Repaint PDF highlights by row, send rasters by shared memory, and animate messages

PDF highlights (hover preview, search, selection) are baked into page rasters,
and any change re-rendered the whole page with MuPDF; the TTY then re-sent it
as base64 (4.7 MB a page), the GUI as a new texture. Worse, a pointer motion
over a PDF invalidated the page even when no preview was shown, so every
motion paid that. Now:

- A raster whose baked highlight set equals the wanted one is left alone.
- A highlighted page keeps its clean rows (before highlights and tint); a
  change repaints only the rows of quads that differ, running MuPDF's
  highlight pass (pardes_pdf_paint_highlights) over those clean rows and
  tinting them: the operations a full render performs, so the pixels are
  identical. MuPDF band renders are NOT bit-identical to a whole page (edge
  rows, resampled images), so they are never used to patch; the comment
  claiming otherwise is corrected.
- ImagePlace.patch hands shells the changed rows; the GUI uploads just those
  rows into the texture it holds.
- The TTY probes kitty shared memory (t=s) with an id vaxis never reaches and
  sends rasters as a /dev/shm name when the terminal reads it; direct base64
  otherwise (ssh).
- Shells that take row patches (GUI, TTY with shm) repaint a selection while
  it is dragged instead of only on release.

Latency elsewhere:
- TTY: an animating frame no longer sleeps 16 ms blind; a tick thread posts
  into the input queue, so input inside the frame is handled at once.
- TTY and GUI: queued pointer motions coalesce to the last.
- GUI: a skipped swapchain image re-arms the frame (3 retries); animations
  still tick while nothing presents.
- Editing: the line index is carried across an edit instead of rebuilt from
  a scan of the whole file per keystroke.

Messages fall into their row (ease-in; the GUI slides the band out from under
the tagline, a terminal fades it), stay until the next input as before, linger
MessageLinger ms (default 800), and dissolve (ease-out). MessageAnimation
toggles it; both are settings, in Config and startup files. The snapshot
harness pins the old behaviour. The detached server now ticks animations.

A restored terminal comes back live: the old screen and scrollback (dumped
as clean VT by ghostty's formatter, replayed at the new size; older dumps
fall back to their rendered text), a dim
"restored history" marker, then a new shell in the directory it was in.

Right-click on a line number in a file pane looks at that line (a sticky
context header's number included).

Measured with an external pty driver (TTY), an in-process fence trace
(GUI, PARDES_TEST_LATENCY), and test/pdf_pointer_bench.zig (pixel identity
against the baseline and a whole-page oracle); balanced A/A/B rounds, paired
per-round statistics.

Messages stack: each event gets its own row and its own fall, linger and
dissolve; a line keeps its row until it leaves and a new one fills the first
free row. Announcements and statuses are replaced in place, not stacked.
MessageFall, MessageDissolve and DumpDir are settings Config reports.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

1 files changed, 63 insertions, 3 deletions

diff --git a/src/config.zig b/src/config.zig
index 98bbf3f4..527c3752 100644
--- a/src/config.zig
+++ b/src/config.zig
@@ -102,6 +102,11 @@ pub const leader_path = paths: {
         table.set(.TaglineSize, null);
     }
     if (pardes.platform == .gui) table.set(.Pet, null);
+    table.set(.MessageAnimation, null);
+    table.set(.MessageLinger, null);
+    table.set(.MessageFall, null);
+    table.set(.MessageDissolve, null);
+    table.set(.DumpDir, null);
     if (builtins.capabilities.window_opacity) table.set(.WindowOpacity, null);
     if (builtins.capabilities.window_blur) table.set(.WindowBlur, null);
     if (builtins.capabilities.panel_transitions) {
@@ -269,6 +274,10 @@ pub const wheel_cols: i32 = 4;
 
 pub const look_preview_delay_frames: ?u16 = 2;
 
+/// The longest any message timing (MessageLinger, MessageFall,
+/// MessageDissolve) may be set to, in milliseconds.
+pub const message_ms_max: u16 = 60_000;
+
 // Tag fonts keep body-cell geometry; valid sizes are 1...100 percent.
 pub const gui_tagline_font_percent: u8 = 82;
 comptime {
@@ -558,6 +567,17 @@ pub const Runtime = struct {
     syntax_bold: bool = false,
     /// Builtins announce themselves on the message row.
     verbose: bool = true,
+    /// A message falls into its row and dissolves out of it.
+    message_animation: bool = true,
+    /// How long a message stays after the key or click that dismisses it.
+    message_linger_ms: u16 = 800,
+    /// How long its ease-in fall into the row takes.
+    message_fall_ms: u16 = 180,
+    /// How long its ease-out dissolve takes.
+    message_dissolve_ms: u16 = 300,
+    /// Where Dump writes and a relative Restore looks; empty is the default
+    /// ($XDG_DATA_HOME/pardes, else ~/.local/share/pardes).
+    dump_dir: Text(limits.host_path_cap) = .{},
     window_opacity: u8 = 100,
     window_blur: u8 = 0,
     window_opacity_pending: bool = true,
@@ -655,7 +675,10 @@ pub const Runtime = struct {
 
     pub const Capability = std.meta.FieldEnum(Capabilities);
 
-    pub const Toggle = enum { colors, wrap, tree_context_tag_style, tag_bottom, debug, focus_tint, column_tags, syntax_bold, verbose };
+    /// The message timings a setting word sets, each in milliseconds.
+    pub const MessageTime = enum { linger, fall, dissolve };
+
+    pub const Toggle = enum { colors, wrap, tree_context_tag_style, tag_bottom, debug, focus_tint, column_tags, syntax_bold, verbose, message_animation };
     pub const Scene = std.meta.FieldEnum(layout.SceneEffect);
 
     pub const Action = union(enum) {
@@ -666,6 +689,8 @@ pub const Runtime = struct {
         tagline_size,
         window_opacity,
         window_blur,
+        message_ms: MessageTime,
+        dump_dir,
         transition: layout.Transition,
         scene: Scene,
     };
@@ -679,7 +704,7 @@ pub const Runtime = struct {
             return switch (setting.action) {
                 // A toggle flips when it is a bare tagline word and SETS when
                 // it is given `on` or `off`, so the report is configuration.
-                .shell, .theme, .font, .tagline_size, .window_opacity, .window_blur, .toggle => true,
+                .shell, .theme, .font, .tagline_size, .window_opacity, .window_blur, .message_ms, .dump_dir, .toggle => true,
                 else => false,
             };
         }
@@ -703,6 +728,11 @@ pub const Runtime = struct {
         .{ .word = "ColumnTags", .action = .{ .toggle = .column_tags } },
         .{ .word = "SyntaxBold", .action = .{ .toggle = .syntax_bold } },
         .{ .word = "Verbose", .action = .{ .toggle = .verbose } },
+        .{ .word = "MessageAnimation", .action = .{ .toggle = .message_animation } },
+        .{ .word = "MessageLinger", .action = .{ .message_ms = .linger } },
+        .{ .word = "MessageFall", .action = .{ .message_ms = .fall } },
+        .{ .word = "MessageDissolve", .action = .{ .message_ms = .dissolve } },
+        .{ .word = "DumpDir", .action = .dump_dir },
         .{ .word = "Theme", .action = .theme },
         .{ .word = "Shell", .action = .shell },
         .{ .word = "Font", .action = .font, .availability = .font_picker },
@@ -827,6 +857,17 @@ pub const Runtime = struct {
                 if (percent > 100) return false;
                 state.window_blur = percent;
             },
+            // Bare, it returns to the default directory.
+            .dump_dir => if (!state.dump_dir.set(std.mem.trim(u8, argument orelse "", " \t\r\n"))) return false,
+            .message_ms => |which| {
+                const text = std.mem.trim(u8, argument orelse return false, " \t\r\n");
+                for (text) |byte| if (!std.ascii.isDigit(byte)) return false;
+                const ms = std.fmt.parseInt(u16, text, 10) catch return false;
+                if (ms > message_ms_max) return false;
+                switch (which) {
+                    inline else => |w| @field(state, "message_" ++ @tagName(w) ++ "_ms") = ms,
+                }
+            },
             .transition => |effect| state.toggleTransition(effect),
             .scene => |effect| switch (effect) {
                 inline else => |field| {
@@ -847,6 +888,9 @@ pub const Runtime = struct {
         compiled_default_shell: []const u8,
         gui_shader_source_mode: ?[]const u8 = null,
         hover_delay_frames: ?u16,
+        /// Where dumps go when `DumpDir` is unset; empty without a host
+        /// filesystem.
+        default_dump_dir: []const u8 = "",
         native_images: bool,
         capabilities: Capabilities,
         state: *const Runtime,
@@ -895,6 +939,13 @@ pub const Runtime = struct {
                 else
                     try out.print("{s} unsupported\n", .{setting.word});
             },
+            .dump_dir => {
+                const dir = if (state.dump_dir.len > 0) state.dump_dir.get() else context.default_dump_dir;
+                try out.print("{s} {s}\n", .{ setting.word, if (dir.len > 0) dir else "(none)" });
+            },
+            .message_ms => |which| try out.print("{s} {d}\n", .{ setting.word, switch (which) {
+                inline else => |w| @field(state, "message_" ++ @tagName(w) ++ "_ms"),
+            } }),
             .shell => {
                 const chosen = state.shell.requested.get();
                 try out.print(
@@ -993,7 +1044,7 @@ pub const Runtime = struct {
             for (settings[i + 1 ..]) |later|
                 try std.testing.expect(!std.mem.eql(u8, setting.word, later.word));
             try std.testing.expectEqual(switch (setting.action) {
-                .shell, .theme, .font, .tagline_size, .window_opacity, .window_blur, .toggle => true,
+                .shell, .theme, .font, .tagline_size, .window_opacity, .window_blur, .message_ms, .dump_dir, .toggle => true,
                 else => false,
             }, setting.takesArg());
         }
@@ -1152,6 +1203,8 @@ pub const Runtime = struct {
                 .tagline_size => "73",
                 .window_opacity => "85",
                 .window_blur => "40",
+                .message_ms => "1500",
+                .dump_dir => "~/dumps",
                 else => null,
             };
             try std.testing.expect(apply(&state, setting, argument));
@@ -1170,11 +1223,18 @@ pub const Runtime = struct {
                     .column_tags => "ColumnTags off\n",
                     .syntax_bold => "SyntaxBold on\n",
                     .verbose => "Verbose off\n",
+                    .message_animation => "MessageAnimation off\n",
                 },
                 .shell => "Shell requested (new panes) fish\n",
                 .tagline_size => "TaglineSize 73\n",
                 .window_opacity => "WindowOpacity 85 (pending)\n",
                 .window_blur => "WindowBlur 40\n",
+                .dump_dir => "DumpDir ~/dumps\n",
+                .message_ms => |which| switch (which) {
+                    .linger => "MessageLinger 1500\n",
+                    .fall => "MessageFall 1500\n",
+                    .dissolve => "MessageDissolve 1500\n",
+                },
                 .transition => |transition| switch (transition) {
                     .off => unreachable,
                     .slide => "Panel transition PanelSlide\n",