/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/save.py
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Contents of /branches/WIP-pyshapelib-bramz/Thuban/Model/save.py

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Revision 366 - (show annotations)
Mon Jan 27 11:48:17 2003 UTC (22 years, 1 month ago) by jonathan
Original Path: trunk/thuban/Thuban/Model/save.py
File MIME type: text/x-python
File size: 9419 byte(s)
added support to save classification information

1 # Copyright (c) 2001, 2002 by Intevation GmbH
2 # Authors:
3 # Jan-Oliver Wagner <[email protected]>
4 # Bernhard Herzog <[email protected]>
5 #
6 # This program is free software under the GPL (>=v2)
7 # Read the file COPYING coming with Thuban for details.
8
9 """
10 Functions to save a session to a file
11 """
12
13 __version__ = "$Revision$"
14
15 import os
16 import string
17
18 import Thuban.Lib.fileutil
19
20 from Thuban.Model.color import Color
21
22 #
23 # one level of indention
24 #
25 TAB = " "
26
27 def relative_filename(dir, filename):
28 """Return a filename relative to dir for the absolute file name absname.
29
30 This is almost the same as the function in fileutil, except that dir
31 can be an empty string in which case filename will be returned
32 unchanged.
33 """
34 if dir:
35 return Thuban.Lib.fileutil.relative_filename(dir, filename)
36 else:
37 return filename
38
39 def escape(data):
40 """Escape &, \", ', <, and > in a string of data.
41 """
42 data = string.replace(data, "&", "&amp;")
43 data = string.replace(data, "<", "&lt;")
44 data = string.replace(data, ">", "&gt;")
45 data = string.replace(data, '"', "&quot;")
46 data = string.replace(data, "'", "&apos;")
47 return data
48
49 class Saver:
50
51 """Class to serialize a session into an XML file.
52
53 Applications built on top of Thuban may derive from this class and
54 override or extend the methods to save additinal information. This
55 additional information should take the form of additional attributes
56 or elements whose names are prefixed with a namespace. To define a
57 namespace derived classes should extend the write_session method to
58 pass the namespaces to the default implementation.
59 """
60
61
62 def __init__(self, session):
63 self.session = session
64
65 def write(self, file_or_filename):
66 """Write the session to a file.
67
68 The argument may be either a file object or a filename. If it's
69 a filename, the file will be opened for writing. Files of
70 shapefiles will be stored as filenames relative to the directory
71 the file is stored in (as given by os.path.dirname(filename)) if
72 they have a common parent directory other than the root
73 directory.
74
75 If the argument is a file object (which is determined by the
76 presence of a write method) all filenames will be absolut
77 filenames.
78 """
79
80 self.indent_level = 0
81
82 if hasattr(file_or_filename, "write"):
83 # it's a file object
84 self.file = file_or_filename
85 self.dir = ""
86 else:
87 filename = file_or_filename
88 self.dir = os.path.dirname(filename)
89 self.file = open(filename, 'w')
90 self.write_header()
91 self.write_session(self.session)
92
93 if self.indent_level != 0:
94 raise ValueError("indent_level still positive!")
95
96 def write_attribs(self, attrs):
97 for name, value in attrs.items():
98 if isinstance(value, Color):
99 value = value.hex()
100 else:
101 value = str(value)
102 self.file.write(' %s="%s"' % (escape(name), escape(value)))
103
104 def open_element(self, element, attrs = {}):
105 # Helper function to write an element open tag with attributes
106 self.file.write("%s<%s" % (TAB*self.indent_level, element))
107 self.write_attribs(attrs)
108 self.file.write(">\n")
109
110 self.indent_level += 1
111
112 def close_element(self, element):
113 self.indent_level -= 1
114 if self.indent_level < 0:
115 raise ValueError("close_element called too many times!")
116 self.file.write("%s</%s>\n" % (TAB*self.indent_level, element))
117
118 def write_element(self, element, attrs = {}):
119 # Helper function to write an element open tag with attributes
120 self.file.write("%s<%s" % (TAB*self.indent_level, element))
121 self.write_attribs(attrs)
122 self.file.write("/>\n")
123
124 def write_header(self):
125 """Write the XML header"""
126 self.file.write('<?xml version="1.0" encoding="UTF-8"?>\n')
127 self.file.write('<!DOCTYPE session SYSTEM "thuban.dtd">\n')
128
129 def write_session(self, session, attrs = None, namespaces = ()):
130 """Write the session and its contents
131
132 By default, write a session element with the title attribute and
133 call write_map for each map contained in the session.
134
135 The optional argument attrs is for additional attributes and, if
136 given, should be a mapping from attribute names to attribute
137 values. The values should not be XML-escaped yet.
138
139 The optional argument namespaces, if given, should be a sequence
140 of (name, URI) pairs. The namespaces are written as namespace
141 attributes into the session element. This is mainly useful for
142 derived classes that need to store additional information in a
143 thuban session file.
144 """
145 if attrs is None:
146 attrs = {}
147 attrs["title"] = session.title
148 for name, uri in namespaces:
149 attrs["xmlns:" + name] = uri
150 self.open_element("session", attrs)
151 for map in session.Maps():
152 self.write_map(map)
153 self.close_element("session")
154
155 def write_map(self, map):
156 """Write the map and its contents.
157
158 By default, write a map element element with the title
159 attribute, call write_projection to write the projection
160 element, call write_layer for each layer contained in the map
161 and finally call write_label_layer to write the label layer.
162 """
163 write = self.file.write
164 self.open_element('map title="%s"' % escape(map.title))
165 self.write_projection(map.projection)
166 for layer in map.Layers():
167 self.write_layer(layer)
168 self.write_label_layer(map.LabelLayer())
169 self.close_element('map')
170
171 def write_projection(self, projection):
172 """Write the projection.
173 """
174 if projection and len(projection.params) > 0:
175 self.open_element("projection")
176 for param in projection.params:
177 self.write_element('parameter value="%s"' % escape(param))
178 self.close_element("projection")
179
180 def write_layer(self, layer, attrs = None):
181 """Write the layer.
182
183 The optional argument attrs is for additional attributes and, if
184 given, should be a mapping from attribute names to attribute
185 values. The values should not be XML-escaped yet.
186 """
187 if attrs is None:
188 attrs = {}
189 attrs["title"] = layer.title
190 attrs["filename"] = relative_filename(self.dir, layer.filename)
191 attrs["stroke_width"] = str(layer.stroke_width)
192 fill = layer.fill
193 if fill is None:
194 attrs["fill"] = "None"
195 else:
196 attrs["fill"] = fill.hex()
197 stroke = layer.stroke
198 if stroke is None:
199 attrs["stroke"] = "None"
200 else:
201 attrs["stroke"] = stroke.hex()
202
203 self.open_element("layer", attrs)
204 self.write_classification(layer)
205 self.close_element("layer")
206
207 def write_classification(self, layer, attrs = None):
208 if attrs is None:
209 attrs = {}
210
211 lc = layer.classification
212
213 field = lc.field
214
215 #
216 # there isn't a classification of anything
217 # so don't do anything
218 #
219 if field is None: return
220
221 attrs["field"] = field
222 self.open_element("classification", attrs)
223
224 if lc.NullData is not None:
225 self.open_element("clnull")
226 self.write_element("cldata", lc.NullData)
227 self.close_element("clnull")
228
229 if lc.points != {}:
230 for value, data in lc.points.items():
231 self.open_element('clpoint value="%s"' % (escape(str(value))))
232 self.write_element("cldata", data)
233 self.close_element('clpoint')
234
235 if lc.ranges != []:
236 for p in lc.ranges:
237 self.open_element('clrange min="%s" max="%s"'
238 % (escape(str(p[0])), escape(str(p[1]))))
239 self.write_element("cldata", p[2])
240 self.close_element('clrange')
241
242 self.close_element("classification")
243
244 def write_label_layer(self, layer):
245 """Write the label layer.
246 """
247 labels = layer.Labels()
248 if labels:
249 self.open_element('labellayer')
250 for label in labels:
251 self.write_element(('label x="%g" y="%g" text="%s"'
252 ' halign="%s" valign="%s"')
253 % (label.x, label.y, label.text, label.halign,
254 label.valign))
255 self.close_element('labellayer')
256
257
258
259 def save_session(session, file, saver_class = None):
260 """Save the session session to a file.
261
262 The file argument may either be a filename or an open file object.
263
264 The optional argument saver_class is the class to use to serialize
265 the session. By default or if it's None, the saver class will be
266 Saver.
267
268 If writing the session is successful call the session's
269 UnsetModified method
270 """
271 if saver_class is None:
272 saver_class = Saver
273 saver = saver_class(session)
274 saver.write(file)
275
276 # after a successful save consider the session unmodified.
277 session.UnsetModified()

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