             case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_RGB:                 $colorSpace = new Zend_Pdf_Element_Name('DeviceRGB');                 break;              case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_GRAY:                 $colorSpace = new Zend_Pdf_Element_Name('DeviceGray');                 break;              case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_INDEXED:                 