Enum PropTag 

#[non_exhaustive]
#[repr(u8)]
pub enum PropTag {
    FbId = 0,
    FbModifier = 1,
    CrtcId = 2,
    CrtcX = 3,
    CrtcY = 4,
    CrtcW = 5,
    CrtcH = 6,
    SrcX = 7,
    SrcY = 8,
    SrcW = 9,
    SrcH = 10,
    Rotation = 11,
    Alpha = 12,
    Zpos = 13,
    PixelFormat = 14,
    InFenceFd = 15,
}

Property tags a layer recognizes.

The set is closed: every KMS plane property a layer carries lives here, and an unrecognized name handed to Layer::set_property_by_name is dropped — a kernel commit would reject it with EINVAL anyway, so accepting it would only hide the typo. The scene writes a few per-plane extras, such as COLOR_ENCODING and FB_DAMAGE_CLIPS, from plane capabilities rather than from the layer.

Adding a property means adding a variant here and extending PropTag::name and PropTag::class. Both are exhaustive matches, so the compiler names every place that needs updating.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

FbId = 0

FB_ID — the framebuffer to scan out.

FbModifier = 1

FB_MODIFIER — the layout of that framebuffer.

CrtcId = 2

CRTC_ID — which CRTC the plane feeds.

CrtcX = 3

CRTC_X — destination x, in pixels.

CrtcY = 4

CRTC_Y — destination y, in pixels.

CrtcW = 5

CRTC_W — destination width, in pixels.

CrtcH = 6

CRTC_H — destination height, in pixels.

SrcX = 7

SRC_X — source x, 16.16 fixed point.

SrcY = 8

SRC_Y — source y, 16.16 fixed point.

SrcW = 9

SRC_W — source width, 16.16 fixed point.

SrcH = 10

SRC_H — source height, 16.16 fixed point.

Rotation = 11

rotation — rotate/reflect bitmask.

Alpha = 12

alpha — per-plane alpha, u16.

Zpos = 13

zpos — stacking order.

PixelFormat = 14

pixel_format — the FourCC.

InFenceFd = 15

IN_FENCE_FD — a fence the flip waits on.

Implementations

impl PropTag

pub const ALL: [Self; 16]

Every tag, in enum order.

Listing them explicitly rather than deriving a count keeps the exhaustiveness of PropTag::class meaningful: a variant inserted without being added here breaks the index-contiguity check in every_prop_tag_is_classified. One appended at the end is not caught, so keep the array’s size in step.

pub const fn index(self) -> usize

Index into a layer’s property array.

pub const fn name(self) -> &'static str

The canonical KMS property name.

pub const fn class(self) -> PropClass

Whether this property describes content or placement.

See PropClass. The match is exhaustive by construction: adding a variant without classifying it is a compile error, which is the whole reason this is a function rather than a lookup table with a default.

pub fn from_name(name: &str) -> Option<Self>

Look up a tag by its canonical KMS name.

A linear scan over 16 entries: branchless, cache-friendly, and faster than a hash map at this size — the same reasoning the C++ records.

Trait Implementations

impl Clone for PropTag

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for PropTag

impl Debug for PropTag

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

Formats the value using the given formatter.

impl Eq for PropTag

impl Hash for PropTag

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for PropTag

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for PropTag

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for PropTag

fn partial_cmp(&self, other: &Self) -> 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 StructuralPartialEq for PropTag