Struct DHasher 

pub struct DHasher { /* private fields */ }

Difference hash (dHash) for fast duplicate detection.

dHash computes a gradient-based hash by comparing adjacent pixels. It’s very fast and works well for detecting near-duplicate frames.

Algorithm

1. Resize image to (hash_width + 1, hash_height)
2. Convert to grayscale
3. Compare each pixel to its right neighbor
4. Set bit to 1 if left > right, else 0

Example

use figif_core::hashers::DHasher;
use figif_core::traits::FrameHasher;

let hasher = DHasher::new();
let hash = hasher.hash_frame(&image);

Implementations

impl DHasher

pub fn new() -> Self

Create a new dHash hasher with default 8x8 hash size.

pub fn with_size(width: u32, height: u32) -> Self

Create a dHash hasher with custom hash dimensions.

Larger sizes provide more precision but slower comparison. Common sizes: 8x8 (64-bit), 16x16 (256-bit).

pub fn hash_width(&self) -> u32

Get the hash width.

pub fn hash_height(&self) -> u32

Get the hash height.

pub fn hash_bits(&self) -> u32

Get the total hash bits.

Trait Implementations

impl Clone for DHasher

fn clone(&self) -> DHasher

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DHasher

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

Formats the value using the given formatter.

impl Default for DHasher

fn default() -> Self

Returns the “default value” for a type.

impl FrameHasher for DHasher

type Hash = ImageHash

The hash type produced by this hasher.

fn hash_frame(&self, image: &RgbaImage) -> Self::Hash

Compute the perceptual hash for a single frame.

fn distance(&self, a: &Self::Hash, b: &Self::Hash) -> u32

Compute the distance between two hashes.

fn name(&self) -> &'static str

Get the name of this hasher for logging/debugging.

fn suggested_threshold(&self) -> u32

Suggested threshold for considering frames as duplicates.