[ui] Intersect segment with 2 points instead of using a Rect diagonal

Fix a bug related to the SelectionLine, as the Rect was converted within
a mapItem to use positive width/height.
As a result the wrong diagonal of the Rect was sometimes used for the
intersection test.

Author: fabiencastan

meshroom/ui/components/edge.py

@@ -110,16 +110,16 @@ def setContainsMouse(self, value):
         self._containsMouse = value
         self.containsMouseChanged.emit()
 
-    @Slot(QRectF, result=bool)
-    def intersects(self, rect):
-        """ Checks whether the given rectangle's diagonal intersects with the Path. """
+    @Slot(QPointF, QPointF, result=bool)
+    def intersectsSegment(self, p1, p2):
+        """ Checks whether the given segment (p1, p2) intersects with the Path. """
         path = QPainterPath()
         # Starting point
-        path.moveTo(QPointF(rect.x(), rect.y()))
+        path.moveTo(p1)
         # Create a diagonal line to the other end of the rect
-        path.lineTo(QPointF(rect.width() + rect.x(), rect.height() + rect.y()))
-
-        return self._path.intersects(path)
+        path.lineTo(p2)
+        v = self._path.intersects(path)
+        return v
 
     thicknessChanged = Signal()
     thickness = Property(float, getThickness, setThickness, notify=thicknessChanged)

meshroom/ui/qml/Controls/DelegateSelectionLine.qml

@@ -17,12 +17,13 @@ SelectionLine {
     // Emitted when the selection has ended, with the list of selected indices and modifiers.
     signal delegateSelectionEnded(list<int> indices, int modifiers)
 
-    onSelectionEnded: function(selectionRect, modifiers) {
+    onSelectionEnded: function(selectionP1, selectionP2, modifiers) {
         let selectedIndices = [];
-        const mappedSelectionRect = mapToItem(container, selectionRect);
+        const mappedP1 = mapToItem(container, selectionP1);
+        const mappedP2 = mapToItem(container, selectionP2);
         for (var i = 0; i < modelInstantiator.count; ++i) {
             const delegate = modelInstantiator.itemAt(i);
-            if (delegate.intersects(mappedSelectionRect)) {
+            if (delegate.intersectsSegment(mappedP1, mappedP2)) {
                 selectedIndices.push(i);
             }
         }

meshroom/ui/qml/Controls/SelectionLine.qml

@@ -9,7 +9,7 @@ Usage:
 2. Bind the selectionShape to the MouseArea by setting the `mouseArea` property.
 3. Call startSelection() with coordinates when the selection starts.
 4. Call endSelection() when the selection ends.
-5. Listen to the selectionEnded signal to get the rectangle whose Diagonal is the selection line.
+5. Listen to the selectionEnded signal to get the segment (defined by 2 points).
 */
 
 Item {
@@ -19,7 +19,7 @@ Item {
 
     readonly property bool active: mouseArea.drag.target == dragTarget
 
-    signal selectionEnded(rect selectionRect, int modifiers)
+    signal selectionEnded(point selectionP1, point selectionP2, int modifiers)
 
     function startSelection(mouse) {
         dragTarget.startPos.x = dragTarget.x = mouse.x;
@@ -33,8 +33,9 @@ Item {
             return;
         }
         mouseArea.drag.target = null;
-        const rect = Qt.rect(selectionShape.x, selectionShape.y, selectionShape.width, selectionShape.height)
-        selectionEnded(rect, dragTarget.modifiers);
+        const p1 = Qt.point(selectionShape.x, selectionShape.y);
+        const p2 = Qt.point(selectionShape.x + selectionShape.width, selectionShape.y + selectionShape.height);
+        selectionEnded(p1, p2, dragTarget.modifiers);
     }
 
     visible: active

meshroom/ui/qml/GraphEditor/Edge.qml

@@ -23,7 +23,7 @@ Item {
     property int loopSize: 0
     property int iteration: 0
 
-    // BUG: edgeArea is destroyed before path, need to test if not null to avoid warnings
+    // Note: edgeArea is destroyed before path, so we need to test if not null to avoid warnings.
     readonly property bool containsMouse: (loopArea && loopArea.containsMouse) || (edgeArea && edgeArea.containsMouse)
 
     signal pressed(var event)
@@ -40,15 +40,14 @@ Item {
     property real endY: height
 
 
-    function intersects(rect) {
+    function intersectsSegment(p1, p2) {
         /**
          * Detects whether a line along the given rects diagonal intersects with the edge mouse area.
          */
         // The edgeArea is within the parent Item and its bounds and position are relative to its parent
         // Map the original rect to the coordinates of the edgeArea by subtracting the parent's coordinates from the rect
         // This mapped rect would ensure that the rect coordinates map to 0 of the edge area
-        const mappedRect = Qt.rect(rect.x - x, rect.y - y, rect.width, rect.height);
-        return edgeArea.intersects(mappedRect);
+        return edgeArea.intersectsSegment(Qt.point(p1.x - x, p1.y - y), Qt.point(p2.x - x, p2.y - y));
     }
 
     Shape {