Many of the adjustments of the value of openfile->current_y appear to be
a holdover from the days when certain functions had to account for what
is now called STATIONARY scrolling mode, which depends on the value of
current_y.  Remove these adjustement where they are superfluous.

do_para_begin(), do_para_end(), and do_bracket_match() update the screen
through edit_redraw(), which uses either CENTERING or FLOWING scrolling
mode, so their setting of current_y is redundant and useless, as it will
be ignored and then overridden by the next call to reset_cursor().

findnextstr() is called by go_looking() [which calls edit_redraw(), see
above], and by do_replace_loop() and do_int_spell_fix(), which both call
edit_refresh(), which in this case only uses CENTERING scrolling mode
since focusing is TRUE.

(Additionally, the adjustments of current_y in findnextstr() and
do_bracket_match() use incorrect values when in softwrap mode.)

find_paragraph() doesn't need to save or restore current_y, because it
doesn't do any screen updates.  do_justify() calls edit_refresh() with
focusing set to TRUE, so it uses the CENTERING scrolling mode.

do_alt_speller() and do_formatter() do not need to save and restore
current_y, because they don't modify it in any way.

This addresses https://savannah.gnu.org/patch/?9197.

Like do_down() does already, do_pageup() and do_right() should use
editwincols instead of COLS.

This addresses https://savannah.gnu.org/bugs/?49796.

This fixes https://savannah.gnu.org/bugs/?49467.

Also, don't bother conditionalizing two booleans for the tiny version.

It does not update anything -- it just picks a new point from
where to start displaying the buffer.  All actual updating of
the screen is done by edit_refresh() and edit_redraw() and such.

It can be activated with --linenumbers on the command line or with
'set linenumbers' in a nanorc file, and it can be toggled with M-#.
Signed-off-by: Faissal Bensefia <faissaloo@gmail.com>
Signed-off-by: Benno Schulenberg <bensberg@justemail.net>

This fixes https://savannah.gnu.org/bugs/?49099,
and fixes the unreported corresponding bugs for
<End> and <Del> and typing extra characters.

So the softwrap code in do_down() can compute the correct amount to scroll.

This fixes https://savannah.gnu.org/bugs/?49374.

This fixes https://savannah.gnu.org/bugs/?49086.

And also case-sensitive searches, backward searches, and searching again.

Mentioning "GNU nano" instead of "This program" and referring to the
website instead of to a postal address.

Even when the edit window consists of just one or two lines, the PageUp
and PageDown functions (^Y and ^V) should continue to move the window.

This fixes https://savannah.gnu.org/bugs/?48805.

When doing an <Up> on the top line, or a <Down> on the bottom line of
the edit window, the affected lines have already been redrawn by the
scrolling code, so there is no need to do that again.

(However, that does not prevent the second line (or the last-but-one
line) from being redrawn unnecessarily when using the M-- (or M-+)
command elsewhere on the screen and /that/ line is horizontally
scrolled.  But we'll let that pass for now.)

For horizontal scrolling, it is not the /desired/ column position that
is relevant for determining whether a line needs to be redrawn after a
cursor movement, but the /actual/ column positions before and after.

This fixes https://savannah.gnu.org/bugs/?48627,
and fixes https://savannah.gnu.org/bugs/?48629.

Having two unneeded parameters in the tiny version is acceptable --
the code gets so much more readable.

It is nicer to have a predictable cursor position and not see it hop
left and right on differently indented lines.

And hard-bind the keys Ctrl+Up and Ctrl+Down to these functions.

Unlike the paragraph-jumping code, these new functions disregard
any indentation, treating only blank lines as separators.  They
also do an automatic smart home when that option is set.

This fulfills https://savannah.gnu.org/bugs/?48291.

Since nano-2.4.1, reading in or pasting a large piece of text would put
the cursor on the bottom line, leaving only one line of the non-read or
non-pasted text visible.  This is different from the centering behavior
of Pico, and somewhat disorienting, as you can't see "where you are" any
more in relation to the file as it was.

So now center the cursor whenever the read or pasted text is larger than
the screen, but don't center it when the text fits entirely on the screen.
(The latter avoids the effect of the screen jumping unnecessarily when
inserting just a few lines while the cursor is near the bottom.)

To achieve this behavior: default to focusing, and temporarily set it to
FALSE when the focusing effect is unwanted.

This fixes https://savannah.gnu.org/bugs/?47841.

For a little contrast with the function edit_refresh() -- it's
annoying that when you search for the latter you get to see all
the settings of the flag too.

The function edit_update() is called by edit_refresh() itself, so it is
silly that the first sets 'edit_refresh_needed' to TRUE.  This setting
is needed only in a few cases -- in the others it's not needed because
the screen does not need to be refreshed (it was just about positioning
the cursor), or 'edit_refresh_needed' has already been set by a call to
goto_line_posx().  So, just set the flag in the five places that need it
and spare the other four calls.

The number of lines to scroll is: the y position of the start of the
current line, plus the extra lines that this line occupies, plus the
extra lines that the next line occupies, plus one, minus the y position
of the last window line.

The y position of the start of the current line is current_y -
xplustabs() / COLS, the extra lines are strlenpt(data) / COLS,
and the y position of the last window line is editwinrows - 1.

Note that we first compute the amount to scroll before actually moving
to the next line, because we need the current value of current_x, not
the one that it will have in the next line.  The placewewant value is
not good either, because it might be beyond where we actually are.

This fixes https://savannah.gnu.org/bugs/?47665.

When in softwrap mode and scrolling down a line, and thus going to
do a full refresh, get out and don't bother redrawing the current
and prior lines first.

When moving the cursor up or down one line, redraw the new current
line only when the target column (placewewant) is beyond the screen,
or when the mark is on.

(This still redraws the current and prior lines unnecessarily when
they are in fact shorter than the screen is wide and the mark is off,
but we'll let that pass for now.)

Also, when softwrap is on, we don't have have to redraw the current
and prior lines at all (when the mark is off): they are in full view,
there is nothing to show or hide.

When scrolling down a line, a full refresh of the edit window is only
needed when softwrap is on, because only then the movement is irregular.
When each file line takes up just one screen line (softwrap is off),
edit_scroll() is perfectly able to scroll and redraw only the necessary
lines.

(But... when doing a full refresh anyway with softwrap, why bother
scrolling at all?  Why not just adjust edittop and call refresh?)

Instead of saving the current value of placewewant, then setting the
new value, and then passing the old value to edit_redraw() in seven
different places, just let edit_redraw() do this saving and setting.

In the bargain placewewant is now only recalculated when it matters
-- when allow_update is TRUE -- and not when it's superfluous.

Add a third mode of scrolling, FLOWING, besides CENTERING and STATIONARY.
This is used for word and paragraph jumping (and for bracket matching,
but that worked correctly already), and only when focusing is FALSE.

The new mode prevents the screen from scrolling too many lines when
there are several blank lines at the bottom of the edit window and
the next word or paragraph is out of view.

This fixes https://savannah.gnu.org/bugs/?47194.

the backward one first.


git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@5661 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@5492 35c25a1d-7b9e-4130-9fde-d3aeb78583b8