tagbottom: the message row sits just above the tagline, not at the top

8 files changed, 128 insertions, 33 deletions

diff --git a/src/builtins.zig b/src/builtins.zig
index 934b3996..ee542e77 100644
--- a/src/builtins.zig
+++ b/src/builtins.zig
@@ -194,9 +194,9 @@ pub const Wrap = struct {
 /// Taglines at the BOTTOM of every pane instead of the top. Global like Wrap
 /// and for the same reason — a layout where some panes label themselves above
 /// and others below is unreadable, so it is one switch for the whole screen.
-/// The transient message row moves the other way to keep out of its way (see
-/// render), which puts the two strips of chrome at the ends they always were,
-/// just swapped.
+/// The transient message row gives that row up and takes the one above it (see
+/// render), so it is the pane's last BODY row either way and a prompt stays
+/// beside the tag it is typed into.
 pub const Tagbottom = struct {
     pub fn run(c: Ctx) void {
         c.p.tag_bottom = !c.p.tag_bottom;
diff --git a/src/pardes.zig b/src/pardes.zig
index 592dd059..ef606f23 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -12084,17 +12084,17 @@ pub const Pardes = struct {
             try p.renderPane(arena, pane, p.rects[id], id == p.active);
         }
 
-        // ---- the transient message row: the end away from the tag ----
+        // ---- the transient message row: the pane's last body row ----
         //
         // An OVERLAY, not geometry: no rect moves, no pane shrinks, and a pane
         // with neither a message nor an armed prompt is not touched at all.
         // Drawn after every pane's body so it lands OVER whatever that row was
-        // showing, and painted in the tag bar's own colours — it is the
-        // tagline's twin at the other end of the pane, and reading as chrome is
-        // what keeps it from being mistaken for content. Out here rather than
-        // at the end of renderPane because renderPane returns early for a
-        // native PDF page and for an image, and a `/` on a PDF is a real search
-        // whose prompt has to be visible like any other.
+        // showing, and painted across the whole row — it is the tagline's twin,
+        // and reading as one strip rather than a stamp on a body line is what
+        // keeps it from being mistaken for content. Out here rather than at the
+        // end of renderPane because renderPane returns early for a native PDF
+        // page and for an image, and a `/` on a PDF is a real search whose
+        // prompt has to be visible like any other.
         //
         // Exactly two things can occupy the row and an ARMED PROMPT beats a
         // MESSAGE, because they are not the same kind of thing: a message is a
@@ -12104,15 +12104,19 @@ pub const Pardes = struct {
         //
         // ponytail: the row is draw-only. A click on it lands wherever the body
         // under it says (tag clicks map to tag_col on the TAG row), so a prompt
-        // that moved down here cannot be clicked into or swept the way one on
-        // the tagline could — the keyboard still edits it in full. Upgrade path
+        // that moved off the tagline cannot be clicked into or swept the way it
+        // could up there — the keyboard still edits it in full. Upgrade path
         // is a hit test here that maps a press on this row to tag_col + the
         // marker offset, i.e. the tag row's own mapping with a constant added.
         for (&p.panes, 0..) |*slot, id| {
             const pane = slot.* orelse continue;
             const r = p.rects[id];
             // no body row (a one-row pane, or one squeezed out entirely): the
-            // tag row is not ours to overwrite, so the message just waits
+            // tag row is not ours to overwrite, so the message just waits. One
+            // guard for both placements, because the row picked below is the
+            // last BODY row either way — "the pane has a body row" is the whole
+            // condition, and it is what keeps r.h - 1 - BOX_H from underflowing
+            // or landing above the pane.
             if (r.w <= config.GUTTER or r.h <= BOX_H) continue;
             // the same one input model renderPane cut off the tagline; only one
             // of the two can ever be armed (a body key arms one, exitTagEdit
@@ -12128,10 +12132,13 @@ pub const Pardes = struct {
             if (text.len == 0 and !leader_here) continue;
             const tx = r.x + config.GUTTER;
             const tw = r.w - config.GUTTER;
-            // ...at the OTHER end from the tagline, whichever end that is:
-            // Tagbottom moved the tag onto this row, so the twin moves to the
-            // pane's first. They stay a pair with the body between them.
-            const row = if (p.tag_bottom) r.y else r.y + r.h - 1;
+            // the pane's last BODY row: its last row outright, or one up from
+            // that when Tagbottom has taken the last for the tagline. The first
+            // cut of Tagbottom sent this row to the pane's FIRST instead — the
+            // far end, symmetric with the tag — which put the prompt you are
+            // typing as far as the pane allows from the tag you are typing
+            // into. Beside the tagline is where it is read, so it stays there.
+            const row = if (p.tag_bottom) r.y + r.h - 1 - BOX_H else r.y + r.h - 1;
             // In the EDITOR's colours, not the tag bar's: this row is the one
             // place the program talks back to you about the buffer you are in,
             // and it reads as part of that buffer rather than as another strip
diff --git a/test/snapshots/tagbottom.golden b/test/snapshots/tagbottom.golden
index 27c6d42a..486390e2 100644
--- a/test/snapshots/tagbottom.golden
+++ b/test/snapshots/tagbottom.golden
@@ -277,7 +277,7 @@
 |
 |
 |  /tmp/pardes-snap/tagbottom/cwd/bottom.txt                         Save New Del
-== snap search-prompt grid=100x30 cursor=6,11
+== snap search-prompt grid=100x30 cursor=6,28
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
 |     2 bbb
 |     3 ccc
@@ -289,7 +289,7 @@
 |     9 iii
 |    10 jjj
 |  /tmp/pardes-snap/tagbottom/cwd/top.txt          bottom.txt                   Save New Del
-|   /ZZ
+|     1 ZZONE
 |     2 ZZTWO
 |
 |
@@ -306,7 +306,7 @@
 |
 |
 |
-|
+|   /ZZ
 |  /tmp/pardes-snap/tagbottom/cwd/bottom.txt                         Save New Del
 == snap leader grid=100x30 cursor=9,13
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
@@ -320,7 +320,7 @@
 |     9 iii
 |    10 jjj
 |  /tmp/pardes-snap/tagbottom/cwd/top.txt          bottom.txt                   Save New Del
-|                                                                                                 SPC
+|     1 ZZONE
 |     2 ZZTWO
 |
 |
@@ -337,7 +337,7 @@
 |
 |
 |
-|
+|                                                                                                 SPC
 |  /tmp/pardes-snap/tagbottom/cwd/bottom.txt                         Save New Del
 == snap cut-down grid=100x30 cursor=7,4
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
diff --git a/test/snapshots/tagbottom.snap b/test/snapshots/tagbottom.snap
index 389e0c36..5d30f7c6 100644
--- a/test/snapshots/tagbottom.snap
+++ b/test/snapshots/tagbottom.snap
@@ -1,6 +1,6 @@
-# Tagbottom: every pane's tagline on its LAST row instead of its first, and
-# the transient message row (prompts, messages, the SPC indicator) at the other
-# end with it. One global bool, so the whole screen flips at once.
+# Tagbottom: every pane's tagline on its LAST row instead of its first, and the
+# transient message row (prompts, messages, the SPC indicator) stepping up to
+# the row just above it. One global bool, so the whole screen flips at once.
 #
 # The two things worth pinning here are not pixels. The first is that a click
 # still lands where it looks like it lands: the Sel coordinate space is
@@ -96,9 +96,10 @@ release left 1 4
 stable 400 8000
 snap gutter-click
 # `/` in the lower pane's body arms the search input. The prompt is CUT off the
-# tagline and drawn on the message row with the cursor — and with Tagbottom
-# those two are at opposite ends of the pane: the tail keeps its builtins on
-# row 29 while `/ZZ` and the cursor sit up on row 11, the lower pane's first.
+# tagline and drawn on the message row with the cursor — and with Tagbottom the
+# two are adjacent: the tail keeps its builtins on row 29 while `/ZZ` and the
+# cursor sit on row 28, the last body row. The tagline under it stays whole —
+# the prompt must not have eaten the row it was cut from.
 press left 10 14
 release left 10 14
 stable 400 5000
diff --git a/test/snapshots/tagbottomimage.golden b/test/snapshots/tagbottomimage.golden
index 5508d01a..72b31809 100644
--- a/test/snapshots/tagbottomimage.golden
+++ b/test/snapshots/tagbottomimage.golden
@@ -91,9 +91,9 @@
 |27: 0-0 d,#121212, 1-9 d,#080808, 10-11 #6c6c6c,#959595, 12-12 #6c6c6c,#352879, 13-13 #352879,#6c6c6c, 14-14 #352879,#6c5eb5, 15-65 #352879,#352879, 66-74 d,#080808, 75-75 d,#444444, 76-76 d,#080808, 77-149 #bdbdbd,#080808,
 |28: 0-0 d,#121212, 1-9 d,#080808, 10-10 #6c6c6c,#352879, 11-11 #352879,#6c6c6c, 12-65 #352879,#352879, 66-74 d,#080808, 75-75 d,#444444, 76-76 d,#080808, 77-149 #bdbdbd,#080808,
 |29: 0-1 #ffffff,#626262, 2-56 #949494,#121212, 57-74 d,#121212, 75-76 #ffffff,#262626, 77-129 #949494,#121212, 130-149 d,#121212,
-== snap search-prompt grid=150x30 cursor=6,1
+== snap search-prompt grid=150x30 cursor=6,28
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|   /ZZ
+|          (f🬱]0V7R*%m🬶🬁G🬬tN#XR9q🬢tC#f/🬜_GR(🬞🬙tCRp$o*7^+[#H7s🬢YDZ🬝▟
 |          iU)dSotT[r27T"\*Fh▐🬅g,🬰p🬛▙🬲&*3/9xy🬛▀0kCg▛🬱C,>C}PC06m🬝▟█            pic.ppm
 |          "S▄;$gs,Xa▟T🬔s▖┼W▘?by🬋🬭uCR3/A3🬶lO▖▞🬃🬘╳🬟#=🬺🬕yoaJ@>4🬝🬵
 |          ─m!fAAD🬒jW>7JkR▄▜🬫🬞🬢FWx╲▟2ZT🬥/▖jteR?q🬶^🬅▀_@N─u4🬹🬝🬹
@@ -120,7 +120,7 @@
 |          eP🬗<┼A🬝🬹█
 |          ▀(u🬬🬝▟
 |          fc🬎🬹█
-|          🬝🬹
+|   /ZZ
 |  img /tmp/pardes-snap/tagbottomimage/cwd/pic.ppm New Del                    /tmp/pardes-snap/tagbottomimage/cwd           New Del
 == snap del-image grid=150x30 cursor=5,6
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
diff --git a/test/snapshots/tagbottomimage.snap b/test/snapshots/tagbottomimage.snap
index e46e19ba..8ac06d55 100644
--- a/test/snapshots/tagbottomimage.snap
+++ b/test/snapshots/tagbottomimage.snap
@@ -32,8 +32,8 @@ snapstyle img-bottom
 # `/` on an image pane. There is no text to search, and that is the point: the
 # prompt is drawn by the message-row pass, which runs OUTSIDE renderPane
 # precisely so an early-returning pane still gets one. With Tagbottom it lands
-# on the pane's FIRST row (grid 1), the end away from the tag — over the top
-# row of the art, not over the tagline that is now beneath it.
+# on the last row of the art (grid 28), just above the tagline on grid 29 —
+# over the picture, never over the tag it was cut from.
 key /
 send ZZ
 stable 600 8000
diff --git a/test/snapshots/tagbottomshort.golden b/test/snapshots/tagbottomshort.golden
new file mode 100644
index 00000000..599dd29b
--- /dev/null
+++ b/test/snapshots/tagbottomshort.golden
@@ -0,0 +1,38 @@
+== snap roomy grid=80x10 cursor=6,8
+|New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
+|     1 one
+|     2 two
+|     3 three
+|     4 four
+|     5 five
+|     6 six
+|
+|   /ZZ
+|  /tmp/pardes-snap/tagbottomshort/cwd/s.txt     Save New Del
+== snap two-body grid=80x4 cursor=6,2
+|New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
+|     1 one
+|   /ZZ
+|  /tmp/pardes-snap/tagbottomshort/cwd/s.txt     Save New Del
+== snap one-body grid=80x3 cursor=6,1
+|New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
+|   /ZZ
+|  /tmp/pardes-snap/tagbottomshort/cwd/s.txt     Save New Del
+== snap tag-only grid=80x2 cursor=64,1
+|New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
+|  /tmp/pardes-snap/tagbottomshort/cwd/s.txt     Save New Del
+== snap regrown grid=80x10 cursor=6,8
+|New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
+|     1 one
+|     2 two
+|     3 three
+|     4 four
+|     5 five
+|     6 six
+|
+|   /ZZ
+|  /tmp/pardes-snap/tagbottomshort/cwd/s.txt     Save New Del
+== snap leader-one-body grid=80x3 cursor=7,1
+|New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
+|                                                                             SPC
+|  /tmp/pardes-snap/tagbottomshort/cwd/s.txt     Save New Del
diff --git a/test/snapshots/tagbottomshort.snap b/test/snapshots/tagbottomshort.snap
new file mode 100644
index 00000000..a6ca2828
--- /dev/null
+++ b/test/snapshots/tagbottomshort.snap
@@ -0,0 +1,49 @@
+# The Tagbottom message row against a pane with almost no body. That row is the
+# pane's LAST BODY row — the tagline's neighbour once Tagbottom has taken the
+# last row — so it only exists while the pane HAS a body row. Two rows is the
+# smallest pane that does. One row is a tagline and nothing else, and there the
+# message waits: not drawn over the tag, and not on the row above the pane,
+# which is what `r.y + r.h - 1 - BOX_H` gives you when the guard is off by one.
+file s.txt one\ntwo\nthree\nfour\nfive\nsix
+start 10 80 s.txt
+wait 8000 s.txt
+stable 700 20000
+key space t b
+stable 700 15000
+# `/` with room to spare: the prompt is cut off the tagline (grid 9) and drawn
+# on grid 8, the last body row, with the cursor.
+key /
+send ZZ
+stable 600 8000
+stable 400 5000
+snap roomy
+# two body rows left; the prompt takes the lower one and line 1 still shows
+resize 4 80
+stable 700 10000
+snap two-body
+# one body row, and the prompt takes it. The tagline underneath must still be
+# drawn in full — this is where an off-by-one eats it.
+resize 3 80
+stable 700 10000
+snap one-body
+# the tagline alone. No body row, so nothing of the prompt is drawn anywhere —
+# not over the tag, not on the row above the pane. The tagline itself is
+# untouched: the marker sits after the builtins, so cutting the tail there
+# leaves every column of it exactly as `tag-only` would look unarmed.
+resize 2 80
+stable 700 10000
+snap tag-only
+# ...and grown back, still armed, back on the last body row
+resize 10 80
+stable 700 10000
+snap regrown
+key esc
+settle 100
+stable 400 5000
+# the SPC leader indicator rides the same row, right-aligned, and shrinks onto
+# the single body row with it
+resize 3 80
+stable 700 10000
+key space
+stable 400 8000
+snap leader-one-body