epicsPVLabel.py.precon

"""
   This module provides a class library for a GUI label field widget bound to an Epics PV. The PV is monitored
   and the field is updated when the PV changes

Author:         John Skinner
Created:        Nov, 2 2009
Modifications:
"""

import epicsPV
from Tkinter import *
import Pmw
from beamline_support import *

class epicsPVLabel:
   """
   This module provides a class library for a GUI label field widget bound to an Epics PV. The PV is monitored
   and the field is updated when the PV changes

   """
   is_drawn = 0

   def __init__(self, pvname,parent,input_width,precision = 2,highlight_on_change=0):
      """

      Inputs:
         pvname:
            The name of the epics process variable.
         parent:
            The container to place the entry widget.
         input_width:
         precision:
         highlight_on_change:

      Example:
        detstat_file = epicsPVLabel("x12c_comm:datafilename",filestat_frame,70)
        detstat_file.getEntry().pack(side=LEFT,fill=X,expand=YES)


      """
      self.pv_statestrings = [] #for enums, b/c this CaChannel ignores type conversions on callback returns
      self.precision = precision
      self.highlight_on_change = highlight_on_change
      self.entry_var = StringVar()
      self.entry_pv = pvCreate(pvname)
      if (ca.dbf_text(self.entry_pv.field_type()) == "DBF_ENUM"):
        self.entry_pv.getControl()
        self.pv_statestrings = getattr(self.entry_pv.callBack,'pv_statestrings')
      self._set_entry_var_with_precision(pvGet(self.entry_pv))            
      self.entry = Label(parent,textvariable=self.entry_var,width=input_width)
      add_callback(self.entry_pv,self._entry_pv_movingCb,self.entry_var)
      
   def _entry_pv_movingCb(self,epics_args, user_args):
#      print "in callback " + str(epics_args['pv_value']) + " " + ca.dbf_text(epics_args['type'])
      if not (epicsPVLabel.is_drawn):
        return
      if (ca.dbf_text(epics_args['type']) == "DBF_CHAR"):         
        user_args[0].set(waveform_to_string(epics_args['pv_value']))
      elif (ca.dbf_text(epics_args['type']) == "DBF_ENUM"):
        if (self.pv_statestrings):
          user_args[0].set(self.pv_statestrings[epics_args['pv_value']])
        else:
          user_args[0].set(epics_args['pv_value'])
      else:
        if (self.highlight_on_change):
          self.entry.configure(background="green")                               
        self._set_entry_var_with_precision(epics_args['pv_value'])                    
#        user_args[0].set("%.4f" % (epics_args['pv_value']))

        
   def _set_entry_var_with_precision(self,inval):
      try:
        val = float(inval)
        if (self.precision == 0):
           self.entry_var.set("%.0f" % val)
        elif (self.precision == 1):
           self.entry_var.set("%.1f" % val)
        elif (self.precision == 2):
           self.entry_var.set("%.2f" % val)
        elif (self.precision == 3):
           self.entry_var.set("%.3f" % val)
        elif (self.precision == 4):
           self.entry_var.set("%.4f" % val)
        else:
           self.entry_var.set("%.5f" % val)
      except TypeError:
         self.entry_var.set(waveform_to_string(inval))
      except ValueError:
         self.entry_var.set(waveform_to_string(inval))
         

   def pack(self,side=LEFT,padx=0,pady=0): #pass the params in
      self.entry.pack(side=side,padx=padx,pady=pady)

   def getEntry(self):
      return self.entry

   def getField(self):
      return self.entry_var.get()
   
   def setField(self,value):
      self.entry_var.set(value)
   
   def setColor(self,color_string):
      self.entry.configure(background=color_string)