Struct dither::ditherer::Ditherer

pub struct Ditherer<'a> {
    pub div: f64,
    pub offsets: &'a [(isize, isize, f64)],
    pub name: Option<&'a str>,
}

A type of Dither. See the documentation for the constants (i.e, ATKINSON) for the dither matrices themselves. A ditherer carries error from quantiation to nearby pixels after dividing by div and multiplying by the given scalar in offset; "spreading" the error, eg, take floyd-steinberg dithering: div=16

• . x 7
• 7 5 1

Suppose we have an grayscale image where the f64 pixel "p"" at (x=3, y=0) is 100., and we quantize to black (0.0) and white(255.0) The ditherer sets p=0 and has a carried error of 100. The spread error is then:

• [[0.0, 0.0, 43.75],`
• [43.75, 31.25, 6.25]]`

See tanner helland's excellent writeup on dithering algorithms for details.

Fields

div: f64

the divisor for the spilled error. see the third element of [Ditherer.offsets]

offsets: &'a [(isize, isize, f64)]

offsets represents a triplet (dx, dy, mul).

name: Option<&'a str>

the name of the ditherer, for debug output

Methods

impl<'a> Ditherer<'a>

pub const fn new(div: f64, offsets: &'a [(isize, isize, f64)]) -> Self

Trait Implementations

impl<'a, P> Dither<P> for Ditherer<'a> where
    P: Add<Output = P> + Clone + Default,
    P: Mul<f64, Output = P> + Div<f64, Output = P>, 

fn dither(&self, img: Img<P>, quantize: impl FnMut(P) -> (P, P)) -> Img<P>

dither an image using the specified offsets and divisor. P is the type of pixel; in practice, it is either f64 or [RGB<f64]

impl<'a> Clone for Ditherer<'a>

fn clone(&self) -> Ditherer<'a>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'a> PartialEq<Ditherer<'a>> for Ditherer<'a>

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

This method tests for self and other values to be equal, and is used by ==.

#[must_use]

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

This method tests for !=.

impl<'a> Eq for Ditherer<'a>

impl<'a> Default for Ditherer<'a>

fn default() -> Self

Returns the "default value" for a type.

impl<'a> Debug for Ditherer<'a>

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

Formats the value using the given formatter.

impl<'a> Display for Ditherer<'a>

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

Formats the value using the given formatter.

impl FromStr for Ditherer<'static>

type Err = ErrorUnknownDitherer

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.