Commit: patch 9.1.2006: MS-Windows: ANSI colors not correct in terminal

[Christian Brabandt]

patch 9.1.2006: MS-Windows: ANSI colors not correct in terminal

Commit: https://github.com/vim/vim/commit/86855ea8ee6d81926cfadcebce984afc94fc82dc
Author: Muraoka Taro <koron....@gmail.com>
Date: Sun Dec 21 19:42:23 2025 +0000

patch 9.1.2006: MS-Windows: ANSI colors not correct in terminal

Problem: ANSI escape colors are not displayed correctly in
non-termguicolors in vim (cli) on Windows. The red and blue
channels seem to be swapped.
Cause: When converting VTerm ANSI index colors to cterm colors in
terminal.c, the Windows case equivalent to NR-16 (:help
cterm-colors) is ignored.
Solution: Created and used a table to convert ANSI indexed colors to
cterm's NR-16 representation (Windows only). This table
corresponds to the inverse conversion of cterm_ansi_idx in
term.c. The values in both tables are exactly the same, but
the meanings are opposite, so they are separate tables
(Muraoka Taro).

closes: #18931

Signed-off-by: Muraoka Taro <koron....@gmail.com>
Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/src/term.c b/src/term.c
index d3939ef4d..503ec3895 100644
--- a/src/term.c
+++ b/src/term.c
@@ -7642,7 +7642,7 @@ static const char_u ansi_table[16][3] = {

# if defined(MSWIN)
// Mapping between cterm indices < 16 and their counterpart in the ANSI palette.
-static const char_u cterm_ansi_idx[] = {
+const char_u cterm_ansi_idx[] = {
0, 4, 2, 6, 1, 5, 3, 7, 8, 12, 10, 14, 9, 13, 11, 15
};
# endif
diff --git a/src/termdefs.h b/src/termdefs.h
index 2b65abb1c..d611fcf44 100644
--- a/src/termdefs.h
+++ b/src/termdefs.h
@@ -233,3 +233,8 @@ typedef enum {
TMODE_RAW, // terminal mode for Normal and Insert mode
TMODE_UNKNOWN // after executing a shell
} tmode_T;
+
+#if defined(MSWIN)
+// Mapping between cterm indices < 16 and their counterpart in the ANSI palette.
+extern const char_u cterm_ansi_idx[];
+#endif
diff --git a/src/terminal.c b/src/terminal.c
index 404cfa125..48b9e06c4 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -3033,7 +3033,20 @@ color2index(VTermColor *color, int fg, int *boldp)
{
// Use the color as-is if possible, give up otherwise.
if (color->index < t_colors)
- return color->index + 1;
+ {
+ uint8_t index = color->index;
+#ifdef MSWIN
+ // Convert ANSI palette to cterm color index.
+ // cterm_ansi_idx is a table for the reverse conversion from cterm
+ // color index to ANSI palette. However, the current table can
+ // be used for this conversion as well.
+ // Note: If the contents of cterm_ansi_idx change in the future, a
+ // different table may be needed for this purpose.
+ if (index < 16)
+ index = cterm_ansi_idx[index];
+#endif
+ return index + 1;
+ }
// 8-color terminals can actually display twice as many colors by
// setting the high-intensity/bold bit.
else if (t_colors == 8 && fg && color->index < 16)
diff --git a/src/testdir/test_terminal3.vim b/src/testdir/test_terminal3.vim
index 218b4e6a0..5049f913c 100644
--- a/src/testdir/test_terminal3.vim
+++ b/src/testdir/test_terminal3.vim
@@ -1037,4 +1037,55 @@ func Test_terminal_visual_empty_listchars()
call StopVimInTerminal(buf)
endfunc

+func Test_terminal_ansi_color_windows_cui()
+ if !has('win32') || has('gui_running')
+ throw 'Skipped: only for the Windows CUI'
+ endif
+ if exists('$APPVEYOR')
+ throw 'Skipped: this test cannot be performed because AppVeyor does not support ANSI escape sequences'
+ endif
+
+ call assert_equal('dark', &background)
+
+ " Outputs 16 ANSI colors as background colors
+ let ansi = ''
+ for i in range(16)
+ let ansi ..= printf(" [%dm%X", i + (i < 8 ? 40 : 92), i)
+ endfor
+ let ansi ..= " [40m
"
+ call writefile([ansi], 'XANSIcolor', 'D')
+
+ let expected_chars = '0123456789ABCDEF'
+ let expected_colors = [
+ \ '#000000', '#e00000', '#00e000', '#e0e000',
+ \ '#0000e0', '#e000e0', '#00e0e0', '#e0e0e0',
+ \ '#808080', '#ff4040', '#40ff40', '#ffff40',
+ \ '#4040ff', '#ff40ff', '#40ffff', '#ffffff',
+ \ ]
+
+ " Ideally, 16 colors should be checked. However, in the current CI
+ " environment, the 16th color is something other than white, and we don't
+ " know the cause nor solution. After discussion, we decided to check only 15
+ " colors for the time being.
+ " FIXME: Check all 16 colors in the future.
+ let len_to_check = 15
+ let expected_colors = expected_colors[:len_to_check-1]
+
+ " First, make sure vim can display correct ANSI color text in terminal.
+ let buf = term_start("cmd /C type XANSIcolor")
+ call WaitForAssert({-> assert_equal(expected_chars, term_scrape(buf, 1)[:15]->map({_, v -> v['chars']})->join(''))})
+ call assert_equal(expected_colors, term_scrape(buf, 1)[:len_to_check-1]->map({_, v -> v['bg']}))
+ bwipeout!
+
+ " Next, check if vim can do the same thing in the vim terminal in terminal.
+ let lines = [
+ \ 'call term_start("cmd /C type XANSIcolor")'
+ \ ]
+ call writefile(lines, 'XloadANSI', 'D')
+ let cmd = GetVimCommandCleanTerm()
+ let buf = term_start(cmd .. '-S XloadANSI')
+ call WaitForAssert({-> assert_equal(expected_chars, term_scrape(buf, 1)[:15]->map({_, v -> v['chars']})->join(''))})
+ call assert_equal(expected_colors, term_scrape(buf, 1)[:len_to_check-1]->map({_, v -> v['bg']}))
+endfunc
+
" vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index 2d4b1df97..12dfb27af 100644
--- a/src/version.c
+++ b/src/version.c
@@ -734,6 +734,8 @@ static char *(features[]) =

static int included_patches[] =
{ /* Add new patch number below this line */
+/**/
+ 2006,
/**/
2005,
/**/