pyx/pdfwriter.py

   1 import sys
   2 try:
   3     import zlib
   4     haszlib = 1
   5 except:
   6     haszlib = 0
   7
   8 import style
   9
  10 PDFcatalog = "Catalog"
  11 PDFpages = "Pages"
  12 PDFpage = "Page%i"
  13 PDFmediabox = "MediaBox%i"
  14 PDFresources = "Resources%i"
  15 PDFcontents = "Contents%i"
  16 PDFcontentslength = "ContentsLength%i"
  17
  18 class pdfwriter:
  19
  20     def __init__(self, filename, compress=1, compresslevel=6):
  21         self.file = open(filename, "wb")
  22         if compress and not haszlib:
  23             compress = 0
  24             sys.stderr.write("*** PyXWarning: compression disabled due to missing zlib module\n")
  25         self.compress = compress
  26         self.compresslevel = compresslevel
  27
  28         self.compressstream = None
  29         self.refdict = {} # id -> ref-no
  30         self.refs = [] # refno - 1 -> filepos
  31         self.pages = 0
  32
  33         self.write("%%PDF-1.4\n%%%s%s%s%s\n" % (chr(195), chr(182), chr(195), chr(169)))
  34
  35     def write(self, str):
  36         if self.compressstream is not None:
  37             self.file.write(self.compressstream.compress(str))
  38         else:
  39             self.file.write(str)
  40
  41     def beginobj(self, object):
  42         self.refs.append(self.file.tell())
  43         ref = len(self.refs)
  44         self.refdict[object] = ref
  45         self.write("%i 0 obj\n" % ref)
  46
  47     def endobj(self):
  48         self.write("endobj\n")
  49
  50     def beginstream(self):
  51         self.write("stream\n")
  52         self.beginstreampos = self.file.tell()
  53         if self.compress:
  54             if self.compressstream is not None:
  55                 raise RuntimeError("compression within compression")
  56             self.compressstream = zlib.compressobj(self.compresslevel)
  57
  58     def endstream(self):
  59         if self.compressstream is not None:
  60             self.file.write(self.compressstream.flush())
  61             self.compressstream = None
  62         length = self.file.tell() - self.beginstreampos
  63         self.write("endstream\n")
  64         return length
  65
  66     def page(self, abbox, canvas, mergedprolog, ctrafo):
  67         # media box
  68         self.beginobj(PDFmediabox % self.pages)
  69         abbox.outputPDF(self)
  70         self.endobj()
  71
  72         # resources
  73         self.beginobj(PDFresources % self.pages)
  74         self.write("<<\n")
  75         if len([pritem for pritem in mergedprolog if isinstance(pritem, prolog.fontdefinition)]):
  76             self.write("/Font\n"
  77                        "<<\n")
  78             for pritem in mergedprolog:
  79                 if isinstance(pritem, prolog.fontdefinition):
  80                     self.write("/%s %d 0 R\n" % (pritem.font.getpsname(),
  81                                                  self.refdict[pritem.font.getpsname()]))
  82             self.write(">>\n")
  83         self.write(">>\n")
  84         self.endobj()
  85
  86         # contents
  87         contentslengthref = len(self.refs) + 2
  88         self.beginobj(PDFcontents % self.pages)
  89         self.write("<<\n"
  90                    "/Length %i 0 R\n" % contentslengthref)
  91         if self.compress:
  92             self.write("/Filter /FlateDecode\n")
  93         self.write(">>\n")
  94         self.beginstream()
  95         # apply a possible global transformation
  96         if ctrafo: ctrafo.outputPDF(self)
  97         style.linewidth.normal.outputPDF(self)
  98         canvas.outputPDF(self)
  99         contentslength = self.endstream()
 100         self.endobj()
 101
 102         # contents length
 103         self.beginobj(PDFcontentslength % self.pages)
 104         self.write("%i\n" % contentslength)
 105         self.endobj()
 106         assert contentslengthref == self.refdict[PDFcontentslength % self.pages]
 107
 108         self.pages += 1
 109
 110     def close(self):
 111         # page objects and pages object
 112         # XXX: note that the page objects and the pages object refer to each other
 113         pagesref = len(self.refs) + self.pages + 1
 114         for page in range(self.pages):
 115             self.beginobj(PDFpage % page)
 116             self.write("<<\n"
 117                        "/Type /Page\n"
 118                        "/Parent %i 0 R\n"
 119                        "/MediaBox %i 0 R\n"
 120                        "/Resources %i 0 R\n"
 121                        "/Contents %i 0 R\n"
 122                        ">>\n" % (pagesref,
 123                                  self.refdict[PDFmediabox % page],
 124                                  self.refdict[PDFresources % page],
 125                                  self.refdict[PDFcontents % page]))
 126             self.endobj()
 127         self.beginobj(PDFpages)
 128         self.write("<<\n"
 129                    "/Type /Pages\n"
 130                    "/Kids [%s]\n"
 131                    "/Count %i\n"
 132                    ">>\n" % (" ".join(["%i 0 R" % self.refdict[PDFpage % page]
 133                                        for page in range(self.pages)]),
 134                              self.pages))
 135         self.endobj()
 136         assert pagesref == self.refdict[PDFpages]
 137
 138         # catalog
 139         self.beginobj(PDFcatalog)
 140         self.write("<<\n"
 141                    "/Type /Catalog\n"
 142                    "/Pages %i 0 R\n"
 143                    ">>\n" % self.refdict[PDFpages])
 144         self.endobj()
 145
 146         # xref
 147         xrefpos = self.file.tell()
 148         self.write("xref\n"
 149                    "0 %d\n"
 150                    "0000000000 65535 f \n" % (len(self.refs)+1))
 151         for ref in self.refs:
 152             self.file.write("%010i 00000 n \n" % ref)
 153
 154         # trailer
 155         self.write("trailer\n"
 156                    "<<\n"
 157                    "/Size %i\n"
 158                    "/Root %i 0 R\n"
 159                    ">>\n"
 160                    "startxref\n"
 161                    "%i\n"
 162                    "%%%%EOF\n" % (len(self.refs)+1, self.refdict[PDFcatalog], xrefpos))
 163         self.file.close()
 164