PIL.PsdImagePlugin 源代码
#
# The Python Imaging Library
# $Id$
#
# Adobe PSD 2.5/3.0 file handling
#
# History:
# 1995-09-01 fl Created
# 1997-01-03 fl Read most PSD images
# 1997-01-18 fl Fixed P and CMYK support
# 2001-10-21 fl Added seek/tell support (for layers)
#
# Copyright (c) 1997-2001 by Secret Labs AB.
# Copyright (c) 1995-2001 by Fredrik Lundh
#
# See the README file for information on usage and redistribution.
#
import io
from . import Image, ImageFile, ImagePalette
from ._binary import i8
from ._binary import i16be as i16
from ._binary import i32be as i32
from ._binary import si16be as si16
MODES = {
# (photoshop mode, bits) -> (pil mode, required channels)
(0, 1): ("1", 1),
(0, 8): ("L", 1),
(1, 8): ("L", 1),
(2, 8): ("P", 1),
(3, 8): ("RGB", 3),
(4, 8): ("CMYK", 4),
(7, 8): ("L", 1), # FIXME: multilayer
(8, 8): ("L", 1), # duotone
(9, 8): ("LAB", 3),
}
# --------------------------------------------------------------------.
# read PSD images
def _accept(prefix):
return prefix[:4] == b"8BPS"
##
# Image plugin for Photoshop images.
[文档]class PsdImageFile(ImageFile.ImageFile):
format = "PSD"
format_description = "Adobe Photoshop"
_close_exclusive_fp_after_loading = False
def _open(self):
read = self.fp.read
#
# header
s = read(26)
if not _accept(s) or i16(s, 4) != 1:
raise SyntaxError("not a PSD file")
psd_bits = i16(s, 22)
psd_channels = i16(s, 12)
psd_mode = i16(s, 24)
mode, channels = MODES[(psd_mode, psd_bits)]
if channels > psd_channels:
raise OSError("not enough channels")
self.mode = mode
self._size = i32(s, 18), i32(s, 14)
#
# color mode data
size = i32(read(4))
if size:
data = read(size)
if mode == "P" and size == 768:
self.palette = ImagePalette.raw("RGB;L", data)
#
# image resources
self.resources = []
size = i32(read(4))
if size:
# load resources
end = self.fp.tell() + size
while self.fp.tell() < end:
read(4) # signature
id = i16(read(2))
name = read(i8(read(1)))
if not (len(name) & 1):
read(1) # padding
data = read(i32(read(4)))
if len(data) & 1:
read(1) # padding
self.resources.append((id, name, data))
if id == 1039: # ICC profile
self.info["icc_profile"] = data
#
# layer and mask information
self.layers = []
size = i32(read(4))
if size:
end = self.fp.tell() + size
size = i32(read(4))
if size:
_layer_data = io.BytesIO(ImageFile._safe_read(self.fp, size))
self.layers = _layerinfo(_layer_data, size)
self.fp.seek(end)
self.n_frames = len(self.layers)
self.is_animated = self.n_frames > 1
#
# image descriptor
self.tile = _maketile(self.fp, mode, (0, 0) + self.size, channels)
# keep the file open
self.__fp = self.fp
self.frame = 1
self._min_frame = 1
[文档] def seek(self, layer):
if not self._seek_check(layer):
return
# seek to given layer (1..max)
try:
name, mode, bbox, tile = self.layers[layer - 1]
self.mode = mode
self.tile = tile
self.frame = layer
self.fp = self.__fp
return name, bbox
except IndexError as e:
raise EOFError("no such layer") from e
[文档] def load_prepare(self):
# create image memory if necessary
if not self.im or self.im.mode != self.mode or self.im.size != self.size:
self.im = Image.core.fill(self.mode, self.size, 0)
# create palette (optional)
if self.mode == "P":
Image.Image.load(self)
def _close__fp(self):
try:
if self.__fp != self.fp:
self.__fp.close()
except AttributeError:
pass
finally:
self.__fp = None
def _layerinfo(fp, ct_bytes):
# read layerinfo block
layers = []
def read(size):
return ImageFile._safe_read(fp, size)
ct = si16(read(2))
# sanity check
if ct_bytes < (abs(ct) * 20):
raise SyntaxError("Layer block too short for number of layers requested")
for i in range(abs(ct)):
# bounding box
y0 = i32(read(4))
x0 = i32(read(4))
y1 = i32(read(4))
x1 = i32(read(4))
# image info
info = []
mode = []
ct_types = i16(read(2))
types = list(range(ct_types))
if len(types) > 4:
continue
for i in types:
type = i16(read(2))
if type == 65535:
m = "A"
else:
m = "RGBA"[type]
mode.append(m)
size = i32(read(4))
info.append((m, size))
# figure out the image mode
mode.sort()
if mode == ["R"]:
mode = "L"
elif mode == ["B", "G", "R"]:
mode = "RGB"
elif mode == ["A", "B", "G", "R"]:
mode = "RGBA"
else:
mode = None # unknown
# skip over blend flags and extra information
read(12) # filler
name = ""
size = i32(read(4)) # length of the extra data field
combined = 0
if size:
data_end = fp.tell() + size
length = i32(read(4))
if length:
fp.seek(length - 16, io.SEEK_CUR)
combined += length + 4
length = i32(read(4))
if length:
fp.seek(length, io.SEEK_CUR)
combined += length + 4
length = i8(read(1))
if length:
# Don't know the proper encoding,
# Latin-1 should be a good guess
name = read(length).decode("latin-1", "replace")
combined += length + 1
fp.seek(data_end)
layers.append((name, mode, (x0, y0, x1, y1)))
# get tiles
i = 0
for name, mode, bbox in layers:
tile = []
for m in mode:
t = _maketile(fp, m, bbox, 1)
if t:
tile.extend(t)
layers[i] = name, mode, bbox, tile
i += 1
return layers
def _maketile(file, mode, bbox, channels):
tile = None
read = file.read
compression = i16(read(2))
xsize = bbox[2] - bbox[0]
ysize = bbox[3] - bbox[1]
offset = file.tell()
if compression == 0:
#
# raw compression
tile = []
for channel in range(channels):
layer = mode[channel]
if mode == "CMYK":
layer += ";I"
tile.append(("raw", bbox, offset, layer))
offset = offset + xsize * ysize
elif compression == 1:
#
# packbits compression
i = 0
tile = []
bytecount = read(channels * ysize * 2)
offset = file.tell()
for channel in range(channels):
layer = mode[channel]
if mode == "CMYK":
layer += ";I"
tile.append(("packbits", bbox, offset, layer))
for y in range(ysize):
offset = offset + i16(bytecount, i)
i += 2
file.seek(offset)
if offset & 1:
read(1) # padding
return tile
# --------------------------------------------------------------------
# registry
Image.register_open(PsdImageFile.format, PsdImageFile, _accept)
Image.register_extension(PsdImageFile.format, ".psd")
Image.register_mime(PsdImageFile.format, "image/vnd.adobe.photoshop")
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