Struct fidl_fuchsia_ui_composition::LayoutInfo

pub struct LayoutInfo {
    pub logical_size: Option<SizeU>,
    pub device_pixel_ratio: Option<VecF>,
    pub inset: Option<Inset>,
    /* private fields */
}

The return type of [GetLayout]. This table contains most of the information necessary for a client to decide how to layout their content in a Flatland instance. This data may be provided to the client before the command that creates the View is presented, so that the client may lay out content properly before their first call to [Present].

Fields

logical_size: Option<SizeU>

The layout size of a View in logical pixels, defined by the parent’s call to [SetViewportProperties].

The logical size also serves as the clip boundary of the View. Anything outside the clip boundary will not be rendered. Hence, the View’s Root Transform has a useful coordinate space of (0, 0) to (logical_size.width, logical_size.height).

Clients should re-layout their content when this value changes.

device_pixel_ratio: Option<VecF>

The ratio of display’s physical pixels to device independent pixels. Each logical pixel of a View is displayed on-screen by one or more physical pixels, as determined by this scale. Clients should not necessarily re-layout their content when this value changes, but accommodate by reallocating their Image buffers to avoid sampling artifacts. The HiDPI-aware client should allocate buffers that are sized (logical_size*device_pixel_ratio).

inset: Option<Inset>

The offsets between the edges and the visible rectangle of the View. The clients can assume that the boundary region between the inset and the View edge is occluded, and should adjust content layout to avoid this region. This inset is described in the view’s logical coordinate system. The HiDPI-aware clients should scale this by device_pixel_ratio.

Trait Implementations

impl Clone for LayoutInfo

fn clone(&self) -> LayoutInfo

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for LayoutInfo

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

Formats the value using the given formatter.

impl Decode<LayoutInfo> for LayoutInfo

fn new_empty() -> Self

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<'_>, offset: usize, depth: Depth ) -> Result<()>

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

impl Default for LayoutInfo

fn default() -> LayoutInfo

Returns the “default value” for a type.

impl Encode<LayoutInfo> for &LayoutInfo

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

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

impl PartialEq for LayoutInfo

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

This method tests for self and other values to be equal, and is used by ==.

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

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

impl TypeMarker for LayoutInfo

type Owned = LayoutInfo

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 LayoutInfo

type Borrowed<'a> = &'a LayoutInfo

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<'a>(value: &'a <Self as TypeMarker>::Owned) -> Self::Borrowed<'a>

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

impl Persistable for LayoutInfo

impl StructuralPartialEq for LayoutInfo