Port methods for retrieving item at a point to layouts

python/core/layout/qgslayout.sip

@@ -96,6 +96,20 @@ class QgsLayout : QGraphicsScene, QgsExpressionContextGenerator, QgsLayoutUndoOb
  :rtype: QgsLayoutItem
 %End
 
+    QgsLayoutItem *layoutItemAt( QPointF position, const bool ignoreLocked = false ) const;
+%Docstring
+ Returns the topmost layout item at a specified ``position``. Ignores paper items.
+ If ``ignoreLocked`` is set to true any locked items will be ignored.
+ :rtype: QgsLayoutItem
+%End
+
+    QgsLayoutItem *layoutItemAt( QPointF position, const QgsLayoutItem *belowItem, const bool ignoreLocked = false ) const;
+%Docstring
+ Returns the topmost composer item at a specified ``position`` which is below a specified ``item``. Ignores paper items.
+ If ``ignoreLocked`` is set to true any locked items will be ignored.
+ :rtype: QgsLayoutItem
+%End
+
     void setUnits( QgsUnitTypes::LayoutUnit units );
 %Docstring
  Sets the native measurement ``units`` for the layout. These also form the default unit

src/core/layout/qgslayout.cpp

@@ -105,6 +105,42 @@ QgsLayoutItem *QgsLayout::itemByUuid( const QString &uuid )
   return nullptr;
 }
 
+QgsLayoutItem *QgsLayout::layoutItemAt( QPointF position, const bool ignoreLocked ) const
+{
+  return layoutItemAt( position, nullptr, ignoreLocked );
+}
+
+QgsLayoutItem *QgsLayout::layoutItemAt( QPointF position, const QgsLayoutItem *belowItem, const bool ignoreLocked ) const
+{
+  //get a list of items which intersect the specified position, in descending z order
+  const QList<QGraphicsItem *> itemList = items( position, Qt::IntersectsItemShape, Qt::DescendingOrder );
+
+  bool foundBelowItem = false;
+  for ( QGraphicsItem *graphicsItem : itemList )
+  {
+    QgsLayoutItem *layoutItem = dynamic_cast<QgsLayoutItem *>( graphicsItem );
+    QgsLayoutItemPage *paperItem = dynamic_cast<QgsLayoutItemPage *>( layoutItem );
+    if ( layoutItem && !paperItem )
+    {
+      // If we are not checking for a an item below a specified item, or if we've
+      // already found that item, then we've found our target
+      if ( ( ! belowItem || foundBelowItem ) && ( !ignoreLocked || !layoutItem->isLocked() ) )
+      {
+        return layoutItem;
+      }
+      else
+      {
+        if ( layoutItem == belowItem )
+        {
+          //Target item is next in list
+          foundBelowItem = true;
+        }
+      }
+    }
+  }
+  return nullptr;
+}
+
 double QgsLayout::convertToLayoutUnits( const QgsLayoutMeasurement &measurement ) const
 {
   return mContext.measurementConverter().convert( measurement, mUnits ).length();

src/core/layout/qgslayout.h

@@ -132,6 +132,18 @@ class CORE_EXPORT QgsLayout : public QGraphicsScene, public QgsExpressionContext
      */
     QgsLayoutItem *itemByUuid( const QString &uuid );
 
+    /**
+     * Returns the topmost layout item at a specified \a position. Ignores paper items.
+     * If \a ignoreLocked is set to true any locked items will be ignored.
+     */
+    QgsLayoutItem *layoutItemAt( QPointF position, const bool ignoreLocked = false ) const;
+
+    /**
+     * Returns the topmost composer item at a specified \a position which is below a specified \a item. Ignores paper items.
+     * If \a ignoreLocked is set to true any locked items will be ignored.
+     */
+    QgsLayoutItem *layoutItemAt( QPointF position, const QgsLayoutItem *belowItem, const bool ignoreLocked = false ) const;
+
     /**
      * Sets the native measurement \a units for the layout. These also form the default unit
      * for measurements for the layout.

tests/src/python/test_qgslayout.py

@@ -26,7 +26,9 @@
                        QgsLayoutMeasurement,
                        QgsFillSymbol,
                        QgsReadWriteContext,
-                       QgsLayoutItemMap)
+                       QgsLayoutItemMap,
+                       QgsLayoutSize,
+                       QgsLayoutPoint)
 from qgis.PyQt.QtCore import Qt, QCoreApplication, QEvent, QPointF, QRectF
 from qgis.PyQt.QtTest import QSignalSpy
 from qgis.PyQt.QtXml import QDomDocument
@@ -140,6 +142,43 @@ def testSelections(self):
         self.assertEqual(len(select_changed_spy), 5)
         self.assertEqual(select_changed_spy[-1][0], None)
 
+    def testLayoutItemAt(self):
+        p = QgsProject()
+        l = QgsLayout(p)
+
+        # add some items
+        item1 = QgsLayoutItemMap(l)
+        item1.attemptMove(QgsLayoutPoint(4, 8, QgsUnitTypes.LayoutMillimeters))
+        item1.attemptResize(QgsLayoutSize(18, 12, QgsUnitTypes.LayoutMillimeters))
+        l.addItem(item1)
+
+        item2 = QgsLayoutItemMap(l)
+        item2.attemptMove(QgsLayoutPoint(6, 10, QgsUnitTypes.LayoutMillimeters))
+        item2.attemptResize(QgsLayoutSize(18, 12, QgsUnitTypes.LayoutMillimeters))
+        l.addItem(item2)
+
+        item3 = QgsLayoutItemMap(l)
+        item3.attemptMove(QgsLayoutPoint(8, 12, QgsUnitTypes.LayoutMillimeters))
+        item3.attemptResize(QgsLayoutSize(18, 12, QgsUnitTypes.LayoutMillimeters))
+        item3.setLocked(True)
+        l.addItem(item3)
+
+        self.assertIsNone(l.layoutItemAt(QPointF(0, 0)))
+        self.assertIsNone(l.layoutItemAt(QPointF(100, 100)))
+
+        self.assertEqual(l.layoutItemAt(QPointF(5, 9)), item1)
+        self.assertEqual(l.layoutItemAt(QPointF(25, 23)), item3)
+        self.assertIsNone(l.layoutItemAt(QPointF(25, 23), True))
+        self.assertEqual(l.layoutItemAt(QPointF(7, 11)), item2)
+        self.assertEqual(l.layoutItemAt(QPointF(9, 13)), item3)
+        self.assertEqual(l.layoutItemAt(QPointF(9, 13), True), item2)
+
+        self.assertEqual(l.layoutItemAt(QPointF(9, 13), item3), item2)
+        self.assertEqual(l.layoutItemAt(QPointF(9, 13), item2), item1)
+        self.assertIsNone(l.layoutItemAt(QPointF(9, 13), item1))
+        item2.setLocked(True)
+        self.assertEqual(l.layoutItemAt(QPointF(9, 13), item3, True), item1)
+
 
 if __name__ == '__main__':
     unittest.main()