src/KML.py

   1 """
   2 Utility classes for working with the Keyhole Markup Language (KML).
   3 """
   4
   5 import sys
   6 from xml.sax.saxutils import escape
   7
   8
   9 class KmlObject(object):
  10     """
  11     The base class of all KML elements, according to the reference:
  12
  13       http://code.google.com/apis/kml/documentation/kmlreference.html
  14
  15     Every other class in this module should derive from
  16     KmlObject. This class provides a default constructor which creates
  17     some necessary attributes, and default implementations of to_kml()
  18     and render().
  19
  20     The to_kml() methods of our subclasses will, in general, generate
  21     an opening tag, render themselves (whatever that means), and then
  22     generate a closing tag. A call to render() generally returns the
  23     element's text, and renders its children recursively.
  24     """
  25
  26     OPEN_TAG = ''
  27     CLOSE_TAG = ''
  28
  29     def __init__(self, initial_text=''):
  30         self.children = []
  31         self.text = initial_text
  32
  33
  34     def to_kml(self):
  35         return self.render()
  36
  37
  38     def render(self):
  39         kml = self.OPEN_TAG
  40         kml += escape(self.text)
  41
  42         for c in self.children:
  43             kml += c.to_kml()
  44
  45         kml += self.CLOSE_TAG + "\n"
  46
  47         return kml
  48
  49
  50     def print_kml(self):
  51         print self.OPEN_TAG
  52         self.render_to_stdout()
  53         print self.CLOSE_TAG
  54
  55
  56     def render_to_stdout(self):
  57         if (len(self.text) > 0):
  58             print escape(self.text)
  59
  60         for c in self.children:
  61             c.print_kml()
  62
  63
  64
  65 class Color(KmlObject):
  66
  67     OPEN_TAG = '<color>'
  68     CLOSE_TAG = '</color>'
  69
  70
  71 class Document(KmlObject):
  72
  73     OPEN_TAG = """<?xml version=\"1.0\" encoding=\"UTF-8\"?>
  74 <kml xmlns=\"http://www.opengis.net/kml/2.2\">
  75 <Document>"""
  76
  77     CLOSE_TAG = """</Document>
  78     </kml>"""
  79
  80     def __init__(self, initial_text=''):
  81         super(Document, self).__init__(initial_text)
  82         self.styles = []
  83
  84
  85     def render(self):
  86         kml = ''
  87
  88         for s in self.styles:
  89             kml += s.to_kml()
  90
  91         for c in self.children:
  92             kml += c.to_kml()
  93
  94         return kml
  95
  96
  97     def render_to_stdout(self):
  98         for s in self.styles:
  99             s.print_kml()
 100
 101         for c in self.children:
 102             c.print_kml()
 103
 104
 105
 106 class Description(KmlObject):
 107
 108     OPEN_TAG = '<description>'
 109     CLOSE_TAG = '</description>'
 110
 111
 112
 113 class Name(KmlObject):
 114
 115     OPEN_TAG = '<name>'
 116     CLOSE_TAG = '</name>'
 117
 118
 119
 120 class Placemark(KmlObject):
 121
 122     OPEN_TAG = '<Placemark>'
 123     CLOSE_TAG = '</Placemark>'
 124
 125
 126
 127 class PolyStyle(KmlObject):
 128
 129     OPEN_TAG = '<PolyStyle>'
 130     CLOSE_TAG = '</PolyStyle>'
 131
 132
 133
 134 class Style(KmlObject):
 135
 136     OPEN_TAG = "<Style id=\"%s\">"
 137     CLOSE_TAG = '</Style>'
 138
 139     def __init__(self, initial_text='', initial_id=''):
 140         super(Style, self).__init__(initial_text)
 141         self.id = initial_id
 142
 143
 144     def to_kml(self):
 145         kml = ''
 146         kml += (self.OPEN_TAG % self.id + "\n")
 147         kml += self.render()
 148         kml += self.CLOSE_TAG + "\n"
 149
 150         return kml
 151
 152
 153     def print_kml(self):
 154         print (self.OPEN_TAG % self.id)
 155         self.render_to_stdout()
 156         print self.CLOSE_TAG
 157
 158
 159
 160 class StyleUrl(KmlObject):
 161
 162     OPEN_TAG = '<styleUrl>'
 163     CLOSE_TAG = '</styleUrl>'
 164
 165
 166
 167 class RawText(KmlObject):
 168
 169     def to_kml(self):
 170         return self.text
 171
 172     def print_kml(self):
 173         if (len(self.text) > 0):
 174             print self.text