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Added crop option #5

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Added crop option #5

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3007d13
Update dhash.php
mrAceT Apr 1, 2021
8792b79
added crop option (note)
mrAceT Apr 2, 2021
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13 changes: 7 additions & 6 deletions dhash.php
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
<?php //Author: Tom64b | Website: github.com/Tom64b | Code based on article by Dr. Neal Krawetz | License: MIT | Date: 2017-05-12
function dhash($fname, $onlyJPG = true)
<?php //Author: Tom64b | crop: mrAceT 2021-04-02 | Website: github.com/Tom64b | Code based on article by Dr. Neal Krawetz | License: MIT | Date: 2017-05-12
// crop = 0 => default, crop = 1 => skip the outer pixels, effectively cropping the thumb (remove border noise!)
function dhash($fname, $crop = 0, $onlyJPG = true)
{
// load exif thumbnail if possible; otherwise- load the image
$thumb = exif_thumbnail($fname, $wid, $hei);
Expand All @@ -11,21 +12,21 @@ function dhash($fname, $onlyJPG = true)
unset($thumb);
}
// resize to 9x8 = 72 pixels, apply grayscale
$img = imagecreatetruecolor(9, 8);
imagecopyresampled($img, $src, 0, 0, 0, 0, 9, 8, $wid, $hei);
$img = imagecreatetruecolor(9+$crop*2, 8+$crop*2);
imagecopyresampled($img, $src, 0, 0, 0, 0, 9+$crop*2, 8+$crop*2, $wid, $hei);
imagedestroy($src);
imagefilter($img, IMG_FILTER_GRAYSCALE);
//calculate dHash (hackerfactor.com/blog/?/archives/529-Kind-of-Like-That.html)
$hash = 0;
$bit = 1;
for ($y=0; $y<8; $y++) {
for ($y=0+$crop; $y<8; $y++) {
if ($y == 4) { //second half of the image, this whole IF can be removed on 64bit machines
$res = sprintf("%08x", $hash);
$hash = 0;
$bit = 1;
}
$previous = imagecolorat($img, 0, $y) & 0xFF;
for ($x=1; $x<9; $x++) {
for ($x=1+$crop; $x<9; $x++) {
$current = imagecolorat($img, $x, $y) & 0xFF;
if ($previous > $current) {
$hash |= $bit;
Expand Down