Struct fast_dhash::Dhash

pub struct Dhash { /* private fields */ }

Dhash

basic usage

use fast_dhash::Dhash;

use image;
use std::path::Path;

fn main() {
    let path = Path::new("../image.jpg");
    let image = image::open(path);
 
    if let Ok(image) = image {
        let hash = Dhash::new(&image);
        println!("hash: {}", hash);
        // hash: d6a288ac6d5cce14
    }
}

comparaison

Dhash implements PartialEq instead of Eq to match cases where the compared hashes represent a variation of the same image.

to check the equality use hash.hamming_distance(&other_hash) == 0

example

use fast_dhash::Dhash;
 
fn main() {
    let hash = Dhash::from_str("d6a288ac6d5cce14").unwrap();
    let similar = Dhash::from_str("d6a088ac6d5cce14").unwrap();
    let different = Dhash::from_str("a63ebccdfd5dbfff").unwrap();
 
    assert!(hash == similar);
    assert!(hash.hamming_distance(&similar) == 1);
 
    assert!(hash != different);
    assert!(hash.hamming_distance(&different) == 26);
}
 

Implementations

impl Dhash

pub fn new(image: &DynamicImage) -> Self

dhash algorithm

generates a new dhash from a DynamicImage

paincs

panics with images bigger than 34,952 x 34,952 (~1.2 billion pixels)

pub fn from_string(hash_hex: &String) -> Result<Self, ParseIntError>

Dhash from String

converts an hex String to Dhash

example

use fast_dhash::Dhash;

fn main() {
    let string = "d6a288ac6d5cce14".to_string();

    let hash = Dhash::from_string(&string).unwrap();
    let hash_u64 = hash.to_u64();

    assert_eq!(hash_u64, 15466074344494255636u64);
}

pub fn from_str(hash_hex: &str) -> Result<Self, ParseIntError>

Dhash from str

converts an hex str to Dhash

example

use fast_dhash::Dhash;

fn main() {
    let hash = Dhash::from_str("d6a288ac6d5cce14").unwrap();
    let hash_u64 = hash.to_u64();

    assert_eq!(hash_u64, 15466074344494255636u64);
}

pub fn from_u64(hash: u64) -> Self

Dhash from u64 hash

parse a u64

pub fn hamming_distance(&self, other: &Self) -> u32

dhash hamming distance

compares two hashes and returns a value between 0 and 64

0 identical

1~10 variation

>10 different

pub fn to_u64(&self) -> u64

u64 hash

returns the u64 hash

Trait Implementations

impl Clone for Dhash

fn clone(&self) -> Dhash

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Dhash

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Dhash

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for Dhash

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

Formats the value using the given formatter.

impl PartialEq<Dhash> for Dhash

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

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

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Dhash

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for Dhash