def _read_channel_image_data(fp, layer, depth):
"""
Reads image data for all channels in a layer.
"""
channel_data = []
bytes_per_pixel = depth // 8
for channel in layer.channels:
if channel.id == ChannelID.USER_LAYER_MASK:
w, h = layer.mask_data.width(), layer.mask_data.height()
else:
w, h = layer.width(), layer.height()
start_pos = fp.tell()
compress_type = read_fmt("H", fp)[0]
data = None
if compress_type == Compression.RAW:
data_size = w * h * bytes_per_pixel
data = fp.read(data_size)
elif compress_type == Compression.PACK_BITS:
byte_counts = read_be_array("H", h, fp)
data_size = sum(byte_counts) * bytes_per_pixel
data = fp.read(data_size)
elif compress_type == Compression.ZIP:
data = zlib.decompress(fp.read(channel.length - 2))
elif compress_type == Compression.ZIP_WITH_PREDICTION:
decompressed = zlib.decompress(fp.read(channel.length - 2))
data = compression.decode_prediction(decompressed, w, h, bytes_per_pixel)
if data is None:
return []
channel_data.append(ChannelData(compress_type, data))
remaining_bytes = channel.length - (fp.tell() - start_pos) - 2
if remaining_bytes > 0:
fp.seek(remaining_bytes, 1)
return channel_data
def test_prediction(fixture, width, height, depth):
encoded = encode_prediction(fixture, width, height, depth)
decoded = decode_prediction(encoded, width, height, depth)
assert fixture == decoded
def _read_channel_image_data(fp, layer, depth):
"""
Reads image data for all channels in a layer.
"""
bytes_per_pixel = depth // 8
channel_data = []
for channel in layer.channels:
logger.debug(" reading %s", channel)
if channel.id == ChannelID.USER_LAYER_MASK:
w, h = layer.mask_data.width(), layer.mask_data.height()
elif channel.id == ChannelID.REAL_USER_LAYER_MASK:
w, h = layer.mask_data.real_width(), layer.mask_data.real_height()
else:
w, h = layer.width(), layer.height()
start_pos = fp.tell()
compress_type = read_fmt("H", fp)[0]
logger.debug(" start_pos=%s, compress_type=%s",
start_pos, Compression.name_of(compress_type))
# read or calculate data size
if compress_type == Compression.RAW:
data_size = w * h * bytes_per_pixel
logger.debug(' data size = %sx%sx%s=%s bytes', w, h, bytes_per_pixel, data_size)
elif compress_type == Compression.PACK_BITS:
byte_counts = read_be_array("H", h, fp)
data_size = sum(byte_counts)
logger.debug(' data size = %s bytes', data_size)
elif compress_type in (Compression.ZIP, Compression.ZIP_WITH_PREDICTION):
data_size = channel.length - 2
logger.debug(' data size = %s-2=%s bytes', channel.length, data_size)
else:
warnings.warn("Bad compression type %s" % compress_type)
return []
# read the data itself
if data_size > channel.length:
warnings.warn("Incorrect data size: %s > %s" % (data_size, channel.length))
else:
data = fp.read(data_size)
if compress_type == Compression.ZIP:
data = zlib.decompress(data)
elif compress_type == Compression.ZIP_WITH_PREDICTION:
data = zlib.decompress(data)
data = compression.decode_prediction(data, w, h, bytes_per_pixel)
if data is None:
warnings.warn("Prediction decode failed!")
return []
channel_data.append(ChannelData(compress_type, data))
remaining_length = channel.length - (fp.tell() - start_pos)
if remaining_length > 0:
fp.seek(remaining_length, 1)
logger.debug(' skipping %s bytes', remaining_length)
return channel_data
def _read_channel_image_data(fp, layer, depth):
"""
Reads image data for all channels in a layer.
"""
channel_data = []
bytes_per_pixel = depth // 8
for idx, channel in enumerate(layer.channels):
logger.debug(" reading %s", channel)
if channel.id == ChannelID.USER_LAYER_MASK:
w, h = layer.mask_data.width(), layer.mask_data.height()
elif channel.id == ChannelID.REAL_USER_LAYER_MASK:
w, h = layer.mask_data.real_width(), layer.mask_data.real_height()
else:
w, h = layer.width(), layer.height()
start_pos = fp.tell()
compress_type = read_fmt("H", fp)[0]
logger.debug(" start_pos=%s, compress_type=%s", start_pos,
Compression.name_of(compress_type))
data = None
# read data size
if compress_type == Compression.RAW:
data_size = w * h * bytes_per_pixel
logger.debug(' data size = %sx%sx%s=%s bytes', w, h,
bytes_per_pixel, data_size)
elif compress_type == Compression.PACK_BITS:
byte_counts = read_be_array("H", h, fp)
data_size = sum(byte_counts)
logger.debug(' data size = %s bytes', data_size)
elif compress_type in (Compression.ZIP,
Compression.ZIP_WITH_PREDICTION):
data_size = channel.length - 2
logger.debug(' data size = %s-2=%s bytes', channel.length,
data_size)
else:
warnings.warn("Bad compression type %s" % compress_type)
return []
# read the data itself
if data_size > channel.length:
warnings.warn("Incorrect data size: %s > %s" %
(data_size, channel.length))
else:
raw_data = fp.read(data_size)
if compress_type in (Compression.RAW, Compression.PACK_BITS):
data = raw_data
elif compress_type == Compression.ZIP:
data = zlib.decompress(raw_data)
elif compress_type == Compression.ZIP_WITH_PREDICTION:
decompressed = zlib.decompress(raw_data)
data = compression.decode_prediction(decompressed, w, h,
bytes_per_pixel)
if data is None:
return []
channel_data.append(ChannelData(compress_type, data))
remaining_length = channel.length - (fp.tell() - start_pos)
if remaining_length > 0:
fp.seek(remaining_length, 1)
logger.debug(' skipping %s bytes', remaining_length)
return channel_data
def _read_channel_image_data(fp, layer, depth):
"""
Reads image data for all channels in a layer.
"""
channel_data = []
bytes_per_pixel = depth // 8
for idx, channel in enumerate(layer.channels):
logger.debug(" reading %s", channel)
if channel.id == ChannelID.USER_LAYER_MASK:
w, h = layer.mask_data.width(), layer.mask_data.height()
else:
w, h = layer.width(), layer.height()
start_pos = fp.tell()
compress_type = read_fmt("H", fp)[0]
logger.debug(" start_pos=%s, compress_type=%s",
start_pos, Compression.name_of(compress_type))
data = None
# read data size
if compress_type == Compression.RAW:
data_size = w * h * bytes_per_pixel
logger.debug(' data size = %sx%sx%s=%s bytes', w, h, bytes_per_pixel, data_size)
elif compress_type == Compression.PACK_BITS:
byte_counts = read_be_array("H", h, fp)
sum_counts = sum(byte_counts)
data_size = sum_counts * bytes_per_pixel
logger.debug(' data size = %sx%s=%s bytes', sum_counts, bytes_per_pixel, data_size)
elif compress_type == Compression.ZIP:
data_size = channel.length - 2
logger.debug(' data size = %s-2=%s bytes', channel.length, data_size)
elif compress_type == Compression.ZIP_WITH_PREDICTION:
data_size = channel.length - 2
logger.debug(' data size = %s-2=%s bytes', channel.length, data_size)
else:
warnings.warn("Bad compression type %s" % compress_type)
return []
# read the data itself
if data_size > channel.length:
warnings.warn("Incorrect data size: %s > %s" % (data_size, channel.length))
else:
raw_data = fp.read(data_size)
if compress_type in (Compression.RAW, Compression.PACK_BITS):
data = raw_data
elif compress_type == Compression.ZIP:
data = zlib.decompress(raw_data)
elif compress_type == Compression.ZIP_WITH_PREDICTION:
decompressed = zlib.decompress(raw_data)
data = compression.decode_prediction(decompressed, w, h, bytes_per_pixel)
if data is None:
return []
channel_data.append(ChannelData(compress_type, data))
remaining_bytes = channel.length - (fp.tell() - start_pos) - 2
if remaining_bytes > 0:
fp.seek(remaining_bytes, 1)
logger.debug(' skipping %s bytes', remaining_bytes)
return channel_data
