Add method to determine whether an annotation layer is empty

qgis · Sep 1, 2020 · b9cd453 · b9cd453
1 parent 636653d
commit b9cd453
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Showing 4 changed files with 19 additions and 0 deletions.
diff --git a/python/core/auto_generated/annotations/qgsannotationlayer.sip.in b/python/core/auto_generated/annotations/qgsannotationlayer.sip.in
@@ -72,6 +72,11 @@ Removes (and deletes) the item with matching ``id``.
     void clear();
 %Docstring
 Removes all items from the layer.
+%End
+
+    bool isEmpty() const;
+%Docstring
+Returns ``True`` if the annotation layer is empty and contains no annotations.
 %End
 
     QMap<QString, QgsAnnotationItem *> items() const;

diff --git a/src/core/annotations/qgsannotationlayer.cpp b/src/core/annotations/qgsannotationlayer.cpp
@@ -73,6 +73,11 @@ void QgsAnnotationLayer::clear()
   triggerRepaint();
 }
 
+bool QgsAnnotationLayer::isEmpty() const
+{
+  return mItems.empty();
+}
+
 void QgsAnnotationLayer::setOpacity( double opacity )
 {
   mOpacity = opacity;

diff --git a/src/core/annotations/qgsannotationlayer.h b/src/core/annotations/qgsannotationlayer.h
@@ -96,6 +96,11 @@ class CORE_EXPORT QgsAnnotationLayer : public QgsMapLayer
      */
     void clear();
 
+    /**
+     * Returns TRUE if the annotation layer is empty and contains no annotations.
+     */
+    bool isEmpty() const;
+
     /**
      * Returns a map of items contained in the layer, by unique item ID.
      *

diff --git a/tests/src/python/test_qgsannotationlayer.py b/tests/src/python/test_qgsannotationlayer.py
@@ -62,11 +62,14 @@ def testItems(self):
         layer = QgsAnnotationLayer('test', QgsAnnotationLayer.LayerOptions(QgsProject.instance().transformContext()))
         self.assertTrue(layer.isValid())
 
+        self.assertTrue(layer.isEmpty())
+
         polygon_item_id = layer.addItem(QgsAnnotationPolygonItem(QgsPolygon(QgsLineString([QgsPoint(12, 13), QgsPoint(14, 13), QgsPoint(14, 15), QgsPoint(12, 13)]))))
         linestring_item_id = layer.addItem(QgsAnnotationLineItem(QgsLineString([QgsPoint(11, 13), QgsPoint(12, 13), QgsPoint(12, 15)])))
         marker_item_id = layer.addItem(QgsAnnotationMarkerItem(QgsPoint(12, 13)))
 
         self.assertEqual(len(layer.items()), 3)
+        self.assertFalse(layer.isEmpty())
 
         self.assertIsInstance(layer.items()[polygon_item_id], QgsAnnotationPolygonItem)
         self.assertIsInstance(layer.items()[linestring_item_id], QgsAnnotationLineItem)
@@ -86,6 +89,7 @@ def testItems(self):
 
         self.assertTrue(layer.removeItem(marker_item_id))
         self.assertEqual(len(layer.items()), 0)
+        self.assertTrue(layer.isEmpty())
 
         layer.addItem(QgsAnnotationPolygonItem(QgsPolygon(QgsLineString([QgsPoint(12, 13), QgsPoint(14, 13), QgsPoint(14, 15), QgsPoint(12, 13)]))))
         layer.addItem(QgsAnnotationLineItem(QgsLineString([QgsPoint(11, 13), QgsPoint(12, 13), QgsPoint(12, 15)])))