fixes 0003689: Snap to grid checkbox in edit control widget does not update

src/Base/Tools.h

@@ -32,6 +32,44 @@
 #include <string>
 #include <boost/signals2.hpp>
 #include <QString>
+#include <QObject>
+
+#if (QT_VERSION < 0x050300)
+class QSignalBlocker
+{
+public:
+    QSignalBlocker(QObject *object)
+      : object(object)
+      , blocked(object && object->blockSignals(true))
+      , inhibited(false)
+    {
+    }
+    ~QSignalBlocker()
+    {
+        if (object && !inhibited)
+            object->blockSignals(blocked);
+    }
+    void reblock()
+    {
+        if (object)
+            object->blockSignals(true);
+        inhibited = false;
+    }
+    void unblock()
+    {
+        if (object)
+            object->blockSignals(blocked);
+        inhibited = true;
+    }
+
+private:
+    QObject *object;
+    bool blocked;
+    bool inhibited;
+};
+#endif
+
+// ----------------------------------------------------------------------------
 
 namespace Base
 {