From 86641d965b60c5a2c5895973562b33d901e257a7 Mon Sep 17 00:00:00 2001
From: MH <q6rrzz@gmail.com>
Date: Mon, 19 Oct 2026 12:52:52 +0300
Subject: [PATCH] Grid: explicit Left/Right alignment keeps its side on a
 right-to-left sheet

Cells are painted left to right and a right-to-left sheet is mirrored
afterwards, so an explicit Align Right ended up on the left (and Align
Left on the right). Excel keeps an explicit alignment on the side it
names in either sheet direction; General alignment follows the sheet.

The alignment is now swapped before painting (painted_halign), for
straight and rotated text alike.

Signed-off-by: MH <q6rrzz@gmail.com>
---
 crates/ui-egui/src/grid.rs | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/crates/ui-egui/src/grid.rs b/crates/ui-egui/src/grid.rs
index 90a39cb06..d5d9f030e 100644
--- a/crates/ui-egui/src/grid.rs
+++ b/crates/ui-egui/src/grid.rs
@@ -1178,7 +1178,7 @@ pub(crate) fn paint_quadrant(
                 _ if numeric => HAlign::Right,
                 _ => HAlign::Left,
             },
-            h => h,
+            h => painted_halign(h, geo.rtl),
         };
         let indent = st.align.indent as f32 * 9.0 * z;
         let pad = 2.5 * z;
@@ -1296,7 +1296,7 @@ pub(crate) fn paint_quadrant(
             } else {
                 galley.clone()
             };
-            let pos = rotated_text_pos(*rect, galley.size(), angle, st.align.h, st.align.v, pad, indent);
+            let pos = rotated_text_pos(*rect, galley.size(), angle, painted_halign(st.align.h, geo.rtl), st.align.v, pad, indent);
             let mut shape = egui::epaint::TextShape::new(pos, galley, color);
             shape.angle = angle;
             cp.add(shape);
@@ -3336,8 +3336,34 @@ mod selection_fill_tests {
     }
 }
 
+/// The horizontal alignment to paint with. Cells are painted left to right and a right-to-left
+/// sheet is mirrored afterwards, so an explicit Left or Right is swapped first to end up on the
+/// side the user chose: Align Right stays on the right in either sheet direction, as in Excel.
+/// General alignment is resolved from the value before this and follows the sheet direction.
+fn painted_halign(h: HAlign, rtl: bool) -> HAlign {
+    match h {
+        HAlign::Left if rtl => HAlign::Right,
+        HAlign::Right if rtl => HAlign::Left,
+        h => h,
+    }
+}
+
 #[cfg(test)]
 mod tests {
+
+    #[test]
+    fn explicit_left_and_right_keep_their_side_on_a_right_to_left_sheet() {
+        use super::{HAlign, painted_halign};
+        // Painted before the mirror: swapped, so they land where the user put them.
+        assert_eq!(painted_halign(HAlign::Right, true), HAlign::Left);
+        assert_eq!(painted_halign(HAlign::Left, true), HAlign::Right);
+        // Left-to-right sheets and the other alignments are painted as they are.
+        assert_eq!(painted_halign(HAlign::Right, false), HAlign::Right);
+        assert_eq!(painted_halign(HAlign::Left, false), HAlign::Left);
+        for h in [HAlign::Center, HAlign::Justify, HAlign::Fill] {
+            assert_eq!(painted_halign(h, true), h);
+        }
+    }
     use super::*;
 
     #[test]