Viewing file:  Switchboard.py (4.7 KB) -rw-r--r--
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"""Switchboard class.
This class is used to coordinate updates among all Viewers. Every Viewer must
conform to the following interface:
- it must include a method called update_yourself() which takes three
arguments; the red, green, and blue values of the selected color.
- When a Viewer selects a color and wishes to update all other Views, it
should call update_views() on the Switchboard object. Note that the
Viewer typically does *not* update itself before calling update_views(),
since this would cause it to get updated twice.
Optionally, Viewers can also implement:
- save_options() which takes an optiondb (a dictionary). Store into this
dictionary any values the Viewer wants to save in the persistent
~/.pynche file. This dictionary is saved using marshal. The namespace
for the keys is ad-hoc; make sure you don't clobber some other Viewer's
keys!
- withdraw() which takes no arguments. This is called when Pynche is
unmapped. All Viewers should implement this.
- colordb_changed() which takes a single argument, an instance of
ColorDB. This is called whenever the color name database is changed and
gives a chance for the Viewers to do something on those events. See
ListViewer for details.
External Viewers are found dynamically. Viewer modules should have names such
as FooViewer.py. If such a named module has a module global variable called
ADDTOVIEW and this variable is true, the Viewer will be added dynamically to
the `View' menu. ADDTOVIEW contains a string which is used as the menu item
to display the Viewer (one kludge: if the string contains a `%', this is used
to indicate that the next character will get an underline in the menu,
otherwise the first character is underlined).
FooViewer.py should contain a class called FooViewer, and its constructor
should take two arguments, an instance of Switchboard, and optionally a Tk
master window.
"""
import sys
from types import DictType
import marshal
class Switchboard:
def __init__(self, initfile):
self.__initfile = initfile
self.__colordb = None
self.__optiondb = {}
self.__views = []
self.__red = 0
self.__green = 0
self.__blue = 0
self.__canceled = 0
# read the initialization file
fp = None
if initfile:
try:
try:
fp = open(initfile)
self.__optiondb = marshal.load(fp)
if not isinstance(self.__optiondb, DictType):
print >> sys.stderr, \
'Problem reading options from file:', initfile
self.__optiondb = {}
except (IOError, EOFError, ValueError):
pass
finally:
if fp:
fp.close()
def add_view(self, view):
self.__views.append(view)
def update_views(self, red, green, blue):
self.__red = red
self.__green = green
self.__blue = blue
for v in self.__views:
v.update_yourself(red, green, blue)
def update_views_current(self):
self.update_views(self.__red, self.__green, self.__blue)
def current_rgb(self):
return self.__red, self.__green, self.__blue
def colordb(self):
return self.__colordb
def set_colordb(self, colordb):
self.__colordb = colordb
for v in self.__views:
if hasattr(v, 'colordb_changed'):
v.colordb_changed(colordb)
self.update_views_current()
def optiondb(self):
return self.__optiondb
def save_views(self):
# save the current color
self.__optiondb['RED'] = self.__red
self.__optiondb['GREEN'] = self.__green
self.__optiondb['BLUE'] = self.__blue
for v in self.__views:
if hasattr(v, 'save_options'):
v.save_options(self.__optiondb)
# save the name of the file used for the color database. we'll try to
# load this first.
self.__optiondb['DBFILE'] = self.__colordb.filename()
fp = None
try:
try:
fp = open(self.__initfile, 'w')
except IOError:
print >> sys.stderr, 'Cannot write options to file:', \
self.__initfile
else:
marshal.dump(self.__optiondb, fp)
finally:
if fp:
fp.close()
def withdraw_views(self):
for v in self.__views:
if hasattr(v, 'withdraw'):
v.withdraw()
def canceled(self, flag=1):
self.__canceled = flag
def canceled_p(self):
return self.__canceled
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