Systems and methods are described to render borders of controls and indicators in a graphical user interface (GUI), such that the rendered borders have continuous curvatures. In one aspect, a method includes generating a border of a GUI element to be represented in a GUI. The border includes a first straight side, a second straight side, and a corner portion that joins together the first straight side and the second straight side, such that a portion of the border that includes the first straight side, the corner portion and the second straight side is continuous and has continuous curvature. Additionally, the method includes representing the GUI element in the GUI.