| 23 |
<holder>Intevation GmbH</holder> |
<holder>Intevation GmbH</holder> |
| 24 |
</copyright> |
</copyright> |
| 25 |
<revhistory> |
<revhistory> |
| 26 |
|
<!-- comment this first revision out when releasing a real version --> |
| 27 |
|
<!-- |
| 28 |
|
<revision> |
| 29 |
|
<revnumber>CVS version $Id$</revnumber> |
| 30 |
|
<date></date> |
| 31 |
|
<revremark>Under development.</revremark> |
| 32 |
|
</revision> |
| 33 |
|
--> |
| 34 |
|
<revision> |
| 35 |
|
<revnumber>1.0pre2</revnumber> |
| 36 |
|
<date>29-Aug-2003</date> |
| 37 |
|
<revremark> |
| 38 |
|
Corresponds to Thuban development release 0.8.1. |
| 39 |
|
New: chapter on extensions. |
| 40 |
|
</revremark> |
| 41 |
|
</revision> |
| 42 |
<revision> |
<revision> |
| 43 |
<revnumber>1.0pre1</revnumber> |
<revnumber>1.0pre1</revnumber> |
| 44 |
<date>08-Aug-2003</date> |
<date>08-Aug-2003</date> |
| 45 |
<revremark>Corresponds to Thuban development release 0.8.1</revremark> |
<revremark>Corresponds to Thuban development release 0.8.1.</revremark> |
| 46 |
</revision> |
</revision> |
| 47 |
</revhistory> |
</revhistory> |
| 48 |
|
|
| 247 |
|
|
| 248 |
<section><title>Adding and Removing Layers</title> |
<section><title>Adding and Removing Layers</title> |
| 249 |
<para> |
<para> |
| 250 |
There are two types of layers that can be added to a map: shape layers |
There are two types of layers that can be added to a map: Shape layers |
| 251 |
and image layers. Shape layers are stored in Shapefile format, a |
and image layers. Shape layers are stored in Shapefile format, a |
| 252 |
standard file format for storing geographic objects. These |
widely used file format for storing geographic objects. These |
| 253 |
files have the extension ``.shp''. Associated with |
files have the extension ``.shp''. Associated with |
| 254 |
the shape file is a database file which stores attributes for |
the shape file is a database file which stores attributes for |
| 255 |
each shape in the shape file. This file, in dBase format, |
each shape in the Shape file. This file, in dBase format, |
| 256 |
has the extension ``.dbf''. Both files must have the same base name. |
has the extension ``.dbf''. Both files must have the same base name. |
| 257 |
For example, if there is a shape file named roads.shp there must |
For example, if there is a shape file named roads.shp there must |
| 258 |
also be a file roads.dbf. |
also be a file roads.dbf. |
| 263 |
<guimenu>Map</guimenu> |
<guimenu>Map</guimenu> |
| 264 |
<guimenuitem>Add Layer</guimenuitem> |
<guimenuitem>Add Layer</guimenuitem> |
| 265 |
</menuchoice>. |
</menuchoice>. |
| 266 |
Thuban will load all files with the same base name, so it doesn't |
Initially, only the ``.shp'' files are shown which is enough for the |
| 267 |
matter if the shape file or database file is selected. |
selection. However, if you switch to display all files and select one |
| 268 |
|
of the associated files (e.g. ``.dbf''), Thuban will recognize the base |
| 269 |
|
name and load the corresponding Shape file. |
| 270 |
|
</para> |
| 271 |
|
<para> |
| 272 |
|
The file dialog for Shape files allows to select multiple files. |
| 273 |
|
Use the shift-button together with the left mouse button to extend |
| 274 |
|
the selection. |
| 275 |
</para> |
</para> |
| 276 |
|
|
| 277 |
<para> |
<para> |
| 1235 |
</section> |
</section> |
| 1236 |
</chapter> |
</chapter> |
| 1237 |
|
|
| 1238 |
|
<chapter><title>Extensions</title> |
| 1239 |
|
<para> |
| 1240 |
|
Thuban is designed to be extensible. The term Extension is used as a |
| 1241 |
|
general term for anything that extends Thuban. |
| 1242 |
|
This chapter introduces into some oppportunities how to add and |
| 1243 |
|
handle extra functionality developed by your own or third parties. |
| 1244 |
|
</para> |
| 1245 |
|
|
| 1246 |
|
<section><title>Add personal extensions via thubanstart.py</title> |
| 1247 |
|
<para> |
| 1248 |
|
After Thuban has been started for the first time, a directory |
| 1249 |
|
.thuban is created within your home directory. |
| 1250 |
|
There you can add a file thubanstart.py which will be imported |
| 1251 |
|
by Thuban at start-up. It is recommended to add only import-statements |
| 1252 |
|
to this file to keep the actual code of extensions separate. |
| 1253 |
|
</para> |
| 1254 |
|
<para> |
| 1255 |
|
The modules to import must either be found though the environment |
| 1256 |
|
variable PYTHONPATH or directly be placed into the .thuban-directory. |
| 1257 |
|
</para> |
| 1258 |
|
<para> |
| 1259 |
|
As an example, copy the file examples/simple_extensions/hello_world.py |
| 1260 |
|
of the Thuban source code into the .thuban-directory of your home |
| 1261 |
|
directory. Now add add the statement import hello_world to the |
| 1262 |
|
file thubanstart.py and run Thuban. You will notice an additional |
| 1263 |
|
menu <menuchoice><guimenu>Extensions</guimenu></menuchoice> where |
| 1264 |
|
the new item for the Hello-World extension is placed - select it |
| 1265 |
|
to see the Hello-World message. |
| 1266 |
|
</para> |
| 1267 |
|
</section> |
| 1268 |
|
|
| 1269 |
|
<section><title>Writing simple extensions</title> |
| 1270 |
|
<para> |
| 1271 |
|
Writing an extension for Thuban basically means to |
| 1272 |
|
implement the extra functionality in Python with all of the |
| 1273 |
|
Thuban classes, methods and variables available. |
| 1274 |
|
</para> |
| 1275 |
|
<para> |
| 1276 |
|
All classes and their methods are documented in the source code |
| 1277 |
|
(see their doc-strings). Here is an example from |
| 1278 |
|
Thuban/Model/layer.py that describes some of the methods |
| 1279 |
|
of a Layer object: |
| 1280 |
|
</para> |
| 1281 |
|
<programlisting> |
| 1282 |
|
<![CDATA[ |
| 1283 |
|
class BaseLayer(TitledObject, Modifiable): |
| 1284 |
|
|
| 1285 |
|
"""Base class for the layers.""" |
| 1286 |
|
|
| 1287 |
|
def __init__(self, title, visible = True, projection = None): |
| 1288 |
|
"""Initialize the layer. |
| 1289 |
|
|
| 1290 |
|
title -- the title |
| 1291 |
|
visible -- boolean. If true the layer is visible. |
| 1292 |
|
""" |
| 1293 |
|
TitledObject.__init__(self, title) |
| 1294 |
|
Modifiable.__init__(self) |
| 1295 |
|
self.visible = visible |
| 1296 |
|
self.projection = projection |
| 1297 |
|
|
| 1298 |
|
def Visible(self): |
| 1299 |
|
"""Return true if layer is visible""" |
| 1300 |
|
return self.visible |
| 1301 |
|
|
| 1302 |
|
def SetVisible(self, visible): |
| 1303 |
|
"""Set the layer's visibility.""" |
| 1304 |
|
self.visible = visible |
| 1305 |
|
self.issue(LAYER_VISIBILITY_CHANGED, self) |
| 1306 |
|
|
| 1307 |
|
def HasClassification(self): |
| 1308 |
|
"""Determine if this layer support classifications.""" |
| 1309 |
|
... |
| 1310 |
|
]]> |
| 1311 |
|
</programlisting> |
| 1312 |
|
<para> |
| 1313 |
|
This example intends to give you an impression of the |
| 1314 |
|
source-code-level documentation. |
| 1315 |
|
You have to make yourself familiar with |
| 1316 |
|
the Python programming language to understand some special |
| 1317 |
|
code elements. |
| 1318 |
|
</para> |
| 1319 |
|
<section><title>hello_world.py</title> |
| 1320 |
|
<para> |
| 1321 |
|
Traditionally, the first example should welcome the world. |
| 1322 |
|
Most of the code handles the frame for integrating a menu |
| 1323 |
|
item into Thuban while the actual raising of a message |
| 1324 |
|
is done in a single line. |
| 1325 |
|
</para> |
| 1326 |
|
<programlisting> |
| 1327 |
|
<![CDATA[ |
| 1328 |
|
# Copyright (C) 2003 by Intevation GmbH |
| 1329 |
|
# Authors: |
| 1330 |
|
# Jan-Oliver Wagner <[email protected]> |
| 1331 |
|
# |
| 1332 |
|
# This program is free software under the GPL (>=v2) |
| 1333 |
|
# Read the file COPYING coming with Thuban for details. |
| 1334 |
|
|
| 1335 |
|
""" |
| 1336 |
|
Extend Thuban with a sample Hello World to demonstrate simple |
| 1337 |
|
extensions. |
| 1338 |
|
""" |
| 1339 |
|
|
| 1340 |
|
__version__ = '$Revision$' |
| 1341 |
|
|
| 1342 |
|
# use _() already now for all strings that may later be translated |
| 1343 |
|
from Thuban import _ |
| 1344 |
|
|
| 1345 |
|
# Thuban has named commands which can be registered in the central |
| 1346 |
|
# instance registry. |
| 1347 |
|
from Thuban.UI.command import registry, Command |
| 1348 |
|
|
| 1349 |
|
# The instance of the main menu of the Thuban application |
| 1350 |
|
# See Thuban/UI/menu.py for the API of the Menu class |
| 1351 |
|
from Thuban.UI.mainwindow import main_menu |
| 1352 |
|
|
| 1353 |
|
def hello_world_dialog(context): |
| 1354 |
|
"""Just raise a simple dialog to greet the world. |
| 1355 |
|
|
| 1356 |
|
context -- The Thuban context. |
| 1357 |
|
""" |
| 1358 |
|
context.mainwindow.RunMessageBox(_('Hello World'), _('Hello World!')) |
| 1359 |
|
|
| 1360 |
|
|
| 1361 |
|
# create a new command and register it |
| 1362 |
|
registry.Add(Command('hello_world', _('Hello World'), hello_world_dialog, |
| 1363 |
|
helptext = _('Welcome everyone on this planet'))) |
| 1364 |
|
|
| 1365 |
|
# find the extensions menu (create it anew if not found) |
| 1366 |
|
extensions_menu = main_menu.find_menu('extensions') |
| 1367 |
|
if extensions_menu is None: |
| 1368 |
|
extensions_menu = main_menu.InsertMenu('extensions', _('E&xtensions')) |
| 1369 |
|
|
| 1370 |
|
# finally bind the new command with an entry in the extensions menu |
| 1371 |
|
extensions_menu.InsertItem('hello_world') |
| 1372 |
|
]]> |
| 1373 |
|
</programlisting> |
| 1374 |
|
</section> |
| 1375 |
|
<section><title>Registering a Command</title> |
| 1376 |
|
<para> |
| 1377 |
|
Mainly, our new function has to be registered to the Thuban |
| 1378 |
|
framework in order to connect it to the menu. A registered |
| 1379 |
|
command can also be connected to e.g. a toolbar button. |
| 1380 |
|
</para> |
| 1381 |
|
<para> |
| 1382 |
|
The instances and classes for this are imported at the beginning. |
| 1383 |
|
Any code not inside a method or class is directly executed when |
| 1384 |
|
the source-code module is imported. Therefore, the second |
| 1385 |
|
part of this example consist of the plain statements to create a new |
| 1386 |
|
Command and to add it to the menu. |
| 1387 |
|
</para> |
| 1388 |
|
<para> |
| 1389 |
|
By convention, it looks for a menu registered as ``extensions'' to |
| 1390 |
|
insert the new command. If it does not exist yet, it gets created. |
| 1391 |
|
It is advisable to copy this code for any of your extensions. |
| 1392 |
|
</para> |
| 1393 |
|
</section> |
| 1394 |
|
<section><title>The Thuban context</title> |
| 1395 |
|
<para> |
| 1396 |
|
A registered command that is called, always receives the |
| 1397 |
|
Thuban context. This instance provides our method with |
| 1398 |
|
hook references to all important components of the Thuban |
| 1399 |
|
application. |
| 1400 |
|
</para> |
| 1401 |
|
<para> |
| 1402 |
|
In the example hello_world.py, our function uses the |
| 1403 |
|
mainwindow component which offers a method to raise a |
| 1404 |
|
message dialog. In total there are three hooks: |
| 1405 |
|
<itemizedlist> |
| 1406 |
|
<listitem> |
| 1407 |
|
<para>application: |
| 1408 |
|
This object is the instance of the Thuban Application class. |
| 1409 |
|
Except maybe for loading or savinf sessions, you will not |
| 1410 |
|
need this object for a simple extension. |
| 1411 |
|
See Thuban/UI/application.py for the API. |
| 1412 |
|
</para> |
| 1413 |
|
</listitem> |
| 1414 |
|
<listitem> |
| 1415 |
|
<para>session: |
| 1416 |
|
The instance of the current session. It manages the sessions' |
| 1417 |
|
map and tables. You can set and remove the map or tables. |
| 1418 |
|
In may also get the map object. However, you should know that |
| 1419 |
|
internally it is already prepared to handle many maps. |
| 1420 |
|
Therfore, currently you would always receive a list with exactlty |
| 1421 |
|
one element. In the future, if there are more than one map, |
| 1422 |
|
you will not know which one is the currently display one and |
| 1423 |
|
therefore you should use the mainwindow as hook to find |
| 1424 |
|
the currently displayed map. |
| 1425 |
|
See Thuban/Model/session.py for the API. |
| 1426 |
|
</para> |
| 1427 |
|
</listitem> |
| 1428 |
|
<listitem> |
| 1429 |
|
<para> |
| 1430 |
|
mainwindow: The mainwindow object is central to manage various |
| 1431 |
|
GUI things such as the Legend sub-window. Most notably, |
| 1432 |
|
you get access to the canvas which is the window part where |
| 1433 |
|
the map is drawn. The canvas knows, which map it currently |
| 1434 |
|
draws and therefore you get the current map via |
| 1435 |
|
context.mainwindow.canvas.Map(). |
| 1436 |
|
See Thuban/UI/mainwindow.py for the API. |
| 1437 |
|
</para> |
| 1438 |
|
</listitem> |
| 1439 |
|
</itemizedlist> |
| 1440 |
|
</para> |
| 1441 |
|
</section> |
| 1442 |
|
</section> |
| 1443 |
|
</chapter> |
| 1444 |
|
|
| 1445 |
<chapter><title>Trouble Shooting</title> |
<chapter><title>Trouble Shooting</title> |
| 1446 |
<para> |
<para> |
| 1447 |
Here are a few problems that users have encountered when first using Thuban. |
Here are a few problems that users have encountered when first using Thuban. |
Parent Directory
| 
Revision Log
| 
Patch