19.13 How Text Is Displayed
ASCII printing characters (octal codes 040 through 0176) in Emacs
buffers are displayed with their graphics, as are non-ASCII multibyte
printing characters (octal codes above 0400).
Some ASCII control characters are displayed in special ways. The
newline character (octal code 012) is displayed by starting a new line.
The tab character (octal code 011) is displayed by moving to the next
tab stop column (normally every 8 columns).
Other ASCII control characters are normally displayed as a caret
(‘^’) followed by the non-control version of the character; thus,
control-A is displayed as ‘^A’.
Non-ASCII characters 0200 through 0237 (octal) are displayed with
octal escape sequences; thus, character code 0230 (octal) is displayed
as ‘\230’. The display of character codes 0240 through 0377
(octal) may be either as escape sequences or as graphics. They do not
normally occur in multibyte buffers, but if they do, they are displayed
as Latin-1 graphics. In unibyte mode, if you enable European display
they are displayed using their graphics (assuming your terminal supports
them), otherwise as escape sequences. See Single-Byte Character Support.
Some character sets define “no-break” versions of the space and
hyphen characters, which are used where a line should not be broken.
Emacs normally displays these characters with special faces
distinguish them from ordinary spaces and hyphens. You can turn off
this feature by setting the variable
nil. If you set the variable to any other value, that means to
prefix these characters with an escape character.