From 64c83b5460d30e108b11656c28d59ad914761cff Mon Sep 17 00:00:00 2001
From: facile pop culture reference <donotem@ilme.no>
Date: Sat, 1 Aug 2026 21:25:29 +0300
Subject: [PATCH] layout (no-draw) mode for tui

---
 src/lib.rs         | 154 ++++++++++++++++++++++++++++++---------------
 src/term/border.rs |   8 +--
 src/term/repeat.rs |  20 +++---
 src/term/scroll.rs |  90 +++++++++++++-------------
 4 files changed, 167 insertions(+), 105 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 48415ef..45d50a2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1325,21 +1325,45 @@ macro_rules! eval_xy (
         crossterm::event::read,
     };
 
-    impl Deref         for Tui { type Target = Buffer; fn deref (&self) -> &Buffer { &self.0 } }
-    impl DerefMut      for Tui { fn deref_mut (&mut self) -> &mut Buffer { &mut self.0 } }
-    impl AsMut<Buffer> for Tui { fn as_mut (&mut self) -> &mut Buffer { &mut self.0 } }
-    impl Wide<u16>     for Tui { fn w (&self) -> u16 { self.1.2 } }
-    impl Tall<u16>     for Tui { fn h (&self) -> u16 { self.1.3 } }
+    //impl Deref         for Tui { type Target = Buffer; fn deref (&self) -> &Buffer { &self.0 } }
+    //impl DerefMut      for Tui { fn deref_mut (&mut self) -> &mut Buffer { &mut self.0 } }
+    //impl AsMut<Buffer> for Tui { fn as_mut (&mut self) -> &mut Buffer { &mut self.0 } }
+    impl AsRef<XYWH<u16>> for Tui {
+        fn as_ref (&self) -> &XYWH<u16> {
+            match self {
+                Self::Draw(_, area) => area,
+                Self::Layout(area) => area
+            }
+        }
+    }
+
+    impl Wide<u16> for Tui {
+        fn w (&self) -> u16 { self.as_ref().2 }
+    }
+
+    impl Tall<u16> for Tui {
+        fn h (&self) -> u16 { self.as_ref().3 }
+    }
+
+    impl Xy<u16> for Tui {
+        fn x (&self) -> u16 { self.as_ref().0 }
+        fn y (&self) -> u16 { self.as_ref().1 }
+    }
+
     impl HasOrigin     for Tui { fn origin (&self) -> Azimuth { Azimuth::NW } }
-    impl Xy<u16>       for Tui { fn x (&self) -> u16 { self.1.0 } fn y (&self) -> u16 { self.1.1 } }
 
     /// Terminal output.
-    pub struct Tui(
-        /// Ratatui buffer; area is screen size
-        pub Buffer,
-        /// Current draw area
-        pub XYWH<u16>
-    );
+    pub enum Tui {
+        Draw (
+            /// Ratatui buffer; area is screen size
+            Buffer,
+            /// Current draw area
+            XYWH<u16>
+        ),
+        Layout (
+            XYWH<u16>
+        )
+    }
 
     impl Tui {
         pub fn setup_panic () {
@@ -1402,14 +1426,16 @@ macro_rules! eval_xy (
             disable_raw_mode().map_err(Into::into)
         }
         pub fn new (width: u16, height: u16) -> Self {
-            Self(Buffer::empty(Rect { x: 0, y: 0, width, height }), XYWH(0, 0, width, height))
+            Self::Draw(Buffer::empty(Rect { x: 0, y: 0, width, height }), XYWH(0, 0, width, height))
         }
         pub fn resize <W: Write> (&mut self, back: &mut CrosstermBackend<W>, width: u16, height: u16) {
             let size = Rect { x: 0, y: 0, width, height };
-            if self.0.area != size {
-                back.clear_region(ClearType::All).unwrap();
-                self.0.resize(size);
-                self.0.reset();
+            if let Self::Draw(buffer, ..) = self {
+                if buffer.area != size {
+                    back.clear_region(ClearType::All).unwrap();
+                    buffer.resize(size);
+                    buffer.reset();
+                }
             }
         }
         pub fn redraw <'b, W: Write> (
@@ -1417,20 +1443,25 @@ macro_rules! eval_xy (
             back: &mut CrosstermBackend<W>,
             mut next: &'b mut Self
         ) {
-            let updates = self.0.diff(&next.0);
-            back.draw(updates.into_iter()).expect("failed to render");
-            Backend::flush(back).expect("failed to flush output new");
-            std::mem::swap(self, &mut next);
-            next.0.reset();
+            if let Self::Draw(prev, ..) = self && let Self::Draw(next, ..) = next {
+                let updates = prev.diff(&next);
+                back.draw(updates.into_iter()).expect("failed to render");
+                Backend::flush(back).expect("failed to flush output new");
+                std::mem::swap(prev, next);
+                next.reset();
+            }
         }
         pub fn update (&mut self, callback: &impl Fn(&mut Cell, u16, u16)) -> XYWH<u16> {
-            for row in 0..self.h() {
-                let y = self.y() + row;
-                for col in 0..self.w() {
-                    let x = self.x() + col;
-                    if x < self.0.area.width && y < self.0.area.height {
-                        if let Some(cell) = self.0.cell_mut(Position { x, y }) {
-                            callback(cell, col, row);
+            let XYWH(x0, y0, w, h) = self.area();
+            if let Self::Draw(buffer, ..) = self {
+                for row in 0..h {
+                    let y = y0 + row;
+                    for col in 0..w {
+                        let x = x0 + col;
+                        if x < buffer.area.width && y < buffer.area.height {
+                            if let Some(cell) = buffer.cell_mut(Position { x, y }) {
+                                callback(cell, col, row);
+                            }
                         }
                     }
                 }
@@ -1438,17 +1469,21 @@ macro_rules! eval_xy (
             self.xywh()
         }
         pub fn blit (&mut self, text: &impl AsRef<str>, x: u16, y: u16, style: Option<Style>) {
-            let text = text.as_ref();
-            let style = style.unwrap_or(Style::default());
-            if x < self.0.area.width && y < self.0.area.height {
-                self.0.set_string(x, y, text, style);
+            if let Self::Draw(buffer, ..) = self {
+                let text = text.as_ref();
+                let style = style.unwrap_or(Style::default());
+                if x < buffer.area.width && y < buffer.area.height {
+                    buffer.set_string(x, y, text, style);
+                }
             }
         }
         pub fn tint_all (&mut self, fg: Color, bg: Color, modifier: Modifier) {
-            for cell in self.0.content.iter_mut() {
-                cell.fg = fg;
-                cell.bg = bg;
-                cell.modifier = modifier;
+            if let Self::Draw(buffer, ..) = self {
+                for cell in buffer.content.iter_mut() {
+                    cell.fg = fg;
+                    cell.bg = bg;
+                    cell.modifier = modifier;
+                }
             }
         }
         /// Spawn the TUI output thread which writes colored characters to the terminal.
@@ -1488,7 +1523,7 @@ macro_rules! eval_xy (
                     prev.redraw(&mut backend, &mut next);
                 }
                 let timer = format!("{:>3.3}ms", perf.used.load(Relaxed));
-                prev.set_string(0, 0, &timer, Style::default());
+                prev.blit(&timer, 0, 0, Some(Style::default()));
             })?)
         }
         /// Draw TUI content or its error message.
@@ -1647,25 +1682,35 @@ macro_rules! eval_xy (
                 if string_width > max_width {
                     break
                 }
-                if let Some(cell) = self.0.cell_mut(ratatui::prelude::Position { x, y }) {
-                    cell.set_char(character);
-                } else {
-                    break
+                if let Self::Draw(buffer, ..) = self {
+                    if let Some(cell) = buffer.cell_mut(ratatui::prelude::Position { x, y }) {
+                        cell.set_char(character);
+                    } else {
+                        break
+                    }
                 }
             }
             Ok(Some(XYWH(x0, y, string_width, 1)))
         }
+
+        /// Get mutable reference to current clipping area
+        fn area_mut (&mut self) -> &mut XYWH<u16> {
+            match self {
+                Self::Draw(_, area) => area,
+                Self::Layout(area) => area,
+            }
+        }
     }
 
     impl Screen for Tui {
         type Unit = u16;
         /// Render drawable in subarea specified by `area`
         fn show (&mut self, content: impl Draw<Self>) -> Perhaps<XYWH<u16>> {
-            let previous_area = self.1;
-            Ok(if let Some(area) = content.layout(self.1)? {
-                self.1 = area;
+            let previous_area = self.area();
+            Ok(if let Some(area) = content.layout(self.area())? {
+                *self.area_mut() = area;
                 if let Some(result_area) = content.draw(self)? {
-                    self.1 = previous_area;
+                    *self.area_mut() = previous_area;
                     Some(result_area)
                 } else {
                     None
@@ -1677,7 +1722,10 @@ macro_rules! eval_xy (
 
         /// Get current clipping area
         fn area (&self) -> XYWH<Self::Unit> {
-            self.1
+            match self {
+                Self::Draw(_, area) => *area,
+                Self::Layout(area) => *area,
+            }
         }
 
         fn clip <T> (
@@ -1685,12 +1733,12 @@ macro_rules! eval_xy (
             area: impl Into<Option<XYWH<u16>>>,
             draw: impl FnOnce(&mut Self)->T
         ) -> T {
-            let prev = self.1;
+            let prev = self.area();
             if let Some(area) = area.into() {
-                self.1 = area.into();
+                *self.area_mut() = area.into();
             }
             let result = draw(self);
-            self.1 = prev;
+            *self.area_mut() = prev;
             result
         }
     }
@@ -1776,8 +1824,10 @@ macro_rules! eval_xy (
                     break
                 }
                 let pos = Position { x: x + width - 1, y };
-                if let Some(cell) = to.0.cell_mut(pos) {
-                    cell.set_char(c);
+                if let Tui::Draw(buffer, _) = to {
+                    if let Some(cell) = buffer.cell_mut(pos) {
+                        cell.set_char(c);
+                    }
                 }
                 width += c.width().unwrap_or(0) as u16;
             }
diff --git a/src/term/border.rs b/src/term/border.rs
index b38a5b7..d6c6cd7 100644
--- a/src/term/border.rs
+++ b/src/term/border.rs
@@ -8,7 +8,7 @@ use super::{*, draw::*};
 pub fn border (on: bool, style: impl BorderStyle, item: impl Draw<Tui>) -> impl Draw<Tui> {
     let content = item.pad_wh(1, 1);
     let outline = when(on, draw(move|to: &mut Tui|{
-        let XYWH(x, y, w, h) = to.1;
+        let XYWH(x, y, w, h) = to.area();
         if w > 0 && h > 0 {
             to.blit(&style.border_nw(), x, y, style.style());
             to.blit(&style.border_ne(), x + w - 1, y, style.style());
@@ -178,7 +178,7 @@ pub trait BorderStyle: Draw<Tui> + Copy {
             self.draw_v(to, None)?;
             self.draw_c(to, None)?;
         }
-        Ok(to.1)
+        Ok(to.area())
     }
     #[inline] fn draw_h (self, to: &mut Tui, style: Option<Style>) -> Usually<XYWH<u16>> {
         let style = style.or_else(||self.style_horizontal());
@@ -191,7 +191,7 @@ pub trait BorderStyle: Draw<Tui> + Copy {
         Ok(to.xywh())
     }
     #[inline] fn draw_v (self, to: &mut Tui, style: Option<Style>) -> Usually<XYWH<u16>> {
-        let area = to.1;
+        let area = to.area();
         let style = style.or_else(||self.style_vertical());
         let [x, x2, y, y2] = area.lrtb();
         let h = y2 - y;
@@ -207,7 +207,7 @@ pub trait BorderStyle: Draw<Tui> + Copy {
         Ok(area)
     }
     #[inline] fn draw_c (self, to: &mut Tui, style: Option<Style>) -> Usually<XYWH<u16>> {
-        let area = to.1;
+        let area = to.area();
         let style = style.or_else(||self.style_corners());
         let XYWH(x, y, w, h) = area;
         if w > 1 && h > 1 {
diff --git a/src/term/repeat.rs b/src/term/repeat.rs
index 0e5b812..16c6228 100644
--- a/src/term/repeat.rs
+++ b/src/term/repeat.rs
@@ -5,8 +5,10 @@ pub const fn x_repeat (c: &str) -> impl Draw<Tui> {
     draw(move|to: &mut Tui|{
         let XYWH(x, y, w, _h) = to.xywh();
         for x in x..x+w {
-            if let Some(cell) = to.0.cell_mut(Position::from((x, y))) {
-                cell.set_symbol(&c);
+            if let Tui::Draw(buf, ..) = to {
+                if let Some(cell) = buf.cell_mut(Position::from((x, y))) {
+                    cell.set_symbol(&c);
+                }
             }
         }
         Ok(Some(XYWH(x, y, w, 1)))
@@ -17,8 +19,10 @@ pub const fn y_repeat (c: &str) -> impl Draw<Tui> {
     draw(move|to: &mut Tui|{
         let XYWH(x, y, _w, h) = to.xywh();
         for y in y..y+h {
-            if let Some(cell) = to.0.cell_mut(Position::from((x, y))) {
-                cell.set_symbol(&c);
+            if let Tui::Draw(buf, ..) = to {
+                if let Some(cell) = buf.cell_mut(Position::from((x, y))) {
+                    cell.set_symbol(&c);
+                }
             }
         }
         Ok(Some(XYWH(x, y, 1, h)))
@@ -31,9 +35,11 @@ pub const fn xy_repeat (c: &str) -> impl Draw<Tui> {
         let a = c.len();
         for (_v, y) in (y..y+h).enumerate() {
             for (u, x) in (x..x+w).enumerate() {
-                if let Some(cell) = to.0.cell_mut(Position::from((x, y))) {
-                    let u = u % a;
-                    cell.set_symbol(&c[u..u+1]);
+                if let Tui::Draw(buf, ..) = to {
+                    if let Some(cell) = buf.cell_mut(Position::from((x, y))) {
+                        let u = u % a;
+                        cell.set_symbol(&c[u..u+1]);
+                    }
                 }
             }
         }
diff --git a/src/term/scroll.rs b/src/term/scroll.rs
index 83f761f..062602f 100644
--- a/src/term/scroll.rs
+++ b/src/term/scroll.rs
@@ -7,58 +7,64 @@ pub const ICON_DEC_H: &[char] = &[' ', '🞀', ' '];
 pub const ICON_INC_H: &[char] = &[' ', '🞂', ' '];
 
 pub fn x_scroll () -> impl Draw<Tui> {
-    draw(|Tui(buf, XYWH(x1, y1, w, _h)): &mut Tui|{
-        let x2 = *x1 + *w;
-        for (i, x) in (*x1..=x2).enumerate() {
-            if let Some(cell) = buf.cell_mut(Position::from((x, *y1))) {
-                if i < (ICON_DEC_H.len()) {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Rgb(0, 0, 0));
-                    cell.set_char(ICON_DEC_H[i as usize]);
-                } else if i > (*w as usize - ICON_INC_H.len()) {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Rgb(0, 0, 0));
-                    cell.set_char(ICON_INC_H[*w as usize - i]);
-                } else if false {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Reset);
-                    cell.set_char('━');
-                } else {
-                    cell.set_fg(Rgb(0, 0, 0));
-                    cell.set_bg(Reset);
-                    cell.set_char('╌');
+    draw(|to: &mut Tui|{
+        let XYWH(x1, y1, w, _h) = to.area();
+        let x2 = x1 + w;
+        for (i, x) in (x1..=x2).enumerate() {
+            if let Tui::Draw(buf, ..) = to {
+                if let Some(cell) = buf.cell_mut(Position::from((x, y1))) {
+                    if i < (ICON_DEC_H.len()) {
+                        cell.set_fg(Rgb(255, 255, 255));
+                        cell.set_bg(Rgb(0, 0, 0));
+                        cell.set_char(ICON_DEC_H[i as usize]);
+                    } else if i > (w as usize - ICON_INC_H.len()) {
+                        cell.set_fg(Rgb(255, 255, 255));
+                        cell.set_bg(Rgb(0, 0, 0));
+                        cell.set_char(ICON_INC_H[w as usize - i]);
+                    } else if false {
+                        cell.set_fg(Rgb(255, 255, 255));
+                        cell.set_bg(Reset);
+                        cell.set_char('━');
+                    } else {
+                        cell.set_fg(Rgb(0, 0, 0));
+                        cell.set_bg(Reset);
+                        cell.set_char('╌');
+                    }
                 }
             }
         }
-        Ok(Some(XYWH(*x1, *y1, *w, 1)))
+        Ok(Some(XYWH(x1, y1, w, 1)))
     })
 }
 
 pub fn y_scroll () -> impl Draw<Tui> {
-    draw(|Tui(buf, XYWH(x1, y1, _w, h)): &mut Tui|{
-        let y2 = *y1 + *h;
-        for (i, y) in (*y1..=y2).enumerate() {
-            if let Some(cell) = buf.cell_mut(Position::from((*x1, y))) {
-                if (i as usize) < (ICON_DEC_V.len()) {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Rgb(0, 0, 0));
-                    cell.set_char(ICON_DEC_V[i as usize]);
-                } else if (i as usize) > (*h as usize - ICON_INC_V.len()) {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Rgb(0, 0, 0));
-                    cell.set_char(ICON_INC_V[*h as usize - i]);
-                } else if false {
-                    cell.set_fg(Rgb(255, 255, 255));
-                    cell.set_bg(Reset);
-                    cell.set_char('‖'); // ━
-                } else {
-                    cell.set_fg(Rgb(0, 0, 0));
-                    cell.set_bg(Reset);
-                    cell.set_char('╎'); // ━
+    draw(|to: &mut Tui|{
+        let XYWH(x1, y1, _w, h) = to.area();
+        let y2 = y1 + h;
+        for (i, y) in (y1..=y2).enumerate() {
+            if let Tui::Draw(buf, ..) = to {
+                if let Some(cell) = buf.cell_mut(Position::from((x1, y))) {
+                    if (i as usize) < (ICON_DEC_V.len()) {
+                        cell.set_fg(Rgb(255, 255, 255));
+                        cell.set_bg(Rgb(0, 0, 0));
+                        cell.set_char(ICON_DEC_V[i as usize]);
+                    } else if (i as usize) > (h as usize - ICON_INC_V.len()) {
+                        cell.set_fg(Rgb(255, 255, 255));
+                        cell.set_bg(Rgb(0, 0, 0));
+                        cell.set_char(ICON_INC_V[h as usize - i]);
+                    } else if false {
+                        cell.set_fg(Rgb(255, 255, 255));
+                        cell.set_bg(Reset);
+                        cell.set_char('‖'); // ━
+                    } else {
+                        cell.set_fg(Rgb(0, 0, 0));
+                        cell.set_bg(Reset);
+                        cell.set_char('╎'); // ━
+                    }
                 }
             }
         }
-        Ok(Some(XYWH(*x1, *y1, 1, *h)))
+        Ok(Some(XYWH(x1, y1, 1, h)))
     })
 }