Add method to detect whether layout has uniform page sizes

nyalldawson · nyalldawson · commit 5cf36cd819fc · 2017-12-17T14:14:31.000+10:00
diff --git a/python/core/layout/qgslayoutpagecollection.sip b/python/core/layout/qgslayoutpagecollection.sip
@@ -198,6 +198,15 @@ Returns the maximum width of pages in the collection. The returned value is
 in layout units.
 %End
 
+    bool hasUniformPageSizes() const;
+%Docstring
+ Returns true if the layout has uniform page sizes, e.g. all pages are the same size.
+
+ This method does not consider differing units as non-uniform sizes, only the actual
+ physical size of the pages.
+ :rtype: bool
+%End
+
     int pageNumberForPoint( QPointF point ) const;
 %Docstring
 Returns the page number corresponding to a ``point`` in the layout (in layout units).
diff --git a/src/core/layout/qgslayoutpagecollection.cpp b/src/core/layout/qgslayoutpagecollection.cpp
@@ -95,6 +95,24 @@ QSizeF QgsLayoutPageCollection::maximumPageSize() const
   return maxSize;
 }
 
+bool QgsLayoutPageCollection::hasUniformPageSizes() const
+{
+  QSizeF size;
+  for ( QgsLayoutItemPage *page : mPages )
+  {
+    QSizeF pageSize = mLayout->convertToLayoutUnits( page->pageSize() );
+    if ( !size.isValid() )
+      size = pageSize;
+    else
+    {
+      if ( !qgsDoubleNear( pageSize.width(), size.width(), 0.01 )
+           || !qgsDoubleNear( pageSize.height(), size.height(), 0.01 ) )
+        return false;
+    }
+  }
+  return true;
+}
+
 int QgsLayoutPageCollection::pageNumberForPoint( QPointF point ) const
 {
   int pageNumber = 0;
diff --git a/src/core/layout/qgslayoutpagecollection.h b/src/core/layout/qgslayoutpagecollection.h
@@ -242,6 +242,14 @@ class CORE_EXPORT QgsLayoutPageCollection : public QObject, public QgsLayoutSeri
      */
     QSizeF maximumPageSize() const;
 
+    /**
+     * Returns true if the layout has uniform page sizes, e.g. all pages are the same size.
+     *
+     * This method does not consider differing units as non-uniform sizes, only the actual
+     * physical size of the pages.
+     */
+    bool hasUniformPageSizes() const;
+
     /**
      * Returns the page number corresponding to a \a point in the layout (in layout units).
      *
diff --git a/tests/src/python/test_qgslayoutpagecollection.py b/tests/src/python/test_qgslayoutpagecollection.py
@@ -282,6 +282,34 @@ def testMaxPageWidthAndSize(self):
         self.assertEqual(collection.maximumPageSize().width(), 100000.0)
         self.assertEqual(collection.maximumPageSize().height(), 100000.0)
 
+    def testUniformPageSizes(self):
+        """
+        Test detection of uniform page sizes
+        """
+        p = QgsProject()
+        l = QgsLayout(p)
+        collection = l.pageCollection()
+
+        self.assertTrue(collection.hasUniformPageSizes())
+
+        # add a page
+        page = QgsLayoutItemPage(l)
+        page.setPageSize('A4')
+        collection.addPage(page)
+        self.assertTrue(collection.hasUniformPageSizes())
+
+        # add a second page
+        page2 = QgsLayoutItemPage(l)
+        page2.setPageSize(QgsLayoutSize(21.0, 29.7, QgsUnitTypes.LayoutCentimeters))
+        collection.addPage(page2)
+        self.assertTrue(collection.hasUniformPageSizes())
+
+        # add a page with other units
+        page3 = QgsLayoutItemPage(l)
+        page3.setPageSize('A5')
+        collection.addPage(page3)
+        self.assertFalse(collection.hasUniformPageSizes())
+
     def testReflow(self):
         """
         Test reflowing pages
