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68 lines
2.1 KiB
68 lines
2.1 KiB
// Copyright 2016 Drew Short <drew@sothr.com>.
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//
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// Licensed under the MIT license<LICENSE-MIT or http://opensource.org/licenses/MIT>.
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// This file may not be copied, modified, or distributed except according to those terms.
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use super::{HashType, PerceptualHash, Precision, PreparedImage};
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use super::prepare_image;
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use super::image::{GenericImage, Pixel};
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use std::path::Path;
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use cache::Cache;
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pub struct DHash<'a> {
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prepared_image: Box<PreparedImage<'a>>,
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}
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impl<'a> DHash<'a> {
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pub fn new(path: &'a Path, precision: &Precision, cache: &Option<Cache>) -> Self {
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DHash {
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prepared_image: Box::new(prepare_image(&path, &HashType::DHash, &precision, cache)),
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}
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}
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}
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impl<'a> PerceptualHash for DHash<'a> {
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/**
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* Calculate the dhash of the provided prepared image
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*
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* # Return
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*
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* Returns a u64 representing the value of the hash
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*/
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fn get_hash(&self, _: &Option<Cache>) -> u64 {
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match self.prepared_image.image {
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Some(ref image) => {
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let first_pixel_val = image.pixels().nth(0).unwrap().channels()[0];
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let last_pixel_val = image.pixels().last().unwrap().channels()[0];
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// Calculate the dhash
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let mut previous_pixel_val = 0u64;
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let mut hash = 0u64;
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for (index, pixel) in image.pixels().enumerate() {
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if index == 0 {
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previous_pixel_val = pixel.channels()[0] as u64;
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continue;
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}
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let channels = pixel.channels();
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let pixel_val = channels[0] as u64;
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if pixel_val >= previous_pixel_val {
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hash |= 1;
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} else {
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hash |= 0;
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}
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hash <<= 1;
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previous_pixel_val = channels[0] as u64;
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}
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if first_pixel_val >= last_pixel_val {
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hash |= 1;
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} else {
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hash |= 0;
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}
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hash
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}
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None => 0u64,
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}
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}
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}
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