function extract_mean_colour($image, $ref)
{
# for image $image, calculate the mean colour and update this to the image_red, image_green, image_blue tables
# in the resources table.
# Also - we insert the height and width of the thumbnail at this stage as all information is available and we
# are already performing an update on the resource record.
$width = imagesx($image);
$height = imagesy($image);
$totalred = 0;
$totalgreen = 0;
$totalblue = 0;
$total = 0;
for ($y = 0; $y < 20; $y++) {
for ($x = 0; $x < 20; $x++) {
$rgb = imagecolorat($image, $x * ($width / 20), $y * ($height / 20));
$red = $rgb >> 16 & 0xff;
$green = $rgb >> 8 & 0xff;
$blue = $rgb & 0xff;
# calculate deltas (remove brightness factor)
$cmax = max($red, $green, $blue);
$cmin = min($red, $green, $blue);
if ($cmax == $cmin) {
$cmax = 10;
$cmin = 0;
}
# avoid division errors
if (abs($cmax - $cmin) >= 20) {
$red = floor(($red - $cmin) / ($cmax - $cmin) * 1000);
$green = floor(($green - $cmin) / ($cmax - $cmin) * 1000);
$blue = floor(($blue - $cmin) / ($cmax - $cmin) * 1000);
$total++;
$totalred += $red;
$totalgreen += $green;
$totalblue += $blue;
}
}
}
if ($total == 0) {
$total = 1;
}
$totalred = floor($totalred / $total);
$totalgreen = floor($totalgreen / $total);
$totalblue = floor($totalblue / $total);
$colkey = get_colour_key($image);
update_portrait_landscape_field($ref, $image);
sql_query("update resource set image_red='{$totalred}', image_green='{$totalgreen}', image_blue='{$totalblue}',colour_key='{$colkey}',thumb_width='{$width}', thumb_height='{$height}' where ref='{$ref}'");
}
<?php
# This script is for updating the $portrait_landscape_field
include "../../include/db.php";
include "../../include/authenticate.php";
if (!checkperm("a")) {
exit("Permission denied");
}
include "../../include/general.php";
include "../../include/resource_functions.php";
include "../../include/image_processing.php";
set_time_limit(60 * 60 * 40);
echo "Updating portrait_landscape_field (field {$portrait_landscape_field})...";
$rd = sql_query("select ref,file_extension from resource where has_image=1 ");
for ($n = 0; $n < count($rd); $n++) {
$ref = $rd[$n]['ref'];
echo "<br />" . $ref;
update_portrait_landscape_field($ref);
flush();
ob_flush();
}
echo "...done.";