Tools/pynche/Switchboard.py

   1 """Switchboard class.
   2
   3 This class is used to coordinate updates among all Viewers.  Every Viewer must
   4 conform to the following interface:
   5
   6     - it must include a method called update_yourself() which takes three
   7       arguments; the red, green, and blue values of the selected color.
   8
   9     - When a Viewer selects a color and wishes to update all other Views, it
  10       should call update_views() on the Switchboard object.  Note that the
  11       Viewer typically does *not* update itself before calling update_views(),
  12       since this would cause it to get updated twice.
  13
  14 Optionally, Viewers can also implement:
  15
  16     - save_options() which takes an optiondb (a dictionary).  Store into this
  17       dictionary any values the Viewer wants to save in the persistent
  18       ~/.pynche file.  This dictionary is saved using marshal.  The namespace
  19       for the keys is ad-hoc; make sure you don't clobber some other Viewer's
  20       keys!
  21
  22     - withdraw() which takes no arguments.  This is called when Pynche is
  23       unmapped.  All Viewers should implement this.
  24
  25     - colordb_changed() which takes a single argument, an instance of
  26       ColorDB.  This is called whenever the color name database is changed and
  27       gives a chance for the Viewers to do something on those events.  See
  28       ListViewer for details.
  29
  30 External Viewers are found dynamically.  Viewer modules should have names such
  31 as FooViewer.py.  If such a named module has a module global variable called
  32 ADDTOVIEW and this variable is true, the Viewer will be added dynamically to
  33 the `View' menu.  ADDTOVIEW contains a string which is used as the menu item
  34 to display the Viewer (one kludge: if the string contains a `%', this is used
  35 to indicate that the next character will get an underline in the menu,
  36 otherwise the first character is underlined).
  37
  38 FooViewer.py should contain a class called FooViewer, and its constructor
  39 should take two arguments, an instance of Switchboard, and optionally a Tk
  40 master window.
  41
  42 """
  43
  44 import sys
  45 from types import DictType
  46 import marshal
  47
  48
  49 \f
  50 class Switchboard:
  51     def __init__(self, initfile):
  52         self.__initfile = initfile
  53         self.__colordb = None
  54         self.__optiondb = {}
  55         self.__views = []
  56         self.__red = 0
  57         self.__green = 0
  58         self.__blue = 0
  59         self.__canceled = 0
  60         # read the initialization file
  61         fp = None
  62         if initfile:
  63             try:
  64                 try:
  65                     fp = open(initfile)
  66                     self.__optiondb = marshal.load(fp)
  67                     if not isinstance(self.__optiondb, DictType):
  68                         print >> sys.stderr, \
  69                               'Problem reading options from file:', initfile
  70                         self.__optiondb = {}
  71                 except (IOError, EOFError, ValueError):
  72                     pass
  73             finally:
  74                 if fp:
  75                     fp.close()
  76
  77     def add_view(self, view):
  78         self.__views.append(view)
  79
  80     def update_views(self, red, green, blue):
  81         self.__red = red
  82         self.__green = green
  83         self.__blue = blue
  84         for v in self.__views:
  85             v.update_yourself(red, green, blue)
  86
  87     def update_views_current(self):
  88         self.update_views(self.__red, self.__green, self.__blue)
  89
  90     def current_rgb(self):
  91         return self.__red, self.__green, self.__blue
  92
  93     def colordb(self):
  94         return self.__colordb
  95
  96     def set_colordb(self, colordb):
  97         self.__colordb = colordb
  98         for v in self.__views:
  99             if hasattr(v, 'colordb_changed'):
 100                 v.colordb_changed(colordb)
 101         self.update_views_current()
 102
 103     def optiondb(self):
 104         return self.__optiondb
 105
 106     def save_views(self):
 107         # save the current color
 108         self.__optiondb['RED'] = self.__red
 109         self.__optiondb['GREEN'] = self.__green
 110         self.__optiondb['BLUE'] = self.__blue
 111         for v in self.__views:
 112             if hasattr(v, 'save_options'):
 113                 v.save_options(self.__optiondb)
 114         # save the name of the file used for the color database.  we'll try to
 115         # load this first.
 116         self.__optiondb['DBFILE'] = self.__colordb.filename()
 117         fp = None
 118         try:
 119             try:
 120                 fp = open(self.__initfile, 'w')
 121             except IOError:
 122                 print >> sys.stderr, 'Cannot write options to file:', \
 123                       self.__initfile
 124             else:
 125                 marshal.dump(self.__optiondb, fp)
 126         finally:
 127             if fp:
 128                 fp.close()
 129
 130     def withdraw_views(self):
 131         for v in self.__views:
 132             if hasattr(v, 'withdraw'):
 133                 v.withdraw()
 134
 135     def canceled(self, flag=1):
 136         self.__canceled = flag
 137
 138     def canceled_p(self):
 139         return self.__canceled