EpsImagePlugin.py

#
# The Python Imaging Library.
# $Id$
#
# EPS file handling
#
# History:
# 1995-09-01 fl   Created (0.1)
# 1996-05-18 fl   Don't choke on "atend" fields, Ghostscript interface (0.2)
# 1996-08-22 fl   Don't choke on floating point BoundingBox values
# 1996-08-23 fl   Handle files from Macintosh (0.3)
# 2001-02-17 fl   Use 're' instead of 'regex' (Python 2.1) (0.4)
# 2003-09-07 fl   Check gs.close status (from Federico Di Gregorio) (0.5)
# 2014-05-07 e    Handling of EPS with binary preview and fixed resolution
#                 resizing
#
# Copyright (c) 1997-2003 by Secret Labs AB.
# Copyright (c) 1995-2003 by Fredrik Lundh
#
# See the README file for information on usage and redistribution.
#

import re
import io
import sys
from PIL import Image, ImageFile, _binary

__version__ = "0.5"

#
# --------------------------------------------------------------------

i32 = _binary.i32le
o32 = _binary.o32le

split = re.compile(r"^%%([^:]*):[ \t]*(.*)[ \t]*$")
field = re.compile(r"^%[%!\w]([^:]*)[ \t]*$")

gs_windows_binary = None
if sys.platform.startswith('win'):
    import shutil
    if hasattr(shutil, 'which'):
        which = shutil.which
    else:
        # Python < 3.3
        import distutils.spawn
        which = distutils.spawn.find_executable
    for binary in ('gswin32c', 'gswin64c', 'gs'):
        if which(binary) is not None:
            gs_windows_binary = binary
            break
    else:
        gs_windows_binary = False


def has_ghostscript():
    if gs_windows_binary:
        return True
    if not sys.platform.startswith('win'):
        import subprocess
        try:
            gs = subprocess.Popen(['gs', '--version'], stdout=subprocess.PIPE)
            gs.stdout.read()
            return True
        except OSError:
            # no ghostscript
            pass
    return False


def Ghostscript(tile, size, fp, scale=1):
    """Render an image using Ghostscript"""

    # Unpack decoder tile
    decoder, tile, offset, data = tile[0]
    length, bbox = data

    # Hack to support hi-res rendering
    scale = int(scale) or 1
    # orig_size = size
    # orig_bbox = bbox
    size = (size[0] * scale, size[1] * scale)
    # resolution is dependent on bbox and size
    res = (float((72.0 * size[0]) / (bbox[2]-bbox[0])),
           float((72.0 * size[1]) / (bbox[3]-bbox[1])))
    # print("Ghostscript", scale, size, orig_size, bbox, orig_bbox, res)

    import os
    import subprocess
    import tempfile

    out_fd, outfile = tempfile.mkstemp()
    os.close(out_fd)

    infile_temp = None
    if hasattr(fp, 'name') and os.path.exists(fp.name):
        infile = fp.name
    else:
        in_fd, infile_temp = tempfile.mkstemp()
        os.close(in_fd)
        infile = infile_temp

        # ignore length and offset!
        # ghostscript can read it
        # copy whole file to read in ghostscript
        with open(infile_temp, 'wb') as f:
            # fetch length of fp
            fp.seek(0, 2)
            fsize = fp.tell()
            # ensure start position
            # go back
            fp.seek(0)
            lengthfile = fsize
            while lengthfile > 0:
                s = fp.read(min(lengthfile, 100*1024))
                if not s:
                    break
                lengthfile -= len(s)
                f.write(s)

    # Build ghostscript command
    command = ["gs",
               "-q",                         # quiet mode
               "-g%dx%d" % size,             # set output geometry (pixels)
               "-r%fx%f" % res,              # set input DPI (dots per inch)
               "-dNOPAUSE",                  # don't pause between pages,
               "-dSAFER",                    # safe mode
               "-sDEVICE=ppmraw",            # ppm driver
               "-sOutputFile=%s" % outfile,  # output file
               "-c", "%d %d translate" % (-bbox[0], -bbox[1]),
                                             # adjust for image origin
               "-f", infile,                 # input file
               ]

    if gs_windows_binary is not None:
        if not gs_windows_binary:
            raise WindowsError('Unable to locate Ghostscript on paths')
        command[0] = gs_windows_binary

    # push data through ghostscript
    try:
        gs = subprocess.Popen(command, stdin=subprocess.PIPE,
                              stdout=subprocess.PIPE)
        gs.stdin.close()
        status = gs.wait()
        if status:
            raise IOError("gs failed (status %d)" % status)
        im = Image.core.open_ppm(outfile)
    finally:
        try:
            os.unlink(outfile)
            if infile_temp:
                os.unlink(infile_temp)
        except OSError:
            pass

    return im


class PSFile(object):
    """
    Wrapper for bytesio object that treats either CR or LF as end of line.
    """
    def __init__(self, fp):
        self.fp = fp
        self.char = None

    def seek(self, offset, whence=0):
        self.char = None
        self.fp.seek(offset, whence)

    def readline(self):
        s = self.char or b""
        self.char = None

        c = self.fp.read(1)
        while c not in b"\r\n":
            s = s + c
            c = self.fp.read(1)

        self.char = self.fp.read(1)
        # line endings can be 1 or 2 of \r \n, in either order
        if self.char in b"\r\n":
            self.char = None

        return s.decode('latin-1')


def _accept(prefix):
    return prefix[:4] == b"%!PS" or \
           (len(prefix) >= 4 and i32(prefix) == 0xC6D3D0C5)

##
# Image plugin for Encapsulated Postscript.  This plugin supports only
# a few variants of this format.


class EpsImageFile(ImageFile.ImageFile):
    """EPS File Parser for the Python Imaging Library"""

    format = "EPS"
    format_description = "Encapsulated Postscript"

    mode_map = {1: "L", 2: "LAB", 3: "RGB"}

    def _open(self):
        (length, offset) = self._find_offset(self.fp)

        # Rewrap the open file pointer in something that will
        # convert line endings and decode to latin-1.
        try:
            if bytes is str:
                # Python2, no encoding conversion necessary
                fp = open(self.fp.name, "Ur")
            else:
                # Python3, can use bare open command.
                fp = open(self.fp.name, "Ur", encoding='latin-1')
        except:
            # Expect this for bytesio/stringio
            fp = PSFile(self.fp)

        # go to offset - start of "%!PS"
        fp.seek(offset)

        box = None

        self.mode = "RGB"
        self.size = 1, 1  # FIXME: huh?

        #
        # Load EPS header

        s = fp.readline().strip('\r\n')

        while s:
            if len(s) > 255:
                raise SyntaxError("not an EPS file")

            try:
                m = split.match(s)
            except re.error as v:
                raise SyntaxError("not an EPS file")

            if m:
                k, v = m.group(1, 2)
                self.info[k] = v
                if k == "BoundingBox":
                    try:
                        # Note: The DSC spec says that BoundingBox
                        # fields should be integers, but some drivers
                        # put floating point values there anyway.
                        box = [int(float(i)) for i in v.split()]
                        self.size = box[2] - box[0], box[3] - box[1]
                        self.tile = [("eps", (0, 0) + self.size, offset,
                                      (length, box))]
                    except:
                        pass

            else:
                m = field.match(s)
                if m:
                    k = m.group(1)

                    if k == "EndComments":
                        break
                    if k[:8] == "PS-Adobe":
                        self.info[k[:8]] = k[9:]
                    else:
                        self.info[k] = ""
                elif s[0] == '%':
                    # handle non-DSC Postscript comments that some
                    # tools mistakenly put in the Comments section
                    pass
                else:
                    raise IOError("bad EPS header")

            s = fp.readline().strip('\r\n')

            if s[:1] != "%":
                break

        #
        # Scan for an "ImageData" descriptor

        while s[:1] == "%":

            if len(s) > 255:
                raise SyntaxError("not an EPS file")

            if s[:11] == "%ImageData:":
                # Encoded bitmapped image.
                x, y, bi, mo = s[11:].split(None, 7)[:4]

                if int(bi) != 8:
                    break
                try:
                    self.mode = self.mode_map[int(mo)]
                except ValueError:
                    break

                self.size = int(x), int(y)
                return

            s = fp.readline().strip('\r\n')
            if not s:
                break

        if not box:
            raise IOError("cannot determine EPS bounding box")

    def _find_offset(self, fp):

        s = fp.read(160)

        if s[:4] == b"%!PS":
            # for HEAD without binary preview
            fp.seek(0, 2)
            length = fp.tell()
            offset = 0
        elif i32(s[0:4]) == 0xC6D3D0C5:
            # FIX for: Some EPS file not handled correctly / issue #302
            # EPS can contain binary data
            # or start directly with latin coding
            # more info see:
            # http://partners.adobe.com/public/developer/en/ps/5002.EPSF_Spec.pdf
            offset = i32(s[4:8])
            length = i32(s[8:12])
        else:
            raise SyntaxError("not an EPS file")

        return (length, offset)

    def load(self, scale=1):
        # Load EPS via Ghostscript
        if not self.tile:
            return
        self.im = Ghostscript(self.tile, self.size, self.fp, scale)
        self.mode = self.im.mode
        self.size = self.im.size
        self.tile = []

    def load_seek(self, *args, **kwargs):
        # we can't incrementally load, so force ImageFile.parser to
        # use our custom load method by defining this method.
        pass


#
# --------------------------------------------------------------------

def _save(im, fp, filename, eps=1):
    """EPS Writer for the Python Imaging Library."""

    #
    # make sure image data is available
    im.load()

    #
    # determine postscript image mode
    if im.mode == "L":
        operator = (8, 1, "image")
    elif im.mode == "RGB":
        operator = (8, 3, "false 3 colorimage")
    elif im.mode == "CMYK":
        operator = (8, 4, "false 4 colorimage")
    else:
        raise ValueError("image mode is not supported")

    class NoCloseStream(object):
        def __init__(self, fp):
            self.fp = fp

        def __getattr__(self, name):
            return getattr(self.fp, name)

        def close(self):
            pass

    base_fp = fp
    if fp != sys.stdout:
        fp = NoCloseStream(fp)
        if sys.version_info[0] > 2:
            fp = io.TextIOWrapper(fp, encoding='latin-1')

    if eps:
        #
        # write EPS header
        fp.write("%!PS-Adobe-3.0 EPSF-3.0\n")
        fp.write("%%Creator: PIL 0.1 EpsEncode\n")
        # fp.write("%%CreationDate: %s"...)
        fp.write("%%%%BoundingBox: 0 0 %d %d\n" % im.size)
        fp.write("%%Pages: 1\n")
        fp.write("%%EndComments\n")
        fp.write("%%Page: 1 1\n")
        fp.write("%%ImageData: %d %d " % im.size)
        fp.write("%d %d 0 1 1 \"%s\"\n" % operator)

    #
    # image header
    fp.write("gsave\n")
    fp.write("10 dict begin\n")
    fp.write("/buf %d string def\n" % (im.size[0] * operator[1]))
    fp.write("%d %d scale\n" % im.size)
    fp.write("%d %d 8\n" % im.size)  # <= bits
    fp.write("[%d 0 0 -%d 0 %d]\n" % (im.size[0], im.size[1], im.size[1]))
    fp.write("{ currentfile buf readhexstring pop } bind\n")
    fp.write(operator[2] + "\n")
    if hasattr(fp, "flush"):
        fp.flush()

    ImageFile._save(im, base_fp, [("eps", (0, 0)+im.size, 0, None)])

    fp.write("\n%%%%EndBinary\n")
    fp.write("grestore end\n")
    if hasattr(fp, "flush"):
        fp.flush()

#
# --------------------------------------------------------------------

Image.register_open(EpsImageFile.format, EpsImageFile, _accept)

Image.register_save(EpsImageFile.format, _save)

Image.register_extension(EpsImageFile.format, ".ps")
Image.register_extension(EpsImageFile.format, ".eps")

Image.register_mime(EpsImageFile.format, "application/postscript")