Return empty rectangle from GetItemRect() if item is not visible

This was already the case if the item was not visible because its parent
was not expanded, but now make it also true for the items which are not
visible due to the current scrollbar position.

Add unit tests checking for this and also verifying that GetItemRect()
returns the coordinates in the physical window coordinates.

interface/wx/dataview.h

@@ -1448,8 +1448,9 @@ public:
     /**
         Returns item rectangle.
 
-        If item is not currently visible because its parent is collapsed,
-        return an empty rectangle.
+        If item is not currently visible, either because its parent is
+        collapsed or it is outside of the visible part of the control due to
+        the current vertical scrollbar position, return an empty rectangle.
 
         Coordinates of the rectangle are specified in wxDataViewCtrl client
         area coordinates.

src/generic/datavgen.cpp

@@ -3839,6 +3839,14 @@ wxRect wxDataViewMainWindow::GetItemRect( const wxDataViewItem & item,
     GetOwner()->CalcScrolledPosition(  itemRect.x,  itemRect.y,
                                       &itemRect.x, &itemRect.y );
 
+    // Check if the rectangle is completely outside of the currently visible
+    // area and, if so, return an empty rectangle to indicate that the item is
+    // not visible.
+    if ( itemRect.GetBottom() < 0 || itemRect.GetTop() > GetClientSize().y )
+    {
+        return wxRect();
+    }
+
     return itemRect;
 }
 
@@ -5853,8 +5861,11 @@ wxRect wxDataViewCtrl::GetItemRect( const wxDataViewItem & item,
     // Convert position from the main window coordinates to the control coordinates.
     // (They can be different due to the presence of the header.).
     wxRect r = m_clientArea->GetItemRect(item, column);
-    const wxPoint ctrlPos = ScreenToClient(m_clientArea->ClientToScreen(r.GetPosition()));
-    r.SetPosition(ctrlPos);
+    if ( r.width || r.height )
+    {
+        const wxPoint ctrlPos = ScreenToClient(m_clientArea->ClientToScreen(r.GetPosition()));
+        r.SetPosition(ctrlPos);
+    }
     return r;
 }
 

tests/controls/dataviewctrltest.cpp

@@ -208,6 +208,9 @@ TEST_CASE_METHOD(SingleSelectDataViewCtrlTestCase,
     const wxRect rect1 = m_dvc->GetItemRect(m_child1);
     const wxRect rect2 = m_dvc->GetItemRect(m_child2);
 
+    CHECK( rect1 != wxRect() );
+    CHECK( rect2 != wxRect() );
+
     CHECK( rect1.x == rect2.x );
     CHECK( rect1.width == rect2.width );
     CHECK( rect1.height == rect2.height );
@@ -215,6 +218,30 @@ TEST_CASE_METHOD(SingleSelectDataViewCtrlTestCase,
 
     const wxRect rectNotShown = m_dvc->GetItemRect(m_grandchild);
     CHECK( rectNotShown == wxRect() );
+
+    // Append enough items to make the window scrollable.
+    for ( int i = 3; i < 100; ++i )
+        m_dvc->AppendItem(m_root, wxString::Format("child%d", i));
+
+    const wxDataViewItem last = m_dvc->AppendItem(m_root, "last");
+
+    // This should scroll the window to bring this item into view.
+    m_dvc->EnsureVisible(last);
+
+    // Check that this was indeed the case.
+    const wxDataViewItem top = m_dvc->GetTopItem();
+    CHECK( top != m_root );
+
+    // Verify that the coordinates are returned in physical coordinates of the
+    // window and not the logical coordinates affected by scrolling.
+    const wxRect rectScrolled = m_dvc->GetItemRect(top);
+    CHECK( rectScrolled.GetBottom() > 0 );
+    CHECK( rectScrolled.GetTop() <= m_dvc->GetClientSize().y );
+
+    // Also check that the root item is not currently visible (because it's
+    // scrolled off).
+    const wxRect rectRoot = m_dvc->GetItemRect(m_root);
+    CHECK( rectRoot == wxRect() );
 #endif
 }