--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Widgets/Fadable.py	Wed Jul 03 09:37:57 2002 +0000
@@ -0,0 +1,143 @@
+# taken from SnackMix -- now that's reusable code
+from Tix import *
+import time
+
+class Fadable:
+    """Fading mixin: must mix in with a Tk widget (or something that has
+    'after' at least) This is currently used by VolumeBox and MixerTk.
+    It's probably too specialized to be used elsewhere, but could possibly
+    work with an Entry or a Meter, I guess.
+
+    var is a Tk variable that should be used to set and get the levels.
+    If use_fades is true, it will use fades to move between levels.
+    If key_bindings is true, it will install these keybindings:
+
+    Press a number to fade to that amount (e.g. '5' = 50%).  Also,
+    '`' (grave) will fade to 0 and '0' will fade to 100%.
+
+    If mouse_bindings is true, the following mouse bindings will be
+    installed: Right clicking toggles muting.  The mouse wheel will
+    raise or lower the volume.  Shift-mouse wheeling will cause a more
+    precise volume adjustment.  Control-mouse wheeling will cause a
+    longer fade."""
+    def __init__(self, var, wheel_step=5, use_fades=1, key_bindings=1,
+                 mouse_bindings=1):
+        self.use_fades = use_fades # whether increase and decrease should fade
+        self.wheel_step = wheel_step # amount that increase and descrease should
+                                     # change volume (by default)
+        
+        self.fade_start_level = 0
+        self.fade_end_level = 0
+        self.fade_start_time = 0
+        self.fade_length = 1
+        self.fade_step_time = 10
+        self.fade_var = var
+        self.fading = 0 # whether a fade is in progress
+
+        if key_bindings:
+            for k in range(1, 10):
+                self.bind("<Key-%d>" % k,
+                    lambda evt, k=k: self.fade(k / 10.0))
+            self.bind("<Key-0>", lambda evt: self.fade(100))
+            self.bind("<grave>", lambda evt: self.fade(0))
+
+            # up / down arrows
+            self.bind("<Key-Up>", lambda evt: self.increase())
+            self.bind("<Key-Down>", lambda evt: self.decrease())
+
+        if mouse_bindings:
+            # right mouse button toggles muting
+            # self.bind('<3>', lambda evt: self.toggle_mute())
+            # "NOT ANY MORE!" - homer
+
+            # mouse wheel
+            self.bind('<4>', lambda evt: self.increase())
+            self.bind('<5>', lambda evt: self.decrease())
+
+            # modified mouse wheel
+            self.bind('<Shift-4>', lambda evt: self.increase(multiplier=0.2))
+            self.bind('<Shift-5>', lambda evt: self.decrease(multiplier=0.2))
+            self.bind('<Control-4>', lambda evt: self.increase(length=1))
+            self.bind('<Control-5>', lambda evt: self.decrease(length=1))
+
+        self.last_level = 0 # used for muting
+    def fade(self, value, length=0.5, step_time=10):
+        """Fade to value in length seconds with steps every step_time
+        seconds"""
+        self.fade_start_time = time.time()
+        self.fade_length = length
+
+        self.fade_start_level = self.fade_var.get()
+        self.fade_end_level = value
+        
+        self.fade_step_time = step_time
+        if not self.fading:
+            self.fading = 1
+            self.do_fade()
+    def do_fade(self):
+        """Actually performs the fade for Fadable.fade.  Shouldn't be called
+        directly."""
+        now = time.time()
+        elapsed = now - self.fade_start_time
+        complete = elapsed / self.fade_length
+        complete = min(1.0, complete)
+        diff = self.fade_end_level - self.fade_start_level
+        newlevel = (complete * diff) + self.fade_start_level
+        self.fade_var.set(newlevel)
+        if complete < 1:
+            self.after(self.fade_step_time, self.do_fade)
+        else:
+            self.fading = 0
+    def increase(self, multiplier=1, length=0.3):
+        """Increases the volume by multiplier * wheel_step.  If use_fades is
+        true, it do this as a fade over length time."""
+        amount = self.wheel_step * multiplier
+        if self.fading:
+            newlevel = self.fade_end_level + amount
+        else:
+            newlevel = self.fade_var.get() + amount
+        newlevel = min(100, newlevel)
+        self.set_volume(newlevel, length)
+    def decrease(self, multiplier=1, length=0.3):
+        """Descreases the volume by multiplier * wheel_step.  If use_fades
+        is true, it do this as a fade over length time."""
+        amount = self.wheel_step * multiplier
+        if self.fading:
+            newlevel = self.fade_end_level - amount
+        else:
+            newlevel = self.fade_var.get() - amount
+        newlevel = max(0, newlevel)
+        self.set_volume(newlevel, length)
+    def set_volume(self, newlevel, length=0.3):
+        """Sets the volume to newlevel, performing a fade of length if
+        use_fades is true."""
+        if self.use_fades:
+            self.fade(newlevel, length=length)
+        else:
+            self.fade_var.set(newlevel)
+    def toggle_mute(self):
+        """Toggles whether the volume is being muted."""
+        curlevel = self.fade_var.get()
+        if curlevel:
+            newlevel = 0
+            self.last_level = curlevel
+            self['bg'] = 'red' # TODO: let them choose these colors
+        else:
+            newlevel = self.last_level
+            self['bg'] = 'lightGray'
+
+        self.fade_var.set(newlevel)
+
+if __name__ == "__main__":
+    class SubScale(Scale, Fadable):
+        def __init__(self, master, *args, **kw):
+            self.scale_var = DoubleVar()
+            kw['variable'] = self.scale_var
+            Scale.__init__(self, master, *args, **kw)
+            Fadable.__init__(self, var=self.scale_var)
+
+    root = Tk()
+    root.tk_focusFollowsMouse()
+    ss = SubScale(root, from_=100, to_=0,)
+    ss.pack()
+    mainloop()