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201/NMODE Manual (Controlling the Display) Page 17-1
202/17. Controlling the Display
201/Since only part of a large file fits on the screen, NMODE tries to show the
part that is likely to be interesting. The display control commands allow you
to ask to see a different part of the file.
C-L Clear and redisplay screen, putting point at a specified
vertical position.
ESC-J Clear and rewrite display, but without moving text or point.
C-V Scroll forwards (a screen or a few lines).
M-V Scroll backwards.
M-R Move point to the text at a given vertical position.
C-M-R Shift the function point is in onto the screen.
ESC-S scroll window up line
ESC-T scroll window down line
ESC-U scroll window up page
ESC-V scroll window down page
C-X < scroll window left
C-X > scroll window right
The terminal screen is rarely large enough to display all of your file. If
the whole buffer doesn't fit on the screen, NMODE shows a contiguous portion
of it, containing point. It continues to show approximately the same portion
until point moves outside of it; then NMODE chooses a new portion centered
around the new point. This is NMODE's guess as to what you are most
interested in seeing. But if the guess is wrong, you can use the display
control commands to see a different portion. The finite area of screen
through which you can see part of the buffer is called 202/the window201/, and the
choice of where in the buffer to start displaying is also called 202/the window201/.
The basic display control command is C-L (203/nmode-refresh-command201/). In its
simplest form, with no argument, it clears the screen and tells NMODE to
choose a new window position. If enough of the buffer is above point,
NMODE will pick the window's position in the file so that point is about
two-thirds of the way down the screen. If there is not enough of the buffer
above point to fill up two-thirds of the screen, NMODE will pick the window
position so that point is one-third of the way down the screen. If there isn't
even enough of the buffer above point to fill a third of the screen, NMODE
will put the top of the buffer at the top of the screen and let point fall
where it may.
Another command that can be used to help clear up the screen is ESC-J
(203/nmode-full-refresh201/). This clears and rewrites the display, but without
changing the portion of the buffer displayed on the screen.
C-L with a positive argument chooses a new window so as to put point that
many lines from the top. An argument of zero puts point on the very top
line. Point does not move with respect to the text; rather, the text and
point move rigidly on the screen. C-L with a negative argument puts point
that many lines from the bottom of the window. For example, C-U -1 C-L
puts point on the bottom line, and C-U -5 C-L puts it five lines from the
bottom. C-L with an argument does not clear the screen, so that it can move
the text on the screen instead of printing it again if the terminal allows that.
201/Page 17-2 NMODE Manual (Controlling the Display)
The 202/scrolling 201/commands C-V and M-V let you move the whole display up or
down a few lines. C-V (203/next-screen-command201/) with an argument shows you
that many more lines at the bottom of the screen, moving the text and point
up together as C-L might. C-V with a negative argument shows you more
lines at the top of the screen, as does Meta-V (203/previous-screen-command201/)
with a positive argument.
There are two other commands that let you move the whole display up or
down by a few lines. These are ESC-S (203/scroll-window-up-line-command201/) and
ESC-T (203/scroll-window-down-line-command201/). These move text and point
together up and down respectively relative to the screen.
To read the buffer a screenful at a time, use the C-V command with no
argument. Each C-V shows the "next screenful" of text. Point is put at the
same point on the screen as on the previous screen. To move backward, use
M-V without an argument, which moves a whole screenful backwards.
To move by multiple screenfuls in the buffer, ESC-U
(203/scroll-window-up-page-command201/) and ESC-V
(203/scroll-window-down-page-command201/) can be used. These functions accept
command arguments and then move the text in the screen up or down by
command-argument pages. They will reverse direction if given negative
arguments.
In Lisp mode, one can use the C-M-R command
(203/reposition-window-command201/) to scroll the buffer so that the current function
(defun) is positioned conveniently on the screen. This command tries to get
as much as possible of the current function, preferring the beginning to the
end, but not moving point off the screen.
There are also commands to scroll the window horizontally. C-X <
(203/scroll-window-left-command201/) and C-X > (203/scroll-window-right-command201/).
These scroll the portion of the buffer viewed by the screen to the left or
right respectively. These commands have the opposite movement conventions
from the other scrolling commands. In all the other commands, one gets the
correct direction of movement by imagining that it is the characters visible on
the CRT that are moving. For these commands one should think of the
screen as a movable hole looking at the buffer, and it is the movement of the
hole that is named by the commands.
C-L in all its forms changes the position of point on the screen, carrying
the text with it. Another command moves point the same way but leaves the
text fixed. It is called Meta-R (203/move-to-screen-edge-command201/). With no
argument, it puts point in the line at the center of the screen, at the
current vertical column. An argument is used to specify the line to put it
on, counting from the top if the argument is positive, or from the bottom if it
is negative. Thus, Meta-R with an argument of 0 puts point on the top line
of the screen. Meta-R never causes any text to move on the screen; it
causes point to move with respect to the screen and the text.