Allow non-fixed popups to be shifted even when wrap is set

[bstaletic]

As discussed, this is the implementation of #16231

This pull request makes it possible for a popup window to use both, fixed == 0 and wrap == 1.
This is achieved by first shifting the window to the left until it is either fully visible or is moved all the way to the left.
Then, if the popup window is all the way to the left and some line is still too long to fit on screen, wrapping is performed.

[bfrg]

There are some issues with this fix. When border and/or padding is set, the right side of the popup is cut off:

Example:

vim9script

set showbreak=+++

def Test()
    popup_atcursor(repeat("0123456789 ", 20), {
        moved: 'any',
        border: [1, 1, 1, 1],
        padding: [0, 1, 0, 1],
    })
enddef

nnoremap gh <ScriptCmd>Test()<Cr>

There's also an extra line printed when the cursor is at the far right:

[bstaletic]

The behaviour regarding cutting off the right edge padding did not change with the pull request.
It used to happen before whenever the popup was allowed to shift to the left.

I am not sure what you mean by the last part:

There's also an extra line printed when the cursor is at the far right:

EDIT: Maybe I'm wrong about the right edge paddig getting cut off before.

[bfrg]

I am not sure what you mean by the last part:

There's also an extra line printed when the cursor is at the far right:

What I meant was that there's an extra empty line displayed in the popup (see the 2nd screenshot above).

[bstaletic]

Got it.
First, if we moved the popup all the way left and it still goes off screen and wrapping is on, the maxwidth needs to be lowered by right_extra.
That solves the right edge padding being missing.

The second problem is caused by shifting left mutating wp, so line needs to be recalculated after shifting.

Recording of the fix: https://asciinema.org/a/Ha8ciJG5veAuvWqToImDlzOIb

Diff:

diff --git a/src/popupwin.c b/src/popupwin.c
index 404549097..417533016 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -1444,15 +1444,18 @@ popup_adjust_position(win_T *wp)

            if (shift_by > wp->w_wincol)
            {
-               int truncate_shift = shift_by - wp->w_wincol;
-
-               shift_by -= truncate_shift;
+               shift_by -= shift_by - wp->w_wincol;
+               if (wp->w_p_wrap)
+               {
+                   maxwidth -= right_extra;
+               }
            }

            wp->w_wincol -= shift_by;
            maxwidth += shift_by;
            wp->w_width = maxwidth;
        }
+       len = linetabsize(wp, lnum);
        if (wp->w_p_wrap)
        {
            while (len + margin_width > maxwidth)

I don't see a good way of testing this except with the screendump tests. Unfortunately, I don't yet know how they work and won't be near my computer for the next 10 days.

[chrisbra]

@bfrg can you please test it? Regarading the screendump tests. It's not so hard. Have a look at e.g. this one here:

vim/src/testdir/test_popupwin.vim

Lines 9 to 25 in 92195ae

	func Test_simple_popup()
	CheckScreendump
	let lines =<< trim END
	call setline(1, range(1, 100))
	hi PopupColor1 ctermbg=lightblue
	hi PopupColor2 ctermbg=lightcyan
	hi EndOfBuffer ctermbg=lightgrey
	hi Comment ctermfg=red
	call prop_type_add('comment', #{highlight: 'Comment'})
	let winid = popup_create('hello there', #{line: 3, col: 11, minwidth: 20, highlight: 'PopupColor1'})
	let winid2 = popup_create(['another one', 'another two', 'another three'], #{line: 3, col: 25, minwidth: 20})
	call setwinvar(winid2, '&wincolor', 'PopupColor2')
	END
	call writefile(lines, 'XtestPopup', 'D')
	let buf = RunVimInTerminal('-S XtestPopup', #{rows: 10})
	call VerifyScreenDump(buf, 'Test_popupwin_01', {})

Now when you first run it, you will find the "failed" screendump file inside testdir/failed/. You can inspect the file using the term_dumpload() function and need to manually verify that the screen dump looks like you expect it. Once you are satisfied with it, copy it to the testdir/dumps directory and on next run of the test, Vim will verify the screendump test against the file in testdir/dumps directory. See also the README

[bfrg]

I just tried the above patch and it doesn't work yet. The same script as above (notice the cursor position):

[bstaletic]

This patch works better:

diff --git a/src/popupwin.c b/src/popupwin.c
index 404549097..10cc12221 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -1444,14 +1444,17 @@ popup_adjust_position(win_T *wp)

            if (shift_by > wp->w_wincol)
            {
-               int truncate_shift = shift_by - wp->w_wincol;
-
-               shift_by -= truncate_shift;
+               shift_by -= shift_by - wp->w_wincol;
+               if (wp->w_p_wrap)
+               {
+                   maxwidth -= right_extra;
+               }
            }

            wp->w_wincol -= shift_by;
            maxwidth += shift_by;
            wp->w_width = maxwidth;
+           len = linetabsize(wp, lnum);
        }
        if (wp->w_p_wrap)
        {

Still, if the text is wide, but does not wrap yet, and it gets shifted, then there's a len(&showbreak) extra spaces to the right.
I do not understand why, but linetabsize(wp, lnum) returns a larger number than expected.

Another recording:
https://asciinema.org/a/Bp4BSkyM7dgBZkczHSpMrPXgj