Struct Viewport 

pub struct Viewport {
    pub extents: Option<[[f32; 2]; 2]>,
    pub viewport_to_context_transform: Option<[f32; 9]>,
}

A rectangular region that directs injected events into a target.

The viewport relates a pointer’s position across multiple independent coordinate systems: the context, the viewport, and the dispatch clients. Intuitively, the viewport is how a pointer’s position is mapped to an interactive part of the scene.

A matrix is used to relate the viewport coordinate system to the context coordinate system. A pair of extents defines the viewport’s size in the viewport coordinate system. Together, they define the viewport’s placement in the context coordinate system.

The viewport coordinate system is used to convey a pointer’s coordinates in a scale-invariant way to dispatch clients, so that pointer movement can be interpreted correctly under effects like magnification. The context defines the viewport’s minimal and maximal extents in the viewport coordinate system.

• The boundary of the viewport, a rectangle, is axis aligned with the viewport coordinate system; however it may otherwise be freely positioned (“float”) within it: there is translation and scaling, but no rotation.
• Floating gives the injector some choice in how to convey coordinates, such as in Vulkan NDC, or in display pixel coordinates.
• The viewport rectangle defines a latch region used in dispatch (described below).

A dispatch client receives a pointer’s coordinates in the viewport coordinate system, along with a matrix to convert coordinates from the viewport coordinate system to the dispatch client’s coordinate system.

All fields required.

TODO(https://fxbug.dev/42162296): Rename Viewport, it is used in Flatland.

Fields

extents: Option<[[f32; 2]; 2]>

viewport_to_context_transform: Option<[f32; 9]>

Trait Implementations

impl Clone for Viewport

fn clone(&self) -> Viewport

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Viewport

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Viewport

fn default() -> Viewport

Returns the “default value” for a type.

impl<'a, ___E> Encode<Viewport<'static>, ___E> for &'a Viewport

where ___E: Encoder + ?Sized,

fn encode( self, encoder: &mut ___E, out: &mut MaybeUninit<Viewport<'static>>, _: (), ) -> Result<(), EncodeError>

Encodes this value into an encoder and output.

const COPY_OPTIMIZATION: CopyOptimization<Self, W> = _

Whether the conversion from Self to W is equivalent to copying the raw bytes of Self.

impl<___E> Encode<Viewport<'static>, ___E> for Viewport

where ___E: Encoder + ?Sized,

fn encode( self, encoder: &mut ___E, out: &mut MaybeUninit<Viewport<'static>>, _: (), ) -> Result<(), EncodeError>

Encodes this value into an encoder and output.

const COPY_OPTIMIZATION: CopyOptimization<Self, W> = _

Whether the conversion from Self to W is equivalent to copying the raw bytes of Self.

impl<'de> FromWire<Viewport<'de>> for Viewport

fn from_wire(wire_: Viewport<'de>) -> Self

Converts the given owned value to this type.

const COPY_OPTIMIZATION: CopyOptimization<W, Self> = _

Whether the conversion from W to Self is equivalent to copying the raw bytes of W.

impl<'de> FromWireRef<Viewport<'de>> for Viewport

fn from_wire_ref(wire: &Viewport<'de>) -> Self

Converts the given reference to this type.

impl PartialEq for Viewport

fn eq(&self, other: &Viewport) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Viewport

fn partial_cmp(&self, other: &Viewport) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Viewport

impl StructuralPartialEq for Viewport