IMAGECONVOLUTION(3)							 1						       IMAGECONVOLUTION(3)

imageconvolution - Apply a 3x3 convolution matrix, using coefficient and offset

SYNOPSIS

       bool imageconvolution (resource	$image, array  $matrix, float  $div, float  $offset)

DESCRIPTION

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

PARAMETERS

	      o $
		image -An image resource, returned by one of the image creation functions, such as imagecreatetruecolor(3).

	      o $matrix
		- A 3x3 matrix: an array of three arrays of three floats.

	      o $div
		- The divisor of the result of the convolution, used for normalization.

	      o $offset
		- Color offset.

RETURN VALUES

	Returns TRUE on success or FALSE on failure.

EXAMPLES

       Example #1

	      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:[NOT DISPLAYABLE MEDIA]Output of example : Embossing the PHP.net logo

       Example #2

	      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:[NOT DISPLAYABLE MEDIA]Output of example : Gaussian blur

NOTES

       Note

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

SEE ALSO

       imagefilter(3).

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