Manual Imagick crop via gravity

gistfile1.aw

<?php
			$this->imgMetadata['format'] = strtolower($this->imagickObj->getImageFormat());									
			$this->imgMetadata['width'] = $this->imagickObj->getImageWidth();
			$this->imgMetadata['height'] = $this->imagickObj->getImageHeight();	

$x = $y = 0;
                        switch ($gravity) {
				case 'center':
// 					$gravity = \Imagick::GRAVITY_CENTER;
					$x = ($this->imgMetadata['width']/2) - ($width/2);
					$y = $this->imgMetadata['height']/2  - ($height/2);
				break;				
				case 'northwest':
// 					$gravity = \Imagick::GRAVITY_NORTHWEST;					
				break;
				case 'north': 
// 					$gravity = \Imagick::GRAVITY_NORTH;
					$x = ($this->imgMetadata['width']/2) - ($width/2);
					break;
				case 'northeast':
// 					$gravity = \Imagick::GRAVITY_NORTHEAST;
					$x = ($this->imgMetadata['width']) - $width;
					break;
				case 'west':
// 					$gravity = \Imagick::GRAVITY_WEST;
					$y = ($this->imgMetadata['height']/2) - ($height/2);
					break;
				case 'east':
// 					$gravity = \Imagick::GRAVITY_EAST;
					$x = $this->imgMetadata['width']- $width;
					$y = ($this->imgMetadata['height']/2)  - ($height/2);
					break;
				case 'southwest':
// 					$gravity = \Imagick::GRAVITY_SOUTHWEST;
					$x = 0;
					$y = $this->imgMetadata['height'] - $height;
					break;
				case 'south':
// 					$gravity = \Imagick::GRAVITY_SOUTH;
					$x = ($this->imgMetadata['width']/2) - ($width/2);
					$y = $this->imgMetadata['height'] - $height;
					break;
				case 'southeast':
// 					$gravity = \Imagick::GRAVITY_SOUTHEAST;
					$x = $this->imgMetadata['width'] - $width;
					$y = $this->imgMetadata['height'] - $height;
					break;
				
				default:
					//throw something
				break;
			}
			
			if('gif'!=$this->imgMetadata['format']){
				//gravity does not work with crop
				// 			$this->imagickObj->setGravity($gravity);
				$this->imagickObj->setImageCompressionQuality($quality);
				$this->imagickObj->cropImage($width,$height,$x,$y);
			}
			else {
				foreach ($this->imagickObj as $frame) {
					//gravity does not work with crop
					// 			$this->imagickObj->setGravity($gravity);
					$frame->setImageCompressionQuality($quality);
					$frame->cropImage($width,$height,$x,$y);
// 					$frame->setImagePage($width, $height, 0, 0);
				}
			}