Resolve "Implement a workspace in the GUI"

Closes #65 (closed)

b_asic/GUI/arrow.py

@@ -28,5 +28,7 @@ class Arrow(QGraphicsLineItem):
 
     def moveLine(self):
         self.setPen(QPen(Qt.black, 3))
-        self.setLine(QLineF(self.source.x()+50, self.source.y()+25,\
-             self.destination.x(), self.destination.y()+25))
+        self.setLine(QLineF(self.source.operation.x()+self.source.x()+14,\
+             self.source.operation.y()+self.source.y()+7.5,\
\ No newline at end of file
+             self.destination.operation.x()+self.destination.x(),\
+             self.destination.operation.y()+self.destination.y()+7.5))