Column Sizing

All columns can be resized by dragging the top right portion of the column.

Enable Sizing

Turn column resizing on for the grid by setting resizable=true for each column. To set resizing for each column, set resizable=true on the default column definition.

The snippet below allows all columns except Address to be resized by explicitly setting each column.

The snippet below allows all columns except Address to be resized by setting resizable=true on the default column definition and then resizable=false on the Address column.

Size Columns to Fit

Call api.sizeColumnsToFit() to make the currently visible columns fit the screen. The columns will scale (growing or shrinking) to fit the available width.

If you don't want a particular column to be included in the auto resize, then set the column definition suppressSizeToFit=true. This is helpful if, for example, you want the first column to remain fixed width, but all other columns to fill the width of the table.

Auto-Size Columns

Just like Excel, each column can be 'auto resized' by double clicking the right side of the header rather than dragging it. When you do this, the grid will work out the best width to fit the contents of the cells in the column.

Note the following with regards autosizing columns:

• The grid works out the best width by considering the virtually rendered rows only. For example, if your grid has 10,000 rows, but only 50 rendered due to virtualisation of rows, then only these 50 will be considered for working out the width to display. The rendered rows are all the rows you can see on the screen through the horizontal scroll plus a small buffer (default buffer size is 20).

• Autosizing columns looks at the rendered cells on the screen, and works out the width based on what it sees. It cannot see the columns that are not rendered due to column virtualisation. Thus it is not possible to autosize a column that is not visible on the screen.

  Column Virtualisation is the technique the grid uses to render large amounts of columns with degrading performance by only rendering columns that are visible due to the horizontal scroll positions. For example, the grid can have 1,000 columns with only 10 rendered if the horizontal scroll is only showing 10 columns.

  To get around this, you can turn off column virtualisation by setting grid property suppressColumnVirtualisation=true. The choice is yours, whether you want column virtualisation working OR auto-size working using off-screen columns.

By default the grid will also resize the column to fit the header. If you do not want the headers to be included in the autosize calculation, set the grid property skipHeaderOnAutoSize=true.

Autosize Column API

Autosizing columns can also be done using the following grid API methods:

• autoSizeColumn(colKey, skipHeader): Autosize one column.
• autoSizeColumns(colKeys, skipHeader): Autosize many columns.
• autoSizeAllColumns(colKey, skipHeader): Autosize all columns.

If skipHeader=true, the header won't be included when calculating the column widths.

Column Groups are never considered when calculating the column widths.

Resizing Example

The example below shows resizing in action. Things to note are as follows:

• Each column can be resized by dragging (or double-clicking or auto resize) the right side of its header.
• The button 'Size to Fit' calls api.sizeColumnsToFit()
• The button 'Auto-Size All' calls columnApi.autoSizeColumns([columnIds])
• The button 'Auto-Size All (Skip Header)' calls columnApi.autoSizeColumns([columnIds], true)
• The first column is fixed width (i.e. suppressSizeToFit = true), which means its size does not change when sizeColumnsToFit is called.
• The 'age' column has both a minimum and maximum size set, so resizing the column will be restricted by these, regardless of dragging the header or using any of the API buttons.

In the example below, also of note is the second column, which has both a min and max size set, which is also respected with sizeColumnsToFit. The remaining columns will spread to fill the remaining space after you press the button.

Sizing Columns By Default

It is possible to have the grid auto size the columns to fill the width by default. Do this by calling api.sizeColumnsToFit() on the gridReady event.

Note that api.sizeColumnsToFit() needs to know the grid width in order to do its maths. If the grid is not attached to the DOM, then this will be unknown. In the example below, the grid is not attached to the DOM when it is created (and hence api.sizeColumnsToFit() should fail). The grid checks again after 100ms, and tries to resize again. This is needed for some frameworks (e.g. Angular) as DOM objects are used before getting attached.

Column Flex

It's often required that one or more columns fill the entire available space in the grid. For this scenario, it is possible to use the flex config. Some columns could be set with a regular width config, while other columns would have a flex config.

Flex sizing works by dividing the remaining space in the grid among all flex columns in proportion to their flex value. For example, suppose the grid has a total width of 450px and it has three columns: the first with width: 150; the second with flex: 1; and third with flex: 2. The first column will be 150px wide, leaving 300px remaining. The column with flex: 2 has twice the size with flex: 1. So final sizes will be: 150px, 100px, 200px.

The example below shows flex in action. Things to note are as follows:

• Column A is fixed size. You can resize it with the drag handle and the other two columns will adjust to fill the available space
• Column B has flex: 2, minWidth: 200 and maxWidth: 350, so it should be constrained to this max/min width.
• Column C has flex: 1 so should be half the size of column B, unless column B is being constrained by its minWidth/maxWidth rules, in which case it should take up the remaining available space.

Shift Resizing

If you hold the Shift key while dragging the resize handle, the column will take space away from the column adjacent to it. This means the total width for all columns will be constant.

You can also change the default behaviour for resizing. Set the grid property colResizeDefault='shift' to have shift resizing as the default and normal resizing to happen when the Shift key is pressed.

In the example below, note the following:

• Grid property colResizeDefault='shift' so default column resizing will behave as if Shift key is pressed.
• Holding down Shift will then resize the normal default way.

Resizing Groups

When you resize a group, it will distribute the extra room to all columns in the group equally. In the example below the groups can be resized as follows:

• The group 'Everything Resizes' will resize all columns.
• The group 'Only Year Resizes' will resize only year, because the other columns have resizable=false.
• The group 'Nothing Resizes' cannot be resized at all because all the columns in the groups have resizable=false.

Resizing Columns When Data Is Rendered

There are two main scenarios where you might want to resize columns based on grid data:

• Row Data is available at grid initialisation
• Row Data is available after grid initialisation, typically after data has been set asynchronously via a server call

In the first case you can fire autoSizeColumns() in either the gridReady or the firstDataRendered event as the row data will have been rendered by the time the grid is ready.

In the second case however you can only reliably use firstDataRendered as the row data will be made available, and hence rendered, after the grid is ready.