Fix fdo#43090: Auto Closing of brackets

Check if we hit the left bracket, left parenthesis or left braces, insert the right close character
and set the current position to center the characters.

Change-Id: If1ee8a00799ef0933d5dfd51c32f669a2a27b2a7
Reviewed-on: https://gerrit.libreoffice.org/4374Reviewed-by: Michael Meeks <michael.meeks@suse.com>
Tested-by: Michael Meeks <michael.meeks@suse.com>

starmath/source/edit.cxx

@@ -455,6 +455,27 @@ void SmEditWindow::KeyInput(const KeyEvent& rKEvt)
             aModifyTimer.Start();
         }
 
+        // get the current char of the key event
+        sal_Unicode charCode = rKEvt.GetCharCode();
+        OUString close;
+
+        if (charCode == '{')
+            close = "  }";
+        else if (charCode == '[')
+            close = "  ]";
+        else if (charCode == '(')
+            close = "  )";
+
+        // auto close the current character
+        if (!close.isEmpty())
+        {
+            pEditView->InsertText(close);
+            // position it at center of brackets
+            ESelection aSelection = pEditView->GetSelection();
+            aSelection.nStartPos = aSelection.nEndPos = aSelection.nEndPos - 2;
+            pEditView->SetSelection(aSelection);
+        }
+
         InvalidateSlots();
     }
 }