pyx/mesh.py

   1 # -*- coding: ISO-8859-1 -*-
   2 #
   3 #
   4 # Copyright (C) 2006 André Wobst <wobsta@users.sourceforge.net>
   5 #
   6 # This file is part of PyX (http://pyx.sourceforge.net/).
   7 #
   8 # PyX is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 2 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # PyX is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with PyX; if not, write to the Free Software
  20 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  21
  22
  23 # Just a quick'n'dirty ascii art (I'll do a nice PyX plot later on):
  24 #
  25 #
  26 #      node1 *
  27 #            | \
  28 #            |   \  neighbor2
  29 #            |     \
  30 #            |       \
  31 #  neighbor3 |element * node3
  32 #            |       /
  33 #            |     /
  34 #            |   /  neighbor1
  35 #            | /
  36 #      node2 *
  37
  38
  39 import struct, binascii, zlib
  40 import bbox, canvas, color, pdfwriter, unit
  41
  42
  43 class node_pt:
  44
  45     def __init__(self, coords_pt, value):
  46         self.coords_pt = coords_pt
  47         self.value = value
  48
  49
  50 class node(node_pt):
  51
  52     def __init__(self, coords, value):
  53         node_pt.__init__(self, [unit.topt(coord) for coord in coords], value)
  54
  55
  56 class element:
  57
  58     def __init__(self, nodes, neighbors=None):
  59         self.nodes = nodes
  60         self.neighbors = neighbors
  61
  62
  63 def coords24bit_pt(coords_pt, min_pt, max_pt):
  64     return struct.pack(">I", int((coords_pt-min_pt)*16777215.0/(max_pt-min_pt)))[1:]
  65
  66
  67 class PDFGenericResource(pdfwriter.PDFobject):
  68
  69     def __init__(self, type, name, content):
  70         pdfwriter.PDFobject.__init__(self, type, name)
  71         self.content = content
  72
  73     def write(self, file, writer, registry):
  74         file.write(self.content)
  75
  76
  77 class mesh(canvas.canvasitem):
  78
  79     def __init__(self, elements, check=1):
  80         self.elements = elements
  81         if check:
  82             colorspacestring = ""
  83             for element in elements:
  84                 if len(element.nodes) != 3:
  85                     raise ValueError("triangular mesh expected")
  86                 try:
  87                     for node in element.nodes:
  88                         if not colorspacestring:
  89                             colorspacestring = node.value.colorspacestring()
  90                         elif node.value.colorspacestring() != colorspacestring:
  91                             raise ValueError("color space mismatch")
  92                 except AttributeError:
  93                     raise ValueError("gray, rgb or cmyk color values expected")
  94                 for node in element.nodes:
  95                     if len(node.coords_pt) != 2:
  96                         raise ValueError("two dimensional coordinates expected")
  97
  98     def bbox(self):
  99         return bbox.bbox_pt(min([node.coords_pt[0] for element in self.elements for node in element.nodes]),
 100                             min([node.coords_pt[1] for element in self.elements for node in element.nodes]),
 101                             max([node.coords_pt[0] for element in self.elements for node in element.nodes]),
 102                             max([node.coords_pt[1] for element in self.elements for node in element.nodes]))
 103
 104     def data(self, bbox):
 105         return "".join(["\000%s%s%s" % (coords24bit_pt(node.coords_pt[0], bbox.llx_pt, bbox.urx_pt),
 106                                         coords24bit_pt(node.coords_pt[1], bbox.lly_pt, bbox.ury_pt),
 107                                         node.value.tostring8bit())
 108                         for element in self.elements for node in element.nodes])
 109
 110     def processPS(self, file, writer, context, registry, bbox):
 111         thisbbox = self.bbox()
 112         bbox += thisbbox
 113         file.write("""<< /ShadingType 4
 114 /ColorSpace %s
 115 /BitsPerCoordinate 24
 116 /BitsPerComponent 8
 117 /BitsPerFlag 8
 118 /Decode [%f %f %f %f %s]
 119 /DataSource currentfile /ASCIIHexDecode filter /FlateDecode filter
 120 >> shfill\n""" % (self.elements[0].nodes[0].value.colorspacestring(),
 121                   thisbbox.llx_pt, thisbbox.urx_pt, thisbbox.lly_pt, thisbbox.ury_pt,
 122                   " ".join(["0 1" for value in self.elements[0].nodes[0].value.tostring8bit()])))
 123         file.write(binascii.b2a_hex(zlib.compress(self.data(thisbbox))))
 124         file.write("\n")
 125
 126     def processPDF(self, file, writer, context, registry, bbox):
 127         thisbbox = self.bbox()
 128         bbox += thisbbox
 129         d = self.data(thisbbox)
 130         if writer.compress:
 131             filter = "/Filter /FlateDecode\n"
 132             d = zlib.compress(d)
 133         else:
 134             filter = ""
 135         name = "shading-%s" % id(self)
 136         shading = PDFGenericResource("shading", name, """<< /ShadingType 4
 137 /ColorSpace %s
 138 /BitsPerCoordinate 24
 139 /BitsPerComponent 8
 140 /BitsPerFlag 8
 141 /Decode [%f %f %f %f %s]
 142 /Length %i
 143 %s>>
 144 stream
 145 %s
 146 endstream\n""" % (self.elements[0].nodes[0].value.colorspacestring(),
 147                   thisbbox.llx_pt, thisbbox.urx_pt, thisbbox.lly_pt, thisbbox.ury_pt,
 148                   " ".join(["0 1" for value in self.elements[0].nodes[0].value.tostring8bit()]),
 149                   len(d), filter, d))
 150         registry.add(shading)
 151         registry.addresource("Shading", name, shading)
 152         file.write("/%s sh\n" % name)