Enum Filter 

#[non_exhaustive]
pub enum Filter {
    Nearest,
    Box,
    Bilinear,
    CatmullRom,
    Mitchell,
    Lanczos2,
    Lanczos3,
}

A resampling filter kernel (SPEC §Core ops).

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.

Nearest

Nearest neighbour. Fastest, blockiest; the only filter that preserves exact sample values, which is why it is the right default for masks and palettes rather than photographs.

Box

Box average over the source footprint. The correct choice for large downscales, where it is both fast and alias-free.

Bilinear

Linear interpolation between the two nearest samples.

CatmullRom

Catmull-Rom cubic. Sharper than Mitchell, mild ringing.

Mitchell

Mitchell-Netravali cubic (B=C=1/3). The usual compromise between blurring and ringing.

Lanczos2

Lanczos windowed sinc, 2 lobes.

Lanczos3

Lanczos windowed sinc, 3 lobes. The default: sharpest of these at the cost of some ringing on hard edges.

Implementations

impl Filter

pub const fn support(self) -> f32

The filter’s radius in output units before scale is applied.

The actual support in input pixels is this scaled by the downsampling ratio, because downscaling must average over everything it discards or it aliases.

pub fn weight(self, x: f32) -> f32

The filter’s weight at signed distance x from the sample centre.

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

A short, stable name for diagnostics and benchmark output.

Trait Implementations

impl Clone for Filter

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 Filter

impl Debug for Filter

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

Formats the value using the given formatter.

impl Default for Filter

fn default() -> Self

Returns the “default value” for a type.

impl Eq for Filter

impl Hash for Filter

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 PartialEq for Filter

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Filter