[ui] allow SfM augmentation when providing new images

* create two separate drop areas when adding images to the project (add images / augment reconstruction)
* add sfm augmentation in graph after intrinsics have been built

meshroom/ui/qml/ImageGallery.qml

@@ -26,7 +26,7 @@ Panel {
     title: "Images"
     property int currentIndex: 0
     readonly property variant viewpoints: cameraInit.attribute('viewpoints').value
-    signal filesDropped(var drop)
+    signal filesDropped(var drop, var augmentSfm)
 
     ColumnLayout {
         anchors.fill: parent
@@ -134,14 +134,56 @@ Panel {
                 enabled: !root.readOnly
                 // TODO: onEntered: call specific method to filter files based on extension
                 onDropped: {
-                    root.filesDropped(drop)
+                    var augmentSfm = augmentArea.hovered
+                    root.filesDropped(drop, augmentSfm)
                 }
-                // DropArea overlay
+
+                // Background opacifier
                 Rectangle {
+                    visible: dropArea.containsDrag
                     anchors.fill: parent
-                    opacity: 0.4
-                    visible: parent.containsDrag
-                    color: palette.highlight
+                    color: palette.window
+                    opacity: 0.8
+                }
+
+                ColumnLayout {
+                    anchors.fill: parent
+                    visible: dropArea.containsDrag
+                    spacing: 1
+                    Label {
+                        id: addArea
+                        property bool hovered: dropArea.drag.y < height
+                        Layout.fillWidth: true
+                        Layout.fillHeight: true
+                        horizontalAlignment: Text.AlignHCenter
+                        verticalAlignment: Text.AlignVCenter
+                        text: "Add Images"
+                        font.bold: true
+                        background: Rectangle {
+                            color: parent.hovered ? palette.highlight : palette.window
+                            opacity: 0.8
+                            border.color: palette.highlight
+                        }
+                    }
+
+                    // DropArea overlay
+                    Label {
+                        id: augmentArea
+                        property bool hovered: visible && dropArea.drag.y >= y
+                        Layout.fillWidth: true
+                        Layout.preferredHeight: parent.height * 0.3
+                        horizontalAlignment: Text.AlignHCenter
+                        verticalAlignment: Text.AlignVCenter
+                        text: "Augment Reconstruction"
+                        font.bold: true
+                        wrapMode: Text.WrapAtWordBoundaryOrAnywhere
+                        visible: viewpoints.count > 0
+                        background: Rectangle {
+                            color: parent.hovered ? palette.highlight : palette.window
+                            opacity: 0.8
+                            border.color: palette.highlight
+                        }
+                    }
                 }
             }
         }

meshroom/ui/qml/WorkspaceView.qml

@@ -67,7 +67,7 @@ Item {
                 currentIndex: reconstruction.cameraInitIndex
                 onCurrentIndexChanged: reconstruction.cameraInitIndex = currentIndex
                 onRemoveImageRequest: reconstruction.removeAttribute(attribute)
-                onFilesDropped: reconstruction.handleFilesDrop(drop, cameraInit)
+                onFilesDropped: reconstruction.handleFilesDrop(drop, augmentSfm ? null : cameraInit)
             }
             LiveSfmView {
                 visible: settings_UILayout.showLiveReconstruction

meshroom/ui/reconstruction.py

@@ -344,7 +344,10 @@ class Reconstruction(UIGraph):
 
         # Duplicate 'cameraInit' outside the graph.
         #   => allows to compute intrinsics without modifying the node or the graph
-        attributes = cameraInit.toDict()["attributes"]
+        # If cameraInit is None (i.e: SfM augmentation):
+        #   * create an uninitialized node
+        #   * wait for the result before actually creating new nodes in the graph (see onIntrinsicsAvailable)
+        attributes = cameraInit.toDict()["attributes"] if cameraInit else {}
         cameraInitCopy = graph.Node("CameraInit", **attributes)
 
         try:
@@ -365,7 +368,27 @@ class Reconstruction(UIGraph):
 
     def onIntrinsicsAvailable(self, cameraInit, views, intrinsics):
         """ Update CameraInit with given views and intrinsics. """
-        with self.groupedGraphModification("Add Images"):
+        augmentSfM = cameraInit is None
+        commandTitle = "Add {} Images"
+
+        # SfM augmentation
+        if augmentSfM:
+            # filter out views already involved in the reconstruction
+            allViewIds = self.allViewIds()
+            views = [view for view in views if int(view["viewId"]) not in allViewIds]
+            commandTitle = "Augment Reconstruction ({} Images)"
+
+        # No additional views: early return
+        if not views:
+            return
+
+        commandTitle = commandTitle.format(len(views))
+        # allow updates between commands so that node depths
+        # are updated after "addSfmAugmentation" (useful for auto layout)
+        with self.groupedGraphModification(commandTitle, disableUpdates=False):
+            if augmentSfM:
+                cameraInit, self.sfm = self.addSfmAugmentation()
+            with self.groupedGraphModification("Set Views and Intrinsics"):
                 self.setAttribute(cameraInit.viewpoints, views)
                 self.setAttribute(cameraInit.intrinsics, intrinsics)
         self.setCameraInit(cameraInit)