[ui] Detect if the reconstruction has been set yet or reset

An `active` property is added to the `Reconstruction` object to share
whether it has been initialized or not.

meshroom/ui/app.py

@@ -97,8 +97,6 @@ class MeshroomApp(QApplication):
 
         args = parser.parse_args(args[1:])
 
-        self._projectOpened = True if getattr(args, "import", None) or args.project or args.importRecursive or args.save or args.pipeline else False
-
         logStringToPython = {
             'fatal': logging.FATAL,
             'error': logging.ERROR,
@@ -492,10 +490,6 @@ class MeshroomApp(QApplication):
     activeProjectChanged = Signal()
     activeProject = Property(Variant, lambda self: self._activeProject, notify=activeProjectChanged)
 
-    # As activeProject is a Reconstruction, we can't use it directly in QML to know if a project is opened or not
-    # So we expose a boolean property to know if a project is opened or not
-    # TODO: find a way to have empty activeProject property
-    projectOpened = Property(bool, lambda self: self._projectOpened, constant=True)
     changelogModel = Property("QVariantList", _changelogModel, constant=True)
     licensesModel = Property("QVariantList", _licensesModel, constant=True)
     pipelineTemplateFilesChanged = Signal()

meshroom/ui/qml/main.qml

@@ -609,7 +609,7 @@ ApplicationWindow {
         anchors.fill: parent
 
         Component.onCompleted: {
-            if (MeshroomApp.projectOpened) {
+            if (_reconstruction.active) {
                 mainStack.push("Application.qml")
             } else {
                 mainStack.push("Homepage.qml")

meshroom/ui/reconstruction.py

@@ -434,11 +434,11 @@ class Reconstruction(UIGraph):
         "matchProvider": ["FeatureMatching", "StructureFromMotion"]
     }
 
-    def __init__(self, undoStack, taskManager, defaultPipeline='', parent=None):
+    def __init__(self, undoStack, taskManager, defaultPipeline="", parent=None):
         super(Reconstruction, self).__init__(undoStack, taskManager, parent)
 
         # initialize member variables for key steps of the 3D reconstruction pipeline
-
+        self._active = False
         self._activeNodes = meshroom.common.DictModel(keyAttrName="nodeType")
         self.initActiveNodes()
 
@@ -477,10 +477,14 @@ class Reconstruction(UIGraph):
         self._workerThreads.terminate()
         self._workerThreads.join()
 
+    def setActive(self, active):
+        self._active = active
+
     @Slot()
     def clear(self):
         self.clearActiveNodes()
         super(Reconstruction, self).clear()
+        self.setActive(False)
 
     def setDefaultPipeline(self, defaultPipeline):
         self._defaultPipeline = defaultPipeline
@@ -534,7 +538,7 @@ class Reconstruction(UIGraph):
                     "Data might have been lost in the process.",
                     "Open it with the corresponding version of Meshroom to recover your data."
                 ))
-
+            self.setActive(True)
             return status
         except FileNotFoundError as e:
             self.error.emit(
@@ -1273,6 +1277,11 @@ class Reconstruction(UIGraph):
     currentViewPathChanged = Signal()
     currentViewPath = Property(str, lambda self: self._currentViewPath, setCurrentViewPath, notify=currentViewPathChanged)
 
+    # Whether the Reconstruction object has been set ("new" has been called) or not ("new" has never
+    # been called or "clear" has been called)
+    activeChanged = Signal()
+    active = Property(bool, lambda self: self._active, setActive, notify=activeChanged)
+
     # Signals to propagate high-level messages
     error = Signal(Message)
     warning = Signal(Message)