Fringe indicators are tiny icons displayed in the window fringe to indicate truncated or continued lines, buffer boundaries, etc.
When this is non-
nil, Emacs displays a special glyph in the
fringe of each empty line at the end of the buffer, on graphical
displays. See Fringes. This variable is automatically
buffer-local in every buffer.
This buffer-local variable controls how the buffer boundaries and window scrolling are indicated in the window fringes.
Emacs can indicate the buffer boundaries—that is, the first and last line in the buffer—with angle icons when they appear on the screen. In addition, Emacs can display an up-arrow in the fringe to show that there is text above the screen, and a down-arrow to show there is text below the screen.
There are three kinds of basic values:
Don’t display any of these fringe icons.
Display the angle icons and arrows in the left fringe.
Display the angle icons and arrows in the right fringe.
Display the angle icons in the left fringe and don’t display the arrows.
Otherwise the value should be an alist that specifies which fringe
indicators to display and where. Each element of the alist should
have the form
(indicator . position). Here,
indicator is one of
down, and t (which covers all the icons not yet
specified), while position is one of
((top . left) (t . right)) places the top angle
bitmap in left fringe, and the bottom angle bitmap as well as both
arrow bitmaps in right fringe. To show the angle bitmaps in the left
fringe, and no arrow bitmaps, use
((top . left) (bottom . left)).
This buffer-local variable specifies the mapping from logical fringe
indicators to the actual bitmaps displayed in the window fringes. The
value is an alist of elements
. bitmaps), where indicator specifies a logical indicator
type and bitmaps specifies the fringe bitmaps to use for that
Each indicator should be one of the following symbols:
Used for truncation and continuation lines.
Used when indicate-buffer-boundaries is non-
down indicate a buffer boundary lying above or
below the window edge;
bottom indicate the
topmost and bottommost buffer text line; and
indicates where there is just one line of text in the buffer.
Used to indicate empty lines when indicate-empty-lines is
Used for overlay arrows (see Overlay Arrow).
Each bitmaps value may be a list of symbols
right [left1 right1]). The left and
right symbols specify the bitmaps shown in the left and/or right
fringe, for the specific indicator. left1 and right1 are
specific to the
top-bottom indicators, and
are used to indicate that the last text line has no final newline.
Alternatively, bitmaps may be a single symbol which is used in
both left and right fringes.
See Fringe Bitmaps, for a list of standard bitmap symbols and how
to define your own. In addition,
nil represents the empty
bitmap (i.e., an indicator that is not shown).
When fringe-indicator-alist has a buffer-local value, and there is no bitmap defined for a logical indicator, or the bitmap is t, the corresponding value from the default value of fringe-indicator-alist is used.