Commit: patch 9.2.0064: popup: opacity feature causes flickering

[Christian Brabandt]

patch 9.2.0064: popup: opacity feature causes flickering

Commit: https://github.com/vim/vim/commit/97c5bed84b5a0b5a861007e23aaccfc76c519b34
Author: Hirohito Higashi <h.eas...@gmail.com>
Date: Thu Feb 26 20:49:06 2026 +0000

patch 9.2.0064: popup: opacity feature causes flickering

Problem: popup: opacity feature causes flickering
(after v9.2.0016)
Solution: Only skip the mask and enable the opacity context if
w_popup_blend is greater than 0 (Hirohito Higashi).

fixes: #19510
fixes: #19499
closes: #19515

Signed-off-by: Hirohito Higashi <h.eas...@gmail.com>
Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/src/popupwin.c b/src/popupwin.c
index e7ab2687e..267ffb6ff 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -4128,9 +4128,10 @@ may_update_popup_mask(int type)
height = popup_height(wp);
popup_update_mask(wp, width, height);

- // Popup with opacitys do not block lower layers from drawing,
- // so they don't participate in the popup_mask.
- if (wp->w_popup_flags & POPF_OPACITY)
+ // Popup with partial transparency do not block lower layers from
+ // drawing, so they don't participate in the popup_mask.
+ // Fully opaque popups (blend == 0) still block lower layers.
+ if ((wp->w_popup_flags & POPF_OPACITY) && wp->w_popup_blend > 0)
continue;

for (line = wp->w_winrow;
@@ -4343,7 +4344,8 @@ update_popups(void (*win_update)(win_T *wp))
screen_zindex = wp->w_zindex;

// Set popup with opacity context for screen drawing.
- if (wp->w_popup_flags & POPF_OPACITY)
+ // Only enable transparency rendering when blend > 0 (not fully opaque).
+ if ((wp->w_popup_flags & POPF_OPACITY) && wp->w_popup_blend > 0)
screen_opacity_popup = wp;
else
screen_opacity_popup = NULL;
diff --git a/src/testdir/dumps/Test_popupwin_opacity_100_blocks_bg.dump b/src/testdir/dumps/Test_popupwin_opacity_100_blocks_bg.dump
new file mode 100644
index 000000000..362259bde
--- /dev/null
+++ b/src/testdir/dumps/Test_popupwin_opacity_100_blocks_bg.dump
@@ -0,0 +1,10 @@
+>b+0&#ffffff0|a|c|k|g|r|o|u|n|d| |t|e|x|t| |h|e|r|e| @54
+|P+0#0000001#ffd7ff255|O|P|U|P| |L|I|N|E| |1| @7| +0#0000000#ffffff0@54
+|P+0#0000001#ffd7ff255|O|P|U|P| |L|I|N|E| |2| @7| +0#0000000#ffffff0@54
+|b|a|c|k|g|r|o|u|n|d| |t|e|x|t| |h|e|r|e| @54
+|b|a|c|k|g|r|o|u|n|d| |t|e|x|t| |h|e|r|e| @54
+|b|a|c|k|g|r|o|u|n|d| |t|e|x|t| |h|e|r|e| @54
+|b|a|c|k|g|r|o|u|n|d| |t|e|x|t| |h|e|r|e| @54
+|b|a|c|k|g|r|o|u|n|d| |t|e|x|t| |h|e|r|e| @54
+|b|a|c|k|g|r|o|u|n|d| |t|e|x|t| |h|e|r|e| @54
+@57|1|,|1| @10|T|o|p|
diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index 24d8fab57..4c41bf75d 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -4813,6 +4813,23 @@ func Test_popup_opacity_highlight()
call StopVimInTerminal(buf)
endfunc

+func Test_popup_opacity_100_blocks_background()
+ CheckScreendump
+
+ " opacity:100 (fully opaque, blend==0) popup should block background content.
+ " Before the fix, POPF_OPACITY caused the popup to be excluded from
+ " popup_mask even with blend==0, making background show through.
+ let lines =<< trim END
+ call setline(1, repeat(['background text here'], 10))
+ call popup_create(['POPUP LINE 1', 'POPUP LINE 2'],
+ \ #{line: 2, col: 1, minwidth: 20, opacity: 100})
+ END
+ call writefile(lines, 'XtestPopupOpaque100', 'D')
+ let buf = RunVimInTerminal('-S XtestPopupOpaque100', #{rows: 10})
+ call VerifyScreenDump(buf, 'Test_popupwin_opacity_100_blocks_bg', {})
+ call StopVimInTerminal(buf)
+endfunc
+
func Test_popup_getwininfo_tabnr()
tab split
let winid1 = popup_create('sup', #{tabpage: 1})
diff --git a/src/version.c b/src/version.c
index 3be922580..4443e6eac 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 */
+/**/
+ 64,
/**/
63,
/**/