import Tkinter
import Pmw
class ScrolledCanvas(Pmw.MegaWidget):
def __init__(self, parent = None, **kw):
# Define the megawidget options.
INITOPT = Pmw.INITOPT
optiondefs = (
('borderframe', 0, INITOPT),
('canvasmargin', 0, INITOPT),
('hscrollmode', 'dynamic', self._hscrollMode),
('labelmargin', 0, INITOPT),
('labelpos', None, INITOPT),
('scrollmargin', 2, INITOPT),
('usehullsize', 0, INITOPT),
('vscrollmode', 'dynamic', self._vscrollMode),
)
self.defineoptions(kw, optiondefs)
# Initialise the base class (after defining the options).
Pmw.MegaWidget.__init__(self, parent)
# Create the components.
self.origInterior = Pmw.MegaWidget.interior(self)
if self['usehullsize']:
self.origInterior.grid_propagate(0)
if self['borderframe']:
# Create a frame widget to act as the border of the canvas.
self._borderframe = self.createcomponent('borderframe',
(), None,
Tkinter.Frame, (self.origInterior,),
relief = 'sunken',
borderwidth = 2,
)
self._borderframe.grid(row = 2, column = 2, sticky = 'news')
# Create the canvas widget.
self._canvas = self.createcomponent('canvas',
(), None,
Tkinter.Canvas, (self._borderframe,),
highlightthickness = 0,
borderwidth = 0,
)
self._canvas.pack(fill = 'both', expand = 1)
else:
# Create the canvas widget.
self._canvas = self.createcomponent('canvas',
(), None,
Tkinter.Canvas, (self.origInterior,),
relief = 'sunken',
borderwidth = 2,
)
self._canvas.grid(row = 2, column = 2, sticky = 'news')
self.origInterior.grid_rowconfigure(2, weight = 1, minsize = 0)
self.origInterior.grid_columnconfigure(2, weight = 1, minsize = 0)
# Create the horizontal scrollbar
self._horizScrollbar = self.createcomponent('horizscrollbar',
(), 'Scrollbar',
Tkinter.Scrollbar, (self.origInterior,),
orient='horizontal',
command=self._canvas.xview
)
# Create the vertical scrollbar
self._vertScrollbar = self.createcomponent('vertscrollbar',
(), 'Scrollbar',
Tkinter.Scrollbar, (self.origInterior,),
orient='vertical',
command=self._canvas.yview
)
self.createlabel(self.origInterior, childCols = 3, childRows = 3)
# Initialise instance variables.
self._horizScrollbarOn = 0
self._vertScrollbarOn = 0
self.scrollTimer = None
self._scrollRecurse = 0
self._horizScrollbarNeeded = 0
self._vertScrollbarNeeded = 0
self.setregionTimer = None
# Check keywords and initialise options.
self.initialiseoptions()
def destroy(self):
if self.scrollTimer is not None:
self.after_cancel(self.scrollTimer)
self.scrollTimer = None
if self.setregionTimer is not None:
self.after_cancel(self.setregionTimer)
self.setregionTimer = None
Pmw.MegaWidget.destroy(self)
# ======================================================================
# Public methods.
def interior(self):
return self._canvas
def resizescrollregion(self):
if self.setregionTimer is None:
self.setregionTimer = self.after_idle(self._setRegion)
# ======================================================================
# Configuration methods.
def _hscrollMode(self):
# The horizontal scroll mode has been configured.
mode = self['hscrollmode']
if mode == 'static':
if not self._horizScrollbarOn:
self._toggleHorizScrollbar()
elif mode == 'dynamic':
if self._horizScrollbarNeeded != self._horizScrollbarOn:
self._toggleHorizScrollbar()
elif mode == 'none':
if self._horizScrollbarOn:
self._toggleHorizScrollbar()
else:
message = 'bad hscrollmode option "%s": should be static, dynamic, or none' % mode
raise ValueError, message
self._configureScrollCommands()
def _vscrollMode(self):
# The vertical scroll mode has been configured.
mode = self['vscrollmode']
if mode == 'static':
if not self._vertScrollbarOn:
self._toggleVertScrollbar()
elif mode == 'dynamic':
if self._vertScrollbarNeeded != self._vertScrollbarOn:
self._toggleVertScrollbar()
elif mode == 'none':
if self._vertScrollbarOn:
self._toggleVertScrollbar()
else:
message = 'bad vscrollmode option "%s": should be static, dynamic, or none' % mode
raise ValueError, message
self._configureScrollCommands()
# ======================================================================
# Private methods.
def _configureScrollCommands(self):
# If both scrollmodes are not dynamic we can save a lot of
# time by not having to create an idle job to handle the
# scroll commands.
# Clean up previous scroll commands to prevent memory leak.
tclCommandName = str(self._canvas.cget('xscrollcommand'))
if tclCommandName != '':
self._canvas.deletecommand(tclCommandName)
tclCommandName = str(self._canvas.cget('yscrollcommand'))
if tclCommandName != '':
self._canvas.deletecommand(tclCommandName)
if self['hscrollmode'] == self['vscrollmode'] == 'dynamic':
self._canvas.configure(
xscrollcommand=self._scrollBothLater,
yscrollcommand=self._scrollBothLater
)
else:
self._canvas.configure(
xscrollcommand=self._scrollXNow,
yscrollcommand=self._scrollYNow
)
def _scrollXNow(self, first, last):
self._horizScrollbar.set(first, last)
self._horizScrollbarNeeded = ((first, last) != ('0', '1'))
if self['hscrollmode'] == 'dynamic':
if self._horizScrollbarNeeded != self._horizScrollbarOn:
self._toggleHorizScrollbar()
def _scrollYNow(self, first, last):
self._vertScrollbar.set(first, last)
self._vertScrollbarNeeded = ((first, last) != ('0', '1'))
if self['vscrollmode'] == 'dynamic':
if self._vertScrollbarNeeded != self._vertScrollbarOn:
self._toggleVertScrollbar()
def _scrollBothLater(self, first, last):
# Called by the canvas to set the horizontal or vertical
# scrollbar when it has scrolled or changed scrollregion.
if self.scrollTimer is None:
self.scrollTimer = self.after_idle(self._scrollBothNow)
def _scrollBothNow(self):
# This performs the function of _scrollXNow and _scrollYNow.
# If one is changed, the other should be updated to match.
self.scrollTimer = None
# Call update_idletasks to make sure that the containing frame
# has been resized before we attempt to set the scrollbars.
# Otherwise the scrollbars may be mapped/unmapped continuously.
self._scrollRecurse = self._scrollRecurse + 1
self.update_idletasks()
self._scrollRecurse = self._scrollRecurse - 1
if self._scrollRecurse != 0:
return
xview = self._canvas.xview()
yview = self._canvas.yview()
self._horizScrollbar.set(xview[0], xview[1])
self._vertScrollbar.set(yview[0], yview[1])
self._horizScrollbarNeeded = (xview != (0.0, 1.0))
self._vertScrollbarNeeded = (yview != (0.0, 1.0))
# If both horizontal and vertical scrollmodes are dynamic and
# currently only one scrollbar is mapped and both should be
# toggled, then unmap the mapped scrollbar. This prevents a
# continuous mapping and unmapping of the scrollbars.
if (self['hscrollmode'] == self['vscrollmode'] == 'dynamic' and
self._horizScrollbarNeeded != self._horizScrollbarOn and
self._vertScrollbarNeeded != self._vertScrollbarOn and
self._vertScrollbarOn != self._horizScrollbarOn):
if self._horizScrollbarOn:
self._toggleHorizScrollbar()
else:
self._toggleVertScrollbar()
return
if self['hscrollmode'] == 'dynamic':
if self._horizScrollbarNeeded != self._horizScrollbarOn:
self._toggleHorizScrollbar()
if self['vscrollmode'] == 'dynamic':
if self._vertScrollbarNeeded != self._vertScrollbarOn:
self._toggleVertScrollbar()
def _toggleHorizScrollbar(self):
self._horizScrollbarOn = not self._horizScrollbarOn
interior = self.origInterior
if self._horizScrollbarOn:
self._horizScrollbar.grid(row = 4, column = 2, sticky = 'news')
interior.grid_rowconfigure(3, minsize = self['scrollmargin'])
else:
self._horizScrollbar.grid_forget()
interior.grid_rowconfigure(3, minsize = 0)
def _toggleVertScrollbar(self):
self._vertScrollbarOn = not self._vertScrollbarOn
interior = self.origInterior
if self._vertScrollbarOn:
self._vertScrollbar.grid(row = 2, column = 4, sticky = 'news')
interior.grid_columnconfigure(3, minsize = self['scrollmargin'])
else:
self._vertScrollbar.grid_forget()
interior.grid_columnconfigure(3, minsize = 0)
def _setRegion(self):
self.setregionTimer = None
region = self._canvas.bbox('all')
if region is not None:
canvasmargin = self['canvasmargin']
region = (region[0] - canvasmargin, region[1] - canvasmargin,
region[2] + canvasmargin, region[3] + canvasmargin)
self._canvas.configure(scrollregion = region)
# Need to explicitly forward this to override the stupid
# (grid_)bbox method inherited from Tkinter.Frame.Grid.
def bbox(self, *args):
return apply(self._canvas.bbox, args)
Pmw.forwardmethods(ScrolledCanvas, Tkinter.Canvas, '_canvas')
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