| # Brightness # | 
 |  | 
 | Brightness comprises Brightness Manager which serves brightness.fidl, | 
 | the Color Tint module which serves color_tint.fidl and a color | 
 | adjustment service which uses color_adjustment.fidl. | 
 |  | 
 | # FIDLs # | 
 |  | 
 | ## brightness.fidl ## | 
 |  | 
 | The FIDL interface in brightness.fidl is typically used by the settings | 
 | component to tell it what to do. The settings component will use this | 
 | interface to control brightness. | 
 |  | 
 | This component manages the screen backlight. It has two modes | 
 | auto-brightness and manual. | 
 |  | 
 | This interface will typically be used by the brightness UI but will | 
 | support concurrent users. | 
 |  | 
 | ### Auto-brightness Mode ### | 
 | In this mode the brightness polls the light sensor and sets the | 
 | backlight as appropriate, darker as the sensor gets less light and | 
 | brighter as it gets more. | 
 |  | 
 | ### Manual Mode ### | 
 | In manual mode the backlight remains at a fixed brightness until the | 
 | brightness component is told to set the backlight to another brightness | 
 | or auto-brightness mode is turned on. | 
 |  | 
 | ### Notes ### | 
 | The brightness component always ensures that the screen backlight | 
 | changes smoothly over short period of time. This means that the | 
 | calling application can abruptly change the screen brightness | 
 | without having to worry about making the user jump! | 
 |  | 
 | ## color_adjustment.fidl ## | 
 |  | 
 | The FIDL interface in color_adjustment.fidl is used by a component to | 
 | provide a handle so that color adjustment matrices can be sent | 
 | at will. | 
 |  | 
 | ## color_tint.fidl ## | 
 |  | 
 | The FIDL interface in color_tint.fidl is used to ask a color tinting | 
 | component to convert a light sensor reading to a screen tint. |