Pillow/src/PIL/WebPImagePlugin.py
Jon Dufresne d50445ff30 Introduce isort to automate import ordering and formatting
Similar to the recent adoption of Black. isort is a Python utility to
sort imports alphabetically and automatically separate into sections. By
using isort, contributors can quickly and automatically conform to the
projects style without thinking. Just let the tool do it.

Uses the configuration recommended by the Black to avoid conflicts of
style.

Rewrite TestImageQt.test_deprecated to no rely on import order.
2019-07-06 16:11:35 -07:00

361 lines
11 KiB
Python

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"
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
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.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)
self.seek(0)
def _getexif(self):
if "exif" not in self.info:
return None
return dict(self.getexif())
@property
def n_frames(self):
return self._n_frames
@property
def is_animated(self):
return self._n_frames > 1
def seek(self, frame):
if not _webp.HAVE_WEBPANIM:
return super(WebPImageFile, self).seek(frame)
# Perform some simple checks first
if frame >= self._n_frames:
raise EOFError("attempted to seek beyond end of sequence")
if frame < 0:
raise EOFError("negative frame index is not valid")
# 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)
raise EOFError("failed to decode next frame in WebP file")
# 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(WebPImageFile, self).load()
def tell(self):
if not _webp.HAVE_WEBPANIM:
return super(WebPImageFile, self).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, 0)
duration = im.encoderinfo.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", "")
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(v >= 0 and v < 256 for v in background)
):
raise IOError(
"Background color is not an RGBA tuple clamped to (0-255): %s"
% str(background)
)
# 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),
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, timestamp, 0, 0, "", lossless, quality, 0)
# Get the final output from the encoder
data = enc.assemble(icc_profile, exif, xmp)
if data is None:
raise IOError("cannot write file as WebP (encoder returned None)")
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", "")
exif = im.encoderinfo.get("exif", "")
if isinstance(exif, Image.Exif):
exif = exif.tobytes()
xmp = im.encoderinfo.get("xmp", "")
if im.mode not in _VALID_WEBP_LEGACY_MODES:
alpha = (
"A" in im.mode
or "a" in im.mode
or (im.mode == "P" and "A" in im.im.getpalettemode())
)
im = im.convert("RGBA" if alpha else "RGB")
data = _webp.WebPEncode(
im.tobytes(),
im.size[0],
im.size[1],
lossless,
float(quality),
im.mode,
icc_profile,
exif,
xmp,
)
if data is None:
raise IOError("cannot write file as WebP (encoder returned None)")
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")