#!/usr/bin/env php

<?php

require dirname(__DIR__) . '/vendor/autoload.php';

use Jcupitt\Vips;

#Vips\Config::setLogger(new Vips\DebugLogger());

if (count($argv) != 4) {

echo("usage: ./watermark.php input-image output-image watermark-image\n");

exit(1);

}

// we can stream the main image

$image = Vips\Image::newFromFile($argv[1], ['access' => 'sequential']);

// we'll read the watermark image many times, so we need random access for this

$watermark = Vips\Image::newFromFile($argv[3]);

// the watermark image needs to have an alpha channel

if (!$watermark->hasAlpha() || $watermark->bands != 4) {

echo("watermark image is not RGBA\n");

exit(1);

}

// make the watermark semi-transparent

$watermark = $watermark->multiply([1, 1, 1, 0.3])->cast("uchar");

// repeat the watermark to the size of the image

$watermark = $watermark->replicate(

1 + $image->width / $watermark->width,

1 + $image->height / $watermark->height

);

$watermark = $watermark->crop(0, 0, $image->width, $image->height);

// composite the watermark over the main image

$image = $image->composite2($watermark, 'over');

$image->writeToFile($argv[2]);

$image = null;

$watermark = null;

Vips\FFI::shutDown();