Struct PlaneDescriptor 

pub struct PlaneDescriptor {
    pub semantic: PlaneSemantic,
    pub channel_type: ChannelType,
    pub h_subsample: u8,
    pub v_subsample: u8,
}

Metadata describing a single plane in a multi-plane image.

This is a pure descriptor — no pixel data, no heap allocation. Subsample factors are explicit per-plane rather than inferred from dimension ratios, because strip-based pipelines don’t carry global image dimensions.

Examples

use zenpixels::{PlaneDescriptor, PlaneSemantic, ChannelType};

let luma = PlaneDescriptor::new(PlaneSemantic::Luma, ChannelType::F32);
assert!(!luma.is_subsampled());
assert_eq!(luma.plane_width(1920), 1920);

let chroma = PlaneDescriptor::new(PlaneSemantic::ChromaCb, ChannelType::F32)
    .with_subsampling(2, 2); // 4:2:0
assert!(chroma.is_subsampled());
assert_eq!(chroma.plane_width(1920), 960);
assert_eq!(chroma.plane_height(1080), 540);

Fields

semantic: PlaneSemantic

What this plane represents.

channel_type: ChannelType

Storage type for each sample in this plane.

h_subsample: u8

Horizontal subsampling factor (1 = full resolution, 2 = half, 4 = quarter).

v_subsample: u8

Vertical subsampling factor (1 = full resolution, 2 = half).

Implementations

impl PlaneDescriptor

pub const fn new( semantic: PlaneSemantic, channel_type: ChannelType, ) -> PlaneDescriptor

Create a full-resolution plane descriptor (no subsampling).

pub const fn with_subsampling(self, h: u8, v: u8) -> PlaneDescriptor

Builder: set subsampling factors.

Panics

Debug-asserts that h and v are non-zero powers of two.

pub const fn plane_width(&self, ref_width: u32) -> u32

Compute the width of this plane given a reference (luma) width.

Uses ceiling division so subsampled planes always cover the full image.

Robustness: h_subsample is a public field, so a struct-literal write or a codec mapping an out-of-range subsampling code to factor 0 can leave the divisor at 0 — which would panic the div_ceil in release. We saturate the divisor at 1 here so production servers never see a divide-by-zero abort; the with_subsampling builder’s debug_assert! still catches the misuse in dev/test.

pub const fn plane_height(&self, ref_height: u32) -> u32

Compute the height of this plane given a reference (luma) height.

Uses ceiling division so subsampled planes always cover the full image.

Robustness: see plane_width — same div-by-zero guard for v_subsample.

pub const fn is_subsampled(&self) -> bool

Whether this plane is subsampled (either axis).

pub const fn bytes_per_sample(&self) -> usize

Bytes per sample in this plane.

Trait Implementations

impl Clone for PlaneDescriptor

fn clone(&self) -> PlaneDescriptor

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for PlaneDescriptor

impl Debug for PlaneDescriptor

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

Formats the value using the given formatter.

impl Display for PlaneDescriptor

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

Formats the value using the given formatter.

impl Eq for PlaneDescriptor

impl Hash for PlaneDescriptor

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

where __H: Hasher,

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 PartialEq for PlaneDescriptor

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for PlaneDescriptor