Enum Filter

#[non_exhaustive]
pub enum Filter {
    NoFilter,
    Sub,
    Up,
    Avg,
    Paeth,
    Adaptive,
}

The byte level filter applied to scanlines to prepare them for compression.

Compression in general benefits from repetitive data. The filter is a content-aware method of compressing the range of occurring byte values to help the compression algorithm. Note that this does not operate on pixels but on raw bytes of a scanline.

Details on how each filter works can be found in the PNG Book.

The default filter is Adaptive, which uses heuristics to select the best filter for every row.

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.

NoFilter

Sub

Up

Avg

Paeth

Adaptive

Trait Implementations

impl Clone for Filter

fn clone(&self) -> Filter

Returns a duplicate of the value.

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

Performs copy-assignment from source.

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 PartialEq for Filter

fn eq(&self, other: &Filter) -> 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 Copy for Filter

impl Eq for Filter

impl StructuralPartialEq for Filter