void highlight(Control *c); void unhighlight(Control *c); int is_highlighted(Control *c); void flash_control(Control *c);
Push buttons, check boxes, radio buttons, etc are highlighted when the user holds down a mouse button inside the control's boundary, and become unhighlighted when the mouse button is released. The highlight function makes a control appear highlighted, and unhighlight returns a control to its normal appearance. Whether or not a control is currently highlighted is reported by is_highlighted.
The function flash_control simulates a mouse button click in a button, check box or radio button. The control will become highlighted and after a short period of time will be unhighlighted. This function does nothing more than change the appearance of the control for a brief period of time.