The imageconvolution() function is an inbuilt function in PHP which is used to modify the image content. It applies a 3 x 3 convolution matrix in the image, using the given coefficient and offset. This function returns true on success or false on failure.
Syntax:
bool imageconvolution ( $image, $matrix, $div, $offset )
Parameters: This function accepts four parameter as mentioned above and described below:
- $image: It is returned by one of the image creation functions, such as imagecreatetruecolor(). It is used to create size of image.
- $matrix: It contains an array of 3 x 3 (3 x 3 matrix) of floats.
- $div: It is divisor of result of the convolution, used for normalization.
- $offset: It is used to set the color offset.
Return Value: This function returns True on success or False on failure.
Below programs illustrate the imageconvolution() function in PHP:
Program 1:
<?php   // Create a gif image $image = imagecreatefromgif(    // Declare a 3X3 matrix $matrix = array(         array(2, 0, 0),         array(0, -1, 0),         array(0, 0, -1) );    // imageconvolution function to modify image elements imageconvolution($image, $matrix, 1, 127);    // Output of image content header('Content-Type: image/png'); imagepng($image, null, 9); ?> |
Output:
Program 2:
<?php   // Create a gif image $image = imagecreatefrompng(    // Declare a 3X3 matrix $emboss = array(                array(0, -1, 2),         array(2, 0, 0),         array(2, 0, -2) );    // imageconvolution function to modify image elements imageconvolution($image, $emboss, 1, 127);   // Output of image content header('Content-Type: image/png'); imagepng($image, null, 9); ?> |
Output:
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Reference: http://php.net/manual/en/function.imageconvolution.php
