function createThumb($file, $ext, $width)
{
$im = '';
$im = openImage($file);
if (empty($im)) {
return false;
}
$old_x = imagesx($im);
$old_y = imagesy($im);
$new_w = (int) $width;
if ($new_w <= 0 or $new_w > $old_x) {
$new_w = $old_x;
}
$new_h = $old_x * ($new_w / $old_x);
if ($old_x > $old_y) {
$thumb_w = $new_w;
$thumb_h = $old_y * ($new_h / $old_x);
}
if ($old_x < $old_y) {
$thumb_w = $old_x * ($new_w / $old_y);
$thumb_h = $new_h;
}
if ($old_x == $old_y) {
$thumb_w = $new_w;
$thumb_h = $new_h;
}
$thumb = imagecreatetruecolor($thumb_w, $thumb_h);
if ($ext == 'png') {
imagealphablending($thumb, false);
$colorTransparent = imagecolorallocatealpha($thumb, 0, 0, 0, 127);
imagefill($thumb, 0, 0, $colorTransparent);
imagesavealpha($thumb, true);
} elseif ($ext == 'gif') {
$trnprt_indx = imagecolortransparent($im);
if ($trnprt_indx >= 0) {
//its transparent
$trnprt_color = imagecolorsforindex($im, $trnprt_indx);
$trnprt_indx = imagecolorallocate($thumb, $trnprt_color['red'], $trnprt_color['green'], $trnprt_color['blue']);
imagefill($thumb, 0, 0, $trnprt_indx);
imagecolortransparent($thumb, $trnprt_indx);
}
}
imagecopyresampled($thumb, $im, 0, 0, 0, 0, $thumb_w, $thumb_h, $old_x, $old_y);
//choose which image program to use
switch (strtolower($ext)) {
case 'jpg':
case 'jpeg':
imagejpeg($thumb, $file);
break;
case 'gif':
imagegif($thumb, $file);
break;
case 'png':
imagepng($thumb, $file);
break;
default:
return false;
break;
}
imagedestroy($im);
imagedestroy($thumb);
}
function fingerprint($src_or_resource) {
$thumbWidth = 150;
$sensitivity = 2;
if (!$image = @openImage($src_or_resource)) return -1;
// Create thumbnail sized copy for fingerprinting
$width = imagesx($image);
$height = imagesy($image);
$ratio = $thumbWidth / $width;
$newwidth = $thumbWidth;
$newheight = round($height * $ratio);
$smallimage = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($smallimage, $image, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
$palette = imagecreatetruecolor(1, 1);
$gsimage = imagecreatetruecolor($newwidth, $newheight);
// Convert each pixel to greyscale, round it off, and add it to the histogram count
$numpixels = $newwidth * $newheight;
$histogram = array();
for ($i = 0; $i < $newwidth; $i++) {
for ($j = 0; $j < $newheight; $j++) {
$pos = imagecolorat($smallimage, $i, $j);
$cols = imagecolorsforindex($smallimage, $pos);
$r = $cols['red'];
$g = $cols['green'];
$b = $cols['blue'];
// Convert the colour to greyscale using 30% Red, 59% Blue and 11% Green
$greyscale = round(($r * 0.3) + ($g * 0.59) + ($b * 0.11));
$greyscale++;
$value = (round($greyscale / 16) * 16) -1;
@$histogram[$value]++;
}
}
// Normalize the histogram by dividing the total of each colour by the total number of pixels
$normhist = array();
foreach ($histogram as $value => $count) {
$normhist[$value] = $count / $numpixels;
}
// Find maximum value (most frequent colour)
$max = 0;
for ($i=0; $i<255; $i++) {
if (@$normhist[$i] > $max) {
$max = $normhist[$i];
}
}
// Create a string from the histogram (with all possible values)
$histstring = "";
for ($i = -1; $i <= 255; $i = $i + 16) {
$h = @(@$normhist[$i] / $max) * $sensitivity;
if ($i < 0) {
$index = 0;
} else {
$index = $i;
}
$height = round($h);
$histstring .= $height;
}
// Destroy all the images that we've created
imagedestroy($image);
imagedestroy($smallimage);
imagedestroy($palette);
imagedestroy($gsimage);
// Generate an md5sum of the histogram values and return it
$checksum = md5($histstring);
return $checksum;
}
