A tag that exactly fills its row stays one row, as acme's does

Tags wrapped one cell early to keep a cell for the caret past a full row,
so a tag that exactly filled its column broke as De / l. acme's frame wraps
a box only when it is wider than what the row has left, and frptofchar
clamps the tick past a full line's end to the frame's edge. Tags now wrap
at their full width; the caret past a full row sits at the tag layer's
edge, and on the pane's last cell in a terminal grid, which has none past
it. Two tiny-screen tests collapse their tags, as the others do, and the 41
goldens that moved were re-recorded by name after the same check: rows
shift back up under the shorter tags and nothing else changes. chordcut's
file-body clicks moved back with them.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

4 files changed, 13 insertions, 6 deletions

diff --git a/src/Terminal.zig b/src/Terminal.zig
index 76be29d0..504ab887 100644
--- a/src/Terminal.zig
+++ b/src/Terminal.zig
@@ -2505,6 +2505,8 @@ test "a prompt row hidden end to end paints nothing at all" {
     defer p.deinit();
     while (p.nextEffect()) |_| {}
     const pane = p.panes[0].?;
+    pane.tag_expanded = false; // a 12x8 screen: the body, not the tag
+    p.sync();
     pane.tty_filter = false;
     pane.body.mode = .normal;
     p.update(.{ .output = .{ .pane = 0, .bytes = "\x1b]133;A\x1b\\\x1b[32maaaaaaaaa\x1b]133;B\x1b\\\x1b[41;36m\u{754C}\x1b[0m\r\n" } });
diff --git a/src/draw.zig b/src/draw.zig
index 963d61c1..fb770b60 100644
--- a/src/draw.zig
+++ b/src/draw.zig
@@ -987,9 +987,11 @@ fn joinPaneTag(p: *Pardes, s: *Surface, arena: std.mem.Allocator, pane: *Pane, r
         // The grid's row: the gap cell and the text, as far as the pane.
         joinCells(s, region.rect.x, region.rect.y + @as(u16, @intCast(line)), storage[line * pitch ..][0..pitch], config.GUTTER, region.rect.w, tag_fg);
     }
-    if (temporary.cursor) |cursor| if (cursor.x - TAG_TEXT_INSET < r.w - TAG_TEXT_INSET) {
-        s.cursor = .{ .x = r.x + cursor.x, .y = region.rect.y + cursor.y, .bar = cursor.bar };
-    };
+    // Past a full row's end the layer's caret is at the tag's edge, as
+    // acme's tick is; the grid has no cell there, so it takes the last one.
+    if (temporary.cursor) |cursor| {
+        s.cursor = .{ .x = r.x + @min(cursor.x, r.w - 1), .y = region.rect.y + cursor.y, .bar = cursor.bar };
+    }
 }
 
 /// A notice chip, painted once as a tag layer at the tagline's pitch, and the
diff --git a/src/look.zig b/src/look.zig
index d90d27b8..17746cd1 100644
--- a/src/look.zig
+++ b/src/look.zig
@@ -1378,6 +1378,7 @@ test "Look hover waits without mutating the pane and input cancels it" {
     while (p.nextEffect()) |_| {}
     const other_id = p.freeSlot() orelse return error.NoSparePaneForHoverTest;
     _ = try p.newShell(other_id, "");
+    p.panes[other_id].?.tag_expanded = false; // the blank spot right of the file is its body, not its tag
     try std.testing.expect(layout.splitColumn(p, 0, other_id, false));
     p.sync();
     while (p.nextEffect()) |_| {}
diff --git a/src/tagline.zig b/src/tagline.zig
index 68fa2645..d024be4e 100644
--- a/src/tagline.zig
+++ b/src/tagline.zig
@@ -286,10 +286,12 @@ pub fn wrapTag(arena: std.mem.Allocator, whole: []const u8, width: usize) !Shown
     return .{ .text = out.items, .soft = soft.items };
 }
 
-/// The tag's width for wrapping: its columns, one kept for the caret past
-/// a full row's end.
+/// The tag's width for wrapping: all its columns. A row the text fills
+/// exactly stays one row, as acme's frame wraps a box only when it is wider
+/// than what is left (libframe frutil.c _frcklinewrap), and the caret past
+/// its end sits at the edge (frptofchar.c clamps it to r.max.x).
 pub fn tagWidth(p: *const Pardes, id: usize) usize {
-    return @max(1, @as(usize, p.tagCapacity(p.rects[id].w -| TAG_TEXT_INSET)) -| 1);
+    return @max(1, @as(usize, p.tagCapacity(p.rects[id].w -| TAG_TEXT_INSET)));
 }
 
 pub fn shownTag(p: *Pardes, arena: std.mem.Allocator, pane: *Pane) !Shown {