Source code for PIL.WebPImagePlugin

from . import Image, ImageFile
try:
    from . import _webp
    SUPPORTED = True
except ImportError as e:
    SUPPORTED = False
from io import BytesIO


_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


[docs]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): from .JpegImagePlugin import _getexif return _getexif(self) @property def n_frames(self): return self._n_frames @property def is_animated(self): return self._n_frames > 1
[docs] 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
[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: self.fp.close() self.fp = BytesIO(data) self.tile = [("raw", (0, 0) + self.size, 0, self.rawmode)] return super(WebPImageFile, self).load()
[docs] 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 += 1 if not hasattr(ims, "n_frames") else ims.n_frames if total == 1: _save(im, fp, filename) return background = encoderinfo.get("background", (0, 0, 0, 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", "") 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 if not hasattr(ims, "n_frames"): nfr = 1 else: nfr = ims.n_frames 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", "") 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")