-
-
Notifications
You must be signed in to change notification settings - Fork 2.2k
/
WebPImagePlugin.py
361 lines (301 loc) · 11 KB
/
WebPImagePlugin.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
from io import BytesIO
from . import Image, ImageFile
try:
from . import _webp
SUPPORTED = True
except ImportError:
SUPPORTED = False
_VALID_WEBP_MODES = {"RGBX": True, "RGBA": True, "RGB": True}
_VALID_WEBP_LEGACY_MODES = {"RGB": True, "RGBA": True}
_VP8_MODES_BY_IDENTIFIER = {
b"VP8 ": "RGB",
b"VP8X": "RGBA",
b"VP8L": "RGBA", # lossless
}
def _accept(prefix):
is_riff_file_format = prefix[:4] == b"RIFF"
is_webp_file = prefix[8:12] == b"WEBP"
is_valid_vp8_mode = prefix[12:16] in _VP8_MODES_BY_IDENTIFIER
if is_riff_file_format and is_webp_file and is_valid_vp8_mode:
if not SUPPORTED:
return (
"image file could not be identified because WEBP support not installed"
)
return True
class WebPImageFile(ImageFile.ImageFile):
format = "WEBP"
format_description = "WebP image"
__loaded = 0
__logical_frame = 0
def _open(self):
if not _webp.HAVE_WEBPANIM:
# Legacy mode
data, width, height, self._mode, icc_profile, exif = _webp.WebPDecode(
self.fp.read()
)
if icc_profile:
self.info["icc_profile"] = icc_profile
if exif:
self.info["exif"] = exif
self._size = width, height
self.fp = BytesIO(data)
self.tile = [("raw", (0, 0) + self.size, 0, self.mode)]
self.n_frames = 1
self.is_animated = False
return
# Use the newer AnimDecoder API to parse the (possibly) animated file,
# and access muxed chunks like ICC/EXIF/XMP.
self._decoder = _webp.WebPAnimDecoder(self.fp.read())
# Get info from decoder
width, height, loop_count, bgcolor, frame_count, mode = self._decoder.get_info()
self._size = width, height
self.info["loop"] = loop_count
bg_a, bg_r, bg_g, bg_b = (
(bgcolor >> 24) & 0xFF,
(bgcolor >> 16) & 0xFF,
(bgcolor >> 8) & 0xFF,
bgcolor & 0xFF,
)
self.info["background"] = (bg_r, bg_g, bg_b, bg_a)
self.n_frames = frame_count
self.is_animated = self.n_frames > 1
self._mode = "RGB" if mode == "RGBX" else mode
self.rawmode = mode
self.tile = []
# Attempt to read ICC / EXIF / XMP chunks from file
icc_profile = self._decoder.get_chunk("ICCP")
exif = self._decoder.get_chunk("EXIF")
xmp = self._decoder.get_chunk("XMP ")
if icc_profile:
self.info["icc_profile"] = icc_profile
if exif:
self.info["exif"] = exif
if xmp:
self.info["xmp"] = xmp
# Initialize seek state
self._reset(reset=False)
def _getexif(self):
if "exif" not in self.info:
return None
return self.getexif()._get_merged_dict()
def getxmp(self):
"""
Returns a dictionary containing the XMP tags.
Requires defusedxml to be installed.
:returns: XMP tags in a dictionary.
"""
return self._getxmp(self.info["xmp"]) if "xmp" in self.info else {}
def seek(self, frame):
if not self._seek_check(frame):
return
# Set logical frame to requested position
self.__logical_frame = frame
def _reset(self, reset=True):
if reset:
self._decoder.reset()
self.__physical_frame = 0
self.__loaded = -1
self.__timestamp = 0
def _get_next(self):
# Get next frame
ret = self._decoder.get_next()
self.__physical_frame += 1
# Check if an error occurred
if ret is None:
self._reset() # Reset just to be safe
self.seek(0)
msg = "failed to decode next frame in WebP file"
raise EOFError(msg)
# Compute duration
data, timestamp = ret
duration = timestamp - self.__timestamp
self.__timestamp = timestamp
# libwebp gives frame end, adjust to start of frame
timestamp -= duration
return data, timestamp, duration
def _seek(self, frame):
if self.__physical_frame == frame:
return # Nothing to do
if frame < self.__physical_frame:
self._reset() # Rewind to beginning
while self.__physical_frame < frame:
self._get_next() # Advance to the requested frame
def load(self):
if _webp.HAVE_WEBPANIM:
if self.__loaded != self.__logical_frame:
self._seek(self.__logical_frame)
# We need to load the image data for this frame
data, timestamp, duration = self._get_next()
self.info["timestamp"] = timestamp
self.info["duration"] = duration
self.__loaded = self.__logical_frame
# Set tile
if self.fp and self._exclusive_fp:
self.fp.close()
self.fp = BytesIO(data)
self.tile = [("raw", (0, 0) + self.size, 0, self.rawmode)]
return super().load()
def tell(self):
if not _webp.HAVE_WEBPANIM:
return super().tell()
return self.__logical_frame
def _save_all(im, fp, filename):
encoderinfo = im.encoderinfo.copy()
append_images = list(encoderinfo.get("append_images", []))
# If total frame count is 1, then save using the legacy API, which
# will preserve non-alpha modes
total = 0
for ims in [im] + append_images:
total += getattr(ims, "n_frames", 1)
if total == 1:
_save(im, fp, filename)
return
background = (0, 0, 0, 0)
if "background" in encoderinfo:
background = encoderinfo["background"]
elif "background" in im.info:
background = im.info["background"]
if isinstance(background, int):
# GifImagePlugin stores a global color table index in
# info["background"]. So it must be converted to an RGBA value
palette = im.getpalette()
if palette:
r, g, b = palette[background * 3 : (background + 1) * 3]
background = (r, g, b, 255)
else:
background = (background, background, background, 255)
duration = im.encoderinfo.get("duration", im.info.get("duration", 0))
loop = im.encoderinfo.get("loop", 0)
minimize_size = im.encoderinfo.get("minimize_size", False)
kmin = im.encoderinfo.get("kmin", None)
kmax = im.encoderinfo.get("kmax", None)
allow_mixed = im.encoderinfo.get("allow_mixed", False)
verbose = False
lossless = im.encoderinfo.get("lossless", False)
quality = im.encoderinfo.get("quality", 80)
method = im.encoderinfo.get("method", 0)
icc_profile = im.encoderinfo.get("icc_profile") or ""
exif = im.encoderinfo.get("exif", "")
if isinstance(exif, Image.Exif):
exif = exif.tobytes()
xmp = im.encoderinfo.get("xmp", "")
if allow_mixed:
lossless = False
# Sensible keyframe defaults are from gif2webp.c script
if kmin is None:
kmin = 9 if lossless else 3
if kmax is None:
kmax = 17 if lossless else 5
# Validate background color
if (
not isinstance(background, (list, tuple))
or len(background) != 4
or not all(0 <= v < 256 for v in background)
):
msg = f"Background color is not an RGBA tuple clamped to (0-255): {background}"
raise OSError(msg)
# Convert to packed uint
bg_r, bg_g, bg_b, bg_a = background
background = (bg_a << 24) | (bg_r << 16) | (bg_g << 8) | (bg_b << 0)
# Setup the WebP animation encoder
enc = _webp.WebPAnimEncoder(
im.size[0],
im.size[1],
background,
loop,
minimize_size,
kmin,
kmax,
allow_mixed,
verbose,
)
# Add each frame
frame_idx = 0
timestamp = 0
cur_idx = im.tell()
try:
for ims in [im] + append_images:
# Get # of frames in this image
nfr = getattr(ims, "n_frames", 1)
for idx in range(nfr):
ims.seek(idx)
ims.load()
# Make sure image mode is supported
frame = ims
rawmode = ims.mode
if ims.mode not in _VALID_WEBP_MODES:
alpha = (
"A" in ims.mode
or "a" in ims.mode
or (ims.mode == "P" and "A" in ims.im.getpalettemode())
)
rawmode = "RGBA" if alpha else "RGB"
frame = ims.convert(rawmode)
if rawmode == "RGB":
# For faster conversion, use RGBX
rawmode = "RGBX"
# Append the frame to the animation encoder
enc.add(
frame.tobytes("raw", rawmode),
round(timestamp),
frame.size[0],
frame.size[1],
rawmode,
lossless,
quality,
method,
)
# Update timestamp and frame index
if isinstance(duration, (list, tuple)):
timestamp += duration[frame_idx]
else:
timestamp += duration
frame_idx += 1
finally:
im.seek(cur_idx)
# Force encoder to flush frames
enc.add(None, round(timestamp), 0, 0, "", lossless, quality, 0)
# Get the final output from the encoder
data = enc.assemble(icc_profile, exif, xmp)
if data is None:
msg = "cannot write file as WebP (encoder returned None)"
raise OSError(msg)
fp.write(data)
def _save(im, fp, filename):
lossless = im.encoderinfo.get("lossless", False)
quality = im.encoderinfo.get("quality", 80)
icc_profile = im.encoderinfo.get("icc_profile") or ""
exif = im.encoderinfo.get("exif", b"")
if isinstance(exif, Image.Exif):
exif = exif.tobytes()
if exif.startswith(b"Exif\x00\x00"):
exif = exif[6:]
xmp = im.encoderinfo.get("xmp", "")
method = im.encoderinfo.get("method", 4)
exact = 1 if im.encoderinfo.get("exact") else 0
if im.mode not in _VALID_WEBP_LEGACY_MODES:
im = im.convert("RGBA" if im.has_transparency_data else "RGB")
data = _webp.WebPEncode(
im.tobytes(),
im.size[0],
im.size[1],
lossless,
float(quality),
im.mode,
icc_profile,
method,
exact,
exif,
xmp,
)
if data is None:
msg = "cannot write file as WebP (encoder returned None)"
raise OSError(msg)
fp.write(data)
Image.register_open(WebPImageFile.format, WebPImageFile, _accept)
if SUPPORTED:
Image.register_save(WebPImageFile.format, _save)
if _webp.HAVE_WEBPANIM:
Image.register_save_all(WebPImageFile.format, _save_all)
Image.register_extension(WebPImageFile.format, ".webp")
Image.register_mime(WebPImageFile.format, "image/webp")