The document, titled "User Interface Contrast Filter," describes a display adjustment tool that can differentiate multiple UI elements and alter their individual appearance with a single user input.
Almost all applications on the market today have visual UIs, which usually take the form of buttons, sliders, menus and selection controls that are overlaid on a background color or image. These elements combine with interactive content display areas to form the basic user interface.
Apple notes that many users adjust the brightness or contrast settings that control how the UI is displayed. How they make these adjustments depends on environment, visibility or personal preference. For example, in iOS the brightness of a display can be dimmed manually or automatically with help from ambient light sensors. The brightness and contrast changes are global, meaning they affect all UI elements equally.
There are times, however, that a user may want to change only certain elements in a UI, while leaving content display areas untouched. Thus, instead of universal display settings, Apple proposes a system that can filter or make intuitive changes to multiple UI elements in a selective manner. This would allow menu bars, text elements and controls to be adjusted separately from content.
To efficiently recognize and change each element, the system looks at color saturation, or more specifically, saturated pixels versus non-saturated pixels. In one embodiment, the non-saturated pixels are associated with areas that don't hold active content, and therefore show the most change when display adjustments are made.
In other embodiments, a mask can be applied to the sections of a display that are not to be modified, such as content areas. When this technique is used, the mask can be a simple generated black and white image. The UI elements under the white portion would become adjustable by the user, while the black areas would remain static.
The paper goes into great detail as to how adjustments are performed on individual pixels, including calibration and luminance data, color saturation, gray values and more. Apple notes that the system can work with automatic display settings with minimal user input. Aside from enhanced visibility, the process may also save battery life in some cases.
With its system-level UI element recognition, the method could theoretically be introduced without putting too much strain on third-party app developers.
Apple's selective UI filter patent application was first filed for in April and credits Patrick O. Heynen, Michael P. Stern, Andrew Bryant, Marian E. Goldeen and William J. Feth as its inventors.