forked from graphicore/multitoner
/
ghostscript_runner.py
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/
ghostscript_runner.py
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#!/usr/bin/python
# -*- coding: utf-8 -*-
# Copyright © 2013 by Lasse Fister <commander@graphicore.de>
#
# This file is part of Multitoner.
#
# Multitoner is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Multitoner is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from __future__ import print_function, unicode_literals
import sys
import ctypes as c
try:
# python 2
from cStringIO import StringIO
except ImportError:
# python 3
from io import BytesIO as StringIO
import ghostscript._gsprint as gs
__all__ = ['GhostscriptError', 'GhostScriptRunner']
GhostscriptError = gs.GhostscriptError
class GhostScriptRunner(object):
""" Render a string of PostScript (better EPS) to a ctypes buffer"""
def __init__(self):
self.args = None
self._args = ['-dEPSCrop']
self.instance = gs.new_instance()
self.stdin = self.width = self.height = self.rgbbuf = self.result \
= self.buf = self.rowstride = None
# need to keep a reference of this stuff around
self._references = {
'stdin': gs.c_stdstream_call_t(self._gsdll_stdin),
'stdout': gs.c_stdstream_call_t(self._gsdll_stdout),
'stderr': gs.c_stdstream_call_t(self._gsdll_stderr),
'display': gs.Display_callback_s(
c.c_int(c.sizeof(gs.Display_callback_s)),
c.c_int(gs.DISPLAY_VERSION_MAJOR),
c.c_int(gs.DISPLAY_VERSION_MINOR),
gs.c_display_open(self.display_open),
gs.c_display_preclose(self.display_preclose),
gs.c_display_close(self.display_close),
gs.c_display_presize(self.display_presize),
gs.c_display_size(self.display_size),
gs.c_display_sync(self.display_sync),
gs.c_display_page(self.display_page),
c.cast(None, gs.c_display_update),
c.cast(None, gs.c_display_memalloc), # NULL, /* memalloc */
c.cast(None, gs.c_display_memfree), # NULL, /* memfree */
c.cast(None, gs.c_display_separation)
)
}
gs.set_stdio(self.instance, self._references['stdin'],
self._references['stdout'], self._references['stderr'])
gs.set_display_callback(self.instance, c.byref(self._references['display']))
def cleanup(self):
""" Purge the ghostscript instance """
gs.delete_instance(self.instance)
self.instance = None
def run(self, eps):
""" Render the string in eps to a buffer in a format suitable for
Cairo surfaces. Return a tuple: (width, height, rowstride, ctypes string buffer)
"""
CAIRO_FORMAT_RGB24 = gs.DISPLAY_COLORS_RGB | gs.DISPLAY_UNUSED_LAST | \
gs.DISPLAY_DEPTH_8 | gs.DISPLAY_LITTLEENDIAN
dformat = "-dDisplayFormat=%d" % \
( CAIRO_FORMAT_RGB24 | gs.DISPLAY_TOPFIRST )
self.stdin = StringIO(eps)
userArgs = self.args or self._args
#"-sDisplayHandle=123456"
args = ['-ignored-', dformat, '-sDEVICE=display', '-r72x72', '-q'] \
+ userArgs + ['-_']
try:
gs.init_with_args(self.instance, args)
except Exception:
# re-raise always
raise
finally:
gs.exit(self.instance)
result = self.result
self.stdin = self.width = self.height = self.result = self.buf \
= self.rowstride = None
return result
def _gsdll_stdin(self, instance, dest, count):
try:
data = self.stdin.read(count)
except Exception:
count = -1
else:
if not data:
count = 0
else:
count = len(data)
c.memmove(dest, c.c_char_p(data), count)
return count
def _gsdll_stdout(self, instance, data, length):
message = data[:length]
if str is not bytes:
message = message.decode('utf-8')
sys.stdout.write(message)
sys.stdout.flush()
return length
def _gsdll_stderr(self, instance, data, length):
message = data[:length]
if str is not bytes:
message = message.decode('utf-8')
sys.stderr.write(message)
sys.stderr.flush()
return length
def display_open(self, handle, device):
return 0
def display_preclose(self, handle, device):
return 0
def display_close(self, handle, device):
return 0
def display_presize(self, handle, device, width, height, raster, format):
return 0
def display_size(self, handle, device, width, height, raster, format, pimage):
self.width = width
self.height = height
self.rowstride = raster
self.buf = pimage
return 0
def display_sync(self, handle, device):
return 0
def display_page(self, handle, device, copies, flush):
buffer_size = self.rowstride * self.height
rgbbuf = c.create_string_buffer(buffer_size)
c.memmove(rgbbuf, self.buf, buffer_size)
self.result = (self.width, self.height, self.rowstride, rgbbuf)
return 0