spec/transpstack.py

   1 #!/usr/bin/python
   2 import sys
   3 sys.path += ["../scripts/"]
   4 import pdf
   5
   6 # a test for transparency groups:
   7 # form xobjects used for doing transparency groups can do savestate (q)
   8 # without ever needing to do a corresponding restorestate (Q) because
   9 # their content stream is self-contained.
  10 #
  11 # Test that this doesn't confuse the pdf reader.
  12
  13 file = pdf.PDF()
  14
  15 page = file.add_page(612,100)
  16
  17 group1 = file.create_object("/XObject", "/Form")
  18 group1.stream = """
  19 0.0 1.0 0.0 rg
  20 0.0 0.0 0.0 RG
  21 10 10 m 70 10 l 70 70 l 10 70 l 10 10 l f
  22 10 10 m 70 10 l 70 70 l 10 70 l 10 10 l s
  23 0.0 0.0 1.0 rg
  24 0.0 0.0 0.0 RG
  25 30 30 m 90 30 l 90 90 l 30 90 l 30 30 l f
  26 30 30 m 90 30 l 90 90 l 30 90 l 30 30 l s
  27 1.0 0 0 1.0 1000 1000 cm q
  28 1.0 0 0 1.0 1000 1000 cm q
  29 1.0 0 0 1.0 1000 1000 cm q
  30 1.0 0 0 1.0 1000 1000 cm q
  31 """
  32 isolated = "true"
  33 knockout = "true"
  34 group1["/Group"] = pdf.PDFDict({"/S": "/Transparency", "/CS": "/DeviceRGB", "/I": isolated, "/K": knockout})
  35 group1["/BBox"] = pdf.PDFArray([0, 0, 100, 100])
  36
  37 gs = file.create_object("/ExtGState")
  38 gs["/BM"] = "/Normal"
  39 gs["/CA"] = "1.0" # stroke alpha
  40 gs["/ca"] = "1.0" # fill alpha
  41
  42 resources = file.create_object("/Resources")
  43 resources["/XObject"] = pdf.PDFDict({"/mygroup": group1})
  44 resources["/ExtGState"] = pdf.PDFDict({"/gs0": gs})
  45
  46 page.header["/Resources"] = resources
  47
  48 page.stream = """q
  49
  50 1.0 0.0 0.0 rg
  51
  52 0 40 m 612 40 l 612 60 l 0 60 l 0 40 l f
  53 q /gs0 gs 1.0 0 0 1.0 0   0 cm /mygroup Do Q
  54
  55 Q"""
  56
  57 file.write("transpstack.pdf")
  58