class BacklightState
Defined at line 23 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
Equivalent to the FIDL type [`fuchsia.hardware.backlight/State`].
See `::fuchsia_hardware_backlight::wire::State` for references.
Instances are guaranteed to represent valid backlight states.
This is a value type. Instances can be stored in containers. Copying, moving
and destruction are trivial.
Public Methods
void BacklightState (const BacklightState & )Defined at line 57 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
void BacklightState (BacklightState && )Defined at line 58 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
BacklightState & operator= (const BacklightState & )Defined at line 59 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
BacklightState & operator= (BacklightState && )Defined at line 60 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
void ~BacklightState ()Defined at line 61 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
bool on ()True iff the backlight is turned on.
When the backlight is turned off, it emits 0 nits (no light).
Defined at line 80 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
double brightness_fraction ()The amount of light emitted by the device, relatively to its maximum power.
Guaranteed to be in [0.0, 1.0]. Guaranteed to be 0.0 if `on` is false.
1.0 maps to the maximum brightness level supported by the hardware.
0.0 maps to the minimum configurable brightness level supported by the
hardware.
TODO(https://fxbug.dev/419035481): Specify the meaning of having `on` set
to true and `brightness_fraction()` / `brightness_nits()` set to 0.0.
Defined at line 92 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
std::optional<double> brightness_nits ()The amount of light emitted by the device, in nits.
Guaranteed to be non-negative. Guaranteed to be 0.0 if `on` is false.
Set to nullopt if the driver does not provide guarantees around the amount
of light emitted.
Defined at line 100 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
bool IsValid (const fuchsia_hardware_backlight::wire::State & fidl_state, bool use_absolute_brightness)True iff `fidl_state` is convertible to a valid BacklightState.
If `use_absolute_brightness` is true, the brightness value in `fidl_state`
maps to `brightness_nits()` and must meet the constraints documented there.
If `use_absolute_brightness` is false, the brightness value in `fidl_state`
maps to `brightness_fraction()`, and must meet the constraints documented
there.
Defined at line 122 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
BacklightState From (const fuchsia_hardware_backlight::wire::State & fidl_state, bool use_absolute_brightness)`fidl_state` must be convertible to a valid BacklightState.
This is not a constructor to allow designated initializer syntax. Making
this a constructor would introduce ambiguity when designated initializer
syntax is used, because `fuchsia.hardware.brightness/State` will eventually
be migrated to have the same field names as our supported designated
initializer syntax.
TODO(https://fxbug.dev/419035481): Remove `use_absolute_brightness` when
the FIDL State structure becomes unambiguous.
Defined at line 145 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
void BacklightState (const BacklightState::ConstructorArgs & args)Constructor that enables the designated initializer syntax with containers.
NOLINTNEXTLINE(google-explicit-constructor)
Defined at line 137 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
fuchsia_hardware_backlight::wire::State ToFidl (bool use_absolute_brightness)`use_absolute_brightness` must only be true if the absolute brightness
information is not nullopt.
Absolute brightness information is dropped if `use_absolute_brightness` is
false. Fractional brightness information is dropped if
`use_absolute_brightness` is true.
TODO(https://fxbug.dev/419035481): Remove `use_absolute_brightness` when
the FIDL State structure becomes unambiguous.
Defined at line 168 of file ../../src/graphics/display/lib/api-types/cpp/backlight-state.h
Friends
bool BacklightState (const BacklightState & lhs, const BacklightState & rhs)bool BacklightState (const BacklightState & lhsconst BacklightState & rhs)