The Imagick::filter() function is an inbuilt function in PHP which is used to apply custom convolution kernel to the image. A kernel, convolution matrix, or mask is a small matrix. It is used for blur, sharpen, embossing, edge detection, and many more.
Syntax:
bool Imagick::filter( $ImagickKernel, $channel = Imagick::CHANNEL_UNDEFINED )
Parameters: This function accepts two parameters as mentioned above and described below:
- $ImagickKernel: It is a kernel or a linked series of multiple kernels that are used to be apply on the image.
- $channel: It is a constant that is used on basis of the modes. It is of integer type and the default value of channel is Imagick::CHANNEL_DEFAULT.
Return Value: It returns true when the filter to the image is successfully applied.
Below program illustrates the Imagick::filter() function in PHP:
Program:
<?php   // Declare an imagick object $imagick = new Imagick(   // Declare convolution matrix $matrix = [     [-1, 0, -1],     [0, 5, 0],     [-1, 0, -1], ];        $kernel = \ImagickKernel::fromMatrix($matrix);   $strength = 0.5;   // Scaling the image on kernel $kernel->scale($strength, \Imagick::NORMALIZE_KERNEL_VALUE);   // Use addUnityKernel() function $kernel->addUnityKernel(1 - $strength);    // Use filter() function $imagick->filter($kernel);   header("Content-Type: image/jpg");   // Display the output image echo $imagick->getImageBlob(); ?> |
Output:
