Adding new "Live Programmable Source" and test

Adds a "Live Programmable Source" to make it easier to add data sources
that are "live" and then add a test for the same.

Applications/ParaView/ParaViewSources.xml

@@ -18,6 +18,7 @@
   <Proxy group="sources" name="PointSource" />
   <Proxy group="sources" name="PolyLineSource" />
   <Proxy group="sources" name="ProgrammableSource" />
+  <Proxy group="sources" name="LiveProgrammableSource" />
   <Proxy group="sources" name="Ruler" />
   <Proxy group="sources" name="SphereSource" />
   <Proxy group="sources" name="SplineSource" />

Applications/ParaView/Testing/XML/CMakeLists.txt

@@ -602,13 +602,14 @@ endif()
 if(PARAVIEW_ENABLE_PYTHON)
   list(APPEND TESTS_WITH_BASELINES
     ${CMAKE_CURRENT_SOURCE_DIR}/ColorByComponentNames.xml # needs programmable filter
+    ${CMAKE_CURRENT_SOURCE_DIR}/LiveProgrammableSource.xml
+    ${CMAKE_CURRENT_SOURCE_DIR}/SaveLoadStatePython.xml
     ${CMAKE_CURRENT_SOURCE_DIR}/SelectionLabels.xml
     ${CMAKE_CURRENT_SOURCE_DIR}/TraceExodus.xml
     ${CMAKE_CURRENT_SOURCE_DIR}/TraceExportAndSaveData.xml
     ${CMAKE_CURRENT_SOURCE_DIR}/TraceSaveGeometry.xml
     ${CMAKE_CURRENT_SOURCE_DIR}/TraceStatisticsFilter.xml
     ${CMAKE_CURRENT_SOURCE_DIR}/TraceSupplementalProxiesFully.xml
-    ${CMAKE_CURRENT_SOURCE_DIR}/SaveLoadStatePython.xml
   )
   list(APPEND TESTS_WITH_INLINE_COMPARES
     ${CMAKE_CURRENT_SOURCE_DIR}/RestoreArrayDefaultTransferFunction.xml

Applications/ParaView/Testing/XML/LiveProgrammableSource.xml

+<?xml version="1.0" ?>
+<pqevents>
+  <pqevent object="pqClientMainWindow/menubar" command="activate" arguments="menuSources" />
+  <pqevent object="pqClientMainWindow/menubar/menuSources" command="activate" arguments="LiveProgrammableSource" />
+  <pqevent object="pqClientMainWindow/propertiesDock/propertiesPanel/scrollArea/qt_scrollarea_viewport/scrollAreaWidgetContents/PropertiesFrame/ProxyPanel/Script/1pqPopOutWidget0/Script" command="set_string" arguments="if not hasattr(self, &quot;_my_counter&quot;):&#xA;  setattr(self, &quot;_my_counter&quot;, -1)&#xA;&#xA;counter = self._my_counter&#xA;if counter &lt; 10:&#xA;  counter += 1&#xA;setattr(self, &quot;_my_counter&quot;, counter)&#xA;&#xA;from paraview.vtk.vtkFiltersSources import vtkSphereSource&#xA;src = vtkSphereSource()&#xA;src.SetStartTheta(275.0 * counter / 10.0)&#xA;src.Update()&#xA;&#xA;self.GetOutputDataObject(0).ShallowCopy(src.GetOutput())&#xA; " />
+
+  <pqevent object="pqClientMainWindow/propertiesDock/propertiesPanel/scrollArea/qt_scrollarea_viewport/scrollAreaWidgetContents/PropertiesFrame/ProxyPanel/CheckNeedsUpdateScript/1pqPopOutWidget0/CheckNeedsUpdateScript" command="set_string" arguments="if hasattr(self, &quot;_my_counter&quot;) and getattr(self, &quot;_my_counter&quot;) &lt; 10:&#xA;  self.SetNeedsUpdate(True)" />
+  <pqevent object="pqClientMainWindow/propertiesDock/propertiesPanel/Accept" command="activate" arguments="" />\
+
+  <pqevent object="pqClientMainWindow" command="process_events" arguments="3000"/>
+</pqevents>

Documentation/release/dev/live-source.md

+# Live Programmable Source
+
+To support use-cases where one wants to develop a programmable source that is *refreshed*
+periodically, we have added **Live Programmable Source**. With this source, one can provide a
+Python script for **CheckNeedsUpdateScript** that can indicate that the source may have new data
+and hence should be updated. The ParaView Qt client can periodically check such source and update
+them, if needed.

ParaViewCore/ServerManager/SMApplication/Resources/pythonfilter.xml

@@ -531,6 +531,32 @@ annotation text.
       </DoubleVectorProperty>
       <!-- End ProgrammableSource -->
     </SourceProxy>
+
+    <SourceProxy class="vtkPythonProgrammableFilter"
+                 label="Live Programmable Source"
+                 name="LiveProgrammableSource"
+                 base_proxygroup="sources"
+                 base_proxyname="ProgrammableSource">
+      <Documentation>
+        A programmable source that can produce new data autonomously.
+      </Documentation>
+      <StringVectorProperty command="SetCheckNeedsUpdateScript"
+                            label="Script (CheckNeedsUpdate)"
+                            name="CheckNeedsUpdateScript"
+                            number_of_elements="1">
+        <Hints>
+          <Widget type="multi_line" syntax="python" />
+        </Hints>
+        <Documentation>
+          Specify the script to use to check if the filter/source has new data.
+          This is only needed for "live" sources, that can cause data to be available
+          outside of ParaView.
+        </Documentation>
+      </StringVectorProperty>
+      <Hints>
+        <LiveSource />
+      </Hints>
+   </SourceProxy>
   </ProxyGroup>
   <!-- =================================================================== -->
   <ProxyGroup name="animation">

Testing/Data/Baseline/LiveProgrammableSource.png.md5

+187755313f1a05cd565445945eaffa8d