in bps:
if bits <= 8:
fmt += 'B'
elif bits <= 16:
fmt += 'H'
elif bits <= 32:
fmt += 'I'
# 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) offset=j * row_nbytes)
return cls(palette, bps, signed, length=length, offset=offset) return cls(palette, bps, signed, length=length, offset=offset)