PHP imageconvolution function

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imageconvolution

(PHP 5 >= 5.1.0RC1)

Applies a convolution matrix on the image, using the given coefficient and
offset.

An image resource, returned by one of the image creation functions,
such as imagecreatetruecolor().

A 3×3 matrix: an array of three arrays of three floats.

The divisor of the result of the convolution, used for normalization.

Returns TRUE on success or FALSE on failure.

Example 1. Embossing the PHP.net logo

$image = imagecreatefromgif('http://www.php.net/images/php.gif');
 
$emboss = array(array(2, 0, 0), array(0, -1, 0), array(0, 0, -1));
imageconvolution($image, $emboss, 1, 127);
 
header('Content-Type: image/png');
imagepng($image, null, 9);

The above example will output:

Example 2. Gaussian blur

$image = imagecreatetruecolor(180,40);
 
// Writes the text and apply a gaussian blur on the image
imagestring($image, 5, 10, 8, 'Gaussian Blur Text', 0x00ff00);
$gaussian = array(array(1.0, 2.0, 1.0), array(2.0, 4.0, 2.0), array(1.0, 2.0, 1.0));
imageconvolution($image, $gaussian, 16, 0);
 
// Rewrites the text for comparison
imagestring($image, 5, 10, 18, 'Gaussian Blur Text', 0x00ff00);
 
header('Content-Type: image/png');
imagepng($image, null, 9);

The above example will output:

Note: This function is only available if
PHP is compiled with the bundled version of the GD library.