# # The Python Imaging Library # $Id$ # # JPEG2000 file handling # # History: # 2014-03-12 ajh Created # # Copyright (c) 2014 Coriolis Systems Limited # Copyright (c) 2014 Alastair Houghton # # See the README file for information on usage and redistribution. # import io import os import struct from . import Image, ImageFile def _parse_codestream(fp): """Parse the JPEG 2000 codestream to extract the size and component count from the SIZ marker segment, returning a PIL (size, mode) tuple.""" hdr = fp.read(2) lsiz = struct.unpack(">H", hdr)[0] siz = hdr + fp.read(lsiz - 2) lsiz, rsiz, xsiz, ysiz, xosiz, yosiz, _, _, _, _, csiz = struct.unpack_from( ">HHIIIIIIIIH", siz ) ssiz = [None] * csiz xrsiz = [None] * csiz yrsiz = [None] * csiz for i in range(csiz): ssiz[i], xrsiz[i], yrsiz[i] = struct.unpack_from(">BBB", siz, 36 + 3 * i) size = (xsiz - xosiz, ysiz - yosiz) if csiz == 1: if (yrsiz[0] & 0x7F) > 8: mode = "I;16" else: mode = "L" elif csiz == 2: mode = "LA" elif csiz == 3: mode = "RGB" elif csiz == 4: mode = "RGBA" else: mode = None return (size, mode) def _parse_jp2_header(fp): """Parse the JP2 header box to extract size, component count and color space information, returning a (size, mode, mimetype) tuple.""" # Find the JP2 header box header = None mimetype = None while True: lbox, tbox = struct.unpack(">I4s", fp.read(8)) if lbox == 1: lbox = struct.unpack(">Q", fp.read(8))[0] hlen = 16 else: hlen = 8 if lbox < hlen: raise SyntaxError("Invalid JP2 header length") if tbox == b"jp2h": header = fp.read(lbox - hlen) break elif tbox == b"ftyp": if fp.read(4) == b"jpx ": mimetype = "image/jpx" fp.seek(lbox - hlen - 4, os.SEEK_CUR) else: fp.seek(lbox - hlen, os.SEEK_CUR) if header is None: raise SyntaxError("could not find JP2 header") size = None mode = None bpc = None nc = None hio = io.BytesIO(header) while True: lbox, tbox = struct.unpack(">I4s", hio.read(8)) if lbox == 1: lbox = struct.unpack(">Q", hio.read(8))[0] hlen = 16 else: hlen = 8 content = hio.read(lbox - hlen) if tbox == b"ihdr": height, width, nc, bpc, c, unkc, ipr = struct.unpack(">IIHBBBB", content) size = (width, height) if unkc: if nc == 1 and (bpc & 0x7F) > 8: mode = "I;16" elif nc == 1: mode = "L" elif nc == 2: mode = "LA" elif nc == 3: mode = "RGB" elif nc == 4: mode = "RGBA" break elif tbox == b"colr": meth, prec, approx = struct.unpack_from(">BBB", content) if meth == 1: cs = struct.unpack_from(">I", content, 3)[0] if cs == 16: # sRGB if nc == 1 and (bpc & 0x7F) > 8: mode = "I;16" elif nc == 1: mode = "L" elif nc == 3: mode = "RGB" elif nc == 4: mode = "RGBA" break elif cs == 17: # grayscale if nc == 1 and (bpc & 0x7F) > 8: mode = "I;16" elif nc == 1: mode = "L" elif nc == 2: mode = "LA" break elif cs == 18: # sYCC if nc == 3: mode = "RGB" elif nc == 4: mode = "RGBA" break if size is None or mode is None: raise SyntaxError("Malformed jp2 header") return (size, mode, mimetype) ## # Image plugin for JPEG2000 images. class Jpeg2KImageFile(ImageFile.ImageFile): format = "JPEG2000" format_description = "JPEG 2000 (ISO 15444)" def _open(self): sig = self.fp.read(4) if sig == b"\xff\x4f\xff\x51": self.codec = "j2k" self._size, self.mode = _parse_codestream(self.fp) else: sig = sig + self.fp.read(8) if sig == b"\x00\x00\x00\x0cjP \x0d\x0a\x87\x0a": self.codec = "jp2" header = _parse_jp2_header(self.fp) self._size, self.mode, self.custom_mimetype = header else: raise SyntaxError("not a JPEG 2000 file") if self.size is None or self.mode is None: raise SyntaxError("unable to determine size/mode") self.reduce = 0 self.layers = 0 fd = -1 length = -1 try: fd = self.fp.fileno() length = os.fstat(fd).st_size except Exception: fd = -1 try: pos = self.fp.tell() self.fp.seek(0, io.SEEK_END) length = self.fp.tell() self.fp.seek(pos) except Exception: length = -1 self.tile = [ ( "jpeg2k", (0, 0) + self.size, 0, (self.codec, self.reduce, self.layers, fd, length), ) ] def load(self): if self.reduce: power = 1 << self.reduce adjust = power >> 1 self._size = ( int((self.size[0] + adjust) / power), int((self.size[1] + adjust) / power), ) if self.tile: # Update the reduce and layers settings t = self.tile[0] t3 = (t[3][0], self.reduce, self.layers, t[3][3], t[3][4]) self.tile = [(t[0], (0, 0) + self.size, t[2], t3)] return ImageFile.ImageFile.load(self) def _accept(prefix): return ( prefix[:4] == b"\xff\x4f\xff\x51" or prefix[:12] == b"\x00\x00\x00\x0cjP \x0d\x0a\x87\x0a" ) # ------------------------------------------------------------ # Save support def _save(im, fp, filename): if filename.endswith(".j2k"): kind = "j2k" else: kind = "jp2" # Get the keyword arguments info = im.encoderinfo offset = info.get("offset", None) tile_offset = info.get("tile_offset", None) tile_size = info.get("tile_size", None) quality_mode = info.get("quality_mode", "rates") quality_layers = info.get("quality_layers", None) if quality_layers is not None and not ( isinstance(quality_layers, (list, tuple)) and all( [ isinstance(quality_layer, (int, float)) for quality_layer in quality_layers ] ) ): raise ValueError("quality_layers must be a sequence of numbers") num_resolutions = info.get("num_resolutions", 0) cblk_size = info.get("codeblock_size", None) precinct_size = info.get("precinct_size", None) irreversible = info.get("irreversible", False) progression = info.get("progression", "LRCP") cinema_mode = info.get("cinema_mode", "no") fd = -1 if hasattr(fp, "fileno"): try: fd = fp.fileno() except Exception: fd = -1 im.encoderconfig = ( offset, tile_offset, tile_size, quality_mode, quality_layers, num_resolutions, cblk_size, precinct_size, irreversible, progression, cinema_mode, fd, ) ImageFile._save(im, fp, [("jpeg2k", (0, 0) + im.size, 0, kind)]) # ------------------------------------------------------------ # Registry stuff Image.register_open(Jpeg2KImageFile.format, Jpeg2KImageFile, _accept) Image.register_save(Jpeg2KImageFile.format, _save) Image.register_extensions( Jpeg2KImageFile.format, [".jp2", ".j2k", ".jpc", ".jpf", ".jpx", ".j2c"] ) Image.register_mime(Jpeg2KImageFile.format, "image/jp2")