The two graphics libraries, AChartEngine for Android and Coreplot for iOS, provided appropriate facilities for these apps and performed adequately when displaying files with several thousand points. Both Android and iOS apps reacted responsively to drag and
pinch interactions. The user interfaces on both apps allow the user to access all
the facilities simply. However, separate menus were used to select spectra in the iOS application. It is more natural to choose a drawn spectrum by touching it rather than selecting it from a menu. Where two spectra are too close to be selected by touch, selecting
the displayed title provides a natural alternative without requiring additional screen space or a pop-up/slide-in menu.