PHP: how to add a watermark to a jpeg file

After the two posts on how to draw a string into an image with php and PHP: How to draw a string on a transparent/translucent png the time to create a more complex script, to apply a watermark to an image, has come.

A watermark is normally used to sign an image with the author of the image name or with a site name to show the site where the image was published. (Naturally you can do some other uses of a watermark)

The following script is based on the two previous posts, so to get more info you can give a look to them.

The script accept five parameters:
 text1 and text2: the text for the watermark, text2 will appear on a new line
 angle          : the angle to draw the text
 imagetochange  : the file to which we want to apply the watermark
 c1, c2 and c3  : the color for the text

And, here you are the code:

#!/usr/bin/php

<?php

    // reading parameters

    $text1          = $argv[1];

    $text2          = $argv[2];

    $angle          = $argv[3];

    $imagetochange  = $argv[4];

    $c1             = $argv[5];

    $c2             = $argv[6];

    $c3             = $argv[7];

    

    $text           = $argv[1]."\n".$argv[2];

 

    // Create the image

    $image = imagecreatetruecolor(800, 600);

    imagealphablending($image, false);

    

    //Create alpha channel for transparent layer

    $col=imagecolorallocatealpha($image,255,255,255,127);

    

    //Create alpha channel for transparent layer

    $stringcolor=imagecolorallocatealpha($image, $c1, $c2, $c3, 80);

    

    //Create overlapping 100×50 transparent layer

    imagefilledrectangle($image, 0, 0, 800, 600,$col);

    

    //Continue to keep layers transparent

    imagealphablending($image,true);

    

    

    // Replace path by your own font path

    $font = '/Library/Fonts/Apple Chancery.ttf';

    

    // Add the text

    imagettftext($image, 48, $angle, 200, 320, $stringcolor, $font, $text);

    

    //Keep transparent when saving

    imagesavealpha($image,true);

    

    //Save & output

    imagepng($image, "simpleimage.png", 1);

    imagedestroy($image);

    $stamp = imagecreatefrompng('simpleimage.png');

    $im = imagecreatefromjpeg($imagetochange);

    

    // Set the margins for the stamp and get the height/width of the stamp image

    $marge_right = 10;

    $marge_bottom = 10;

    $sx = imagesx($stamp);

    $sy = imagesy($stamp);

    

    // Copy the stamp image onto our photo using the margin offsets and the photo

    // width to calculate positioning of the stamp.

    imagecopy($im, $stamp, imagesx($im) – $sx – $marge_right, imagesy($im) – $sy – $marge_bottom, 0, 0, imagesx($stamp), imagesy($stamp));

    

    // Output and free memory

    header('Content-type: image/png');

    imagepng($im, 'watermarked_'.$imagetochange);

    imagedestroy($im);

    ?>

the result file will be named watermarked_<file>.

The following image is the one I want to modify

I simply run the script issueing the following command:

./createimageWithWatermark.php gigi bello 40 heliodore.jpg 255 10 10

and the result is the following

Gg1