from __future__ import annotations
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: bytes) -> bool | str:
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
return False
[docs]
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()
[docs]
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 {}
[docs]
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
[docs]
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()
[docs]
def load_seek(self, pos):
pass
[docs]
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)
alpha_quality = im.encoderinfo.get("alpha_quality", 100)
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,
alpha_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, alpha_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)
alpha_quality = im.encoderinfo.get("alpha_quality", 100)
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),
float(alpha_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")