11.4 Variables Controlling Display

This section contains information for customization only. Beginning users should skip it.

When you reenter SXEmacs after suspending, SXEmacs normally clears the screen and redraws the entire display. On some terminals with more than one page of memory, it is possible to arrange the termcap entry so that the ‘ti’ and ‘te’ strings (output to the terminal when SXEmacs is entered and exited, respectively) switch between pages of memory so as to use one page for SXEmacs and another page for other output. In that case, you might want to set the variable no-redraw-on-reenter to non-nil so that SXEmacs will assume, when resumed, that the screen page it is using still contains what SXEmacs last wrote there.

The variable echo-keystrokes controls the echoing of multi-character keys; its value is the number of seconds of pause required to cause echoing to start, or zero, meaning don’t echo at all. See Echo Area.

If the variable ctl-arrow is nil, control characters in the buffer are displayed with octal escape sequences, all except newline and tab. If its value is t, then control characters will be printed with an up-arrow, for example ^A.

If its value is not t and not nil, then characters whose code is greater than 160 (that is, the space character (32) with its high bit set) will be assumed to be printable, and will be displayed without alteration. This is the default when running under X Windows, since SXEmacs assumes an ISO/8859-1 character set (also known as “Latin1”). The ctl-arrow variable may also be set to an integer, in which case all characters whose codes are greater than or equal to that value will be assumed to be printable.

Altering the value of ctl-arrow makes it local to the current buffer; until that time, the default value is in effect. See Locals.

Normally, a tab character in the buffer is displayed as whitespace which extends to the next display tab stop position, and display tab stops come at intervals equal to eight spaces. The number of spaces per tab is controlled by the variable tab-width, which is made local by changing it, just like ctl-arrow. Note that how the tab character in the buffer is displayed has nothing to do with the definition of TAB as a command.

If you set the variable selective-display-ellipses to nil, the three dots at the end of a line that precedes invisible lines do not appear. There is no visible indication of the invisible lines. This variable becomes local automatically when set.