parameters: (self, pt)
docstring: Tracks a mouse action inside the Alpha channel control.
  
          :param `pt`: an instance of :class:`Point`.
docstring_summary: Tracks a mouse action inside the Alpha channel control.
docstring_tokens: Tracks a mouse action inside the Alpha channel control .
function: def TrackPoint(self, pt):
          """
          Tracks a mouse action inside the Alpha channel control.
  
          :param `pt`: an instance of :class:`Point`.            
          """
  
          alphaRect = self.BuildRect()
          d = alphaRect.GetBottom() - pt.y
          d *= 255
          d /= alphaRect.height
          if d < 0:
             d = 0
          if d > 255:
              d = 255
  
          self._mainDialog._colour._alpha = int(d)
          self.Refresh()
          self._mainDialog.SetSpinVals()
function_tokens: def TrackPoint ( self , pt ) : alphaRect = self . BuildRect ( ) d = alphaRect . GetBottom ( ) - pt . y d *= 255 d /= alphaRect . height if d < 0 : d = 0 if d > 255 : d = 255 self . _mainDialog . _colour . _alpha = int ( d ) self . Refresh ( ) self . _mainDialog . SetSpinVals ( )