PIL.PSDraw 源代码
#
# The Python Imaging Library
# $Id$
#
# Simple PostScript graphics interface
#
# History:
# 1996-04-20 fl Created
# 1999-01-10 fl Added gsave/grestore to image method
# 2005-05-04 fl Fixed floating point issue in image (from Eric Etheridge)
#
# Copyright (c) 1997-2005 by Secret Labs AB. All rights reserved.
# Copyright (c) 1996 by Fredrik Lundh.
#
# See the README file for information on usage and redistribution.
#
import sys
from . import EpsImagePlugin
##
# Simple PostScript graphics interface.
[文档]class PSDraw:
"""
Sets up printing to the given file. If ``fp`` is omitted,
``sys.stdout.buffer`` or ``sys.stdout`` is assumed.
"""
def __init__(self, fp=None):
if not fp:
try:
fp = sys.stdout.buffer
except AttributeError:
fp = sys.stdout
self.fp = fp
[文档] def begin_document(self, id=None):
"""Set up printing of a document. (Write PostScript DSC header.)"""
# FIXME: incomplete
self.fp.write(
b"%!PS-Adobe-3.0\n"
b"save\n"
b"/showpage { } def\n"
b"%%EndComments\n"
b"%%BeginDocument\n"
)
# self.fp.write(ERROR_PS) # debugging!
self.fp.write(EDROFF_PS)
self.fp.write(VDI_PS)
self.fp.write(b"%%EndProlog\n")
self.isofont = {}
[文档] def end_document(self):
"""Ends printing. (Write PostScript DSC footer.)"""
self.fp.write(b"%%EndDocument\nrestore showpage\n%%End\n")
if hasattr(self.fp, "flush"):
self.fp.flush()
[文档] def setfont(self, font, size):
"""
Selects which font to use.
:param font: A PostScript font name
:param size: Size in points.
"""
font = bytes(font, "UTF-8")
if font not in self.isofont:
# reencode font
self.fp.write(b"/PSDraw-%s ISOLatin1Encoding /%s E\n" % (font, font))
self.isofont[font] = 1
# rough
self.fp.write(b"/F0 %d /PSDraw-%s F\n" % (size, font))
[文档] def line(self, xy0, xy1):
"""
Draws a line between the two points. Coordinates are given in
PostScript point coordinates (72 points per inch, (0, 0) is the lower
left corner of the page).
"""
self.fp.write(b"%d %d %d %d Vl\n" % (*xy0, *xy1))
[文档] def rectangle(self, box):
"""
Draws a rectangle.
:param box: A 4-tuple of integers whose order and function is currently
undocumented.
Hint: the tuple is passed into this format string:
.. code-block:: python
%d %d M %d %d 0 Vr\n
"""
self.fp.write(b"%d %d M %d %d 0 Vr\n" % box)
[文档] def text(self, xy, text):
"""
Draws text at the given position. You must use
:py:meth:`~PIL.PSDraw.PSDraw.setfont` before calling this method.
"""
text = bytes(text, "UTF-8")
text = b"\\(".join(text.split(b"("))
text = b"\\)".join(text.split(b")"))
xy += (text,)
self.fp.write(b"%d %d M (%s) S\n" % xy)
[文档] def image(self, box, im, dpi=None):
"""Draw a PIL image, centered in the given box."""
# default resolution depends on mode
if not dpi:
if im.mode == "1":
dpi = 200 # fax
else:
dpi = 100 # greyscale
# image size (on paper)
x = im.size[0] * 72 / dpi
y = im.size[1] * 72 / dpi
# max allowed size
xmax = float(box[2] - box[0])
ymax = float(box[3] - box[1])
if x > xmax:
y = y * xmax / x
x = xmax
if y > ymax:
x = x * ymax / y
y = ymax
dx = (xmax - x) / 2 + box[0]
dy = (ymax - y) / 2 + box[1]
self.fp.write(b"gsave\n%f %f translate\n" % (dx, dy))
if (x, y) != im.size:
# EpsImagePlugin._save prints the image at (0,0,xsize,ysize)
sx = x / im.size[0]
sy = y / im.size[1]
self.fp.write(b"%f %f scale\n" % (sx, sy))
EpsImagePlugin._save(im, self.fp, None, 0)
self.fp.write(b"\ngrestore\n")
# --------------------------------------------------------------------
# PostScript driver
#
# EDROFF.PS -- PostScript driver for Edroff 2
#
# History:
# 94-01-25 fl: created (edroff 2.04)
#
# Copyright (c) Fredrik Lundh 1994.
#
EDROFF_PS = b"""\
/S { show } bind def
/P { moveto show } bind def
/M { moveto } bind def
/X { 0 rmoveto } bind def
/Y { 0 exch rmoveto } bind def
/E { findfont
dup maxlength dict begin
{
1 index /FID ne { def } { pop pop } ifelse
} forall
/Encoding exch def
dup /FontName exch def
currentdict end definefont pop
} bind def
/F { findfont exch scalefont dup setfont
[ exch /setfont cvx ] cvx bind def
} bind def
"""
#
# VDI.PS -- PostScript driver for VDI meta commands
#
# History:
# 94-01-25 fl: created (edroff 2.04)
#
# Copyright (c) Fredrik Lundh 1994.
#
VDI_PS = b"""\
/Vm { moveto } bind def
/Va { newpath arcn stroke } bind def
/Vl { moveto lineto stroke } bind def
/Vc { newpath 0 360 arc closepath } bind def
/Vr { exch dup 0 rlineto
exch dup neg 0 exch rlineto
exch neg 0 rlineto
0 exch rlineto
100 div setgray fill 0 setgray } bind def
/Tm matrix def
/Ve { Tm currentmatrix pop
translate scale newpath 0 0 .5 0 360 arc closepath
Tm setmatrix
} bind def
/Vf { currentgray exch setgray fill setgray } bind def
"""
#
# ERROR.PS -- Error handler
#
# History:
# 89-11-21 fl: created (pslist 1.10)
#
ERROR_PS = b"""\
/landscape false def
/errorBUF 200 string def
/errorNL { currentpoint 10 sub exch pop 72 exch moveto } def
errordict begin /handleerror {
initmatrix /Courier findfont 10 scalefont setfont
newpath 72 720 moveto $error begin /newerror false def
(PostScript Error) show errorNL errorNL
(Error: ) show
/errorname load errorBUF cvs show errorNL errorNL
(Command: ) show
/command load dup type /stringtype ne { errorBUF cvs } if show
errorNL errorNL
(VMstatus: ) show
vmstatus errorBUF cvs show ( bytes available, ) show
errorBUF cvs show ( bytes used at level ) show
errorBUF cvs show errorNL errorNL
(Operand stargck: ) show errorNL /ostargck load {
dup type /stringtype ne { errorBUF cvs } if 72 0 rmoveto show errorNL
} forall errorNL
(Execution stargck: ) show errorNL /estargck load {
dup type /stringtype ne { errorBUF cvs } if 72 0 rmoveto show errorNL
} forall
end showpage
} def end
"""
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