The command C-x 2 (
split-window-vertically) breaks the
selected window into two windows, one above the other. Both windows start
out displaying the same buffer, with the same value of point. By default
the two windows each get half the height of the window that was split; a
numeric argument specifies how many lines to give to the top window.
C-x 3 (
split-window-horizontally) breaks the selected
window into two side-by-side windows. A numeric argument specifies how
many columns to give the one on the left. If you are not using
scrollbars, a vertical line separates the two windows.
You can customize its color with the face
Windows that are not the full width of the screen have mode lines, but
they are truncated. On terminals where Emacs does not support
highlighting, truncated mode lines sometimes do not appear in inverse
You can split a window horizontally or vertically by clicking C-Mouse-2 in the mode line or the scroll bar. The line of splitting goes through the place where you click: if you click on the mode line, the new scroll bar goes above the spot; if you click in the scroll bar, the mode line of the split window is side by side with your click.
When a window occupies less than the full width of the frame, it may
become too narrow for most of the text lines in its buffer. If most of
its lines are continued (see Continuation Lines), the buffer may
become difficult to read. Therefore, Emacs automatically truncates
lines if the window width becomes narrower than 50 columns. This
truncation occurs regardless of the value of the variable
truncate-lines (see Line Truncation); it is instead
controlled by the variable
the value of
truncate-partial-width-windows is a positive integer
(the default is 50), that specifies the minimum width for a
partial-width window before automatic line truncation occurs; if the
nil, automatic line truncation is disabled; and for any
nil value, Emacs truncates lines in every partial-width
window regardless of its width.
Horizontal scrolling is often used in side-by-side windows. See Horizontal Scrolling.
split-window-keep-point is non-
nil, the default,
both of the windows resulting from C-x 2 inherit the value of
point from the window that was split. This means that scrolling is
inevitable. If this variable is
nil, then C-x 2 tries to
avoid scrolling the text currently visible on the screen, by putting
point in each window at a position already visible in the window. It
also selects whichever window contains the screen line that the cursor
was previously on. Some users prefer that mode on slow terminals.