class Layer
Defined at line 34 of file ../../src/ui/scenic/lib/display/internal/layer.h
Manages the state of a single display layer within the `CoordinatorProxy`.
This class maintains a "draft" state, representing pending changes, and an "applied" state,
representing the configuration last known to be successfully applied on the display hardware via
the FIDL `ApplyConfig()` method.
The `Layer` also holds a `LayerEquivalence`, which is a projection of the layer's state used by
`CoordinatorProxy` to determine `CheckConfig()` equivalency.
Workflow:
1. Calls to `Set*()` methods update the `draft_equiv_` and other draft fields
(e.g., `draft_image_`).
2. `CoordinatorProxy` calls `SendDiffsToCoordinator()`. This method compares the current
`draft_equiv_`, `draft_values_`, and `draft_image_` against the `applied_equiv_`,
`applied_values_`, and `applied_image_`. It sends the minimal set of FIDL commands to the
`fuchsia.hardware.display.Coordinator` to make the coordinator's layer state match this
`Layer`'s draft state.
3a. *After* a successful `CheckConfig()` and `ApplyConfig()` sequence in `CoordinatorProxy`, the
proxy calls this `Layer`'s `AcceptDraftState()` method to promote the draft state to the
applied state. Or:
3b. If `CheckConfig()` fails, `CoordinatorProxy` calls `ResetDraftState()` to
revert the draft state back to the last known good applied state.
Public Methods
void SetPrimaryConfig (const Extent2 & image_dimensions, uint32_t image_tiling_type)Corresponds to `fuchsia.hardware.display.Coordinator/SetLayerPrimaryConfig()`.
Modifies the layer's draft state; no FIDL methods are invoked.
Note: calling this clears the image, as done by the coordinator impl.
Defined at line 14 of file ../../src/ui/scenic/lib/display/internal/layer.cc
void SetPrimaryPosition (const RotateFlip &transform,const Rectangle &src,const Rectangle &dst)
Corresponds to `fuchsia.hardware.display.Coordinator/SetLayerPrimaryPosition()`.
Modifies the layer's draft state; no FIDL methods are invoked.
Defined at line 28 of file ../../src/ui/scenic/lib/display/internal/layer.cc
void SetPrimaryAlpha (const BlendMode & blend_mode, float alpha_value)Corresponds to `fuchsia.hardware.display.Coordinator/SetLayerPrimaryAlpha()`.
Modifies the layer's draft state; no FIDL methods are invoked.
Defined at line 37 of file ../../src/ui/scenic/lib/display/internal/layer.cc
void Layer ()Defined at line 43 of file ../../src/ui/scenic/lib/display/internal/layer.h
void SetLayerImage (const ImageId & image_id, const EventId & wait_event_id)Corresponds to `fuchsia.hardware.display.Coordinator/SetLayerPrimaryImage()`.
Modifies the layer's draft state; no FIDL methods are invoked.
Defined at line 46 of file ../../src/ui/scenic/lib/display/internal/layer.cc
void SetColorConfig (const WireColor & color, const Rectangle & display_destination)Corresponds to `fuchsia.hardware.display.Coordinator/SetLayerColorConfig()`.
Modifies the layer's draft state; no FIDL methods are invoked.
Defined at line 52 of file ../../src/ui/scenic/lib/display/internal/layer.cc
void UnsetImage (const ImageId & image_id)If either the draft or applied state includes `image_id`, replace with `kInvalidImageId`.
Defined at line 61 of file ../../src/ui/scenic/lib/display/internal/layer.cc
size_t SendDiffsToCoordinator (const LayerId & layer_id, fidl::WireSharedClient<fuchsia_hardware_display::Coordinator> & coordinator)Compute the diffs between the draft and applied states, and make only the necessary FIDL calls
to make the Coordinator's draft state match this layer's draft state. Returns the number of
FIDL API calls that were sent.
Defined at line 70 of file ../../src/ui/scenic/lib/display/internal/layer.cc
const LayerEquivalence & draft_equiv ()Defined at line 83 of file ../../src/ui/scenic/lib/display/internal/layer.h
void ResetDraftState ()Reset all draft state to be identical to the currently-applied state.
Defined at line 84 of file ../../src/ui/scenic/lib/display/internal/layer.cc
void AcceptDraftState ()Replace the accepted state with the draft state. Afterward, they are identical.
Defined at line 91 of file ../../src/ui/scenic/lib/display/internal/layer.cc