Enum Compositing 

#[non_exhaustive]
pub enum Compositing {
    CellFlattened,
    PixelLayered {
        needs_full_frame: bool,
    },
}

How a backend wants layers handed to Output::draw_layers.

Replaces the independent needs_full_frame/composites_layers booleans this crate used before retroglyph#1278: those could express a combination no backend used and crate::terminal::Terminal::present never honored (needs_full_frame() == true paired with the default composites_layers() == false). Nesting needs_full_frame inside PixelLayered makes that combination unrepresentable instead of merely undocumented.

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.

CellFlattened

Layers are flattened onto layer 0 before they reach the backend; one cell, one draw.

crate::terminal::Terminal::present composites all allocated layers into one frame itself, so layers 1+ still appear on every backend, not only pixel ones, and the backend receives only the changed cells.

PixelLayered

The backend composites layers itself (per pixel or quad), receiving the raw layered stream from Output::draw_layers.

Fields

needs_full_frame: bool

If true, every Output::draw_layers call receives all cells from every allocated layer, not just the changed ones, and the backend should clear its output surface before drawing. Pixel-based backends need this because sub-cell offsets can spill glyph pixels into adjacent cells: without a full redraw, orphaned pixels from the previous frame linger.

Trait Implementations

impl Clone for Compositing

fn clone(&self) -> Compositing

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Compositing

impl Debug for Compositing

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

Formats the value using the given formatter.

impl Eq for Compositing

impl Hash for Compositing

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 Compositing

fn eq(&self, other: &Compositing) -> 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 StructuralPartialEq for Compositing