/[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 466 - (show annotations)
Wed Mar 5 18:18:20 2003 UTC (22 years ago) by jonathan
Original Path: trunk/thuban/Thuban/Model/save.py
File MIME type: text/x-python
File size: 12084 byte(s)
(Saver): Store field type information.

1 # Copyright (c) 2001, 2002, 2003 by Intevation GmbH
2 # Authors:
3 # Jan-Oliver Wagner <[email protected]>
4 # Bernhard Herzog <[email protected]>
5 # Jonathan Coles <[email protected]>
6 #
7 # This program is free software under the GPL (>=v2)
8 # Read the file COPYING coming with Thuban for details.
9
10 """
11 Functions to save a session to a file
12 """
13
14 __version__ = "$Revision$"
15
16 # fix for people using python2.1
17 from __future__ import nested_scopes
18
19 import os
20 import string
21
22 import Thuban.Lib.fileutil
23
24 from Thuban.Model.color import Color
25
26 from Thuban.Model.classification import *
27
28 #
29 # one level of indention
30 #
31 TAB = " "
32
33 def relative_filename(dir, filename):
34 """Return a filename relative to dir for the absolute file name absname.
35
36 This is almost the same as the function in fileutil, except that dir
37 can be an empty string in which case filename will be returned
38 unchanged.
39 """
40 if dir:
41 return Thuban.Lib.fileutil.relative_filename(dir, filename)
42 else:
43 return filename
44
45 def escape(data):
46 """Escape &, \", ', <, and > in a string of data.
47 """
48 data = string.replace(data, "&", "&amp;")
49 data = string.replace(data, "<", "&lt;")
50 data = string.replace(data, ">", "&gt;")
51 data = string.replace(data, '"', "&quot;")
52 data = string.replace(data, "'", "&apos;")
53 return data
54
55 class Saver:
56
57 """Class to serialize a session into an XML file.
58
59 Applications built on top of Thuban may derive from this class and
60 override or extend the methods to save additional information. This
61 additional information should take the form of additional attributes
62 or elements whose names are prefixed with a namespace. To define a
63 namespace derived classes should extend the write_session method to
64 pass the namespaces to the default implementation.
65 """
66
67
68 def __init__(self, session):
69 self.session = session
70
71 def write(self, file_or_filename):
72 """Write the session to a file.
73
74 The argument may be either a file object or a filename. If it's
75 a filename, the file will be opened for writing. Files of
76 shapefiles will be stored as filenames relative to the directory
77 the file is stored in (as given by os.path.dirname(filename)) if
78 they have a common parent directory other than the root
79 directory.
80
81 If the argument is a file object (which is determined by the
82 presence of a write method) all filenames will be absolut
83 filenames.
84 """
85
86 # keep track of how many levels of indentation to write
87 self.indent_level = 0
88 # track whether an element is currently open. see open_element().
89 self.element_open = 0
90
91 if hasattr(file_or_filename, "write"):
92 # it's a file object
93 self.file = file_or_filename
94 self.dir = ""
95 else:
96 filename = file_or_filename
97 self.dir = os.path.dirname(filename)
98 self.file = open(filename, 'w')
99 self.write_header()
100 self.write_session(self.session)
101
102 assert(self.indent_level == 0)
103
104 def write_attribs(self, attrs):
105 for name, value in attrs.items():
106 self.file.write(' %s="%s"' % (escape(name), escape(value)))
107
108 def open_element(self, element, attrs = {}):
109
110 #
111 # we note when an element is opened so that if two open_element()
112 # calls are made successively we can end the currently open
113 # tag and will later write a proper close tag. otherwise,
114 # if a close_element() call is made directly after an open_element()
115 # call we will close the tag with a />
116 #
117 if self.element_open == 1:
118 self.file.write(">\n")
119
120 self.element_open = 1
121
122 # Helper function to write an element open tag with attributes
123 self.file.write("%s<%s" % (TAB*self.indent_level, element))
124 self.write_attribs(attrs)
125
126 self.indent_level += 1
127
128 def close_element(self, element):
129 self.indent_level -= 1
130 assert(self.indent_level >= 0)
131
132 # see open_element() for an explanation
133 if self.element_open == 1:
134 self.element_open = 0
135 self.file.write("/>\n")
136 else:
137 self.file.write("%s</%s>\n" % (TAB*self.indent_level, element))
138
139 def write_element(self, element, attrs = {}):
140 """write an element that won't need a closing tag"""
141 self.open_element(element, attrs)
142 self.close_element(element)
143
144 def write_header(self):
145 """Write the XML header"""
146 self.file.write('<?xml version="1.0" encoding="UTF-8"?>\n')
147 self.file.write('<!DOCTYPE session SYSTEM "thuban.dtd">\n')
148
149 def write_session(self, session, attrs = None, namespaces = ()):
150 """Write the session and its contents
151
152 By default, write a session element with the title attribute and
153 call write_map for each map contained in the session.
154
155 The optional argument attrs is for additional attributes and, if
156 given, should be a mapping from attribute names to attribute
157 values. The values should not be XML-escaped yet.
158
159 The optional argument namespaces, if given, should be a sequence
160 of (name, URI) pairs. The namespaces are written as namespace
161 attributes into the session element. This is mainly useful for
162 derived classes that need to store additional information in a
163 thuban session file.
164 """
165 if attrs is None:
166 attrs = {}
167 attrs["title"] = session.title
168 for name, uri in namespaces:
169 attrs["xmlns:" + name] = uri
170 self.open_element("session", attrs)
171 for map in session.Maps():
172 self.write_map(map)
173 self.close_element("session")
174
175 def write_map(self, map):
176 """Write the map and its contents.
177
178 By default, write a map element element with the title
179 attribute, call write_projection to write the projection
180 element, call write_layer for each layer contained in the map
181 and finally call write_label_layer to write the label layer.
182 """
183 #write = self.file.write
184 self.open_element('map title="%s"' % escape(map.title))
185 self.write_projection(map.projection)
186 for layer in map.Layers():
187 self.write_layer(layer)
188 self.write_label_layer(map.LabelLayer())
189 self.close_element('map')
190
191 def write_projection(self, projection):
192 """Write the projection.
193 """
194 if projection and len(projection.params) > 0:
195 self.open_element("projection")
196 for param in projection.params:
197 self.write_element('parameter value="%s"' % escape(param))
198 self.close_element("projection")
199
200 def write_layer(self, layer, attrs = None):
201 """Write the layer.
202
203 The optional argument attrs is for additional attributes and, if
204 given, should be a mapping from attribute names to attribute
205 values. The values should not be XML-escaped yet.
206 """
207 lc = layer.GetClassification()
208
209 if attrs is None:
210 attrs = {}
211
212 attrs["title"] = layer.title
213 attrs["filename"] = relative_filename(self.dir, layer.filename)
214 attrs["stroke"] = lc.GetDefaultLineColor().hex()
215 attrs["stroke_width"] = str(lc.GetDefaultLineWidth())
216 attrs["fill"] = lc.GetDefaultFill().hex()
217
218 self.open_element("layer", attrs)
219 self.write_classification(layer)
220 self.close_element("layer")
221
222 def write_classification(self, layer, attrs = None):
223 if attrs is None:
224 attrs = {}
225
226 lc = layer.GetClassification()
227
228 field = lc.GetField()
229
230 #
231 # there isn't a classification of anything
232 # so don't do anything
233 #
234 if field is None: return
235
236 attrs["field"] = field
237 attrs["field_type"] = str(lc.GetFieldType())
238 self.open_element("classification", attrs)
239
240
241 # self.open_element("clnull")
242 # write_class_data(lc.GetDefaultData())
243 # self.close_element("clnull")
244
245 # just playing now with lambdas and dictionaries
246
247 types = [[lambda p: 'clnull',
248 lambda p: 'clnull'],
249 [lambda p: 'clpoint value="%s"' %
250 str(p.GetValue()),
251 lambda p: 'clpoint'],
252 [lambda p: 'clrange min="%s" max="%s"' %
253 (str(p.GetMin()),
254 (str(p.GetMax()))),
255 lambda p: 'clrange']]
256
257 def write_class_group(group):
258 type = -1
259 if isinstance(group, ClassGroupDefault): type = 0
260 elif isinstance(group, ClassGroupSingleton): type = 1
261 elif isinstance(group, ClassGroupRange): type = 2
262 elif isinstance(group, ClassGroupMap): type = 3
263 assert(type >= 0)
264
265 if type <= 2:
266 data = group.GetProperties()
267 dict = {'stroke' : data.GetLineColor().hex(),
268 'stroke_width': str(data.GetLineWidth()),
269 'fill' : data.GetFill().hex()}
270
271 self.open_element(types[type][0](group))
272 self.write_element("cldata", dict)
273 self.close_element(types[type][1](group))
274 else: pass # XXX: we need to handle maps
275
276 for i in lc:
277 write_class_group(i)
278
279 # for i in lc:
280 # t = i.GetType()
281 # self.open_element(types[t][0](i))
282 # write_class_data(i)
283 # self.close_element(types[t][1](i))
284
285 # for p in lc:
286 # type = p.GetType()
287 # if p == ClassData.DEFAULT:
288 # lopen = lclose = 'clnull'
289 # elif p == ClassData.POINTS:
290 # lopen = 'clpoint value="%s"' % escape(str(p.GetValue()))
291 # lclose = 'clpoint'
292 # elif p == ClassData.RANGES:
293 # lopen = 'clrange min="%s" max="%s"'
294 # % (escape(str(p.GetMin())), escape(str(p.GetMax()))))
295 # lclose = 'clrange'
296
297 # self.open_element(lopen)
298 # write_class_data(p)
299 # self.close_element(lclose)
300
301 # if lc.points != {}:
302 # for p in lc.points.values():
303 # self.open_element('clpoint value="%s"' %
304 # (escape(str(p.GetValue()))))
305 # write_class_data(p)
306 # self.close_element('clpoint')
307 #
308 # if lc.ranges != []:
309 # for p in lc.ranges:
310 # self.open_element('clrange min="%s" max="%s"'
311 # % (escape(str(p.GetMin())), escape(str(p.GetMax()))))
312 # write_class_data(p)
313 # self.close_element('clrange')
314
315 self.close_element("classification")
316
317 def write_label_layer(self, layer):
318 """Write the label layer.
319 """
320 labels = layer.Labels()
321 if labels:
322 self.open_element('labellayer')
323 for label in labels:
324 self.write_element(('label x="%g" y="%g" text="%s"'
325 ' halign="%s" valign="%s"')
326 % (label.x, label.y, label.text, label.halign,
327 label.valign))
328 self.close_element('labellayer')
329
330
331
332 def save_session(session, file, saver_class = None):
333 """Save the session session to a file.
334
335 The file argument may either be a filename or an open file object.
336
337 The optional argument saver_class is the class to use to serialize
338 the session. By default or if it's None, the saver class will be
339 Saver.
340
341 If writing the session is successful call the session's
342 UnsetModified method
343 """
344 if saver_class is None:
345 saver_class = Saver
346 saver = saver_class(session)
347 saver.write(file)
348
349 # after a successful save consider the session unmodified.
350 session.UnsetModified()

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