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backend_pdf.py

# -*- coding: iso-8859-1 -*-
"""
A PDF matplotlib backend (not yet complete)
Author: Jouni K Seppänen <jks@iki.fi>
"""
from __future__ import division

import md5
import os
import re
import sys
import time
import zlib

from cStringIO import StringIO
from datetime import datetime
from math import ceil, cos, floor, pi, sin

from matplotlib import __version__, rcParams, agg, get_data_path
from matplotlib._pylab_helpers import Gcf
from matplotlib.backend_bases import RendererBase, GraphicsContextBase,\
     FigureManagerBase, FigureCanvasBase
from matplotlib.cbook import Bunch, enumerate, is_string_like, reverse_dict
from matplotlib.figure import Figure
from matplotlib.font_manager import fontManager
from matplotlib.afm import AFM
from matplotlib.dviread import Dvi
from matplotlib.ft2font import FT2Font, FIXED_WIDTH, ITALIC, LOAD_NO_SCALE
from matplotlib.mathtext import math_parse_s_pdf
from matplotlib.numerix import Float32, UInt8, fromstring, arange, infinity, isnan, asarray
from matplotlib.transforms import Bbox

# Overview
#
# The low-level knowledge about pdf syntax lies mainly in the pdfRepr
# function and the classes Reference, Name, Operator, and Stream.  The
# PdfFile class knows about the overall structure of pdf documents.
# It provides a "write" method for writing arbitrary strings in the
# file, and an "output" method that passes objects through the pdfRepr
# function before writing them in the file.  The output method is
# called by the RendererPdf class, which contains the various draw_foo
# methods.  RendererPdf contains a GraphicsContextPdf instance, and
# each draw_foo calls self.check_gc before outputting commands.  This
# method checks whether the pdf graphics state needs to be modified
# and outputs the necessary commands.  GraphicsContextPdf represents
# the graphics state, and its "delta" method returns the commands that
# modify the state.

# Add "pdf.use14corefonts: True" in your configuration file to use only
# the 14 PDF core fonts. These fonts do not need to be embedded; every 
# PDF viewing application is required to have them. This results in very
# light PDF files you can use directly in LaTeX or ConTeXt documents
# generated with pdfTeX, without any conversion.

# These fonts are: Helvetica, Helvetica-Bold, Helvetica-Oblique, 
# Helvetica-BoldOblique, Courier, Courier-Bold, Courier-Oblique, 
# Courier-BoldOblique, Times-Roman, Times-Bold, Times-Italic, 
# Times-BoldItalic, Symbol, ZapfDingbats.
#
# Some tricky points: 
#
# 1. The clip rectangle (which could in pdf be an arbitrary path, not
# necessarily a rectangle) can only be widened by popping from the
# state stack.  Thus the state must be pushed onto the stack before
# narrowing the rectangle.  This is taken care of by
# GraphicsContextPdf.
#
# 2. Sometimes it is necessary to refer to something (e.g. font,
# image, or extended graphics state, which contains the alpha value)
# in the page stream by a name that needs to be defined outside the
# stream.  PdfFile provides the methods fontName, imageObject, and
# alphaState for this purpose.  The implementations of these methods
# should perhaps be generalized.

# TODOs:
#
# * the alpha channel of images
# * image compression could be improved (PDF supports png-like compression) 
# * encoding of fonts, including mathtext fonts and unicode support
# * Type 1 font support (i.e., "pdf.use_afm") 
# * TTF support has lots of small TODOs, e.g. how do you know if a font  
#   is serif/sans-serif, or symbolic/non-symbolic? 
# * draw_markers, draw_line_collection, etc. 
# * use_tex 

def fill(strings, linelen=75):
    """Make one string from sequence of strings, with whitespace
    in between. The whitespace is chosen to form lines of at most
    linelen characters, if possible."""

    s, strings = [strings[0]], strings[1:]
    while strings:
        if len(s[-1]) + len(strings[0]) < linelen:
            s[-1] += ' ' + strings[0]
        else:
            s.append(strings[0])
        strings = strings[1:]
    return '\n'.join(s)


def pdfRepr(obj):
    """Map Python objects to PDF syntax."""

    # Some objects defined later have their own pdfRepr method.
    if 'pdfRepr' in dir(obj):
        return obj.pdfRepr()

    # Floats. PDF does not have exponential notation (1.0e-10) so we
    # need to use %f with some precision.  Perhaps the precision
    # should adapt to the magnitude of the number?
    elif isinstance(obj, float):
        if isnan(obj) or obj in (-infinity, infinity):
            raise ValueError, "Can only output finite numbers in PDF"
        r = "%.10f" % obj
        return r.rstrip('0').rstrip('.')

    # Integers are written as such.
    elif isinstance(obj, (int, long)):
        return "%d" % obj

    # Strings are written in parentheses, with backslashes and parens
    # escaped. Actually balanced parens are allowed, but it is
    # simpler to escape them all. TODO: cut long strings into lines;
    # I believe there is some maximum line length in PDF.
    elif is_string_like(obj):
        return '(' + re.sub(r'([\\()])', r'\\\1', obj) + ')'

    # Dictionaries. The keys must be PDF names, so if we find strings
    # there, we make Name objects from them. The values may be
    # anything, so the caller must ensure that PDF names are
    # represented as Name objects.
    elif isinstance(obj, dict):
        r = ["<<"]
        r.extend(["%s %s" % (Name(key).pdfRepr(), pdfRepr(val))
                  for key, val in obj.items()])
        r.append(">>")
        return fill(r)

    # Lists.
    elif isinstance(obj, (list, tuple)):
        r = ["["]
        r.extend([pdfRepr(val) for val in obj])
        r.append("]")
        return fill(r)

    # Booleans.
    elif isinstance(obj, bool):
        return ['false', 'true'][obj]

    # The null keyword.
    elif obj is None:
        return 'null'

    # A date.
    elif isinstance(obj, datetime):
        r = obj.strftime('D:%Y%m%d%H%M%S')
        if time.daylight: z = time.altzone
        else: z = time.timezone
        if z == 0: r += 'Z'
        elif z < 0: r += "+%02d'%02d'" % ((-z)//3600, (-z)%3600)
        else: r += "-%02d'%02d'" % (z//3600, z%3600)
        return pdfRepr(r)

    else:
        raise TypeError, \
            "Don't know a PDF representation for %s objects." \
            % type(obj)

00169 class Reference:
    """PDF reference object.
    Use PdfFile.reserveObject() to create References.
    """

    def __init__(self, id):
        self.id = id

    def __repr__(self):
        return "<Reference %d>" % self.id

    def pdfRepr(self):
        return "%d 0 R" % self.id

    def write(self, contents, file):
        write = file.write
        write("%d 0 obj\n" % self.id)
        write(pdfRepr(contents))
        write("\nendobj\n")

00189 class Name:
    """PDF name object."""

    def __init__(self, name):
        if isinstance(name, Name):
            self.name = name.name
        else:
            self.name = re.sub(r'[^!-~]', Name.hexify, name)

    def __repr__(self):
        return "<Name %s>" % self.name

    def hexify(match):
        return '#%02x' % ord(match.group())
    hexify = staticmethod(hexify)

    def pdfRepr(self):
        return '/' + self.name

00208 class Operator:
    """PDF operator object."""

    def __init__(self, op):
        self.op = op

    def __repr__(self):
        return '<Operator %s>' % self.op

    def pdfRepr(self):
        return self.op

# PDF operators (not an exhaustive list)
_pdfops = dict(close_fill_stroke='b', fill_stroke='B', fill='f',
               closepath='h', close_stroke='s', stroke='S', endpath='n',
               begin_text='BT', end_text='ET',
               curveto='c', rectangle='re', lineto='l', moveto='m',
               concat_matrix='cm',
               use_xobject='Do',
               setgray_stroke='G', setgray_nonstroke='g',
               setrgb_stroke='RG', setrgb_nonstroke='rg',
               setcolorspace_stroke='CS', setcolorspace_nonstroke='cs',
               setcolor_stroke='SCN', setcolor_nonstroke='scn',
               setdash='d', setlinejoin='j', setlinecap='J', setgstate='gs',
               gsave='q', grestore='Q',
               textpos='Td', selectfont='Tf', textmatrix='Tm',
               show='Tj', showkern='TJ',
               setlinewidth='w', clip='W')

Op = Bunch(**dict([(name, Operator(value)) 
                   for name, value in _pdfops.items()]))

00240 class Stream:
    """PDF stream object.

    This has no pdfRepr method. Instead, call begin(), then output the
    contents of the stream by calling write(), and finally call end().
    """

00247     def __init__(self, id, len, file, extra=None):
        """id: object id of stream; len: an unused Reference object for the
        length of the stream, or None (to use a memory buffer); file:
        a PdfFile; extra: a dictionary of extra key-value pairs to
        include in the stream header """
        self.id = id            # object id
        self.len = len          # id of length object
        self.pdfFile = file
        self.file = file.fh     # file to which the stream is written
        self.compressobj = None # compression object
        if extra is None: self.extra = dict()
        else: self.extra = extra

        self.pdfFile.recordXref(self.id)
        if rcParams['pdf.compression']:
            self.compressobj = zlib.compressobj(rcParams['pdf.compression'])
        if self.len is None:
            self.file = StringIO()
        else: 
            self._writeHeader()
            self.pos = self.file.tell()

    def _writeHeader(self):
        write = self.file.write
        write("%d 0 obj\n" % self.id)
        dict = self.extra
        dict['Length'] = self.len
        if rcParams['pdf.compression']:
            dict['Filter'] = Name('FlateDecode')

        write(pdfRepr(dict))
        write("\nstream\n")

00280     def end(self):
        """Finalize stream."""

        self._flush()
        if self.len is None:
            contents = self.file.getvalue()
            self.len = len(contents)
            self.file = self.pdfFile.fh
            self._writeHeader()
            self.file.write(contents)
            self.file.write("\nendstream\nendobj\n")
        else:
            length = self.file.tell() - self.pos
            self.file.write("\nendstream\nendobj\n")
            self.pdfFile.writeObject(self.len, length)

00296     def write(self, data):
        """Write some data on the stream."""

        if self.compressobj is None:
            self.file.write(data)
        else:
            compressed = self.compressobj.compress(data)
            self.file.write(compressed)

00305     def _flush(self):
        """Flush the compression object."""

        if self.compressobj is not None:
            compressed = self.compressobj.flush()
            self.file.write(compressed)
            self.compressobj = None

00313 class PdfFile:
    """PDF file with one page."""

    def __init__(self, width, height, filename):
        self.width, self.height = width, height
        self.nextObject = 1     # next free object id
        self.xrefTable = [ [0, 65535, 'the zero object'] ]
        fh = file(filename, 'wb')
        self.fh = fh
        self.currentstream = None # stream object to write to, if any
        fh.write("%PDF-1.4\n")    # 1.4 is the first version to have alpha
        # Output some eight-bit chars as a comment so various utilities
        # recognize the file as binary by looking at the first few
        # lines (see note in section 3.4.1 of the PDF reference).
        fh.write("%\254\334 \253\272\n")

        self.rootObject = self.reserveObject('root')
        self.infoObject = self.reserveObject('info')
        pagesObject = self.reserveObject('pages')
        thePageObject = self.reserveObject('page 0')
        contentObject = self.reserveObject('contents of page 0')
        self.fontObject = self.reserveObject('fonts')
        self.alphaStateObject = self.reserveObject('extended graphics states')
        self.hatchObject = self.reserveObject('tiling patterns')
        self.XObjectObject = self.reserveObject('external objects')
        resourceObject = self.reserveObject('resources')

        root = { 'Type': Name('Catalog'),
                 'Pages': pagesObject }
        self.writeObject(self.rootObject, root)

        info = { 'Creator': 'matplotlib ' + __version__ \
                 + ', http://matplotlib.sf.net',
                 'Producer': 'matplotlib pdf backend',
                 'CreationDate': datetime.today() }

        # Possible TODO: Title, Author, Subject, Keywords
        self.writeObject(self.infoObject, info)

        pages = { 'Type': Name('Pages'),
                  'Kids': [ thePageObject ],
                  'Count': 1 }
        self.writeObject(pagesObject, pages)

        thePage = { 'Type': Name('Page'),
                    'Parent': pagesObject,
                    'Resources': resourceObject,
                    'MediaBox': [ 0, 0, 72*width, 72*height ],
                    'Contents': contentObject }
        self.writeObject(thePageObject, thePage)

        # self.fontNames maps filenames to internal font names
        self.fontNames = {}
        self.nextFont = 1       # next free internal font name

        self.alphaStates = {}   # maps alpha values to graphics state objects
        self.nextAlphaState = 1
        self.hatchPatterns = {}
        self.nextHatch = 1

        self.images = {}
        self.nextImage = 1

        self.markers = {}
        self.nextMarker = 1

        # The PDF spec recommends to include every procset
        procsets = [ Name(x)
                     for x in "PDF Text ImageB ImageC ImageI".split() ]

        # Write resource dictionary.
        # Possibly TODO: more general ExtGState (graphics state dictionaries)
        #                ColorSpace Pattern Shading Properties
        resources = { 'Font': self.fontObject,
                      'XObject': self.XObjectObject,
                      'ExtGState': self.alphaStateObject,
                      'Pattern': self.hatchObject,
                      'ProcSet': procsets }
        self.writeObject(resourceObject, resources)

        # Start the content stream of the page
        self.beginStream(contentObject.id,
                         self.reserveObject('length of content stream'))

    def close(self):
        # End the content stream and write out the various deferred
        # objects
        self.endStream()
        self.writeFonts()
        self.writeObject(self.alphaStateObject,
                         dict([(val[0], val[1])
                               for val in self.alphaStates.values()]))
        self.writeHatches()
        xobjects = dict(self.images.values())
        for name, value in self.markers.items():
            xobjects[name] = value[0]
        self.writeObject(self.XObjectObject, xobjects)
        self.writeImages()
        self.writeMarkers()
        self.writeXref()
        self.writeTrailer()
        self.fh.close()

    def write(self, data):
        if self.currentstream is None:
            self.fh.write(data)
        else:
            self.currentstream.write(data)

    def output(self, *data):
        self.write(fill(map(pdfRepr, data)))
        self.write('\n')

    def beginStream(self, id, len, extra=None):
        assert self.currentstream is None
        self.currentstream = Stream(id, len, self, extra)

    def endStream(self):
        self.currentstream.end()
        self.currentstream = None

    def fontName(self, fontprop):
        if is_string_like(fontprop):
            filename = fontprop
        elif rcParams['pdf.use14corefonts']:
            filename = fontManager.findfont(fontprop, fontext='afm')
        else:
            filename = fontManager.findfont(fontprop)
        
        Fx = self.fontNames.get(filename)
        if Fx is None:
            Fx = Name('F%d' % self.nextFont)
            self.fontNames[filename] = Fx
            self.nextFont += 1
        
        return Fx

    def writeFonts(self):
        fonts = {}
        for filename, Fx in self.fontNames.items():
            if filename.endswith('.afm'):
                fontdictObject = self._write_afm_font(filename)
            else:
                fontdictObject = self.embedTTF(filename)
            fonts[Fx] = fontdictObject
            #print >>sys.stderr, filename
        self.writeObject(self.fontObject, fonts)
    
    def _write_afm_font(self, filename):
        fh = file(filename)
        font = AFM(fh)
        fh.close()
        fontname = font.get_fontname()
        fontdict = { 'Type': Name('Font'),
                     'Subtype': Name('Type1'),
                     'BaseFont': Name(fontname),
                     'Encoding': Name('WinAnsiEncoding') }
        fontdictObject = self.reserveObject('font dictionary')
        self.writeObject(fontdictObject, fontdict)
        return fontdictObject
    
00474     def embedTTF(self, filename):
        """Embed the TTF font from the named file into the document."""
        
        font = FT2Font(str(filename))
        
        def cvt(length, upe=font.units_per_EM, nearest=True):
            "Convert font coordinates to PDF glyph coordinates"
            value = length / upe * 1000
            if nearest: return round(value)
            # Perhaps best to round away from zero for bounding
            # boxes and the like
            if value < 0: return floor(value)
            else: return ceil(value)
        
        # You are lost in a maze of TrueType tables, all different...
        ps_name = Name(font.get_sfnt()[(1,0,0,6)])
        pclt = font.get_sfnt_table('pclt') \
            or { 'capHeight': 0, 'xHeight': 0 }
        post = font.get_sfnt_table('post') \
            or { 'italicAngle': (0,0) }
        ff = font.face_flags
        sf = font.style_flags
        
        # Get widths for the 256 characters of PDF encoding "WinAnsiEncoding" (similar to
        # Python encoding "cp1252"). According to the PDF Reference, a simple font, based on
        # single-byte characters, can't manage more than 256 characters, contrary to a
        # composite font, based on multi-byte characters.
        
        from encodings import cp1252
        firstchar, lastchar = 0, 255
        def get_char_width(charcode):
            unicode = cp1252.decoding_map[charcode] or 0
            width = font.load_char(unicode, flags=LOAD_NO_SCALE).horiAdvance
            return cvt(width)
        widths = [ get_char_width(charcode) for charcode in range(firstchar, lastchar+1) ]
        
        widthsObject = self.reserveObject('font widths')
        fontdescObject = self.reserveObject('font descriptor')
        # TODO: "WinAnsiEncoding" could become a parameter of PdfFile. The PDF encoding 
        # "WinAnsiEncoding" matches the Python enconding "cp1252" used in method 
        # RendererPdf.draw_text and RendererPdf.get_text_width_height to encode Unicode strings.
        fontdict = { 'Type': Name('Font'),
                     'Subtype': Name('TrueType'),
                     'Encoding': Name('WinAnsiEncoding'),
                     'BaseFont': ps_name,
                     'FirstChar': firstchar,
                     'LastChar': lastchar,
                     'Widths': widthsObject,
                     'FontDescriptor': fontdescObject }

        flags = 0
        symbolic = False #ps_name.name in ('Cmsy10', 'Cmmi10', 'Cmex10')
        if ff & FIXED_WIDTH: flags |= 1 << 0
        if 0: flags |= 1 << 1 # TODO: serif
        if symbolic: flags |= 1 << 2
        else: flags |= 1 << 5
        if sf & ITALIC: flags |= 1 << 6
        if 0: flags |= 1 << 16 # TODO: all caps
        if 0: flags |= 1 << 17 # TODO: small caps
        if 0: flags |= 1 << 18 # TODO: force bold
            
        descriptor = {
            'Type': Name('FontDescriptor'),
            'FontName': ps_name,
            'Flags': flags,
            'FontBBox': [ cvt(x, nearest=False) for x in font.bbox ],
            'Ascent': cvt(font.ascender, nearest=False),
            'Descent': cvt(font.descender, nearest=False),
            'CapHeight': cvt(pclt['capHeight'], nearest=False),
            'XHeight': cvt(pclt['xHeight']),
            'ItalicAngle': post['italicAngle'][1], # ???
            'FontFile2': self.reserveObject('font file'),
            'MaxWidth': max(widths),
            'StemV': 0 # ???
        }
        
        # Other FontDescriptor keys include:
        # /FontFamily /Times (optional)
        # /FontStretch /Normal (optional)
        # /FontFile (stream for type 1 font)
        # /CharSet (used when subsetting type1 fonts)
        
        # Make an Identity-H encoded CID font for CM fonts? (Doesn't quite work)
        if False:
            del fontdict['Widths'], fontdict['FontDescriptor'], \
                fontdict['LastChar'], fontdict['FirstChar']
            
            fontdict['Subtype'] = Name('Type0')
            fontdict['Encoding'] = Name('Identity-H')
            fontdict2Object = self.reserveObject('descendant font')
            fontdict['DescendantFonts'] = [ fontdict2Object ]
            # TODO: fontdict['ToUnicode']
            fontdict2 = { 'Type': Name('Font'),
                          'Subtype': Name('CIDFontType2'),
                          'BaseFont': ps_name,
                          'W': widthsObject,
                          'CIDSystemInfo': { 'Registry': 'Adobe', 
                                             'Ordering': 'Identity', 
                                             'Supplement': 0 },
                          'FontDescriptor': fontdescObject }
            self.writeObject(fontdict2Object, fontdict2)
            
            widths = [ firstchar, widths ]
        
        fontdictObject = self.reserveObject('font dictionary')
        length1Object = self.reserveObject('decoded length of a font')
        self.writeObject(fontdictObject, fontdict)
        self.writeObject(widthsObject, widths)
        self.writeObject(fontdescObject, descriptor)
        self.beginStream(descriptor['FontFile2'].id,
                         self.reserveObject('length of font stream'),
                         {'Length1': length1Object})
        fontfile = open(filename, 'rb')
        length1 = 0
        while True:
            data = fontfile.read(4096)
            if not data: break
            length1 += len(data)
            self.currentstream.write(data)
        self.endStream()
        self.writeObject(length1Object, length1)
        
        return fontdictObject

00598     def alphaState(self, alpha):
        """Return name of an ExtGState that sets alpha to the given value"""

        state = self.alphaStates.get(alpha, None)
        if state is not None:
            return state[0]

        name = Name('A%d' % self.nextAlphaState)
        self.nextAlphaState += 1
        self.alphaStates[alpha] = \
            (name, { 'Type': Name('ExtGState'),
                     'CA': alpha, 'ca': alpha })
        return name

    def hatchPattern(self, lst):
        pattern = self.hatchPatterns.get(lst, None)
        if pattern is not None:
            return pattern[0]

        name = Name('H%d' % self.nextHatch)
        self.nextHatch += 1
        self.hatchPatterns[lst] = name
        return name

    def writeHatches(self):
        hatchDict = dict()
        sidelen = 144.0
        density = 24.0
        for lst, name in self.hatchPatterns.items():
            ob = self.reserveObject('hatch pattern')
            hatchDict[name] = ob
            res = { 'Procsets': 
                    [ Name(x) for x in "PDF Text ImageB ImageC ImageI".split() ] }
            self.beginStream(
                ob.id, None, 
                { 'Type': Name('Pattern'),
                  'PatternType': 1, 'PaintType': 1, 'TilingType': 1,
                  'BBox': [0, 0, sidelen, sidelen],
                  'XStep': sidelen, 'YStep': sidelen,
                  'Resources': res })

            # lst is a tuple of stroke color, fill color, 
            # number of - lines, number of / lines, 
            # number of | lines, number of \ lines
            rgb = lst[0]
            self.output(rgb[0], rgb[1], rgb[2], Op.setrgb_stroke)
            if lst[1] is not None:
                rgb = lst[1]
                self.output(rgb[0], rgb[1], rgb[2], Op.setrgb_nonstroke,
                            0, 0, sidelen, sidelen, Op.rectangle,
                            Op.fill)
            if lst[2]:                # -
                for j in arange(0.0, sidelen, density/lst[2]):
                    self.output(0, j, Op.moveto,
                                sidelen, j, Op.lineto)
            if lst[3]:                # /
                for j in arange(0.0, sidelen, density/lst[3]):
                    self.output(0, j, Op.moveto,
                                sidelen-j, sidelen, Op.lineto,
                                sidelen-j, 0, Op.moveto,
                                sidelen, j, Op.lineto)
            if lst[4]:                # |
                for j in arange(0.0, sidelen, density/lst[4]):
                    self.output(j, 0, Op.moveto,
                                j, sidelen, Op.lineto)
            if lst[5]:                # \
                for j in arange(sidelen, 0.0, -density/lst[5]):
                    self.output(sidelen, j, Op.moveto,
                                j, sidelen, Op.lineto,
                                j, 0, Op.moveto,
                                0, j, Op.lineto)
            self.output(Op.stroke)

            self.endStream()
        self.writeObject(self.hatchObject, hatchDict)

00674     def imageObject(self, image):
        """Return name of an image XObject representing the given image."""

        pair = self.images.get(image, None)
        if pair is not None:
            return pair[0]

        name = Name('I%d' % self.nextImage)
        ob = self.reserveObject('image %d' % self.nextImage)
        self.nextImage += 1
        self.images[image] = (name, ob)
        return name

    ## These two from backend_ps.py
    ## TODO: alpha (SMask, p. 518 of pdf spec)

00690     def _rgb(self, im):
        h,w,s = im.as_rgba_str()

        rgba = fromstring(s, UInt8)
        rgba.shape = (h, w, 4)
        rgb = rgba[:,:,:3]
        return h, w, rgb.tostring()

    def _gray(self, im, rc=0.3, gc=0.59, bc=0.11):
        rgbat = im.as_rgba_str()
        rgba = fromstring(rgbat[2], UInt8)
        rgba.shape = (rgbat[0], rgbat[1], 4)
        rgba_f = rgba.astype(Float32)
        r = rgba_f[:,:,0]
        g = rgba_f[:,:,1]
        b = rgba_f[:,:,2]
        gray = (r*rc + g*gc + b*bc).astype(UInt8)
        return rgbat[0], rgbat[1], gray.tostring()

    def writeImages(self):
        for img, pair in self.images.items():
            img.flipud_out()
            if img.is_grayscale:
                height, width, data = self._gray(img)
                colorspace = Name('DeviceGray')
            else:
                height, width, data = self._rgb(img)
                colorspace = Name('DeviceRGB')

            self.beginStream(
                pair[1].id,
                self.reserveObject('length of image stream'), 
                {'Type': Name('XObject'), 'Subtype': Name('Image'),
                 'Width': width, 'Height': height,
                 'ColorSpace': colorspace, 'BitsPerComponent': 8 })
            self.currentstream.write(data) # TODO: predictors (i.e., output png)
            self.endStream()

            img.flipud_out()

00730     def markerObject(self, path, fillp, lw):
        """Return name of a marker XObject representing the given path."""

        name = Name('M%d' % self.nextMarker)
        ob = self.reserveObject('marker %d' % self.nextMarker)
        self.nextMarker += 1
        self.markers[name] = (ob, path, fillp, lw)
        return name

    def writeMarkers(self):
        for name, tuple in self.markers.items():
            object, path, fillp, lw = tuple
            self.beginStream(
                object.id, None, 
                {'Type': Name('XObject'), 'Subtype': Name('Form'),
                 'BBox': self.pathBbox(path, lw) })
            self.writePath(path, fillp)
            self.endStream()

    def pathBbox(path, lw):
        path.rewind(0)
        x, y = [], []
        while True:
            code, xp, yp = path.vertex()
            if code & agg.path_cmd_mask in \
                    (agg.path_cmd_move_to, agg.path_cmd_line_to):
                x.append(xp)
                y.append(yp)
            elif code == agg.path_cmd_stop:
                break
        return min(x)-lw, min(y)-lw, max(x)+lw, max(y)+lw
    pathBbox = staticmethod(pathBbox)

    def writePath(self, path, fillp):
        path.rewind(0)
        while True:
            code, xp, yp = path.vertex()
            code = code & agg.path_cmd_mask
            if code == agg.path_cmd_stop:
                break
            elif code == agg.path_cmd_move_to:
                self.output(xp, yp, Op.moveto)
            elif code == agg.path_cmd_line_to:
                self.output(xp, yp, Op.lineto)
            elif code == agg.path_cmd_curve3:
                pass
            elif code == agg.path_cmd_curve4:
                pass
            elif code == agg.path_cmd_end_poly:
                self.output(Op.closepath)
            else:
                print >>sys.stderr, "writePath", code, xp, yp
        if fillp:
            self.output(Op.fill_stroke)
        else:
            self.output(Op.stroke)

00787     def reserveObject(self, name=''):
        """Reserve an ID for an indirect object.
        The name is used for debugging in case we forget to print out
        the object with writeObject.
        """

        id = self.nextObject
        self.nextObject += 1
        self.xrefTable.append([None, 0, name])
        return Reference(id)

    def recordXref(self, id):
        self.xrefTable[id][0] = self.fh.tell()

    def writeObject(self, object, contents):
        self.recordXref(object.id)
        object.write(contents, self)

00805     def writeXref(self):
        """Write out the xref table."""

        self.startxref = self.fh.tell()
        self.write("xref\n0 %d\n" % self.nextObject)
        i = 0
        borken = False
        for offset, generation, name in self.xrefTable:
            if offset is None:
                print >>sys.stderr, \
                    'No offset for object %d (%s)' % (i, name)
                borken = True
            else:
                self.write("%010d %05d n \n" % (offset, generation))
            i += 1
        if borken:
            raise AssertionError, 'Indirect object does not exist'

00823     def writeTrailer(self):
        """Write out the PDF trailer."""

        self.write("trailer\n")
        self.write(pdfRepr(
                {'Size': self.nextObject,
                 'Root': self.rootObject,
                 'Info': self.infoObject }))
        # Could add 'ID'
        self.write("\nstartxref\n%d\n%%%%EOF\n" % self.startxref)

class RendererPdf(RendererBase):

    def __init__(self, file):
        RendererBase.__init__(self)
        self.file = file
        self.gc = self.new_gc()
        self.truetype_font_cache = {}
        self.afm_font_cache = {}

    def finalize(self):
        self.gc.finalize()
        del self.truetype_font_cache
        del self.afm_font_cache

    def check_gc(self, gc, fillcolor=None):
        orig_fill = gc._fillcolor
        gc._fillcolor = fillcolor

        delta = self.gc.delta(gc)
        if delta: self.file.output(*delta)

        # Restore gc to avoid unwanted side effects
        gc._fillcolor = orig_fill

    def draw_arc(self, gcEdge, rgbFace, x, y, width, height, 
                 angle1, angle2, rotation):
        """
        Draw an arc using GraphicsContext instance gcEdge, centered at x,y,
        with width and height and angles from 0.0 to 360.0
        0 degrees is at 3-o'clock, rotated by `rotation` degrees
        positive angles are anti-clockwise

        If the color rgbFace is not None, fill the arc with it.
        """
        # source: agg_bezier_arc.cpp in agg23
        
        def arc_to_bezier(cx, cy, rx, ry, angle1, sweep, rotation):
            halfsweep = sweep / 2.0
            x0, y0 = cos(halfsweep), sin(halfsweep)
            tx = (1.0 - x0) * 4.0/3.0;
            ty = y0 - tx * x0 / y0;
            px =  x0, x0+tx, x0+tx, x0
            py = -y0,   -ty,    ty, y0
            sn, cs = sin(angle1 + halfsweep), cos(angle1 + halfsweep)
            result = [ (rx * (pxi * cs - pyi * sn),
                        ry * (pxi * sn + pyi * cs))
                       for pxi, pyi in zip(px, py) ]
            result = [ (cx + cos(rotation)*x - sin(rotation)*y,
                        cy + sin(rotation)*x + cos(rotation)*y)
                       for x, y in result ]
            return reduce(lambda x, y: x + y, result)

        epsilon = 0.01
        angle1 *= pi/180.0
        angle2 *= pi/180.0
        rotation *= pi/180.0
        sweep = angle2 - angle1
        angle1 = angle1 % (2*pi)
        sweep = min(max(-2*pi, sweep), 2*pi)

        if sweep < 0.0:
            sweep, angle1, angle2 = -sweep, angle2, angle1
        bp = [ pi/2.0 * i 
               for i in range(4) 
               if pi/2.0 * i < sweep-epsilon ]
        bp.append(sweep)
        subarcs = [ arc_to_bezier(x, y, width/2.0, height/2.0,
                                  bp[i], bp[i+1]-bp[i], rotation) 
                    for i in range(len(bp)-1) ]

        self.check_gc(gcEdge, rgbFace)
        self.file.output(subarcs[0][0], subarcs[0][1], Op.moveto)
        for arc in subarcs:
            self.file.output(*(arc[2:] + (Op.curveto,)))

        self.file.output(self.gc.close_and_paint())

    def draw_image(self, x, y, im, bbox):
        #print >>sys.stderr, "draw_image called"

        gc = self.new_gc()
        gc.set_clip_rectangle(bbox.get_bounds())
        self.check_gc(gc)

        h, w = im.get_size_out()
        imob = self.file.imageObject(im)
        self.file.output(Op.gsave, w, 0, 0, h, x, y, Op.concat_matrix,
                         imob, Op.use_xobject, Op.grestore)

    def draw_line(self, gc, x1, y1, x2, y2):
        if isnan(x1) or isnan(x2) or isnan(y1) or isnan(y2):
            return
        self.check_gc(gc)
        self.file.output(x1, y1, Op.moveto,
                         x2, y2, Op.lineto, self.gc.paint())

    def draw_lines(self, gc, x, y, transform=None):
        self.check_gc(gc)
        if transform is not None:
            x, y = transform.seq_x_y(x, y)
        nan_at = isnan(x) | isnan(y)
        next_op = Op.moveto
        for i in range(len(x)):
            if nan_at[i]:
                next_op = Op.moveto
            else:
                self.file.output(x[i], y[i], next_op)
                next_op = Op.lineto
        self.file.output(self.gc.paint())

    def draw_point(self, gc, x, y):
        print >>sys.stderr, "draw_point called"

        self.check_gc(gc, gc._rgb)
        self.file.output(x, y, 1, 1,
                         Op.rectangle, Op.fill_stroke)

    def draw_polygon(self, gcEdge, rgbFace, points):
        # Optimization for axis-aligned rectangles
        if len(points) == 4:
            if points[0][0] == points[1][0] and points[1][1] == points[2][1] and \
               points[2][0] == points[3][0] and points[3][1] == points[0][1]:
                self.draw_rectangle(gcEdge, rgbFace, 
                                    min(points[0][0], points[2][0]),
                                    min(points[1][1], points[3][1]),
                                    abs(points[2][0] - points[0][0]),
                                    abs(points[3][1] - points[1][1]))
                return
            elif points[0][1] == points[1][1] and points[1][0] == points[2][0] and \
                 points[2][1] == points[3][1] and points[3][0] == points[0][0]:
                self.draw_rectangle(gcEdge, rgbFace, 
                                    min(points[1][0], points[3][0]),
                                    min(points[2][1], points[0][1]),
                                    abs(points[1][0] - points[3][0]),
                                    abs(points[2][1] - points[0][1]))
                return

        self.check_gc(gcEdge, rgbFace)
        self.file.output(points[0][0], points[0][1], Op.moveto)
        for x,y in points[1:]:
            self.file.output(x, y, Op.lineto)
        self.file.output(self.gc.close_and_paint())

    def draw_rectangle(self, gcEdge, rgbFace, x, y, width, height):
        self.check_gc(gcEdge, rgbFace)
        self.file.output(x, y, width, height, Op.rectangle)
        self.file.output(self.gc.paint())

    def draw_markers(self, gc, path, rgbFace, x, y, trans):
        self.check_gc(gc, rgbFace)
        fillp = rgbFace is not None
        marker = self.file.markerObject(path, fillp, self.gc._linewidth)
        x, y = trans.numerix_x_y(asarray(x), asarray(y))
        nan_at = isnan(x) | isnan(y)

        self.file.output(Op.gsave)
        ox, oy = 0, 0
        for i in range(len(x)):
            if nan_at[i]: continue
            dx, dy, ox, oy = x[i]-ox, y[i]-oy, x[i], y[i]
            self.file.output(1, 0, 0, 1, dx, dy, 
                             Op.concat_matrix,
                             marker, Op.use_xobject)
        self.file.output(Op.grestore)

    def _setup_textpos(self, x, y, angle, oldx=0, oldy=0, oldangle=0):
        if angle == oldangle == 0:
            self.file.output(x - oldx, y - oldy, Op.textpos)
        else:
            angle = angle / 180.0 * pi
            self.file.output( cos(angle), sin(angle),
                             -sin(angle), cos(angle),
                              x,        y,         Op.textmatrix)

    def draw_mathtext(self, gc, x, y, s, prop, angle):
        # TODO: fix positioning and encoding
        fontsize = prop.get_size_in_points()
        width, height, pswriter = math_parse_s_pdf(s, 72, fontsize)

        self.check_gc(gc, gc._rgb)
        self.file.output(Op.begin_text)
        prev_font = None, None
        oldx, oldy = 0, 0
        for ox, oy, fontname, fontsize, glyph in pswriter:
            #print ox, oy, glyph
            fontname = fontname.lower()
            a = angle / 180.0 * pi
            newx = x + cos(a)*ox - sin(a)*oy
            newy = y + sin(a)*ox + cos(a)*oy
            self._setup_textpos(newx, newy, angle, oldx, oldy)
            oldx, oldy = newx, newy
            if (fontname, fontsize) != prev_font:
                self.file.output(self.file.fontName(fontname), fontsize, 
                                 Op.selectfont)
                prev_font = fontname, fontsize

            #if fontname.endswith('cmsy10.ttf') or \
            #fontname.endswith('cmmi10.ttf') or \
            #fontname.endswith('cmex10.ttf'):
            #        string = '\0' + chr(glyph)

            string = chr(glyph)
            self.file.output(string, Op.show)
        self.file.output(Op.end_text)

    def _draw_tex(self, gc, x, y, s, prop, angle):
        # Rename to draw_tex to enable, but note the following:
        # TODO:
        #  - font sizes other than 10pt
        #  - fonts other than the three ttf files included with matplotlib
        #    (will need to support Type-1 fonts and find them with kpsewhich)
        #  - encoding issues (e.g. \alpha doesn't work now)
        #  - overall robustness
        #  - ...
        texmanager = self.get_texmanager()
        fontsize = prop.get_size_in_points()
        dvifile = texmanager.make_dvi(s, fontsize)
        dvi = Dvi(dvifile)
        dvi.read()
        text, boxes = dvi.output(72)
        fontdir = os.path.join(get_data_path(), 'fonts', 'ttf')

        if angle == 0:          # avoid rounding errors in common case
            def mytrans(x1, y1): 
                return x+x1, y+y1
        else:
            def mytrans(x1, y1, x=x, y=y, a=angle / 180.0 * pi):
                x1 = x + cos(a)*x1 - sin(a)*y1
                y1 = y + sin(a)*x1 + cos(a)*y1
                return x1, y1

        self.check_gc(gc, gc._rgb)
        self.file.output(Op.begin_text)
        oldfont, oldx, oldy = None, 0, 0
        for x1, y1, font, glyph in text:
            if font != oldfont:
                fontname, fontsize = dvi.fontinfo(font)
                fontfile = os.path.join(fontdir, fontname+'.ttf')
                self.file.output(self.file.fontName(fontfile),
                                 fontsize, Op.selectfont)
                oldfont = font
            x1, y1 = mytrans(x1, y1)
            self._setup_textpos(x1, y1, angle, oldx, oldy)
            self.file.output(chr(glyph), Op.show)
            oldx, oldy = x1, y1
        self.file.output(Op.end_text)

        boxgc = self.new_gc()
        boxgc.copy_properties(gc)
        boxgc.set_linewidth(0)
        for x1, y1, h, w in boxes:
            (x1, y1), (x2, y2), (x3, y3), (x4, y4) = \
                mytrans(x1, y1), mytrans(x1+w, y1), \
                mytrans(x1+w, y1+h), mytrans(x1, y1+h)
            self.draw_polygon(boxgc, gc._rgb, 
                              ((x1,y1), (x2,y2), (x3,y3), (x4,y4)))

    def draw_text(self, gc, x, y, s, prop, angle, ismath=False):
        # TODO: combine consecutive texts into one BT/ET delimited section
        
        if isinstance(s, unicode):
            s = s.encode('cp1252', 'replace')
        
        if ismath: return self.draw_mathtext(gc, x, y, s, prop, angle)
        self.check_gc(gc, gc._rgb)
        
        if rcParams['pdf.use14corefonts']:
            font = self._get_font_afm(prop)
            l, b, w, h = font.get_str_bbox(s)
            fontsize = prop.get_size_in_points()
            y -= b * fontsize / 1000
        else:
            font = self._get_font_ttf(prop)
            font.set_text(s, 0.0)
            y += font.get_descent() / 64.0
        
        self.file.output(Op.begin_text, 
                         self.file.fontName(prop),
                         prop.get_size_in_points(),
                         Op.selectfont)
        
        self._setup_textpos(x, y, angle)
        self.file.output(s, Op.show, Op.end_text)

    def get_text_width_height(self, s, prop, ismath):
        if isinstance(s, unicode):
            s = s.encode('cp1252', 'replace')
        
        if ismath:
            fontsize = prop.get_size_in_points()
            w, h, pswriter = math_parse_s_pdf(s, 72, fontsize)
            
        elif rcParams['pdf.use14corefonts']:
            font = self._get_font_afm(prop)
            l, b, w, h = font.get_str_bbox(s)
            fontsize = prop.get_size_in_points()
            w *= fontsize / 1000
            h *= fontsize / 1000
            
        else:
            font = self._get_font_ttf(prop)
            font.set_text(s, 0.0)
            w, h = font.get_width_height()
            w /= 64.0
            h /= 64.0
            
        return w, h

    def _get_font_afm(self, prop):
        key = hash(prop)
        font = self.afm_font_cache.get(key)
        if font is None:
            filename = fontManager.findfont(prop, fontext='afm')
            fh = file(filename)
            font = AFM(fh)
            fh.close()
            self.afm_font_cache[key] = font
        return font

    def _get_font_ttf(self, prop):
        key = hash(prop)
        font = self.truetype_font_cache.get(key)
        if font is None:
            filename = fontManager.findfont(prop)
            font = FT2Font(str(filename))
            self.truetype_font_cache[key] = font
        font.clear()
        font.set_size(prop.get_size_in_points(), 72.0)
        return font

    def flipy(self):
        return False

    def get_canvas_width_height(self):
        return self.file.width / 72.0, self.file.height / 72.0

    def new_gc(self):
        return GraphicsContextPdf(self.file)


class GraphicsContextPdf(GraphicsContextBase):

    def __init__(self, file):
        GraphicsContextBase.__init__(self)
        self._fillcolor = (0.0, 0.0, 0.0)
        self.file = file
        self.parent = None

    def __repr__(self):
        d = dict(self.__dict__)
        del d['file']
        del d['parent']
        return `d`

    def _strokep(self):
        return self._linewidth > 0 and self._alpha > 0

    def _fillp(self):
        return self._fillcolor is not None or self._hatch

    def close_and_paint(self):
        if self._strokep():
            if self._fillp(): 
                return Op.close_fill_stroke
            else:
                return Op.close_stroke
        else:
            if self._fillp():
                return Op.fill
            else:
                return Op.endpath

    def paint(self):
        if self._strokep():
            if self._fillp(): 
                return Op.fill_stroke
            else:
                return Op.stroke
        else:
            if self._fillp():
                return Op.fill
            else:
                return Op.endpath

    capstyles = { 'butt': 0, 'round': 1, 'projecting': 2 }
    joinstyles = { 'miter': 0, 'round': 1, 'bevel': 2 }

    def capstyle_cmd(self, style):
        return [self.capstyles[style], Op.setlinecap]

    def joinstyle_cmd(self, style):
        return [self.joinstyles[style], Op.setlinejoin]

    def linewidth_cmd(self, width):
        return [width, Op.setlinewidth]

    def dash_cmd(self, dashes):
        offset, dash = dashes
        if dash is None: 
            dash = []
            offset = 0
        return [list(dash), offset, Op.setdash]

    def alpha_cmd(self, alpha):
        name = self.file.alphaState(alpha)
        return [name, Op.setgstate]

    def hatch_cmd(self, hatch):
        if not hatch:
            if self._fillcolor:
                return self.fillcolor_cmd(self._fillcolor)
            else:
                return [Name('DeviceRGB'), Op.setcolorspace_nonstroke]
        else:
            hatch = hatch.lower()
            lst = ( self._rgb,
                    self._fillcolor,
                    hatch.count('-') + hatch.count('+'),
                    hatch.count('/') + hatch.count('x'),
                    hatch.count('|') + hatch.count('+'),
                    hatch.count('\\') + hatch.count('x') )
            name = self.file.hatchPattern(lst)
            return [Name('Pattern'), Op.setcolorspace_nonstroke,
                    name, Op.setcolor_nonstroke]

    def rgb_cmd(self, rgb):
        if rcParams['pdf.inheritcolor']:
            return []
        if rgb[0] == rgb[1] == rgb[2]:
            return [rgb[0], Op.setgray_stroke]
        else:
            return list(rgb) + [Op.setrgb_stroke] 

    def fillcolor_cmd(self, rgb):
        if rgb is None or rcParams['pdf.inheritcolor']:
            return []
        elif rgb[0] == rgb[1] == rgb[2]:
            return [rgb[0], Op.setgray_nonstroke]
        else:
            return list(rgb) + [Op.setrgb_nonstroke] 

    def push(self):
        parent = GraphicsContextPdf(self.file)
        parent.copy_properties(self)
        parent.parent = self.parent
        self.parent = parent
        return [Op.gsave]

    def pop(self):
        assert self.parent is not None
        self.copy_properties(self.parent)
        self.parent = self.parent.parent
        return [Op.grestore]

    def cliprect_cmd(self, cliprect):
        """Set clip rectangle. Calls self.pop() and self.push()."""
        cmds = []
        while self._cliprect != cliprect and self.parent is not None:
            cmds.extend(self.pop())
        if self._cliprect != cliprect:
            cmds.extend(self.push() + 
                        [t for t in cliprect] + 
                        [Op.rectangle, Op.clip, Op.endpath])
        return cmds

    commands = (
        ('_cliprect', cliprect_cmd), # must come first since may pop
        ('_alpha', alpha_cmd),
        ('_capstyle', capstyle_cmd),
        ('_fillcolor', fillcolor_cmd),
        ('_joinstyle', joinstyle_cmd),
        ('_linewidth', linewidth_cmd),
        ('_dashes', dash_cmd),
        ('_rgb', rgb_cmd),
        ('_hatch', hatch_cmd),  # must come after fillcolor and rgb
        )

    # TODO: _linestyle

    def copy_properties(self, other):
        """Copy properties of other into self."""
        GraphicsContextBase.copy_properties(self, other)
        self._fillcolor = other._fillcolor

    def delta(self, other):
        """Copy properties of other into self and return PDF commands 
        needed to transform self into other.
        """
        cmds = []
        for param, cmd in self.commands:
            if getattr(self, param) != getattr(other, param):
                cmds.extend(cmd(self, getattr(other, param)))
                setattr(self, param, getattr(other, param))
        return cmds

    def finalize(self):
        """Make sure every pushed graphics state is popped."""
        cmds = []
        while self.parent is not None:
            cmds.extend(self.pop())
        return cmds

########################################################################
#
# The following functions and classes are for pylab and implement
# window/figure managers, etc...
#
########################################################################


def new_figure_manager(num, *args, **kwargs):
    """
    Create a new figure manager instance
    """
    # if a main-level app must be created, this is the usual place to
    # do it -- see backend_wx, backend_wxagg and backend_tkagg for
    # examples.  Not all GUIs require explicit instantiation of a
    # main-level app (egg backend_gtk, backend_gtkagg) for pylab
    FigureClass = kwargs.pop('FigureClass', Figure)
    thisFig = FigureClass(*args, **kwargs)
    canvas = FigureCanvasPdf(thisFig)
    manager = FigureManagerPdf(canvas, num)
    return manager


01359 class FigureCanvasPdf(FigureCanvasBase):
    """
    The canvas the figure renders into.  Calls the draw and print fig
    methods, creates the renderers, etc...

    Public attribute

      figure - A Figure instance
    """

    def draw(self):
        pass

01372     def print_figure(self, filename, dpi=None, facecolor='w', edgecolor='w',
                     orientation='portrait', **kwargs):
        """
        Render the figure to hardcopy. Set the figure patch face and edge
        colors.  This is useful because some of the GUIs have a gray figure
        face color background and you'll probably want to override this on
        hardcopy.

        orientation - only currently applies to PostScript printing.
        """
        self.figure.dpi.set(72) # ignore the dpi kwarg
        self.figure.set_facecolor(facecolor)
        self.figure.set_edgecolor(edgecolor)
        width, height = self.figure.get_size_inches()

        basename, ext = os.path.splitext(filename)
        if ext == '': 
            filename += '.pdf'

        file = PdfFile(width, height, filename)
        renderer = RendererPdf(file)
        self.figure.draw(renderer)
        renderer.finalize()
        file.close()

class FigureManagerPdf(FigureManagerBase):
    pass

FigureManager = FigureManagerPdf

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