Documents: an open block keeps its look

The open field sits in the closed block's frame at its size, line
height and weight; headings keep their step. Code and math keep their
panel. Typewriter centering also keys on the ends' room, so a block
opened at the same height still centers.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/documents/document/look.rs

@@ -90,9 +90,9 @@ impl MarkdownDocument {
             block.size.height -= self.room;
         }
         let view = self.list.viewport_bounds();
-        // A new layout or a resize moves it too.
-        let heights =
-            [block.size.height, view.size.height].map(|height| f32::from(height).round() as u64);
+        // A new layout, a resize or the ends' room moves it.
+        let heights = [block.size.height, view.size.height, self.room]
+            .map(|height| f32::from(height).round() as u64);
         let moved = (ix, self.edits, self.typed, heights);
         if self.centered == Some(moved) {
             return;

src/documents/document/mod.rs

@@ -117,7 +117,7 @@ pub struct MarkdownDocument {
     /// Typewriter room past each end of the list.
     room: Pixels,
     /// The block, text, typing and heights last centered.
-    centered: Option<(usize, u64, u64, [u64; 2])>,
+    centered: Option<(usize, u64, u64, [u64; 3])>,
     focus: FocusHandle,
     /// A secondary press took focus.
     pointing: bool,

src/documents/document/tests/mod.rs

@@ -374,6 +374,7 @@ mod history;
 mod lend;
 mod links;
 mod look;
+mod open_look;
 mod place;
 mod point;
 mod presses;

src/documents/document/tests/open_look.rs

@@ -0,0 +1,73 @@
+//! An open block keeps its place and size (R7.5).
+
+use gpui::{Bounds, Modifiers, Pixels, TestAppContext, VisualTestContext, rems};
+
+use super::{open, press};
+use crate::documents::MarkdownMode;
+
+/// Block 0's bounds closed, then open.
+fn closed_then_open<'a>(
+    source: &str,
+    cx: &'a mut TestAppContext,
+) -> (Bounds<Pixels>, Bounds<Pixels>, &'a mut VisualTestContext) {
+    let (_, cx) = open(source, MarkdownMode::Visual, cx);
+    let closed = cx.debug_bounds("markdown-block-0").expect("drawn");
+    press(0, Modifiers::none(), cx);
+    let open = cx.debug_bounds("markdown-open").expect("the block opens");
+    (closed, open, cx)
+}
+
+/// Within a pixel: a field rounds its line height.
+fn near(a: Pixels, b: Pixels) -> bool {
+    (a - b).abs() < gpui::px(1.0)
+}
+
+#[gpui::test]
+fn an_open_paragraph_keeps_its_place_and_height(cx: &mut TestAppContext) {
+    let (closed, open, _) = closed_then_open("Plain words here.\n", cx);
+    assert!(
+        near(closed.top(), open.top()) && near(closed.left(), open.left()),
+        "{closed:?} {open:?}"
+    );
+    assert!(
+        near(closed.size.height, open.size.height),
+        "{closed:?} {open:?}"
+    );
+}
+
+#[gpui::test]
+fn an_open_heading_keeps_its_size(cx: &mut TestAppContext) {
+    let (closed, open, _) = closed_then_open("## Plain heading\n", cx);
+    assert!(
+        near(closed.top(), open.top()) && near(closed.left(), open.left()),
+        "{closed:?} {open:?}"
+    );
+    assert!(
+        near(closed.size.height, open.size.height),
+        "{closed:?} {open:?}"
+    );
+}
+
+#[gpui::test]
+fn an_open_code_block_keeps_its_panel(cx: &mut TestAppContext) {
+    let (closed, open, cx) = closed_then_open("```\nlet x = 1;\n```\n", cx);
+    assert!(
+        near(closed.top(), open.top()) && near(closed.left(), open.left()),
+        "{closed:?} {open:?}"
+    );
+    // The panel sits inside the frame's border and padding.
+    let (x, y) = cx.update(|window, _| {
+        let rem = window.rem_size();
+        (rems(0.75).to_pixels(rem), rems(0.25).to_pixels(rem))
+    });
+    let panel = cx.debug_bounds("markdown-open-text").expect("drawn");
+    let border = gpui::px(1.0);
+    assert!(
+        near(panel.left(), closed.left() + border + x),
+        "{panel:?} {closed:?}"
+    );
+    assert!(
+        near(panel.top(), closed.top() + border + y),
+        "{panel:?} {closed:?}"
+    );
+}

src/documents/document/visual.rs

@@ -2,14 +2,14 @@ use gpui::{
     AnyElement, App, ClickEvent, Context, ExternalPaths, FontWeight, InteractiveElement,
     IntoElement, KeyBinding, MouseButton, MouseDownEvent, ParentElement, Render,
     StatefulInteractiveElement, Styled, StyledText, Window, actions, div, list,
-    prelude::FluentBuilder as _,
+    prelude::FluentBuilder as _, relative,
 };
 
-use super::{MarkdownDocument, edit::Landing};
+use super::{MarkdownDocument, edit::Landing, parse::Block};
 use crate::{
     documents::{
-        MarkdownMode,
-        render::{Hooks, OpenCell, Pointed, draw_nodes, point_lines},
+        MarkdownMode, TargetBlock,
+        render::{HEAVY, Hooks, OpenCell, Pointed, draw_nodes, heading_step, point_lines},
     },
     forms::{self, Down, Up},
     primitives::FocusRing as _,
@@ -72,22 +72,9 @@ impl MarkdownDocument {
         // Focus fades all but the reader's block.
         let faded = self.look.focus && editing_mode(self.mode) && ix != self.current_block(cx);
         let open = self.open.as_ref();
-        let point = Self::point_in_open(cx);
-        let field = |open: &super::Open| {
-            div()
-                .debug_selector(|| "markdown-open".to_string())
-                .on_mouse_down(MouseButton::Right, point)
-                .text_size(body)
-                .px_3()
-                .py_2()
-                .rounded(radius)
-                .bg(colors.sunken)
-                .child(open.input.clone())
-                .into_any_element()
-        };
         let Some(block) = self.parsed.blocks.get(ix) else {
             return match (open, editing) {
-                (Some(open), _) if open.append => field(open),
+                (Some(open), _) if open.append => self.field(open, None, cx),
                 (_, true) => self
                     .pressable(div().id("more").min_h_8(), None, cx)
                     .into_any_element(),
@@ -95,7 +82,7 @@ impl MarkdownDocument {
             };
         };
         if let Some(open) = open.filter(|open| open.cell.is_none() && open.range == block.range) {
-            return field(open);
+            return self.field(open, Some(block), cx);
         }
         // A cell open in this block, typed in place.
         let cell = open.and_then(|open| {
@@ -168,6 +155,56 @@ impl MarkdownDocument {
         }
     }
 
+    /// The open block in its closed frame, size and weight.
+    fn field(
+        &self,
+        open: &super::Open,
+        block: Option<&Block>,
+        cx: &mut Context<Self>,
+    ) -> AnyElement {
+        let point = Self::point_in_open(cx);
+        let theme = cx.theme();
+        let colors = theme.colors.clone();
+        let body = theme.text_size(TextSize::Base) * self.look.scale;
+        let text = div()
+            .debug_selector(|| "markdown-open-text".to_string())
+            .text_size(body)
+            .line_height(body * 1.6)
+            .text_color(colors.fg);
+        let text = match block.map(|block| (block.kind, block.nodes.is_some())) {
+            Some((TargetBlock::Heading(level), true)) => text
+                .pt_2()
+                .text_size(body * heading_step(level))
+                .line_height(relative(1.3))
+                .font_weight(HEAVY)
+                .when(level == 6, |text| text.text_color(colors.fg_muted)),
+            // Code and math keep their panel.
+            Some((kind @ (TargetBlock::Code | TargetBlock::Math), true)) => text
+                .p_3()
+                .rounded(theme.radius(Radius::Md))
+                .bg(colors.sunken)
+                .when(kind == TargetBlock::Code, |text| {
+                    text.font_family(theme.mono_family.clone())
+                        .text_size(theme.text_size(TextSize::Sm) * self.look.scale)
+                }),
+            // Written as is: mono and muted.
+            Some((_, false)) => text
+                .font_family(theme.mono_family.clone())
+                .line_height(gpui::phi())
+                .text_color(colors.fg_muted),
+            _ => text,
+        };
+        div()
+            .debug_selector(|| "markdown-open".to_string())
+            .on_mouse_down(MouseButton::Right, point)
+            .px_3()
+            .py_1()
+            .border_1()
+            .border_color(gpui::transparent_black())
+            .child(text.child(open.input.clone()))
+            .into_any_element()
+    }
+
     /// A right press in the open field points there.
     fn point_in_open(
         cx: &mut Context<Self>,

src/documents/render.rs

@@ -102,7 +102,18 @@ pub(crate) struct Hooks<'a> {
 }
 
 /// Headings and strong text share one weight.
-const HEAVY: FontWeight = FontWeight::BOLD;
+pub(crate) const HEAVY: FontWeight = FontWeight::BOLD;
+
+/// Typora's heading steps over the body.
+pub(crate) fn heading_step(level: u8) -> f32 {
+    match level {
+        1 => 2.25,
+        2 => 1.75,
+        3 => 1.5,
+        4 => 1.25,
+        _ => 1.0,
+    }
+}
 
 /// How one inline style draws.
 fn highlight(style: &Style, colors: &Palette, rule: Pixels) -> HighlightStyle {
@@ -234,15 +245,8 @@ impl Draw<'_> {
                 .child(self.inline(inline, cx))
                 .into_any_element(),
             Node::Heading(level, inline) => {
-                // Typora's steps over the body; every level bold.
-                let step = match level {
-                    1 => 2.25,
-                    2 => 1.75,
-                    3 => 1.5,
-                    4 => 1.25,
-                    _ => 1.0,
-                };
-                let size = theme.text_size(self.body) * step * self.scale;
+                // Every level bold.
+                let size = theme.text_size(self.body) * heading_step(*level) * self.scale;
                 let ordinal = self.headings.get();
                 self.headings.set(ordinal + 1);
                 let heading = div()

src/editor/tests/wide.rs

@@ -52,7 +52,8 @@ fn an_input_method_edit_measures_before_the_next_draw(cx: &mut TestAppContext) {
     let (editor, cx) = editor("(a)", cx);
     cx.run_until_parked();
     editor.update_in(cx, |editor, window, cx| {
-        editor.select([0..0], cx);
+        let start = 0..0;
+        editor.select([start], cx);
         editor.replace_and_mark_text_in_range(None, "测", None, window, cx);
         let text = editor.row_text(0).to_string();
         for (range, _) in editor.styles(0, cx) {