Pmw/Pmw_1_2/lib/PmwScrolledCanvas.py

   1 import Tkinter
   2 import Pmw
   3
   4 class ScrolledCanvas(Pmw.MegaWidget):
   5     def __init__(self, parent = None, **kw):
   6
   7         # Define the megawidget options.
   8         INITOPT = Pmw.INITOPT
   9         optiondefs = (
  10             ('borderframe',    0,            INITOPT),
  11             ('canvasmargin',   0,            INITOPT),
  12             ('hscrollmode',    'dynamic',    self._hscrollMode),
  13             ('labelmargin',    0,            INITOPT),
  14             ('labelpos',       None,         INITOPT),
  15             ('scrollmargin',   2,            INITOPT),
  16             ('usehullsize',    0,            INITOPT),
  17             ('vscrollmode',    'dynamic',    self._vscrollMode),
  18         )
  19         self.defineoptions(kw, optiondefs)
  20
  21         # Initialise the base class (after defining the options).
  22         Pmw.MegaWidget.__init__(self, parent)
  23
  24         # Create the components.
  25         self.origInterior = Pmw.MegaWidget.interior(self)
  26
  27         if self['usehullsize']:
  28             self.origInterior.grid_propagate(0)
  29
  30         if self['borderframe']:
  31             # Create a frame widget to act as the border of the canvas.
  32             self._borderframe = self.createcomponent('borderframe',
  33                     (), None,
  34                     Tkinter.Frame, (self.origInterior,),
  35                     relief = 'sunken',
  36                     borderwidth = 2,
  37             )
  38             self._borderframe.grid(row = 2, column = 2, sticky = 'news')
  39
  40             # Create the canvas widget.
  41             self._canvas = self.createcomponent('canvas',
  42                     (), None,
  43                     Tkinter.Canvas, (self._borderframe,),
  44                     highlightthickness = 0,
  45                     borderwidth = 0,
  46             )
  47             self._canvas.pack(fill = 'both', expand = 1)
  48         else:
  49             # Create the canvas widget.
  50             self._canvas = self.createcomponent('canvas',
  51                     (), None,
  52                     Tkinter.Canvas, (self.origInterior,),
  53                     relief = 'sunken',
  54                     borderwidth = 2,
  55             )
  56             self._canvas.grid(row = 2, column = 2, sticky = 'news')
  57
  58         self.origInterior.grid_rowconfigure(2, weight = 1, minsize = 0)
  59         self.origInterior.grid_columnconfigure(2, weight = 1, minsize = 0)
  60
  61         # Create the horizontal scrollbar
  62         self._horizScrollbar = self.createcomponent('horizscrollbar',
  63                 (), 'Scrollbar',
  64                 Tkinter.Scrollbar, (self.origInterior,),
  65                 orient='horizontal',
  66                 command=self._canvas.xview
  67         )
  68
  69         # Create the vertical scrollbar
  70         self._vertScrollbar = self.createcomponent('vertscrollbar',
  71                 (), 'Scrollbar',
  72                 Tkinter.Scrollbar, (self.origInterior,),
  73                 orient='vertical',
  74                 command=self._canvas.yview
  75         )
  76
  77         self.createlabel(self.origInterior, childCols = 3, childRows = 3)
  78
  79         # Initialise instance variables.
  80         self._horizScrollbarOn = 0
  81         self._vertScrollbarOn = 0
  82         self.scrollTimer = None
  83         self._scrollRecurse = 0
  84         self._horizScrollbarNeeded = 0
  85         self._vertScrollbarNeeded = 0
  86         self.setregionTimer = None
  87
  88         # Check keywords and initialise options.
  89         self.initialiseoptions()
  90
  91     def destroy(self):
  92         if self.scrollTimer is not None:
  93             self.after_cancel(self.scrollTimer)
  94             self.scrollTimer = None
  95         if self.setregionTimer is not None:
  96             self.after_cancel(self.setregionTimer)
  97             self.setregionTimer = None
  98         Pmw.MegaWidget.destroy(self)
  99
 100     # ======================================================================
 101
 102     # Public methods.
 103
 104     def interior(self):
 105         return self._canvas
 106
 107     def resizescrollregion(self):
 108         if self.setregionTimer is None:
 109             self.setregionTimer = self.after_idle(self._setRegion)
 110
 111     # ======================================================================
 112
 113     # Configuration methods.
 114
 115     def _hscrollMode(self):
 116         # The horizontal scroll mode has been configured.
 117
 118         mode = self['hscrollmode']
 119
 120         if mode == 'static':
 121             if not self._horizScrollbarOn:
 122                 self._toggleHorizScrollbar()
 123         elif mode == 'dynamic':
 124             if self._horizScrollbarNeeded != self._horizScrollbarOn:
 125                 self._toggleHorizScrollbar()
 126         elif mode == 'none':
 127             if self._horizScrollbarOn:
 128                 self._toggleHorizScrollbar()
 129         else:
 130             message = 'bad hscrollmode option "%s": should be static, dynamic, or none' % mode
 131             raise ValueError, message
 132
 133         self._configureScrollCommands()
 134
 135     def _vscrollMode(self):
 136         # The vertical scroll mode has been configured.
 137
 138         mode = self['vscrollmode']
 139
 140         if mode == 'static':
 141             if not self._vertScrollbarOn:
 142                 self._toggleVertScrollbar()
 143         elif mode == 'dynamic':
 144             if self._vertScrollbarNeeded != self._vertScrollbarOn:
 145                 self._toggleVertScrollbar()
 146         elif mode == 'none':
 147             if self._vertScrollbarOn:
 148                 self._toggleVertScrollbar()
 149         else:
 150             message = 'bad vscrollmode option "%s": should be static, dynamic, or none' % mode
 151             raise ValueError, message
 152
 153         self._configureScrollCommands()
 154
 155     # ======================================================================
 156
 157     # Private methods.
 158
 159     def _configureScrollCommands(self):
 160         # If both scrollmodes are not dynamic we can save a lot of
 161         # time by not having to create an idle job to handle the
 162         # scroll commands.
 163
 164         # Clean up previous scroll commands to prevent memory leak.
 165         tclCommandName = str(self._canvas.cget('xscrollcommand'))
 166         if tclCommandName != '':
 167             self._canvas.deletecommand(tclCommandName)
 168         tclCommandName = str(self._canvas.cget('yscrollcommand'))
 169         if tclCommandName != '':
 170             self._canvas.deletecommand(tclCommandName)
 171
 172         if self['hscrollmode'] == self['vscrollmode'] == 'dynamic':
 173             self._canvas.configure(
 174                     xscrollcommand=self._scrollBothLater,
 175                     yscrollcommand=self._scrollBothLater
 176             )
 177         else:
 178             self._canvas.configure(
 179                     xscrollcommand=self._scrollXNow,
 180                     yscrollcommand=self._scrollYNow
 181             )
 182
 183     def _scrollXNow(self, first, last):
 184         self._horizScrollbar.set(first, last)
 185         self._horizScrollbarNeeded = ((first, last) != ('0', '1'))
 186
 187         if self['hscrollmode'] == 'dynamic':
 188             if self._horizScrollbarNeeded != self._horizScrollbarOn:
 189                 self._toggleHorizScrollbar()
 190
 191     def _scrollYNow(self, first, last):
 192         self._vertScrollbar.set(first, last)
 193         self._vertScrollbarNeeded = ((first, last) != ('0', '1'))
 194
 195         if self['vscrollmode'] == 'dynamic':
 196             if self._vertScrollbarNeeded != self._vertScrollbarOn:
 197                 self._toggleVertScrollbar()
 198
 199     def _scrollBothLater(self, first, last):
 200         # Called by the canvas to set the horizontal or vertical
 201         # scrollbar when it has scrolled or changed scrollregion.
 202
 203         if self.scrollTimer is None:
 204             self.scrollTimer = self.after_idle(self._scrollBothNow)
 205
 206     def _scrollBothNow(self):
 207         # This performs the function of _scrollXNow and _scrollYNow.
 208         # If one is changed, the other should be updated to match.
 209         self.scrollTimer = None
 210
 211         # Call update_idletasks to make sure that the containing frame
 212         # has been resized before we attempt to set the scrollbars.
 213         # Otherwise the scrollbars may be mapped/unmapped continuously.
 214         self._scrollRecurse = self._scrollRecurse + 1
 215         self.update_idletasks()
 216         self._scrollRecurse = self._scrollRecurse - 1
 217         if self._scrollRecurse != 0:
 218             return
 219
 220         xview = self._canvas.xview()
 221         yview = self._canvas.yview()
 222         self._horizScrollbar.set(xview[0], xview[1])
 223         self._vertScrollbar.set(yview[0], yview[1])
 224
 225         self._horizScrollbarNeeded = (xview != (0.0, 1.0))
 226         self._vertScrollbarNeeded = (yview != (0.0, 1.0))
 227
 228         # If both horizontal and vertical scrollmodes are dynamic and
 229         # currently only one scrollbar is mapped and both should be
 230         # toggled, then unmap the mapped scrollbar.  This prevents a
 231         # continuous mapping and unmapping of the scrollbars.
 232         if (self['hscrollmode'] == self['vscrollmode'] == 'dynamic' and
 233                 self._horizScrollbarNeeded != self._horizScrollbarOn and
 234                 self._vertScrollbarNeeded != self._vertScrollbarOn and
 235                 self._vertScrollbarOn != self._horizScrollbarOn):
 236             if self._horizScrollbarOn:
 237                 self._toggleHorizScrollbar()
 238             else:
 239                 self._toggleVertScrollbar()
 240             return
 241
 242         if self['hscrollmode'] == 'dynamic':
 243             if self._horizScrollbarNeeded != self._horizScrollbarOn:
 244                 self._toggleHorizScrollbar()
 245
 246         if self['vscrollmode'] == 'dynamic':
 247             if self._vertScrollbarNeeded != self._vertScrollbarOn:
 248                 self._toggleVertScrollbar()
 249
 250     def _toggleHorizScrollbar(self):
 251
 252         self._horizScrollbarOn = not self._horizScrollbarOn
 253
 254         interior = self.origInterior
 255         if self._horizScrollbarOn:
 256             self._horizScrollbar.grid(row = 4, column = 2, sticky = 'news')
 257             interior.grid_rowconfigure(3, minsize = self['scrollmargin'])
 258         else:
 259             self._horizScrollbar.grid_forget()
 260             interior.grid_rowconfigure(3, minsize = 0)
 261
 262     def _toggleVertScrollbar(self):
 263
 264         self._vertScrollbarOn = not self._vertScrollbarOn
 265
 266         interior = self.origInterior
 267         if self._vertScrollbarOn:
 268             self._vertScrollbar.grid(row = 2, column = 4, sticky = 'news')
 269             interior.grid_columnconfigure(3, minsize = self['scrollmargin'])
 270         else:
 271             self._vertScrollbar.grid_forget()
 272             interior.grid_columnconfigure(3, minsize = 0)
 273
 274     def _setRegion(self):
 275         self.setregionTimer = None
 276
 277         region = self._canvas.bbox('all')
 278         if region is not None:
 279             canvasmargin = self['canvasmargin']
 280             region = (region[0] - canvasmargin, region[1] - canvasmargin,
 281                 region[2] + canvasmargin, region[3] + canvasmargin)
 282             self._canvas.configure(scrollregion = region)
 283
 284     # Need to explicitly forward this to override the stupid
 285     # (grid_)bbox method inherited from Tkinter.Frame.Grid.
 286     def bbox(self, *args):
 287         return apply(self._canvas.bbox, args)
 288
 289 Pmw.forwardmethods(ScrolledCanvas, Tkinter.Canvas, '_canvas')