Changeset 856

Timestamp:

May 31, 2012 12:37:51 PM (11 years ago)

Author:

jemian

Message:

try to connect to PV on start, try to add PV name to GUI title bar on connection setup (not working yet)

File:

• qtprobe-demo/traits_probe.py (modified) (5 diffs)

qtprobe-demo/traits_probe.py

@@ -9 +9 @@
 ########### SVN repository information ###################
 
+'''
+EPICS PvProbe built using Enthought Traits
+
+*pvProbe* is one of the simplest EPICS user GUI tools.
+It is used to watch the value of an EPICS Process Variable.
+
+This version is based on the Enthought Traits user interface toolkit.
+
+USAGE::
+
+    [jemian@gov]$ ./pvProbe.py -h
+    usage: pvProbe.py [-h] [pv]
+    
+    pvProbe: EPICS Traits-based version of Probe
+    
+    positional arguments:
+      pv          EPICS PV name
+    
+    optional arguments:
+      -h, --help  show this help message and exit
+
+
+SEE ALSO:
+
+For more information about Python version of pvProbe, see
+this presentation from the 2012 EPICS Collaboration Meeting:
+https://subversion.xor.aps.anl.gov/bcdaext/qtprobe-demo/docs/build/html/index.html
+
+This code is the work entitled *traits_probe.py*.
+'''
+
+__description__ = "EPICS Traits-based version of pvProbe"
+
+
 import argparse
 import epics
 import sys                  #@UnusedImport
 
+
 choose_Qt4 = True
-#choose_Qt4 = False
+choose_Qt4 = False
 from traits.etsconfig.api import ETSConfig
 if choose_Qt4:
@@ -23 +58 @@
 from traits.api import *    #@UnusedWildImport
 from traitsui.api import *  #@UnusedWildImport
-
 from traitsui.key_bindings \
     import KeyBinding, KeyBindings
@@ -38 +72 @@
 
 
-# TraitsUI Handler class for bound methods
+# 
 class CodeHandler ( Handler ):
+    '''TraitsUI Handler class for bound methods
+    '''
     
     def connect ( self, info ):
+        '''handle a request to connect with an EPICS PV
+        '''
+        info.object.do_connect()
         if len(info.object.name) > 0:
-            try:
-                if info.object._chid is not None:
-                    info.object._chid.cancel_callback()
-                    info.object._chid.disconnect()
-            except:
-                pass
-            info.object._chid = epics.PV(str(info.object.name), 
-                                         callback=info.object.do_callback)
+            # FIXME: This is not working
+            info.object.title = "pvProbe: " + str(info.object.name)
 
 
 class Probe( HasTraits ):
+    '''EPICS PvProbe built using Enthought Traits
+    '''
     name = Str
     value = Str
@@ -59 +94 @@
 
     def do_callback(self, value=None, **kwds):
-        "simple monitor callback"
+        """simple monitor callback"""
         self.value = str(value)
 
@@ -67 +102 @@
         resizable=True,
         width = 250,
-        title='Traits-based EPICS Probe',
+        title='pvProbe',
         key_bindings = key_bindings,
         handler   = CodeHandler()
     )
+    
+    def do_connect(self):
+        '''connect this GUI with an EPICS Process Variable
+           and set up a Channel Access monitor to update ``value``
+           whenever the PV changes.
+        '''
+        if len(self.name) > 0:
+            try:
+                if self._chid is not None:
+                    self._chid.cancel_callback()
+                    self._chid.disconnect()
+            except:
+                pass
+            self._chid = epics.PV(str(self.name), 
+                                  callback=self.do_callback)
+    
+    def __init__(self, name=""):
+        HasTraits.__init__(self)
+        self.name = name
+        self.do_connect()
+
 
 if __name__ == '__main__':
-    #pv = ''
-    #if len(sys.argv) == 2:
-    #    pv = sys.argv[1]
-    parser = argparse.ArgumentParser(description="traits_probe")
-    parser.add_argument('pv', action='store', nargs='?', help="EPICS PV name", default="EpicsDemo1")
+    parser = argparse.ArgumentParser(description=__description__)
+    parser.add_argument('pv', 
+                        action='store', 
+                        nargs='?', 
+                        help="EPICS PV name", 
+                        default="EpicsDemo1")
     results = parser.parse_args()