Thursday, December 5, 2013

How To Watermark A Photo Using PHP

Hello Friends, This blog post will help you to create a watermark image using PHP. But first let’s get introduce yourself with watermarking.

What is Watermark?
Watermark is a marker which is embedded inside image (other media). It is use to identify the ownership.

Why we need Watermarking?
Watermarking helps to maintain integrity and avoid unauthorized use for images (other media source also).

For example let’s suppose you are have image hosting website and you provide unique and beautiful images to user. If you want only authorize user should download your images then you need to provide image preview with watermarking and original image to authorized user only so that unauthorized user cannot misuse it.

Now let look at some coding stuff.

First example shows watermarking images with text, normally we use copyright text.
And second example show watermarking with watermark image.

Watermarking using text

// set water mark text
$watermark = 'watermark';

//create source image
$source_image = imagecreatefromjpeg('images/some_image.jpg');

//get image width & height position
$image_x = imagesx($source_image);
$image_y = imagesy($source_image);

$font_size = 48;  //font size

//set font for watermark text
// you can use any font 
// source
$font = 'Roboto-Light.ttf';

// create font size for watermark text
$font_size_box = imagettfbbox($font_size, 0, $font, $watermark);

// generate water text position (middle)
$image_x = ($image_x / 2) - ($font_size_box[2] / 2);
$image_y = ($image_y / 2) - ($font_size_box[5] / 2);;

//create color (white color)
$image_color = imagecolorallocate($source_image, 250, 250, 250);

// create image from combination of image + text
imagettftext($source_image, $font_size, 0, $image_x, $image_y, $image_color, $font, $watermark);

// generate water mark image
imagejpeg($source_image, 'images/watermark_image.jpg');

Watermarking using image

// watermark image
$water_mark_image = imagecreatefrompng('images/watermark.png');

// image to be watermarked
$org_image = imagecreatefromjpeg('images/some_image.jpg');

$margin = 10;

// create watermark position inside original image
// bottom right corner
$water_mark_position_x = imagesx($org_image) - imagesx($water_mark_image) - $margin;
$water_mark_position_y = imagesy($org_image) - imagesy($water_mark_image) - $margin;

// center position
//$water_mark_position_x = imagesx($org_image) / 2 - imagesx($water_mark_image) / 2;
//$water_mark_position_y = imagesy($org_image) / 2 - imagesy($water_mark_image) / 2;

// create image copy by combining original image + watermark image
imagecopy($org_image, $water_mark_image, $water_mark_position_x, $water_mark_position_y, 0, 0, imagesx($water_mark_image), imagesy($water_mark_image));

// create watermark image from image copy
imagepng($org_image, 'images/waterking_image.png');

//destroy images source

If you are providing watermark image for download purpose then it is recommended to add watermark at center position and if it is for only preview then you can add it top corner or bottom corner

Zainul Abedin Shaikh

Founder of Zainabed, Passionate about programming. Follow him on Twitter

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