Imagick::filter

Applies a custom convolution kernel to the image

&imagick.deprecated.function-3-4-4;
&reftitle.description; public `bool` `Imagick::filter` `ImagickKernel` `ImagickKernel` `int` `channel` Imagick::CHANNEL_UNDEFINED

Applies a custom convolution kernel to the image.

&reftitle.parameters;

`ImagickKernel`

- An instance of ImagickKernel that represents either a single kernel or a linked series of kernels.

`channel`

- &imagick.parameter.channel;

&reftitle.returnvalues;

&imagick.return.success;

&reftitle.examples;

### `Imagick::filter`

    <?php
    function filter($imagePath) {
        $imagick = new \Imagick(realpath($imagePath));
        $matrix = [
            [-1, 0, -1],
            [0,  5,  0],
            [-1, 0, -1],
        ];

        $kernel = \ImagickKernel::fromMatrix($matrix);
        $strength = 0.5;
        $kernel->scale($strength, \Imagick::NORMALIZE_KERNEL_VALUE);
        $kernel->addUnityKernel(1 - $strength);

        $imagick->filter($kernel);
        header("Content-Type: image/jpg");
        echo $imagick->getImageBlob();
    }

    ?>