(PHP 5 >= 5.1.0, PHP 7)
Apply a 3x3 convolution matrix, using coefficient and offset
bool imageconvolution ( resource $image, array $matrix, float $div, float $offset )
Applies a convolution matrix on the image, using the given coefficient and offset.
Parameters:
image
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
matrix
A 3x3 matrix: an array of three arrays of three floats.
div
The divisor of the result of the convolution, used for normalization.
offset
Color offset.
Returns:
Returns TRUE on success or FALSE on failure.
Notes:
This function is only available if PHP is compiled with the bundled version of the GD library.
Examples:
Embossing the PHP.net logo
<?php
$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:
Gaussian blur
<?php
$image = imagecreatetruecolor(180,40);
// Writes the text and apply a gaussian blur on the image
imagestring($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:
See also:
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