function _fnCalculateColumnWidths ( oSettings )
	{
		var
			table = oSettings.nTable,
			columns = oSettings.aoColumns,
			scroll = oSettings.oScroll,
			scrollY = scroll.sY,
			scrollX = scroll.sX,
			scrollXInner = scroll.sXInner,
			columnCount = columns.length,
			visibleColumns = _fnGetColumns( oSettings, 'bVisible' ),
			headerCells = $('th', oSettings.nTHead),
			tableWidthAttr = table.getAttribute('width'), // from DOM element
			tableContainer = table.parentNode,
			userInputs = false,
			i, column, columnIdx, width, outerWidth,
			browser = oSettings.oBrowser,
			ie67 = browser.bScrollOversize;
	
		var styleWidth = table.style.width;
		if ( styleWidth && styleWidth.indexOf('%') !== -1 ) {
			tableWidthAttr = styleWidth;
		}
	
		/* Convert any user input sizes into pixel sizes */
		for ( i=0 ; i<visibleColumns.length ; i++ ) {
			column = columns[ visibleColumns[i] ];
	
			if ( column.sWidth !== null ) {
				column.sWidth = _fnConvertToWidth( column.sWidthOrig, tableContainer );
	
				userInputs = true;
			}
		}
	
		/* If the number of columns in the DOM equals the number that we have to
		 * process in DataTables, then we can use the offsets that are created by
		 * the web- browser. No custom sizes can be set in order for this to happen,
		 * nor scrolling used
		 */
		if ( ie67 || ! userInputs && ! scrollX && ! scrollY &&
		     columnCount == _fnVisbleColumns( oSettings ) &&
		     columnCount == headerCells.length
		) {
			for ( i=0 ; i<columnCount ; i++ ) {
				var colIdx = _fnVisibleToColumnIndex( oSettings, i );
	
				if ( colIdx !== null ) {
					columns[ colIdx ].sWidth = _fnStringToCss( headerCells.eq(i).width() );
				}
			}
		}
		else
		{
			// Otherwise construct a single row, worst case, table with the widest
			// node in the data, assign any user defined widths, then insert it into
			// the DOM and allow the browser to do all the hard work of calculating
			// table widths
			var tmpTable = $(table).clone() // don't use cloneNode - IE8 will remove events on the main table
				.css( 'visibility', 'hidden' )
				.removeAttr( 'id' );
	
			// Clean up the table body
			tmpTable.find('tbody tr').remove();
			var tr = $('<tr/>').appendTo( tmpTable.find('tbody') );
	
			// Clone the table header and footer - we can't use the header / footer
			// from the cloned table, since if scrolling is active, the table's
			// real header and footer are contained in different table tags
			tmpTable.find('thead, tfoot').remove();
			tmpTable
				.append( $(oSettings.nTHead).clone() )
				.append( $(oSettings.nTFoot).clone() );
	
			// Remove any assigned widths from the footer (from scrolling)
			tmpTable.find('tfoot th, tfoot td').css('width', '');
	
			// Apply custom sizing to the cloned header
			headerCells = _fnGetUniqueThs( oSettings, tmpTable.find('thead')[0] );
	
			for ( i=0 ; i<visibleColumns.length ; i++ ) {
				column = columns[ visibleColumns[i] ];
	
				headerCells[i].style.width = column.sWidthOrig !== null && column.sWidthOrig !== '' ?
					_fnStringToCss( column.sWidthOrig ) :
					'';
	
				// For scrollX we need to force the column width otherwise the
				// browser will collapse it. If this width is smaller than the
				// width the column requires, then it will have no effect
				if ( column.sWidthOrig && scrollX ) {
					$( headerCells[i] ).append( $('<div/>').css( {
						width: column.sWidthOrig,
						margin: 0,
						padding: 0,
						border: 0,
						height: 1
					} ) );
				}
			}
	
			// Find the widest cell for each column and put it into the table
			if ( oSettings.aoData.length ) {
				for ( i=0 ; i<visibleColumns.length ; i++ ) {
					columnIdx = visibleColumns[i];
					column = columns[ columnIdx ];
	
					$( _fnGetWidestNode( oSettings, columnIdx ) )
						.clone( false )
						.append( column.sContentPadding )
						.appendTo( tr );
				}
			}
	
			// Tidy the temporary table - remove name attributes so there aren't
			// duplicated in the dom (radio elements for example)
			$('[name]', tmpTable).removeAttr('name');
	
			// Table has been built, attach to the document so we can work with it.
			// A holding element is used, positioned at the top of the container
			// with minimal height, so it has no effect on if the container scrolls
			// or not. Otherwise it might trigger scrolling when it actually isn't
			// needed
			var holder = $('<div/>').css( scrollX || scrollY ?
					{
						position: 'absolute',
						top: 0,
						left: 0,
						height: 1,
						right: 0,
						overflow: 'hidden'
					} :
					{}
				)
				.append( tmpTable )
				.appendTo( tableContainer );
	
			// When scrolling (X or Y) we want to set the width of the table as 
			// appropriate. However, when not scrolling leave the table width as it
			// is. This results in slightly different, but I think correct behaviour
			if ( scrollX && scrollXInner ) {
				tmpTable.width( scrollXInner );
			}
			else if ( scrollX ) {
				tmpTable.css( 'width', 'auto' );
				tmpTable.removeAttr('width');
	
				// If there is no width attribute or style, then allow the table to
				// collapse
				if ( tmpTable.width() < tableContainer.clientWidth && tableWidthAttr ) {
					tmpTable.width( tableContainer.clientWidth );
				}
			}
			else if ( scrollY ) {
				tmpTable.width( tableContainer.clientWidth );
			}
			else if ( tableWidthAttr ) {
				tmpTable.width( tableWidthAttr );
			}
	
			// Get the width of each column in the constructed table - we need to
			// know the inner width (so it can be assigned to the other table's
			// cells) and the outer width so we can calculate the full width of the
			// table. This is safe since DataTables requires a unique cell for each
			// column, but if ever a header can span multiple columns, this will
			// need to be modified.
			var total = 0;
			for ( i=0 ; i<visibleColumns.length ; i++ ) {
				var cell = $(headerCells[i]);
				var border = cell.outerWidth() - cell.width();
	
				// Use getBounding... where possible (not IE8-) because it can give
				// sub-pixel accuracy, which we then want to round up!
				var bounding = browser.bBounding ?
					Math.ceil( headerCells[i].getBoundingClientRect().width ) :
					cell.outerWidth();
	
				// Total is tracked to remove any sub-pixel errors as the outerWidth
				// of the table might not equal the total given here (IE!).
				total += bounding;
	
				// Width for each column to use
				columns[ visibleColumns[i] ].sWidth = _fnStringToCss( bounding - border );
			}
	
			table.style.width = _fnStringToCss( total );
	
			// Finished with the table - ditch it
			holder.remove();
		}
	
		// If there is a width attr, we want to attach an event listener which
		// allows the table sizing to automatically adjust when the window is
		// resized. Use the width attr rather than CSS, since we can't know if the
		// CSS is a relative value or absolute - DOM read is always px.
		if ( tableWidthAttr ) {
			table.style.width = _fnStringToCss( tableWidthAttr );
		}
	
		if ( (tableWidthAttr || scrollX) && ! oSettings._reszEvt ) {
			var bindResize = function () {
				$(window).on('resize.DT-'+oSettings.sInstance, _fnThrottle( function () {
					_fnAdjustColumnSizing( oSettings );
				} ) );
			};
	
			// IE6/7 will crash if we bind a resize event handler on page load.
			// To be removed in 1.11 which drops IE6/7 support
			if ( ie67 ) {
				setTimeout( bindResize, 1000 );
			}
			else {
				bindResize();
			}
	
			oSettings._reszEvt = true;
		}
	}
Calculate the width of columns for the table
 @param {object} oSettings dataTables settings object
 @memberof DataTable#oApi