Window types

Table VI also shows the additional energy required for using different types of windows and showing an eighty-letter text. It is obvious that using different window types consumes quite different amounts of energy even when the window sizes and colors are similar, as in a message box and a four-item menu window. Different window types necessitate different user interactions too, which further differentiate their energy consumption. There are several observations worth noting, as discussed next. First, the same interactive function may be implemented using different window types with different energy efficiencies. For instance, both tabbed panels and a scroll bar can be used to browse a long list. Their energy consumption differs drastically since a scroll bar requires many more screen updates than tabbed panels. Second, ``Message box" of Windows outperforms others simply because it allows a ``Message box" to be much simpler than Qt or X/GTK does. For example, ``Message box" of Qt has 3D effects and must contain at least one button. This indicates that an inflexibility in the GUI platform can cause extra energy consumption. Finally, Windows performs much worse for ``Menu," although it does well in other window types, because a menu window is animated in Windows. When a menu is tapped, the menu window gradually, but quickly, drops out. Such an animation or continuous screen change requires many more processor cycles, framebuffer updates and screen refreshes, thus leading to more additional energy. Using a scroll bar to browse a window also requires continuous screen changes. For energy efficiency, such continuous screen changes should be avoided, at the expense of a slight sacrifice in GUI aesthetics.