Added a new debug flags editor widget

This new debug flags editor shows you all the available debug flags
in the session without having to rely on a hardcoded list of prefixes.
It also shows the descriptions of what the debug flags do.

In a follow up change, we'll be removing the Debug menu that is now
no longer needed.

(Internal change: 1970078)

pxr/usdImaging/lib/usdviewq/CMakeLists.txt

@@ -66,6 +66,7 @@ pxr_library(usdviewq
         selectionDataModel.py
         viewSettingsDataModel.py
         freeCamera.py
+        debugFlagsWidget.py
         usdviewstyle.qss
 
     PYSIDE_UI_FILES

pxr/usdImaging/lib/usdviewq/appController.py

@@ -324,6 +324,7 @@ def __init__(self, parserData, resolverContextFn):
             self._currentSpec = None
             self._currentLayer = None
             self._console = None
+            self._debugFlagsWindow = None
             self._interpreter = None
             self._parserData = parserData
             self._noRender = parserData.noRender
@@ -770,6 +771,8 @@ def __init__(self, parserData, resolverContextFn):
 
             self._ui.showInterpreter.triggered.connect(self._showInterpreter)
 
+            self._ui.showDebugFlags.triggered.connect(self._showDebugFlags)
+
             self._ui.redrawOnScrub.toggled.connect(self._redrawOptionToggled)
 
             if self._stageView:
@@ -2276,6 +2279,13 @@ def _showInterpreter(self):
         self._interpreter.activateWindow()
         self._interpreter.setFocus()
 
+    def _showDebugFlags(self):
+        if self._debugFlagsWindow is None:
+            from debugFlagsWidget import DebugFlagsWidget
+            self._debugFlagsWindow = DebugFlagsWidget()
+
+        self._debugFlagsWindow.show()
+
     # Screen capture functionality ===========================================
 
     def GrabWindowShot(self):

pxr/usdImaging/lib/usdviewq/debugFlagsWidget.py

@@ -0,0 +1,115 @@
+#
+# Copyright 2019 Pixar
+#
+# Licensed under the Apache License, Version 2.0 (the "Apache License")
+# with the following modification; you may not use this file except in
+# compliance with the Apache License and the following modification to it:
+# Section 6. Trademarks. is deleted and replaced with:
+#
+# 6. Trademarks. This License does not grant permission to use the trade
+#    names, trademarks, service marks, or product names of the Licensor
+#    and its affiliates, except as required to comply with Section 4(c) of
+#    the License and to reproduce the content of the NOTICE file.
+#
+# You may obtain a copy of the Apache License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the Apache License with the above modification is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied. See the Apache License for the specific
+# language governing permissions and limitations under the Apache License.
+#
+from qt import QtCore, QtGui, QtWidgets
+
+from pxr import Tf
+
+
+# Returns a list of debug flags whose names are prefixed by debugFlagPrefix
+# followed by an '_'.
+#
+def _GetDebugFlagsWithPrefix(debugFlagPrefix):
+    debugFlagPrefix += "_"
+    return [flag for flag in Tf.Debug.GetDebugSymbolNames() 
+            if flag.startswith(debugFlagPrefix)]
+
+# Main DebugFlags editor widget
+#
+class DebugFlagsWidget(QtWidgets.QWidget):
+
+    def __init__(self, parent=None):
+
+        super(DebugFlagsWidget, self).__init__(parent)
+
+        self.setObjectName("Debug Flags")
+        self.setMinimumSize(640, 300)
+        self._listView = QtWidgets.QListView()
+        self._tableWidget = QtWidgets.QTableWidget(0, 2)
+
+
+        # Configure and populate the left list view
+        self._listView.setEditTriggers(
+            QtWidgets.QAbstractItemView.NoEditTriggers)
+
+        self._populateDebugFlagsListView(self._listView)
+
+        self._listView.selectionModel().selectionChanged.connect(
+            self._onFlagSelectionChanged)
+
+
+        # Configure the table widget
+        self._tableWidget.horizontalHeader().setStretchLastSection(True)
+        self._tableWidget.horizontalHeader().setDefaultSectionSize(200)
+        self._tableWidget.setHorizontalHeaderLabels(
+                    ['Debug Symbol', 'Description'])
+        self._tableWidget.verticalHeader().hide()
+
+        self._tableWidget.itemClicked.connect(self._onDebugFlagChecked)
+
+        # Set the layout
+        lay = QtWidgets.QHBoxLayout()
+        lay.addWidget(self._listView, 0)
+        lay.addWidget(self._tableWidget, 1)
+        self.setLayout(lay)
+
+    def _populateDebugFlagsListView(self, listView):
+        allDebugFlags = Tf.Debug.GetDebugSymbolNames()
+        allDebugPrefixes = [ x[:x.find('_')] if x.find('_') > 0 else x
+                for x in allDebugFlags]
+        self._allDebugFlagPrefixes = list(sorted(set(allDebugPrefixes)))
+        listModel = QtGui.QStringListModel(self._allDebugFlagPrefixes)
+        listView.setModel(listModel)
+
+
+    def _populateDebugFlagsTableView(self, debugFlagPrefix):
+        debugFlags = _GetDebugFlagsWithPrefix(debugFlagPrefix)
+
+        self._tableWidget.setRowCount(len(debugFlags))
+        row = 0
+        for f in debugFlags:
+            item = QtWidgets.QTableWidgetItem()
+            item.setFlags(QtCore.Qt.ItemIsUserCheckable | 
+                          QtCore.Qt.ItemIsEnabled)
+            if Tf.Debug.IsDebugSymbolNameEnabled(f):
+                item.setCheckState(QtCore.Qt.Checked)
+            else:
+                item.setCheckState(QtCore.Qt.Unchecked)
+            item.setText(f)
+            self._tableWidget.setItem(row, 0, item)
+
+            item = QtWidgets.QTableWidgetItem()
+            item.setFlags(item.flags() ^ QtCore.Qt.ItemIsEditable)
+            item.setText(Tf.Debug.GetDebugSymbolDescription(f))
+            self._tableWidget.setItem(row, 1, item)
+
+            row += 1
+
+    def _onFlagSelectionChanged(self, selected, deselected):
+        if len(selected.indexes()) > 0:
+            self._populateDebugFlagsTableView(self._allDebugFlagPrefixes[
+                selected.indexes()[0].row()])
+
+    def _onDebugFlagChecked(self, item):
+        value = (item.checkState() == QtCore.Qt.Checked)
+        Tf.Debug.SetDebugSymbolsByName(item.text(), value)

pxr/usdImaging/lib/usdviewq/mainWindowUI.ui

@@ -1450,6 +1450,7 @@
      <string>Window</string>
     </property>
     <addaction name="showInterpreter"/>
+    <addaction name="showDebugFlags"/>
    </widget>
    <widget class="QMenu" name="menuDebug">
     <property name="title">
@@ -2027,6 +2028,17 @@
     <string>I</string>
    </property>
   </action>
+  <action name="showDebugFlags">
+   <property name="checkable">
+    <bool>false</bool>
+   </property>
+   <property name="text">
+    <string>Debug Flags</string>
+   </property>
+   <property name="toolTip">
+    <string>Show Debug Flags Window</string>
+   </property>
+  </action>
   <action name="actionHUD_VBOInfo">
    <property name="checkable">
     <bool>true</bool>