| 1 | |
| 2 | <html> |
| 3 | <head> |
| 4 | <meta name="description" content="Pmw - a toolkit for building high-level compound widgets in Python"> |
| 5 | <meta name="content" content="python, megawidget, mega widget, compound widget, gui, tkinter"> |
| 6 | <title>Pmw.HistoryText reference manual</title> |
| 7 | </head> |
| 8 | |
| 9 | <body bgcolor="#ffffff" text="#000000" link="#0000ee" |
| 10 | vlink="551a8b" alink="ff0000"> |
| 11 | |
| 12 | <h1 ALIGN="CENTER">Pmw.HistoryText</h1> |
| 13 | |
| 14 | <center><IMG SRC=HistoryText.gif ALT="" WIDTH=551 HEIGHT=142></center> |
| 15 | <dl> |
| 16 | <dt> <h3>Name</h3></dt><dd> |
| 17 | <p>Pmw.HistoryText() - |
| 18 | text widget with a course-grained form of history |
| 19 | </p> |
| 20 | |
| 21 | |
| 22 | </dd> |
| 23 | <dt> <h3>Inherits</h3></dt><dd> |
| 24 | <a href="ScrolledText.html">Pmw.ScrolledText</a><br> |
| 25 | </dd> |
| 26 | <dt> <h3>Description</h3></dt><dd> |
| 27 | <p> |
| 28 | A history text is a scrolled text widget with added functionality |
| 29 | to maintain a history of each screen and allow editing of prior |
| 30 | screens. Here, <em>screen</em> refers to the entire contents of the text |
| 31 | widget. This widget does not support a fine-grained history of |
| 32 | every change made to the text.</p> |
| 33 | |
| 34 | <p> Together with a few buttons and a scrolled text to display the |
| 35 | results, a history text can be used as the query-entry part of a |
| 36 | simple interactive text-based database query system. When the |
| 37 | user enters and executes a query, the query (the entire contents |
| 38 | of the text widget) is added to the history list. The user may |
| 39 | view previous queries and either execute them again or modify them |
| 40 | and execute the new query. If a previously executed query is |
| 41 | modified, the user may undo or redo all changes made to the query |
| 42 | <em>before the query is executed</em>.</p> |
| 43 | |
| 44 | <p></p> |
| 45 | |
| 46 | |
| 47 | </dd> |
| 48 | <dt> <h3>Options</h3></dt><dd> |
| 49 | Options for this megawidget and its base |
| 50 | classes are described below.<p></p> |
| 51 | <a name=option.borderframe></a> |
| 52 | <dl><dt> <strong>borderframe |
| 53 | </strong></dt><dd> |
| 54 | Initialisation option. If true, the <strong>borderframe</strong> component will be created. The default is <strong>0</strong>.</p> |
| 55 | |
| 56 | |
| 57 | </dd></dl> |
| 58 | <a name=option.columnheader></a> |
| 59 | <dl><dt> <strong>columnheader |
| 60 | </strong></dt><dd> |
| 61 | Initialisation option. If true, the <strong>columnheader</strong> component will be created. The default is <strong>0</strong>.</p> |
| 62 | |
| 63 | |
| 64 | </dd></dl> |
| 65 | <a name=option.compressany></a> |
| 66 | <dl><dt> <strong>compressany |
| 67 | </strong></dt><dd> |
| 68 | See <code>addhistory()</code>. The default is <strong>1</strong>.</p> |
| 69 | |
| 70 | |
| 71 | </dd></dl> |
| 72 | <a name=option.compresstail></a> |
| 73 | <dl><dt> <strong>compresstail |
| 74 | </strong></dt><dd> |
| 75 | See <code>addhistory()</code>. The default is <strong>1</strong>.</p> |
| 76 | |
| 77 | |
| 78 | </dd></dl> |
| 79 | <a name=option.historycommand></a> |
| 80 | <dl><dt> <strong>historycommand |
| 81 | </strong></dt><dd> |
| 82 | This is a callback to indicate whether the currently displayed |
| 83 | entry in the history list has a previous or next entry. The |
| 84 | callback is given two arguments, <em>prevstate</em> and <em>nextstate</em>. If |
| 85 | the currently displayed entry is first in the history list, then |
| 86 | <em>prevstate</em> is <strong>'disabled'</strong>, otherwise it is <strong>'normal'</strong>. If the |
| 87 | currently displayed entry is last in the history list, then |
| 88 | <em>nextstate</em> is <strong>'disabled'</strong>, otherwise it is <strong>'normal'</strong>. These |
| 89 | values can be used, for example, to modify the state of <strong>Next</strong> and |
| 90 | <strong>Previous</strong> buttons that call the <code>next()</code> and <code>prev()</code> methods. The default is <strong>None</strong>.</p> |
| 91 | |
| 92 | |
| 93 | </dd></dl> |
| 94 | <a name=option.hscrollmode></a> |
| 95 | <dl><dt> <strong>hscrollmode |
| 96 | </strong></dt><dd> |
| 97 | The horizontal scroll mode. If <strong>'none'</strong>, the horizontal scrollbar |
| 98 | will never be displayed. If <strong>'static'</strong>, the scrollbar will always |
| 99 | be displayed. If <strong>'dynamic'</strong>, the scrollbar will be displayed |
| 100 | only if necessary. The default is <strong>'dynamic'</strong>.</p> |
| 101 | |
| 102 | |
| 103 | </dd></dl> |
| 104 | <a name=option.labelmargin></a> |
| 105 | <dl><dt> <strong>labelmargin |
| 106 | </strong></dt><dd> |
| 107 | Initialisation option. If the <strong>labelpos</strong> option is not <strong>None</strong>, this specifies the |
| 108 | distance between the <strong>label</strong> component and the rest of the |
| 109 | megawidget. The default is <strong>0</strong>.</p> |
| 110 | |
| 111 | |
| 112 | </dd></dl> |
| 113 | <a name=option.labelpos></a> |
| 114 | <dl><dt> <strong>labelpos |
| 115 | </strong></dt><dd> |
| 116 | Initialisation option. Specifies where to place the <strong>label</strong> component. If not |
| 117 | <strong>None</strong>, it should be a concatenation of one or two of the |
| 118 | letters <strong>'n'</strong>, <strong>'s'</strong>, <strong>'e'</strong> and <strong>'w'</strong>. The first letter |
| 119 | specifies on which side of the megawidget to place the label. |
| 120 | If a second letter is specified, it indicates where on that |
| 121 | side to place the label. For example, if <strong>labelpos</strong> is <strong>'w'</strong>, |
| 122 | the label is placed in the center of the left hand side; if |
| 123 | it is <strong>'wn'</strong>, the label is placed at the top of the left |
| 124 | hand side; if it is <strong>'ws'</strong>, the label is placed at the |
| 125 | bottom of the left hand side.</p> |
| 126 | <p> If <strong>None</strong>, a label component is not created. The default is <strong>None</strong>.</p> |
| 127 | |
| 128 | |
| 129 | |
| 130 | </dd></dl> |
| 131 | <a name=option.rowcolumnheader></a> |
| 132 | <dl><dt> <strong>rowcolumnheader |
| 133 | </strong></dt><dd> |
| 134 | Initialisation option. If true, the <strong>rowcolumnheader</strong> component will be created. The default is <strong>0</strong>.</p> |
| 135 | |
| 136 | |
| 137 | </dd></dl> |
| 138 | <a name=option.rowheader></a> |
| 139 | <dl><dt> <strong>rowheader |
| 140 | </strong></dt><dd> |
| 141 | Initialisation option. If true, the <strong>rowheader</strong> component will be created. The default is <strong>0</strong>.</p> |
| 142 | |
| 143 | |
| 144 | </dd></dl> |
| 145 | <a name=option.scrollmargin></a> |
| 146 | <dl><dt> <strong>scrollmargin |
| 147 | </strong></dt><dd> |
| 148 | Initialisation option. The distance between the scrollbars and the text widget. The default is <strong>2</strong>.</p> |
| 149 | |
| 150 | |
| 151 | </dd></dl> |
| 152 | <a name=option.usehullsize></a> |
| 153 | <dl><dt> <strong>usehullsize |
| 154 | </strong></dt><dd> |
| 155 | Initialisation option. If true, the size of the megawidget is determined solely by the |
| 156 | width and height options of the <strong>hull</strong> component.</p> |
| 157 | <p> Otherwise, the size of the megawidget is determined by the width |
| 158 | and height of the <strong>text</strong> component, along with the size and/or |
| 159 | existence of the other components, such as the label, the |
| 160 | scrollbars and the scrollmargin option. All these affect the |
| 161 | overall size of the megawidget. The default is <strong>0</strong>.</p> |
| 162 | |
| 163 | |
| 164 | |
| 165 | </dd></dl> |
| 166 | <a name=option.vscrollmode></a> |
| 167 | <dl><dt> <strong>vscrollmode |
| 168 | </strong></dt><dd> |
| 169 | The vertical scroll mode. If <strong>'none'</strong>, the vertical scrollbar |
| 170 | will never be displayed. If <strong>'static'</strong>, the scrollbar will always |
| 171 | be displayed. If <strong>'dynamic'</strong>, the scrollbar will be displayed |
| 172 | only if necessary. The default is <strong>'dynamic'</strong>.</p> |
| 173 | |
| 174 | |
| 175 | </dd></dl> |
| 176 | </dd> |
| 177 | <dt> <h3>Components</h3></dt><dd> |
| 178 | Components created by this megawidget and its base |
| 179 | classes are described below.<p></p> |
| 180 | <a name=component.borderframe></a> |
| 181 | <dl><dt> <strong>borderframe |
| 182 | </strong></dt><dd> |
| 183 | A frame widget which snuggly fits around the text widget, to give |
| 184 | the appearance of a text border. It is created with a border so |
| 185 | that the text widget, which is created without a border, looks |
| 186 | like it has a border. By default, this component is a Tkinter.Frame.</p> |
| 187 | |
| 188 | |
| 189 | </dd></dl> |
| 190 | <a name=component.columnheader></a> |
| 191 | <dl><dt> <strong>columnheader |
| 192 | </strong></dt><dd> |
| 193 | A text widget with a default height of 1 displayed above the main |
| 194 | text widget and which scrolls horizontally in sync with the |
| 195 | horizontal scrolling of the main text widget. By default, this component is a Tkinter.Text. Its component group is <strong>Header</strong>.</p> |
| 196 | |
| 197 | |
| 198 | </dd></dl> |
| 199 | <a name=component.horizscrollbar></a> |
| 200 | <dl><dt> <strong>horizscrollbar |
| 201 | </strong></dt><dd> |
| 202 | The horizontal scrollbar. By default, this component is a Tkinter.Scrollbar. Its component group is <strong>Scrollbar</strong>.</p> |
| 203 | |
| 204 | |
| 205 | </dd></dl> |
| 206 | <a name=component.hull></a> |
| 207 | <dl><dt> <strong>hull |
| 208 | </strong></dt><dd> |
| 209 | This acts as the body for the entire megawidget. Other components |
| 210 | are created as children of the hull to further specialise this |
| 211 | class. By default, this component is a Tkinter.Frame.</p> |
| 212 | |
| 213 | |
| 214 | </dd></dl> |
| 215 | <a name=component.label></a> |
| 216 | <dl><dt> <strong>label |
| 217 | </strong></dt><dd> |
| 218 | If the <strong>labelpos</strong> option is not <strong>None</strong>, this component is |
| 219 | created as a text label for the megawidget. See the |
| 220 | <strong>labelpos</strong> option for details. Note that to set, for example, |
| 221 | the <strong>text</strong> option of the label, you need to use the <strong>label_text</strong> |
| 222 | component option. By default, this component is a Tkinter.Label.</p> |
| 223 | |
| 224 | |
| 225 | </dd></dl> |
| 226 | <a name=component.rowcolumnheader></a> |
| 227 | <dl><dt> <strong>rowcolumnheader |
| 228 | </strong></dt><dd> |
| 229 | A text widget displayed to the top left of the main text widget, |
| 230 | above the row header and to the left of the column header if they |
| 231 | exist. The widget is not scrolled automatically. By default, this component is a Tkinter.Text. Its component group is <strong>Header</strong>.</p> |
| 232 | |
| 233 | |
| 234 | </dd></dl> |
| 235 | <a name=component.rowheader></a> |
| 236 | <dl><dt> <strong>rowheader |
| 237 | </strong></dt><dd> |
| 238 | A text widget displayed to the left of the main text widget and |
| 239 | which scrolls vertically in sync with the vertical scrolling of |
| 240 | the main text widget. By default, this component is a Tkinter.Text. Its component group is <strong>Header</strong>.</p> |
| 241 | |
| 242 | |
| 243 | </dd></dl> |
| 244 | <a name=component.text></a> |
| 245 | <dl><dt> <strong>text |
| 246 | </strong></dt><dd> |
| 247 | The text widget which is scrolled by the scrollbars. If the |
| 248 | <strong>borderframe</strong> option is true, this is created with a borderwidth |
| 249 | of <strong>0</strong> to overcome a known problem with text widgets: if a widget |
| 250 | inside a text widget extends across one of the edges of the text |
| 251 | widget, then the widget obscures the border of the text widget. |
| 252 | Therefore, if the text widget has no border, then this overlapping |
| 253 | does not occur. By default, this component is a Tkinter.Text.</p> |
| 254 | |
| 255 | |
| 256 | </dd></dl> |
| 257 | <a name=component.vertscrollbar></a> |
| 258 | <dl><dt> <strong>vertscrollbar |
| 259 | </strong></dt><dd> |
| 260 | The vertical scrollbar. By default, this component is a Tkinter.Scrollbar. Its component group is <strong>Scrollbar</strong>.</p> |
| 261 | |
| 262 | |
| 263 | </dd></dl> |
| 264 | </dd> |
| 265 | <a name=methods></a> |
| 266 | <dt> <h3>Methods</h3></dt><dd> |
| 267 | Only methods specific to this megawidget are described below. |
| 268 | For a description of its inherited methods, see the |
| 269 | manual for its base class |
| 270 | <strong><a href="ScrolledText.html#methods">Pmw.ScrolledText</a></strong>. |
| 271 | <p></p> |
| 272 | <a name=method.addhistory></a> |
| 273 | <dl><dt> <strong>addhistory</strong>()</dt><dd> |
| 274 | Append the currently displayed text to the history list.</p> |
| 275 | <p> If <strong>compressany</strong> is true, a new entry will be added to the history |
| 276 | list only if the currently displayed entry has changed.</p> |
| 277 | |
| 278 | <p> If <strong>compresstail</strong> is true, a new entry will be added to the |
| 279 | history list only if the currently displayed entry has changed |
| 280 | <em>or</em> if it is not the last entry in the history list.</p> |
| 281 | |
| 282 | |
| 283 | |
| 284 | </dd></dl> |
| 285 | <a name=method.gethistory></a> |
| 286 | <dl><dt> <strong>gethistory</strong>()</dt><dd> |
| 287 | Return the history list. Each entry in the list is a 3-tuple. |
| 288 | The first item in a history entry is the original text as added by |
| 289 | <code>addhistory()</code>. The second item is the edited text (if the user |
| 290 | has modified the entry but <code>addhistory()</code> has not yet been called |
| 291 | on the text). The third item specifies whether the entry should |
| 292 | currently display the original or modified text.</p> |
| 293 | |
| 294 | |
| 295 | </dd></dl> |
| 296 | <a name=method.next></a> |
| 297 | <dl><dt> <strong>next</strong>()</dt><dd> |
| 298 | Display the next screen in the history list.</p> |
| 299 | |
| 300 | |
| 301 | </dd></dl> |
| 302 | <a name=method.prev></a> |
| 303 | <dl><dt> <strong>prev</strong>()</dt><dd> |
| 304 | Display the previous screen in the history list.</p> |
| 305 | |
| 306 | |
| 307 | </dd></dl> |
| 308 | <a name=method.redo></a> |
| 309 | <dl><dt> <strong>redo</strong>()</dt><dd> |
| 310 | Reverse the effect of <code>undo()</code>.</p> |
| 311 | |
| 312 | |
| 313 | </dd></dl> |
| 314 | <a name=method.undo></a> |
| 315 | <dl><dt> <strong>undo</strong>()</dt><dd> |
| 316 | Undo all changes made since this entry was added to the history |
| 317 | list.</p> |
| 318 | |
| 319 | |
| 320 | </dd></dl> |
| 321 | </dd> |
| 322 | <dt> <h3>Example</h3></dt><dd> |
| 323 | The image at the top of this manual is a snapshot |
| 324 | of the window (or part of the window) produced |
| 325 | by the following code.<p></p> |
| 326 | <pre> |
| 327 | class Demo: |
| 328 | def __init__(self, parent): |
| 329 | # Create and pack the PanedWidget to hold the query and result |
| 330 | # windows. |
| 331 | # !! panedwidget should automatically size to requested size |
| 332 | panedWidget = Pmw.PanedWidget(parent, |
| 333 | orient = 'vertical', |
| 334 | hull_height = 400, |
| 335 | hull_width = 550) |
| 336 | panedWidget.add('query', min = 0.05, size = 0.2) |
| 337 | panedWidget.add('buttons', min = 0.1, max = 0.1) |
| 338 | panedWidget.add('results', min = 0.05) |
| 339 | panedWidget.pack(fill = 'both', expand = 1) |
| 340 | |
| 341 | # Create and pack the HistoryText. |
| 342 | self.historyText = Pmw.HistoryText(panedWidget.pane('query'), |
| 343 | text_wrap = 'none', |
| 344 | text_width = 60, |
| 345 | text_height = 10, |
| 346 | historycommand = self.statechange, |
| 347 | ) |
| 348 | self.historyText.pack(fill = 'both', expand = 1) |
| 349 | self.historyText.component('text').focus() |
| 350 | |
| 351 | buttonList = ( |
| 352 | [20, None], |
| 353 | ['Clear', self.clear], |
| 354 | ['Undo', self.historyText.undo], |
| 355 | ['Redo', self.historyText.redo], |
| 356 | [20, None], |
| 357 | ['Prev', self.historyText.prev], |
| 358 | ['Next', self.historyText.next], |
| 359 | [30, None], |
| 360 | ['Execute', Pmw.busycallback(self.executeQuery)], |
| 361 | ) |
| 362 | self.buttonDict = {} |
| 363 | |
| 364 | buttonFrame = panedWidget.pane('buttons') |
| 365 | for text, cmd in buttonList: |
| 366 | if type(text) == type(69): |
| 367 | frame = Tkinter.Frame(buttonFrame, width = text) |
| 368 | frame.pack(side = 'left') |
| 369 | else: |
| 370 | button = Tkinter.Button(buttonFrame, text = text, command = cmd) |
| 371 | button.pack(side = 'left') |
| 372 | self.buttonDict[text] = button |
| 373 | |
| 374 | for text in ('Prev', 'Next'): |
| 375 | self.buttonDict[text].configure(state = 'disabled') |
| 376 | |
| 377 | self.results = Pmw.ScrolledText(panedWidget.pane('results'), text_wrap = 'none') |
| 378 | self.results.pack(fill = 'both', expand = 1) |
| 379 | |
| 380 | def statechange(self, prevstate, nextstate): |
| 381 | self.buttonDict['Prev'].configure(state = prevstate) |
| 382 | self.buttonDict['Next'].configure(state = nextstate) |
| 383 | |
| 384 | def clear(self): |
| 385 | self.historyText.delete('1.0', 'end') |
| 386 | |
| 387 | def addnewlines(self, text): |
| 388 | if len(text) == 1: |
| 389 | text = text + '\n' |
| 390 | if text[-1] != '\n': |
| 391 | text = text + '\n' |
| 392 | if text[-2] != '\n': |
| 393 | text = text + '\n' |
| 394 | return text |
| 395 | |
| 396 | def executeQuery(self): |
| 397 | sql = self.historyText.get() |
| 398 | self.results.insert('end', 'Query:\n' + self.addnewlines(sql)) |
| 399 | self.results.see('end') |
| 400 | self.results.update_idletasks() |
| 401 | self.historyText.addhistory() |
| 402 | results = 'Results:\nfoo' |
| 403 | if len(results) > 0: |
| 404 | self.results.insert('end', self.addnewlines(results)) |
| 405 | self.results.see('end') |
| 406 | |
| 407 | </pre> |
| 408 | </dd> |
| 409 | </dl> |
| 410 | |
| 411 | <center><P ALIGN="CENTER"> |
| 412 | <IMG SRC = blue_line.gif ALT = "" WIDTH=320 HEIGHT=5> |
| 413 | </p></center> |
| 414 | |
| 415 | |
| 416 | <font size=-1> |
| 417 | <center><P ALIGN="CENTER"> |
| 418 | Pmw 1.2 - |
| 419 | 5 Aug 2003 |
| 420 | - <a href="index.html">Home</a> |
| 421 | <br>Manual page last reviewed: 20 May 2002 |
| 422 | </p></center> |
| 423 | </font> |
| 424 | |
| 425 | </body> |
| 426 | </html> |
| 427 | |