light9 Changeset - 548d3aa2660f

Changeset - 548d3aa2660f

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drewp - 22 years ago 2002-07-07 08:04:56

physics model fader!

1 file changed with 89 insertions and 45 deletions:

Widgets/FlyingFader.py

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Widgets/FlyingFader.py

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 from Tkinter import *
 from time import time
 from time import time,sleep
 from __future__ import division
 class Mass:
     def __init__(self):
         self.x=0 # position
         self.xgoal=0 # position goal
         self.v=0 # velocity
         self.maxspeed = .8 # maximum speed, in position/second
         self.maxaccel = 3 # maximum acceleration, in position/second^2
         self.eps = .01 # epsilon - numbers within this much are considered the same
         self._lastupdate=time()
         self._stopped=1
     def equal(self,a,b):
         return abs(a-b)<self.eps
     def stop(self):
         self.v=0
         self.xgoal=self.x
         self._stopped=1
     def update(self):
         t0 = self._lastupdate
         tnow = time()
         self._lastupdate = tnow
         dt = tnow-t0
         self.x += self.v*dt
         # hitting the ends stops the slider
         if self.x>1: self.v=max(self.v,0); self.x=1
         if self.x<0: self.v=min(self.v,0); self.x=0
         if self.equal(self.x,self.xgoal):
             self.x=self.xgoal # clean up value
             self.stop()
             return
         self._stopped=0
         dir = (-1.0,1,0)[self.xgoal>self.x]
         self.v += dir*self.maxaccel*dt # velocity changes with acceleration in the right direction
         self.v = min(max(self.v,-self.maxspeed),self.maxspeed) # clamp velocity
         print "x=%+.03f v=%+.03f a=%+.03f %f" % (self.x,self.v,self.maxaccel,self.xgoal)
     def goto(self,newx):
         self.xgoal=newx
     def ismoving(self):
         return not self._stopped
 class FlyingFader(Frame):
     def __init__(self, master, variable, label, fadedur=1.5, font=('Arial', 8),
@@ @@ -7,10 +62,9 @@ class FlyingFader(Frame): @@
         Frame.__init__(self, master)
         self.name = label
         self.variable = variable
         self.fadedur = fadedur
         self.curfade = None
         self.fadetimes = 0, 0
         self.mass = Mass()
         self.config({'bd':1, 'relief':'raised'})
         scaleopts = {'variable' : variable, 'showvalue' : 0, 'from' : 1.0,
                      'to' : 0, 'res' : 0.001, 'width' : 20, 'length' : 200}
@@ @@ -30,7 +84,7 @@ class FlyingFader(Frame): @@
             self.scale.bind("<Key-%d>" % k,
                 lambda evt, k=k: self.newfade(k / 10.0, evt))
-        self.scale.bind("<Key-0>", lambda evt: self.newfade(100, evt))
+        self.scale.bind("<Key-0>", lambda evt: self.newfade(1.0, evt))
         self.scale.bind("<grave>", lambda evt: self.newfade(0, evt))
         self.scale.bind("<1>", self.cancelfade)
@@ @@ -40,72 +94,53 @@ class FlyingFader(Frame): @@
         self.variable.trace('w', self.updatelabel)
     def cancelfade(self, evt):
         self.fadetimes = 0, 0
         self.curfade = 0, self.variable.get()
         self.fadegoal = self.variable.get()
         self.fadevel = self.fadeacc = 0
         self.scale['troughcolor'] = self.oldtrough
     def mousefade(self, evt):
         target = float(self.tk.call(self.scale, 'get', evt.x, evt.y))
         self.newfade(target, evt)
     def isfading(self):
         return self.fadetimes[0] or self.fadetimes[1]
     def ismoving(self):
         return self.fadevel!=0 or self.fadeacc!=0
     def newfade(self, newlevel, evt=None, length=None):
         if length is None:
             length = self.fadedur
         mult = 1
         if evt.state & 8 and evt.state & 4: mult = 0.25 # both
         elif evt.state & 8: mult = 0.5 # alt
         elif evt.state & 4: mult = 2   # control
         now = time()
         if not self.isfading():
             self.fadetimes = (now, now + (mult * length))
             self.curfade = (self.variable.get(), newlevel)
         else:
             # already fading
             t1,t2=self.fadetimes
             v1,v2=self.curfade
             rate = abs((v2-v1)/(t2-t1))
             vnow=self.variable.get()
             newdist=abs(newlevel-vnow)
             newdur=newdist/rate
             self.fadetimes = (now,now+newdur)
             self.curfade=(vnow,newlevel)
         self.mass.x = self.variable.get()
         self.mass.goto(newlevel)
         self.scale['troughcolor'] = 'red'
         self.gofade()
     def gofade(self):
         now = time()
         start, end = self.fadetimes
         lstart, lend = self.curfade
         if now > end:
             self.fadetimes = 0, 0
             self.variable.set(lend)
         self.mass.update()
         self.variable.set(self.mass.x)
         if not self.mass.ismoving():
             self.scale['troughcolor'] = self.oldtrough
             return
         percent = (now - start) / (end - start)
         newvalue = (percent * (lend - lstart)) + lstart
         self.variable.set(newvalue)
         colorfade(self.scale, percent)
 #        colorfade(self.scale, percent)
         self.after(30, self.gofade)
     def updatelabel(self, *args):
         self.vlabel['text'] = "%.3f" % self.variable.get()
         if self.fadetimes[1] == 0: # no fade
             self.vlabel['fg'] = 'black'
         elif self.curfade[1] > self.curfade[0]:
             self.vlabel['fg'] = 'red'
         else:
             self.vlabel['fg'] = 'blue'
 #        if self.fadetimes[1] == 0: # no fade
 #            self.vlabel['fg'] = 'black'
 #        elif self.curfade[1] > self.curfade[0]:
 #            self.vlabel['fg'] = 'red'
 #        else:
 #            self.vlabel['fg'] = 'blue'
     def get(self):
         return self.scale.get()
@@ @@ -122,6 +157,15 @@ def colorfade(scale, lev): @@
     scale.config(troughcolor=col)
 if __name__ == '__main__':
 #    m=Mass()
 #    m.goto(3)
 #    while 1:
 #        m.update()
 #        print "%.03f %.03f" % (m.x, m.v)
 #        sleep(.02)
     root = Tk()
     root.tk_focusFollowsMouse()

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