Fix: Add redrawCalculations option to dt-api columns().visible() …

…and `dt-api column().visible()` to improve performance in a loop.

docs/api/column().visible().xml

@@ -11,11 +11,14 @@
 	</type>
 
 	<type type="function">
-		<signature>column().visible( show )</signature>
+		<signature>column().visible( show [, redrawCalculations ] )</signature>
 		<description>Set the visibility of the selected column.</description>
 		<parameter type="boolean" name="show">
 			Specify if the column should be visible (`true`) or not (`false`).
 		</parameter>
+		<parameter type="boolean" name="redrawCalculations" default="true">
+			Indicate if DataTables should recalculate the column layout (`true` - default) or not (`false`). Typically this would be left as the default value, but it can be useful to disable when using the method in a loop - so the calculations are performed on every call as they can hamper performance.
+		</parameter>
 		<returns type="DataTables.Api">DataTables API instance with selected column in the result set.</returns>
 	</type>
 
@@ -35,6 +38,15 @@ alert( 'Column index 0 is '+
 var table = $('#example').DataTable();
 
 table.column( 0 ).visible( false );
+]]></example>
+
+	<example title="Hide multiple columns using `redrawCalculations` to improve performance"><![CDATA[
+var table = $('#example').DataTable();
+
+for ( var i=0 ; i<4 ; i++ ) {
+	table.column( i ).visible( false, false );
+}
+table.columns.adjust().draw( false ); // adjust column sizing and redraw
 ]]></example>
 
 	<related type="api">columns().visible()</related>

docs/api/columns().visible().xml

@@ -11,11 +11,14 @@
 	</type>
 
 	<type type="function">
-		<signature>columns().visible( show )</signature>
+		<signature>column().visible( show [, redrawCalculations ] )</signature>
 		<description>Set the visibility of the selected columns.</description>
 		<parameter type="boolean" name="show">
 			Specify if the columns should be visible (`true`) or not (`false`).
 		</parameter>
+		<parameter type="boolean" name="redrawCalculations" default="true">
+			Indicate if DataTables should recalculate the column layout (`true` - default) or not (`false`). Typically this would be left as the default value, but it can be useful to disable when using the method in a loop - so the calculations are performed on every call as they can hamper performance.
+		</parameter>
 		<returns type="DataTables.Api">DataTables API instance with selected columns in the result set.</returns>
 	</type>
 
@@ -36,6 +39,13 @@ alert( 'Table's column visibility are set to: '+table.columns().visible().join('
 var table = $('#example').DataTable();
 
 table.columns( '.detail' ).visible( false );
+]]></example>
+
+	<example title="Hide multiple columns using `redrawCalculations` to improve performance"><![CDATA[
+var table = $('#example').DataTable();
+
+table.columns( [ 0, 1, 2, 3 ] ).visible( false, false );
+table.columns.adjust().draw( false ); // adjust column sizing and redraw
 ]]></example>
 
 	<related type="api">column().visible()</related>

js/api/api.columns.js

@@ -82,7 +82,7 @@ var __column_selector = function ( settings, selector, opts )
 
 
 
-var __setColumnVis = function ( settings, column, vis ) {
+var __setColumnVis = function ( settings, column, vis, recalc ) {
 	var
 		cols = settings.aoColumns,
 		col  = cols[ column ],
@@ -125,12 +125,14 @@ var __setColumnVis = function ( settings, column, vis ) {
 	_fnDrawHead( settings, settings.aoHeader );
 	_fnDrawHead( settings, settings.aoFooter );
 
-	// Automatically adjust column sizing
-	_fnAdjustColumnSizing( settings );
+	if ( recalc === undefined || recalc ) {
+		// Automatically adjust column sizing
+		_fnAdjustColumnSizing( settings );
 
-	// Realign columns for scrolling
-	if ( settings.oScroll.sX || settings.oScroll.sY ) {
-		_fnScrollDraw( settings );
+		// Realign columns for scrolling
+		if ( settings.oScroll.sX || settings.oScroll.sY ) {
+			_fnScrollDraw( settings );
+		}
 	}
 
 	_fnCallbackFire( settings, null, 'column-visibility', [settings, column, vis] );
@@ -217,11 +219,11 @@ _api_registerPlural( 'columns().nodes()', 'column().nodes()', function () {
 
 
 
-_api_registerPlural( 'columns().visible()', 'column().visible()', function ( vis ) {
+_api_registerPlural( 'columns().visible()', 'column().visible()', function ( vis, calc ) {
 	return this.iterator( 'column', function ( settings, column ) {
 		return vis === undefined ?
 			settings.aoColumns[ column ].bVisible :
-			__setColumnVis( settings, column, vis );
+			__setColumnVis( settings, column, vis, calc );
 	} );
 } );