Imbo\Image\Transformation\Border::transform PHP Method

    public function transform(EventInterface $event)
    {
        $image = $event->getArgument('image');
        $params = $event->getArgument('params');
        $color = !empty($params['color']) ? $this->formatColor($params['color']) : $this->color;
        $width = isset($params['width']) ? (int) $params['width'] : $this->width;
        $height = isset($params['height']) ? (int) $params['height'] : $this->height;
        $mode = !empty($params['mode']) ? $params['mode'] : $this->mode;
        try {
            if ($mode === 'outbound') {
                // Paint the border outside of the image, increasing the width/height
                if ($this->imagick->getImageAlphaChannel() !== 0) {
                    // If we have an alpha channel and call `borderImage()`, Imagick will remove
                    // the alpha channel - if we have an alpha channel, use an alternative approach
                    $this->expandImage($color, $width, $height, $image);
                } else {
                    // If we don't have an alpha channel, use the more cost-efficient `borderImage()`
                    $this->imagick->borderImage($color, $width, $height);
                }
            } else {
                // Paint the border inside of the image, keeping the orignal width/height
                $this->drawBorderInside($color, $width, $height, $image);
            }
            $size = $this->imagick->getImageGeometry();
            $image->setWidth($size['width'])->setHeight($size['height'])->hasBeenTransformed(true);
        } catch (ImagickException $e) {
            throw new TransformationException($e->getMessage(), 400, $e);
        } catch (ImagickPixelException $e) {
            throw new TransformationException($e->getMessage(), 400, $e);
        }
    }