def decode(effects):
"""
Reads and decodes info about layer effects.
"""
fp = io.BytesIO(effects)
version, effects_count = read_fmt("HH", fp)
effects_list = []
for idx in range(effects_count):
sig = fp.read(4)
if sig != b'8BIM':
raise Error("Error parsing layer effect: invalid signature (%r)" %
sig)
effect_type = fp.read(4)
if not EffectOSType.is_known(effect_type):
warnings.warn("Unknown effect type (%s)" % effect_type)
effect_info_length = read_fmt("I", fp)[0]
effect_info = fp.read(effect_info_length)
decoder = _effect_info_decoders.get(effect_type, lambda data: data)
effects_list.append(LayerEffect(effect_type, decoder(effect_info)))
return Effects(version, effects_count, effects_list)
def _read_layer_record(fp, encoding, version):
"""
Reads single layer record.
"""
top, left, bottom, right, num_channels = read_fmt("4i H", fp)
logger.debug(' top=%d, left=%d, bottom=%d, right=%d, num_channels=%d',
top, left, bottom, right, num_channels)
channel_info = []
for channel_num in range(num_channels):
if version == 1:
info = ChannelInfo(*read_fmt("hI", fp))
elif version == 2:
info = ChannelInfo(*read_fmt("hQ", fp))
channel_info.append(info)
sig = fp.read(4)
if sig != b'8BIM':
raise Error("Error parsing layer: invalid signature (%r)" % sig)
blend_mode = fp.read(4)
if not BlendMode.is_known(blend_mode):
warnings.warn("Unknown blend mode (%s)" % blend_mode)
opacity, clipping, flags, extra_length = read_fmt("BBBxI", fp)
if not Clipping.is_known(clipping):
warnings.warn("Unknown clipping (%s)" % clipping)
logger.debug(' extra_length=%s', extra_length)
flags = LayerFlags(
bool(flags & 1),
not bool(flags & 2), # why "not"?
bool(flags & 16) if bool(flags & 8) else None)
start_pos = fp.tell()
mask_data = _read_layer_mask_data(fp)
blending_ranges = _read_layer_blending_ranges(fp)
name = read_pascal_string(fp, encoding, 4)
remaining_length = extra_length - (fp.tell() - start_pos)
logger.debug(' reading layer tagged blocks...')
logger.debug(' length=%d, start_pos=%d', remaining_length, fp.tell())
tagged_blocks = _read_layer_tagged_blocks(fp, remaining_length, version)
remaining_length = extra_length - (fp.tell() - start_pos)
if remaining_length > 0:
fp.seek(remaining_length, 1) # skip the remainder
logger.debug(' skipping %s bytes', remaining_length)
return LayerRecord(top, left, bottom, right, num_channels, channel_info,
blend_mode, opacity, clipping, flags, mask_data,
blending_ranges, name, tagged_blocks)
def _read_blend_mode(fp):
sig = fp.read(4)
if sig != b'8BIM':
raise Error("Error parsing layer effect: invalid signature (%r)" % sig)
blend_mode = fp.read(4)
if not BlendMode.is_known(blend_mode):
warnings.warn("Unknown blend mode (%s)" % blend_mode)
return blend_mode
def read(fp):
"""
Reads PSD file header.
"""
logger.debug("reading header..")
signature = fp.read(4)
if signature != b'8BPS':
raise Error("This is not a PSD or PSB file")
version = read_fmt("H", fp)[0]
if not version in (1, 2):
raise Error("Unsupported PSD version (%s)" % version)
header = PsdHeader(version, *read_fmt("6x HIIHH", fp))
if not ColorMode.is_known(header.color_mode):
warnings.warn("Unknown color mode: %s" % header.color_mode)
logger.debug(header)
return header
def _read_block(fp, encoding):
"""
Reads single image resource block. Such blocks contain non-pixel data
for the images (e.g. pen tool paths).
"""
sig = fp.read(4)
if sig not in [b'8BIM', b'MeSa']:
raise Error("Invalid resource signature (%r)" % sig)
resource_id = read_fmt("H", fp)[0]
name = read_pascal_string(fp, encoding, 2)
data_size = pad(read_fmt("I", fp)[0], 2)
data = fp.read(data_size)
return ImageResource(resource_id, name, data)
def _read_layer_record(fp, encoding):
"""
Reads single layer record.
"""
top, left, bottom, right, num_channels = read_fmt("4i H", fp)
channel_info = []
for channel_num in range(num_channels):
info = ChannelInfo(*read_fmt("hI", fp))
channel_info.append(info)
sig = fp.read(4)
if sig != b'8BIM':
raise Error("Error parsing layer: invalid signature (%r)" % sig)
blend_mode = fp.read(4).decode('ascii')
if not BlendMode.is_known(blend_mode):
warnings.warn("Unknown blend mode (%s)" % blend_mode)
opacity, clipping, flags, extra_length = read_fmt("BBBxI", fp)
flags = LayerFlags(bool(flags & 1), not bool(flags & 2)) # why not?
if not Clipping.is_known(clipping):
warnings.warn("Unknown clipping: %s" % clipping)
start = fp.tell()
mask_data = _read_layer_mask_data(fp)
blending_ranges = _read_layer_blending_ranges(fp)
name = read_pascal_string(fp, encoding, 4)
remaining_length = extra_length - (fp.tell()-start)
tagged_blocks = _read_layer_tagged_blocks(fp, remaining_length)
remaining_length = extra_length - (fp.tell()-start)
fp.seek(remaining_length, 1) # skip the reminder
return LayerRecord(
top, left, bottom, right,
num_channels, channel_info,
blend_mode, opacity, clipping, flags,
mask_data, blending_ranges, name,
tagged_blocks
)