Pillow/PIL/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.
#

__version__ = "0.5"

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

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

i32 = _binary.i32le
o32 = _binary.o32le

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

gs_windows_binary = None
import sys
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 dependend 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 tempfile, os, subprocess

    out_fd, outfile = tempfile.mkstemp()
    os.close(out_fd)
    in_fd, infile = tempfile.mkstemp()
    os.close(in_fd)
    
    # ignore length and offset!
    # ghostscript can read it   
    # copy whole file to read in ghostscript
    with open(infile, '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
            length -= 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 -dSAFER",         # don't pause between pages, 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)
            os.unlink(infile)
        except: pass
    
    return im


class PSFile:
    """Wrapper that treats either CR or LF as end of line."""
    def __init__(self, fp):
        self.fp = fp
        self.char = None
    def __getattr__(self, id):
        v = getattr(self.fp, id)
        setattr(self, id, v)
        return v
    def seek(self, offset, whence=0):
        self.char = None
        self.fp.seek(offset, whence)
    def read(self, count):
        return self.fp.read(count).decode('latin-1')
    def readbinary(self, count):
        return self.fp.read(count)
    def tell(self):
        pos = self.fp.tell()
        if self.char:
            pos -= 1
        return pos
    def readline(self):
        s = b""
        if self.char:
            c = self.char
            self.char = None
        else:
            c = self.fp.read(1)
        while c not in b"\r\n":
            s = s + c
            c = self.fp.read(1)
        if c == b"\r":
            self.char = self.fp.read(1)
            if self.char == b"\n":
                self.char = None
        return s.decode('latin-1') + "\n"

class PSFpWrapper:
    """ Wrapper for a filepointer that has been opened in universal mode """
    def __init__(self,fp):
        self.fp = fp

    def __getattr__(self, attr):
        """ Delegate everything that we're not wrapping """
        return getattr(self.fp, attr)

    def read(self, count):
        return self.fp.read(count)

    readbinary = read


def _accept(prefix):
    return prefix[:4] == b"%!PS" or 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"

    def _open(self):

        try:
            fp = PSFpWrapper(open(self.fp.name, "Ur", 'latin-1'))
        except:
            print ("fallback to psfile")
            fp = PSFile(self.fp)

        # FIX for: Some EPS file not handled correctly / issue #302 
        # EPS can contain binary data
        # or start directly with latin coding
        # read header in both ways to handle both
        # file types
        # more info see http://partners.adobe.com/public/developer/en/ps/5002.EPSF_Spec.pdf
        
        # for HEAD without binary preview
        s = fp.read(4)
        # for HEAD with binary preview
        fp.seek(0)
        sb = fp.readbinary(160)

        if s[:4] == "%!PS":
            fp.seek(0, 2)
            length = fp.tell()
            offset = 0
        elif i32(sb[0:4]) == 0xC6D3D0C5:
            offset = i32(sb[4:8])
            length = i32(sb[8:12])
        else:
            raise SyntaxError("not an EPS file")

        # 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()
        
        while s:

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

            if s[-2:] == '\r\n':
                s = s[:-2]
            elif s[-1:] == '\n':
                s = s[:-1]

            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(s)) for s 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[0:1] == '%':
                    # handle non-DSC Postscript comments that some
                    # tools mistakenly put in the Comments section
                    pass
                else:
                    raise IOError("bad EPS header")

            s = fp.readline()

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


        #
        # Scan for an "ImageData" descriptor

        while s[0] == "%":

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

            if s[-2:] == '\r\n':
                s = s[:-2]
            elif s[-1:] == '\n':
                s = s[:-1]

            if s[:11] == "%ImageData:":

                [x, y, bi, mo, z3, z4, en, id] =\
                    s[11:].split(None, 7)

                x = int(x); y = int(y)

                bi = int(bi)
                mo = int(mo)

                en = int(en)

                if en == 1:
                    decoder = "eps_binary"
                elif en == 2:
                    decoder = "eps_hex"
                else:
                    break
                if bi != 8:
                    break
                if mo == 1:
                    self.mode = "L"
                elif mo == 2:
                    self.mode = "LAB"
                elif mo == 3:
                    self.mode = "RGB"
                else:
                    break

                if id[:1] == id[-1:] == '"':
                    id = id[1:-1]

                # Scan forward to the actual image data
                while True:
                    s = fp.readline()
                    if not s:
                        break
                    if s[:len(id)] == id:
                        self.size = x, y
                        self.tile2 = [(decoder,
                                       (0, 0, x, y),
                                       fp.tell(),
                                       0)]
                        return

            s = fp.readline()
            if not s:
                break

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

    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:
        def __init__(self, fp):
            self.fp = fp
        def __getattr__(self, name):
            return getattr(self.fp, name)
        def close(self):
            pass

    base_fp = fp
    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")
    fp.flush()

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

    fp.write("\n%%%%EndBinary\n")
    fp.write("grestore end\n")
    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")