# # 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. # from PIL import Image, ImageFile import struct import os import io __version__ = "0.1" 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, xtsiz, ytsiz, \ xtosiz, ytosiz, csiz \ = struct.unpack('>HHIIIIIIIIH', siz[:38]) ssiz = [None]*csiz xrsiz = [None]*csiz yrsiz = [None]*csiz for i in range(csiz): ssiz[i], xrsiz[i], yrsiz[i] \ = struct.unpack('>BBB', siz[36 + 3 * i:39 + 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 PIL (size, mode) tuple.""" # Find the JP2 header box header = 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 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('>BBB', content[:3]) if meth == 1: cs = struct.unpack('>I', content[3:7])[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) ## # 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" self.size, self.mode = _parse_jp2_header(self.fp) 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: fd = -1 try: pos = self.fp.tell() self.fp.seek(0, 2) length = self.fp.tell() self.fp.seek(pos, 0) except: length = -1 self.tile = [('jpeg2k', (0, 0) + self.size, 0, (self.codec, self.reduce, self.layers, fd, length, self.fp))] 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)] 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) 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: 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_extension(Jpeg2KImageFile.format, '.jp2') Image.register_extension(Jpeg2KImageFile.format, '.j2k') Image.register_extension(Jpeg2KImageFile.format, '.jpc') Image.register_extension(Jpeg2KImageFile.format, '.jpf') Image.register_extension(Jpeg2KImageFile.format, '.jpx') Image.register_extension(Jpeg2KImageFile.format, '.j2c') Image.register_mime(Jpeg2KImageFile.format, 'image/jp2') Image.register_mime(Jpeg2KImageFile.format, 'image/jpx')