public function setImportantPart(array $importantPart = null)
	{
		if ($importantPart !== null)
		{
			if (!isset($importantPart['x']) || !isset($importantPart['y']) || !isset($importantPart['width']) || !isset($importantPart['height']))
			{
				throw new \InvalidArgumentException('Malformed array for setting the important part!');
			}

			$this->importantPart = array
			(
				'x' => max(0, min($this->fileObj->viewWidth - 1, (int) $importantPart['x'])),
				'y' => max(0, min($this->fileObj->viewHeight - 1, (int) $importantPart['y'])),
			);

			$this->importantPart['width'] = max(1, min($this->fileObj->viewWidth - $this->importantPart['x'], (int) $importantPart['width']));
			$this->importantPart['height'] = max(1, min($this->fileObj->viewHeight - $this->importantPart['y'], (int) $importantPart['height']));

		}
		else
		{
			$this->importantPart = null;
		}

		return $this;
	}