pyx/svgwriter.py

   1 # -*- encoding: utf-8 -*-
   2 #
   3 #
   4 # Copyright (C) 2015 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 import io, copy, time, xml.sax.saxutils
  23 from . import bbox, config, style, version, unit, trafo
  24
  25 svg_uri = "http://www.w3.org/2000/svg"
  26 xlink_uri = "http://www.w3.org/1999/xlink"
  27
  28 class SVGregistry:
  29
  30     def __init__(self):
  31         # in order to keep a consistent order of the registered resources we
  32         # not only store them in a hash but also keep an ordered list (up to a
  33         # possible merging of resources, in which case the first instance is
  34         # kept)
  35         self.resourceshash = {}
  36         self.resourceslist = []
  37
  38     def add(self, resource):
  39         rkey = (resource.type, resource.id)
  40         if rkey in self.resourceshash:
  41            self.resourceshash[rkey].merge(resource)
  42         else:
  43            self.resourceshash[rkey] = resource
  44            self.resourceslist.append(resource)
  45
  46     def mergeregistry(self, registry):
  47         for resource in registry.resources:
  48             self.add(resource)
  49
  50     def output(self, xml, writer):
  51         if self.resourceslist:
  52             xml.startSVGElement("defs", {})
  53             for resource in self.resourceslist:
  54                 resource.output(xml, writer, self)
  55             xml.endSVGElement("defs")
  56
  57 #
  58 # Abstract base class
  59 #
  60
  61 class SVGresource:
  62
  63     def __init__(self, type, id):
  64         # Every SVGresource has to have a type and a unique id.
  65         # Resources with the same type and id will be merged
  66         # when they are registered in the SVGregistry
  67         self.type = type
  68         self.id = id
  69
  70     def merge(self, other):
  71         """ merge self with other, which has to be a resource of the same type and with
  72         the same id"""
  73         pass
  74
  75     def output(self, xml, writer, registry):
  76         raise NotImplementedError("output not implemented for %s" % repr(self))
  77
  78
  79 #
  80 # XML generator with shortcut namespace support
  81 #
  82
  83 class SVGGenerator(xml.sax.saxutils.XMLGenerator):
  84
  85     def __init__(self, svg, xlink=True):
  86         super().__init__(svg, "utf-8", short_empty_elements=True)
  87         self.svg = svg
  88         self.xlink_enabled = xlink
  89         self.passthrough = False
  90
  91     def convertName(self, name):
  92         split = name.split(":")
  93         if len(split) == 1:
  94             uri = svg_uri
  95             name = split[0]
  96         else:
  97             short_uri, name = split
  98             assert short_uri == "xlink"
  99             if not self.xlink_enabled:
 100                 raise ValueError("xlink namespace found but not enabled")
 101             self.xlink_used = True
 102             uri = xlink_uri
 103         return uri, name
 104
 105     def convertAttrs(self, attrs):
 106         return {self.convertName(name): value for name, value in attrs.items()}
 107
 108     def startDocument(self, *args, **kwargs):
 109         if not self.passthrough:
 110             raise NotImplemented("use startSVGDocument")
 111
 112     def endDocument(self, *args, **kwargs):
 113         if not self.passthrough:
 114             raise NotImplemented("use endSVGDocument")
 115
 116     def startElementNS(self, *args, **kwargs):
 117         if not self.passthrough:
 118             raise NotImplemented("use startSVGElement")
 119         super().startElementNS(*args, **kwargs)
 120
 121     def endElementNS(self, *args, **kwargs):
 122         if not self.passthrough:
 123             raise NotImplemented("use endSVGElement")
 124         super().endElementNS(*args, **kwargs)
 125
 126     def startSVGDocument(self):
 127         super().startDocument()
 128         super().startPrefixMapping(None, svg_uri)
 129         if self.xlink_enabled:
 130             super().startPrefixMapping("xlink", xlink_uri)
 131         self.indent = 0
 132         self.newline = True
 133         self.xlink_used = False
 134
 135     def startSVGElement(self, name, attrs):
 136         if name != "tspan":
 137             if not self.newline:
 138                 self.characters("\n")
 139             self.characters(" "*self.indent)
 140         super().startElementNS(self.convertName(name), None, self.convertAttrs(attrs))
 141         if name != "tspan":
 142             self.indent += 1
 143             self.last_was_end = False
 144             self.newline = False
 145
 146     def newline_and_tell(self):
 147         self.characters("\n")
 148         self.newline = True
 149         return self.svg.tell()
 150
 151     def endSVGElement(self, name):
 152         if name != "tspan":
 153             self.indent -= 1
 154             if self.last_was_end:
 155                 if not self.newline:
 156                     self.characters("\n")
 157                 self.characters(" "*self.indent)
 158         super().endElementNS(self.convertName(name), None)
 159         if name != "tspan":
 160             self.last_was_end = True
 161             self.newline = False
 162
 163     def endSVGDocument(self):
 164         assert not self.indent
 165         self.characters("\n")
 166         super().endPrefixMapping(None)
 167         if self.xlink_enabled:
 168             super().endPrefixMapping("xlink")
 169         super().endDocument()
 170
 171
 172 #
 173 # Writer
 174 #
 175
 176 class SVGwriter:
 177
 178     def __init__(self, document, file, text_as_path=True, mesh_as_bitmap_resolution=300):
 179         self._fontmap = None
 180         self.text_as_path = text_as_path
 181         self.mesh_as_bitmap_resolution = mesh_as_bitmap_resolution
 182
 183         # dictionary mapping font names to dictionaries mapping encoding names to encodings
 184         # encodings themselves are mappings from glyphnames to codepoints
 185         self.encodings = {}
 186
 187         if len(document.pages) != 1:
 188             raise ValueError("SVG file can be constructed out of a single page document only")
 189         page = document.pages[0]
 190
 191         pagefile = io.BytesIO()
 192         pagesvg = SVGGenerator(pagefile)
 193         registry = SVGregistry()
 194         acontext = context()
 195         pagebbox = bbox.empty()
 196
 197         pagesvg.startSVGDocument()
 198         pagesvg.startSVGElement("svg", {})
 199         pagexml_start = pagesvg.newline_and_tell()
 200         page.processSVG(pagesvg, self, acontext, registry, pagebbox)
 201         pagexml_end = pagesvg.newline_and_tell()
 202         pagesvg.endSVGElement("svg")
 203         pagesvg.endSVGDocument()
 204
 205         x = SVGGenerator(file, xlink=pagesvg.xlink_used)
 206         x.startSVGDocument()
 207         attrs = {"fill": "none", "version": "1.1"}
 208         if pagebbox:
 209             # note that svg uses an inverse y coordinate; to compansate this
 210             # PyX writes negative y coordinates and the viewbox needs to be
 211             # adjusted accordingly (by that instead of a transforamtion
 212             # a text remains upright).
 213             llx, lly, urx, ury = pagebbox.highrestuple_pt()
 214             attrs["viewBox"] = "%g %g %g %g" % (llx, -ury, urx-llx, ury-lly)
 215             attrs["x"] = "%gpt" % llx
 216             attrs["y"] = "%gpt" % -ury
 217             attrs["width"] = "%gpt" % (urx-llx)
 218             attrs["height"] = "%gpt" % (ury-lly)
 219         style.linewidth.normal.processSVGattrs(attrs, self, acontext, registry)
 220         style.miterlimit.lessthan11deg.processSVGattrs(attrs, self, acontext, registry)
 221         x.startSVGElement("svg", attrs)
 222         registry.output(x, self)
 223         pagedata = pagefile.getvalue()
 224         x.newline_and_tell()
 225         file.write(pagedata[pagexml_start:pagexml_end])
 226         x.endSVGElement("svg")
 227         x.endSVGDocument()
 228
 229     def getfontmap(self):
 230         if self._fontmap is None:
 231             # late import due to cyclic dependency
 232             from pyx.dvi import mapfile
 233             fontmapfiles = config.getlist("text", "psfontmaps", ["psfonts.map"])
 234             self._fontmap = mapfile.readfontmap(fontmapfiles)
 235         return self._fontmap
 236
 237
 238
 239 class context:
 240
 241     def __init__(self):
 242         self.linewidth_pt = unit.topt(style.linewidth.normal.width)
 243         self.strokeattr = True
 244         self.fillattr = True
 245         self.fillcolor = "black"
 246         self.strokecolor = "black"
 247         self.fillopacity = 1
 248         self.strokeopacity = 1
 249         self.indent = 1
 250
 251     def __call__(self, **kwargs):
 252         newcontext = copy.copy(self)
 253         newcontext.indent += 1
 254         for key, value in list(kwargs.items()):
 255             setattr(newcontext, key, value)
 256         return newcontext