Struct ViewParameters

pub struct ViewParameters {
    pub view: Rectangle,
    pub viewport: Rectangle,
    pub viewport_to_view_transform: [f32; 9],
}

The parameters of the associated view and viewport, sufficient to correctly interpret the position and scale of pointer events dispatched to this view.

Ordering. These parameters arrive over the same channel as pointer events, to provide synchronous context for interpreting the position of pointer events in the view’s local coordinate system.

Inter-protocol redundancy. Some of these parameters may also be sent over an independent channel dedicated to view control; the client is responsible for correct use of asynchronously received parameters.

TODO(https://fxbug.dev/42162292): Rename viewport, it is used in Flatland.

Fields

view: Rectangle

The view’s area of content, placed in the coordinate system of the view.

The rectangle is defined by the parent view’s setup of clipping on this view.

viewport: Rectangle

The viewport’s area of interaction, placed in an independent coordinate system.

A pointer event’s position is defined in the coordinate system of this viewport.

A change in viewport extents means the region for pointer interaction has itself moved, or changed in size, or both.

viewport_to_view_transform: [f32; 9]

The transform matrix that relates a point’s position in the viewport’s coordinate system to its position in the view’s coordinate system.

Trait Implementations

impl Clone for ViewParameters

fn clone(&self) -> ViewParameters

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ViewParameters

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

Formats the value using the given formatter.

impl<D> Decode<ViewParameters, D> for ViewParameters

where D: ResourceDialect,

fn new_empty() -> ViewParameters

Creates a valid instance of Self. The specific value does not matter, since it will be overwritten by decode.

unsafe fn decode( &mut self, decoder: &mut Decoder<'_, D>, offset: usize, _depth: Depth, ) -> Result<(), Error>

Decodes an object of type T from the decoder’s buffers into self.

impl<D> Encode<ViewParameters, D> for &ViewParameters

where D: ResourceDialect,

unsafe fn encode( self, encoder: &mut Encoder<'_, D>, offset: usize, _depth: Depth, ) -> Result<(), Error>

Encodes the object into the encoder’s buffers. Any handles stored in the object are swapped for Handle::INVALID.

impl PartialEq for ViewParameters

fn eq(&self, other: &ViewParameters) -> 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 ViewParameters

fn partial_cmp(&self, other: &ViewParameters) -> 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 TypeMarker for ViewParameters

type Owned = ViewParameters

The owned Rust type which this FIDL type decodes into.

fn inline_align(_context: Context) -> usize

Returns the minimum required alignment of the inline portion of the encoded object. It must be a (nonzero) power of two.

fn inline_size(_context: Context) -> usize

Returns the size of the inline portion of the encoded object, including padding for alignment. Must be a multiple of inline_align.

fn encode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and encoding requires no validation. When true, we can optimize encoding arrays and vectors of Self::Owned to a single memcpy.

fn decode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and decoding requires no validation. When true, we can optimize decoding arrays and vectors of Self::Owned to a single memcpy.

impl ValueTypeMarker for ViewParameters

type Borrowed<'a> = &'a ViewParameters

The Rust type to use for encoding. This is a particular Encode<Self> type cheaply obtainable from &Self::Owned. There are three cases:

fn borrow( value: &<ViewParameters as TypeMarker>::Owned, ) -> <ViewParameters as ValueTypeMarker>::Borrowed<'_>

Cheaply converts from &Self::Owned to Self::Borrowed.

impl Copy for ViewParameters

impl Persistable for ViewParameters

impl StructuralPartialEq for ViewParameters