Download large images of art from National Gallery of Victoria (NGV) website

ngv-download.php

#!/usr/bin/php
<?php

/**
 * Download a large size art image from National Gallery of Victoria (NGV) website
 * Copyleft (C) 2016 BohwaZ http://bohwaz.net/ (Public domain)
 */

if (empty($argv[1]))
{
	echo "Usage: " . $argv[0] . " NGV_URL" . PHP_EOL;
	exit;
}

$url = $argv[1];

if (!preg_match('!^https?://www.ngv.vic.gov.au/explore/collection/work/(\d+)/!i', $url, $match))
{
	echo "Invalid URL supplied." . PHP_EOL;
	exit;
}

$body = file_get_contents($url);

if (!preg_match('/imgWidth\s*=\s*(\d+)/i', $body, $width) 
	|| !preg_match('/imgHeight\s*=\s*(\d+)/i', $body, $height)
	|| !preg_match('/var\s+url\s*=\s*\'(.*?)\'/i',$body, $tiles_url)
	|| !preg_match('!<title>(.*?)</title>!i',$body, $title))
{
	echo "Can not find image size, title or tile URL" . PHP_EOL;
	exit;
}

$width = (int)$width[1];
$height = (int)$height[1];
$tiles_url = $tiles_url[1] . 'TileGroup0/';

$comment = preg_replace('/\|\s*NGV.*$/', '', $title[1]) . ' -- Archived from ' . $url;
$filename = preg_replace('/\|\s*NGV.*$/', '', $title[1]);
$filename = str_replace('|', '-', $filename);
$filename = trim(preg_replace('/[^\w\d -]+/', '', $filename)) . '.jpg';

$tiles_x = ceil($width / 256);
$tiles_y = ceil($height / 256);

$tileSize = 256;
$levels = 0;

// Getting tile size
while ($width > $tileSize || $height > $tileSize)
{
	$levels++;
	$tileSize += $tileSize;
}

$z = $levels;

echo "Size: $width x $height ($tiles_x X $tiles_y Tiles, max zoom = $z)" . PHP_EOL;

$tmpdir = sys_get_temp_dir() . '/ngv-dl.' . uniqid();

mkdir($tmpdir);

echo "Downloading tiles";

$i = 0;

for ($y = 0; $y < $tiles_y; $y++)
{
	for ($x = 0; $x < $tiles_x; $x++)
	{
		echo ".";
		copy($tiles_url . $z . '-' . $x . '-' . $y . '.jpg', $tmpdir . '/tile-' . sprintf('%05d', $i++) . '.jpg');
	}
}

echo PHP_EOL;
echo "Assembling tiles...";

$cmd = 'montage -quality 95 -mode concatenate -tile ' . ($tiles_x) . 'x' . ($tiles_y) . ' ' . $tmpdir . '/tile-*.jpg ' . escapeshellarg($filename);

#echo $cmd . PHP_EOL;

system($cmd);

// Adding comment
system('exiv2 -c ' . escapeshellarg($comment) . ' ' . escapeshellarg($filename));

system('rm -rf ' . escapeshellarg($tmpdir));

echo "OK" . PHP_EOL;