[ui] Hide disabled File attributes and their edges but keep the connections

This commit effectively hides a node's attributes when they are disabled.
If these attributes have connections, the edges representing these
connections are hidden but not destroyed. When the edges are hidden, if
one of the connected attributes is still enabled, its pin becomes empty as
if it was not connected to anything.

If the disabled attribute is re-enabled and the connection has not been
broken (if the enabled attribute on the other side of the edge has not
been reconnected to another attribute, for example), the edge re-appears.
If the connection has been broken, then the attribute will be unconnected.

Hidden connections are saved in project files and taken into account when
a project file containing some is loaded.

meshroom/ui/qml/GraphEditor/AttributePin.qml

@@ -35,6 +35,16 @@ RowLayout {
     layoutDirection: Qt.LeftToRight
     spacing: 3
 
+    function updatePin(isSrc, isVisible)
+    {
+        if (isSrc) {
+            innerOutputAnchor.linkEnabled = isVisible
+        } else {
+            innerInputAnchor.linkEnabled = isVisible
+        }
+
+    }
+
     // Instantiate empty Items for each child attribute
     Repeater {
         id: childrenRepeater
@@ -59,7 +69,9 @@ RowLayout {
         color: Colors.sysPalette.base
 
         Rectangle {
-            visible: inputConnectMA.containsMouse || childrenRepeater.count > 0 || (attribute && attribute.isLink) || inputConnectMA.drag.active || inputDropArea.containsDrag
+            id: innerInputAnchor
+            property bool linkEnabled: true
+            visible: inputConnectMA.containsMouse || childrenRepeater.count > 0 || (attribute && attribute.isLink && linkEnabled) || inputConnectMA.drag.active || inputDropArea.containsDrag
             radius: isList ? 0 : 2
             anchors.fill: parent
             anchors.margins: 2
@@ -207,7 +219,9 @@ RowLayout {
         color: Colors.sysPalette.base
 
         Rectangle {
-            visible: attribute.hasOutputConnections || outputConnectMA.containsMouse || outputConnectMA.drag.active || outputDropArea.containsDrag
+            id: innerOutputAnchor
+            property bool linkEnabled: true
+            visible: (attribute.hasOutputConnections && linkEnabled) || outputConnectMA.containsMouse || outputConnectMA.drag.active || outputDropArea.containsDrag
             radius: isList ? 0 : 2
             anchors.fill: parent
             anchors.margins: 2

meshroom/ui/qml/GraphEditor/GraphEditor.qml

@@ -383,7 +383,7 @@ Item {
                     property var src: root._attributeToDelegate[edge.src]
                     property var dst: root._attributeToDelegate[edge.dst]
                     property bool isValidEdge: src !== undefined && dst !== undefined
-                    visible: isValidEdge
+                    visible: isValidEdge && src.visible && dst.visible
 
                     property bool inFocus: containsMouse || (edgeMenu.opened && edgeMenu.currentEdge === edge)
 
@@ -407,6 +407,30 @@ Item {
                             }
                         }
                     }
+                    onVisibleChanged: {
+                        if (visible) {
+                            // Enable the pins on both sides
+                            src.updatePin(true, true)  // isSrc = true, isVisible = true
+                            dst.updatePin(false, true)  // isSrc = false, isVisible = true
+                        } else {
+                            // One of the attributes is visible, we do not need to handle the case where both attributes are hidden
+                            if (isValidEdge && (src.visible || dst.visible)) {
+                                if (src.visible) {
+                                    src.updatePin(true, false)  // isSrc = true, isVisible = false
+                                } else {
+                                    dst.updatePin(false, false)  // isSrc = false, isVisible = false
+                                }
+                            }
+                        }
+                    }
+
+                    Component.onDestruction: {
+                        // Handles the case where the edge is destroyed while hidden because it is replaced: the pins should be re-enabled
+                        if (src && src !== undefined)
+                            src.updatePin(true, true)  // isSrc = true, isVisible = true
+                        if (dst && dst !== undefined)
+                            dst.updatePin(false, true)  // isSrc = false, isVisible = true
+                    }
                 }
             }
 

meshroom/ui/qml/GraphEditor/Node.qml

@@ -387,12 +387,14 @@ Item {
                             id: outputs
                             width: parent.width
                             spacing: 3
+
                             Repeater {
                                 model: node ? node.attributes : undefined
 
                                 delegate: Loader {
                                     id: outputLoader
-                                    active: object.isOutput && isFileAttributeBaseType(object) && object.desc.visible
+                                    active: object.isOutput && isFileAttributeBaseType(object)
+                                    visible: object.enabled
                                     anchors.right: parent.right
                                     width: outputs.width
 
@@ -421,9 +423,11 @@ Item {
 
                             Repeater {
                                 model: node ? node.attributes : undefined
+
                                 delegate: Loader {
                                     id: inputLoader
                                     active: !object.isOutput && isFileAttributeBaseType(object)
+                                    visible: object.enabled
                                     width: inputs.width
 
                                     sourceComponent: AttributePin {