Merge from origin/emacs-25

ac00a92 Make sh-electric-here-document-mode accessible in sh-mode-hoo...
3287f48 ; Add entry to MAINTAINERS
b85981f * configure.ac (HAVE_MODULES): Exclude gnu-kfreebsd from prev...
0f33284 Make use of rectangle-preview custom variable.
aa0d83a Make use of rectangle-preview face.
33bef6e Use 'grep-find-program' in check-declare.el
a8560e5 Improve "C-h S" for cl-lib symbols
52e798b Fix minor issues with removing left or right fringes
d6ffd64 Speed up redisplay in ansi-term mode
4ab671c Simplify 8-bit character handling by terminal for 'raw-text'
f3653ec * configure.ac (HAVE_MODULES): Treat gnu like gnu-linux.  (Bu...
ab849b7 Fix w32 memory-management problem when extending buffer text

2 files changed, 23 insertions, 0 deletions

diff --git a/doc/emacs/display.texi b/doc/emacs/display.texi
index 01f899f1c09..8039291298c 100644
--- a/doc/emacs/display.texi
+++ b/doc/emacs/display.texi
@@ -1087,6 +1087,23 @@ To disable this, change the variable
 @code{overflow-newline-into-fringe} to @code{nil}; this causes Emacs
 to continue or truncate lines that are exactly as wide as the window.
 
+  If you customize @code{fringe-mode} to remove the fringes on one or
+both sides of the window display, the features that display on the
+fringe are not available.  Indicators of line continuation and
+truncation are an exception: when fringes are not available, Emacs
+uses the leftmost and rightmost character cells to indicate
+continuation and truncation with special ASCII characters, see
+@ref{Continuation Lines}, and @ref{Line Truncation}.  This reduces the
+width available for displaying text on each line, because the
+character cells used for truncation and continuation indicators are
+reserved for that purpose.  Since buffer text can include
+bidirectional text, and thus both left-to-right and right-to-left
+paragraphs (@pxref{Bidirectional Editing}), removing only one of the
+fringes still reserves two character cells, one on each side of the
+window, for truncation and continuation indicators, because these
+indicators are displayed on opposite sides of the window in
+right-to-left paragraphs.
+
 @node Displaying Boundaries
 @section Displaying Boundaries
 
diff --git a/doc/lispref/windows.texi b/doc/lispref/windows.texi
index bb13934fb3a..74837ac82b9 100644
--- a/doc/lispref/windows.texi
+++ b/doc/lispref/windows.texi
@@ -617,6 +617,12 @@ exceed its total height as returned by @code{window-total-height}.
 @cindex body width of a window
 The @dfn{body width} of a window is the width of its text area, which
 does not include the scroll bar, fringes, margins or a right divider.
+Note that when one or both fringes are removed (by setting their width
+to zero), the display engine reserves two character cells, one on each
+side of the window, for displaying the continuation and truncation
+glyphs, which leaves 2 columns less for text display.  (The function
+@code{window-max-chars-per-line}, described below, takes this
+peculiarity into account.)
 
 @defun window-body-width &optional window pixelwise
 This function returns the width, in columns, of the body of window