#### 4.8.1 Making Summaries

Here are the commands to create a summary for the current IMAIL folder. Once the IMAIL folder has a summary buffer, changes in the IMAIL folder (such as deleting or expunging messages, and getting new mail) automatically update the summary.

`h`
`C-M-h`

  Summarize all messages (`imail-summary`).

`l flags RET`
`C-M-l flags RET`

  Summarize messages that have one or more of the specified flags (`imail-summary-by-flags`).

`C-M-r rcpts RET`

  Summarize messages that have one or more of the specified recipients (`imail-summary-by-recipients`).

`C-M-t topic RET`

  Summarize messages that have a match for the specified regexp topic in their subjects (`imail-summary-by-topic`).

`C-M-s regexp RET`

  Summarize messages that have a match for the specified regexp anywhere in their header (`imail-summary-by-regexp`).

The `h` or `C-M-h` (`imail-summary`) command fills the summary buffer for the current IMAIL folder with a summary of all the messages in the folder. It then displays and selects the summary buffer in another window.

`C-M-l flags RET` (`imail-summary-by-flags`) makes a partial summary mentioning only the messages that have one or more of the flags flags. flags should contain flag names separated by commas.

`C-M-r rcpts RET` (`imail-summary-by-recipients`) makes a partial summary mentioning only the messages that have one or more of the recipients rcpts. rcpts should contain mailing addresses separated by commas.

`C-M-t topic RET` (`imail-summary-by-topic`) makes a partial summary mentioning only the messages whose subjects have a match for the regular expression topic.

`C-M-s regexp RET` (`imail-summary-by-regexp`) makes a partial summary mentioning only the messages whose headers contain a match for the regular expression regexp. This match includes all lines in the header, including for example the date and from lines.

Note that there is only one summary buffer for any IMAIL folder; making one kind of summary discards any previously made summary.

There are several variables that affect how summaries are displayed. `imail-summary-height` controls the height of the summary window. If it is an exact positive integer, the summary window is that many lines high. Alternatively, if it is a real number between 0 and 1 exclusive, the height of the summary window is computed by multiplying the number of lines in the message window by `imail-summary-height` and rounding to the nearest integer.

If the variable `imail-summary-fixed-layout` is set to `#t`, then an IMAIL message buffer and its associated summary buffer are always shown in a fixed window layout (provided the summary buffer exists). Selecting either buffer causes all other windows in the current editor frame to be deleted, then splits the frame into two windows showing the summary buffer and message buffer. Selecting any other buffer when this layout is displayed causes both windows to be deleted, and the other buffer displayed in a single window filling the editor frame. Basically, this causes the message and summary buffers to be treated as a unit most of the time. Currently, the default for `imail-summary-fixed-layout` is `#f`, but the feature has been very popular and the default may be changed to `#t` in a future release.

When fixed layout is not used, the variable `imail-summary-pop-up-message` provides a different kind of window splitting for message and summary buffers. If this is set to `#t` (the default), then selecting a new message in the summary buffer causes the message buffer to be popped up in a new window if it isn’t already visible.

If the variable `imail-summary-highlight-message` is `#t`, the message currently selected in the message buffer is highlighted in the summary buffer. This aids navigation in the summary buffer and is thus the default. Set it to `#f` if you don’t like the highlighting.

By default, the summary buffer has five columns: flags, message number, message length, subject, and author. If `imail-summary-show-date` is set to `#t`, a sixth column containing an abbreviated date appears between the message number and the subject.

The width of the subject column is specified by the value of `imail-summary-subject-width`; subject fields longer than this number of characters are truncated.