Add method to determine largest page size

Author: nyalldawson

src/core/layout/qgslayoutpagecollection.cpp

@@ -71,13 +71,30 @@ void QgsLayoutPageCollection::reflow()
 double QgsLayoutPageCollection::maximumPageWidth() const
 {
   double maxWidth = 0;
-  Q_FOREACH ( QgsLayoutItemPage *page, mPages )
+  for ( QgsLayoutItemPage *page : mPages )
   {
     maxWidth = std::max( maxWidth, mLayout->convertToLayoutUnits( page->pageSize() ).width() );
   }
   return maxWidth;
 }
 
+QSizeF QgsLayoutPageCollection::maximumPageSize() const
+{
+  double maxArea = 0;
+  QSizeF maxSize;
+  for ( QgsLayoutItemPage *page : mPages )
+  {
+    QSizeF pageSize = mLayout->convertToLayoutUnits( page->pageSize() );
+    double area = pageSize.width() * pageSize.height();
+    if ( area > maxArea )
+    {
+      maxArea = area;
+      maxSize = pageSize;
+    }
+  }
+  return maxSize;
+}
+
 int QgsLayoutPageCollection::pageNumberForPoint( QPointF point ) const
 {
   int pageNumber = 0;

src/core/layout/qgslayoutpagecollection.h

@@ -229,9 +229,19 @@ class CORE_EXPORT QgsLayoutPageCollection : public QObject, public QgsLayoutSeri
     /**
      * Returns the maximum width of pages in the collection. The returned value is
      * in layout units.
+     *
+     * \see maximumPageSize()
      */
     double maximumPageWidth() const;
 
+    /**
+     * Returns the maximum size of any page in the collection, by area. The returned value
+     * is in layout units.
+     *
+     * \see maximumPageWidth()
+     */
+    QSizeF maximumPageSize() const;
+
     /**
      * Returns the page number corresponding to a \a point in the layout (in layout units).
      *

tests/src/python/test_qgslayoutpagecollection.py

@@ -250,9 +250,9 @@ def testExtendByNewPage(self):
         self.assertEqual(collection.pageCount(), 3)
         self.assertEqual(new_page2.sizeWithUnits(), new_page.sizeWithUnits())
 
-    def testMaxPageWidth(self):
+    def testMaxPageWidthAndSize(self):
         """
-        Test calculating maximum page width
+        Test calculating maximum page width and size
         """
         p = QgsProject()
         l = QgsLayout(p)
@@ -263,18 +263,24 @@ def testMaxPageWidth(self):
         page.setPageSize('A4')
         collection.addPage(page)
         self.assertEqual(collection.maximumPageWidth(), 210.0)
+        self.assertEqual(collection.maximumPageSize().width(), 210.0)
+        self.assertEqual(collection.maximumPageSize().height(), 297.0)
 
         # add a second page
         page2 = QgsLayoutItemPage(l)
         page2.setPageSize('A3')
         collection.addPage(page2)
         self.assertEqual(collection.maximumPageWidth(), 297.0)
+        self.assertEqual(collection.maximumPageSize().width(), 297.0)
+        self.assertEqual(collection.maximumPageSize().height(), 420.0)
 
         # add a page with other units
         page3 = QgsLayoutItemPage(l)
         page3.setPageSize(QgsLayoutSize(100, 100, QgsUnitTypes.LayoutMeters))
         collection.addPage(page3)
         self.assertEqual(collection.maximumPageWidth(), 100000.0)
+        self.assertEqual(collection.maximumPageSize().width(), 100000.0)
+        self.assertEqual(collection.maximumPageSize().height(), 100000.0)
 
     def testReflow(self):
         """