code: protected function prepareImportantPart()
  	{
  		$importantPart = $this->getImportantPart();
  
  		if (substr_count($this->resizeMode, '_') === 1)
  		{
  			$importantPart = array
  			(
  				'x' => 0,
  				'y' => 0,
  				'width' => $this->fileObj->viewWidth,
  				'height' => $this->fileObj->viewHeight,
  			);
  
  			$mode = explode('_', $this->resizeMode);
  
  			if ($mode[0] === 'left')
  			{
  				$importantPart['width'] = 1;
  			}
  			elseif ($mode[0] === 'right')
  			{
  				$importantPart['x'] = $importantPart['width'] - 1;
  				$importantPart['width'] = 1;
  			}
  
  			if ($mode[1] === 'top')
  			{
  				$importantPart['height'] = 1;
  			}
  			elseif ($mode[1] === 'bottom')
  			{
  				$importantPart['y'] = $importantPart['height'] - 1;
  				$importantPart['height'] = 1;
  			}
  		}
  
  		if (!$importantPart['width'] || !$importantPart['height'])
  		{
  			return null;
  		}
  
  		return new ImportantPart(
  			new Point($importantPart['x'], $importantPart['y']),
  			new Box($importantPart['width'], $importantPart['height'])
  		);
  	}
docs: Prepare important part object.
  
  @return ImportantPart