How to put watermark on image? - php

Question

How to put water mark on image without affecting the source image.
$SourceFile = '/uploadedimage/gallery/thumble/';
$DestinationFile = '/uploadedimage/gallery/thumble/image-watermark.jpg';
$WaterMarkText = 'Copyright appsbee.com';
watermarkImage ($SourceFile, $WaterMarkText, $DestinationFile);
function watermarkImage ($SourceFile, $WaterMarkText, $DestinationFile) {
list($width, $height) = getimagesize($SourceFile);
$image_p = imagecreatetruecolor($width, $height);
$image = imagecreatefromjpeg($SourceFile);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width, $height);
$black = imagecolorallocate($image_p, 0, 0, 0);
$font = 'arial.ttf';
$font_size = 10;
imagettftext($image_p, $font_size, 0, 10, 20, $black, $font, $WaterMarkText);
if ($DestinationFile<>'') {
imagejpeg ($image_p, $DestinationFile, 100);
} else {
header('Content-Type: image/jpeg');
imagejpeg($image_p, null, 100);
};
imagedestroy($image);
imagedestroy($image_p);
};
If I do this the image which are present on thumble folder are effected.

Answer 1

Use this class, before putting water mark just make the copy of original image.
<?php
class Watermark{
# given two images, return a blended watermarked image
# given two images, return a blended watermarked image
function create_watermark( $main_img_obj, $watermark_img_obj, $alpha_level = 100 ) {
$alpha_level /= 100; # convert 0-100 (%) alpha to decimal
# calculate our images dimensions
$main_img_obj_w = imagesx( $main_img_obj );
$main_img_obj_h = imagesy( $main_img_obj );
$watermark_img_obj_w = imagesx( $watermark_img_obj );
$watermark_img_obj_h = imagesy( $watermark_img_obj );
# determine center position coordinates
$main_img_obj_min_x = floor( ( $main_img_obj_w / 2 ) - ( $watermark_img_obj_w / 2 ) );
$main_img_obj_max_x = ceil( ( $main_img_obj_w / 2 ) + ( $watermark_img_obj_w / 2 ) );
$main_img_obj_min_y = floor( ( $main_img_obj_h / 2 ) - ( $watermark_img_obj_h / 2 ) );
$main_img_obj_max_y = ceil( ( $main_img_obj_h / 2 ) + ( $watermark_img_obj_h / 2 ) );
# create new image to hold merged changes
$return_img = imagecreatetruecolor( $main_img_obj_w, $main_img_obj_h );
# walk through main image
for( $y = 0; $y < $main_img_obj_h; $y++ ) {
for( $x = 0; $x < $main_img_obj_w; $x++ ) {
$return_color = NULL;
# determine the correct pixel location within our watermark
$watermark_x = $x - $main_img_obj_min_x;
$watermark_y = $y - $main_img_obj_min_y;
# fetch color information for both of our images
$main_rgb = imagecolorsforindex( $main_img_obj, imagecolorat( $main_img_obj, $x, $y ) );
# if our watermark has a non-transparent value at this pixel intersection
# and we're still within the bounds of the watermark image
if ( $watermark_x >= 0 && $watermark_x < $watermark_img_obj_w &&
$watermark_y >= 0 && $watermark_y < $watermark_img_obj_h ) {
$watermark_rbg = imagecolorsforindex( $watermark_img_obj, imagecolorat( $watermark_img_obj, $watermark_x, $watermark_y ) );
# using image alpha, and user specified alpha, calculate average
$watermark_alpha = round( ( ( 127 - $watermark_rbg['alpha'] ) / 127 ), 2 );
$watermark_alpha = $watermark_alpha * $alpha_level;
# calculate the color 'average' between the two - taking into account the specified alpha level
$avg_red = $this->_get_ave_color( $main_rgb['red'], $watermark_rbg['red'], $watermark_alpha );
$avg_green = $this->_get_ave_color( $main_rgb['green'], $watermark_rbg['green'], $watermark_alpha );
$avg_blue = $this->_get_ave_color( $main_rgb['blue'], $watermark_rbg['blue'], $watermark_alpha );
# calculate a color index value using the average RGB values we've determined
$return_color = $this->_get_image_color( $return_img, $avg_red, $avg_green, $avg_blue );
# if we're not dealing with an average color here, then let's just copy over the main color
} else {
$return_color = imagecolorat( $main_img_obj, $x, $y );
} # END if watermark
# draw the appropriate color onto the return image
imagesetpixel( $return_img, $x, $y, $return_color );
} # END for each X pixel
} # END for each Y pixel
# return the resulting, watermarked image for display
return $return_img;
} # END create_watermark()
# average two colors given an alpha
function _get_ave_color( $color_a, $color_b, $alpha_level ) {
return round( ( ( $color_a * ( 1 - $alpha_level ) ) + ( $color_b * $alpha_level ) ) );
} # END _get_ave_color()
# return closest pallette-color match for RGB values
function _get_image_color($im, $r, $g, $b) {
$c=imagecolorexact($im, $r, $g, $b);
if ($c!=-1) return $c;
$c=imagecolorallocate($im, $r, $g, $b);
if ($c!=-1) return $c;
return imagecolorclosest($im, $r, $g, $b);
} # EBD _get_image_color()
} # END watermark API
?>
and this is how to use it
$watermark = new Watermark();
$actual_image = imagecreatefromjpeg("images/$image_file");
$watermark_image = imagecreatefrompng("images/water_mark.png");
//create water marked image with 66% transparency
$return_img_obj = $watermark->create_watermark( $actual_image, $watermark_image, 66 );
//now save the updated image
imagejpeg($return_img_obj,"images/$image_file1");
//clear the memory
imagedestroy($actual_image);
imagedestroy($watermark_image);
imagedestroy($return_img_obj);

Answer 2

without affecting the source image.
Doing this without affecting the actual image is possible only by adding a HTML layer containing a transparent image. That is pretty useless as a means of protection though, because everyone with a tiny bit of technical knowledge can fetch the original image in seconds.

Answer 3

If you don't want to affect the source image, then I'd recommend putting a transparent image in an absolutely positioned div over the image in your HTML. This means you don't have to process an image on each page load (because you want to keep the original intact), and you don't have to mess about with storing an extra image.

Answer 4

Using the GD image library: http://php.net/manual/en/book.image.php
This way I would create a web watermark version of the image and also store the source image.
Unless you mean to add a watermark on the fly in which case I'm not sure you can that easily.

Answer 5

From the first sight, I think this code will not affect the source file if u didn't provide a destination file name to the function.