feat(mtext): integrate every inline format code in MTEXT renderer

Replace the line-based MTEXT pipeline with a run-aware parser + renderer.
Every DXF MTEXT inline code now reaches the stroke output: \H \W \Q \T \A
\C \c \f \F \M \X, the \p block (q/i/l/r/t/s), brace-scoped state, and
the \L\l \O\o \K\k decoration toggles.

Parser ([text_support]): emits Vec<MTextLine{ runs, align, indent_*,
tab_stops }> with per-run RunState; braces scope character state, paragraph
props persist across them.

Renderer ([mtext]): atomise → wrap → render. Per-run height/width/oblique/
tracking/font/colour/decorations/valign; paragraph indents and tab stops
honoured; default 4-em tab fallback.

Plumbing: tessellate() now returns Vec<WireModel>; TextStroke gains an
optional inline-colour override so per-run \C/\c emits one wire per colour.
cxf::tessellate_text_run adds a tracking multiplier. block_cache folds
multi-wire results into a single LocalWire (colour split preserved at
top-level, flattened inside cached defns).

Co-Authored-By: Claude Opus 4.7 <[email protected]>

src/entities/attribute.rs

@@ -218,7 +218,7 @@ fn build_attr_truck(input: AttrTextInputs<'_>, document: &acadrust::CadDocument)
             &resolved.font_name,
             line,
         );
-        strokes_all.push(TextStroke { strokes, origin });
+        strokes_all.push(TextStroke { strokes, origin, color: None });
     }
     let _ = input.line_count; // round-trip only — recomputed above
 

src/entities/mtext.rs

@@ -1,10 +1,12 @@
 use acadrust::entities::{AttachmentPoint, DrawingDirection, MText};
+use acadrust::types::aci_table::aci_to_rgb;
 use glam::Vec3;
 
 use crate::command::EntityTransform;
 use crate::entities::common::{edit_prop as edit, ro_prop as ro, square_grip, triangle_grip};
 use crate::entities::text_support::{
-    measure_mtext_chars, resolve_text_style, split_mtext_lines, strip_mtext_codes, word_wrap,
+    parse_mtext_paragraphs, resolve_text_style, InlineColor, MTextRunKind, ParagraphAlign,
+    RunState, TabStop,
 };
 use crate::entities::traits::{Grippable, PropertyEditable, Transformable, TruckConvertible};
 use crate::scene::acad_to_truck::{TextStroke, TruckEntity, TruckObject};
@@ -75,50 +77,349 @@ fn drawing_dir_str(d: &DrawingDirection) -> &'static str {
     }
 }
 
+// ── Run-based MTEXT layout ──────────────────────────────────────────────────
+//
+// Layout proceeds in three passes:
+//   1. Atomise — turn each MTextLine.runs into a flat sequence of atoms
+//      (Word / Space / Tab) so the wrapper can operate at break boundaries
+//      while keeping per-character formatting state.
+//   2. Wrap   — accumulate atoms into sub-lines using paragraph indents
+//      (`indent_first` for the first sub-line, `indent_left` for
+//      continuations, `indent_right` shrinks the right edge). Each Tab
+//      jumps the cursor to the next tab stop (or the next 4-em default
+//      stop when none is defined).
+//   3. Render — for every sub-line: pick paragraph alignment + indent,
+//      walk atoms left → right, emit one TextStroke per Word using the
+//      atom's RunState (height / width / oblique / tracking / font /
+//      colour / decorations / valign).
+
+#[derive(Clone)]
+enum AtomKind {
+    Word(String),
+    Space,
+    Tab,
+}
+
+#[derive(Clone)]
+struct LayoutAtom {
+    kind: AtomKind,
+    state: RunState,
+}
+
+fn run_scale(state: &RunState, entity_h: f32, base_wf: f32) -> f32 {
+    (state.height_mul * entity_h / 9.0) * (state.width_mul * base_wf.abs())
+}
+
+fn resolve_font<'a>(state: &'a RunState, base: &'a str) -> &'a str {
+    state.font.as_deref().unwrap_or(base)
+}
+
+fn measure_word(text: &str, state: &RunState, entity_h: f32, base_wf: f32, base_font: &str) -> f32 {
+    let scale = run_scale(state, entity_h, base_wf);
+    let font_name = resolve_font(state, base_font);
+    let font = cxf::get_font(font_name);
+    let mut w = 0.0_f32;
+    for ch in text.chars() {
+        w += match font.glyph(ch) {
+            Some(g) => (g.advance + font.letter_spacing * state.tracking) * scale,
+            None => (6.0 + font.letter_spacing * state.tracking) * scale,
+        };
+    }
+    w
+}
+
+fn measure_space(state: &RunState, entity_h: f32, base_wf: f32, base_font: &str) -> f32 {
+    let scale = run_scale(state, entity_h, base_wf);
+    let font_name = resolve_font(state, base_font);
+    cxf::get_font(font_name).word_spacing * scale
+}
+
+fn atom_width(atom: &LayoutAtom, entity_h: f32, base_wf: f32, base_font: &str) -> f32 {
+    match &atom.kind {
+        AtomKind::Word(t) => measure_word(t, &atom.state, entity_h, base_wf, base_font),
+        AtomKind::Space => measure_space(&atom.state, entity_h, base_wf, base_font),
+        AtomKind::Tab => 0.0, // tabs jump the cursor explicitly during wrap / render
+    }
+}
+
+/// Cursor position after a `\t` atom: advance to the next user-defined tab
+/// stop that lies past `cur_x`, falling back to a 4-em default grid when no
+/// stop is reached.
+fn next_tab_position(cur_x: f32, tab_stops: &[TabStop], indent_left: f32, entity_h: f32) -> f32 {
+    let local = cur_x - indent_left; // tabs are measured from the content area's left edge
+    for ts in tab_stops {
+        if ts.position > local + 1e-4 {
+            return indent_left + ts.position;
+        }
+    }
+    let default_interval = entity_h * 4.0; // 4 em fallback, matches AutoCAD's "no tab stops"
+    let n = (local / default_interval).floor() + 1.0;
+    indent_left + n * default_interval
+}
+
+/// Break a flat MText paragraph atom stream into wrap-fit sub-lines.
+fn wrap_paragraph(
+    atoms: Vec<LayoutAtom>,
+    rect_w: f32,
+    indent_first: f32,
+    indent_left: f32,
+    indent_right: f32,
+    tab_stops: &[TabStop],
+    entity_h: f32,
+    base_wf: f32,
+    base_font: &str,
+) -> Vec<Vec<LayoutAtom>> {
+    if rect_w <= 0.0 {
+        return vec![atoms];
+    }
+    let mut sublines: Vec<Vec<LayoutAtom>> = Vec::new();
+    let mut cur: Vec<LayoutAtom> = Vec::new();
+    let mut cur_w = 0.0_f32;
+    let mut subline_idx: usize = 0;
+    let line_start_x = |idx: usize| if idx == 0 { indent_first } else { indent_left };
+    let line_max_w = |idx: usize| (rect_w - indent_right - line_start_x(idx)).max(0.0);
+
+    for atom in atoms {
+        match &atom.kind {
+            AtomKind::Word(_) => {
+                let w = atom_width(&atom, entity_h, base_wf, base_font);
+                let max_w = line_max_w(subline_idx);
+                if !cur.is_empty() && cur_w + w > max_w {
+                    while matches!(cur.last().map(|a| &a.kind), Some(AtomKind::Space)) {
+                        cur.pop();
+                    }
+                    sublines.push(std::mem::take(&mut cur));
+                    cur_w = 0.0;
+                    subline_idx += 1;
+                }
+                cur.push(atom);
+                cur_w += w;
+            }
+            AtomKind::Space => {
+                if cur.is_empty() {
+                    continue;
+                }
+                cur_w += atom_width(&atom, entity_h, base_wf, base_font);
+                cur.push(atom);
+            }
+            AtomKind::Tab => {
+                let start_x = line_start_x(subline_idx);
+                let new_w = next_tab_position(cur_w + start_x, tab_stops, indent_left, entity_h)
+                    - start_x;
+                let max_w = line_max_w(subline_idx);
+                if new_w > max_w && !cur.is_empty() {
+                    sublines.push(std::mem::take(&mut cur));
+                    cur_w = 0.0;
+                    subline_idx += 1;
+                } else {
+                    cur.push(atom);
+                    cur_w = new_w.min(max_w);
+                }
+            }
+        }
+    }
+    if !cur.is_empty() {
+        sublines.push(cur);
+    }
+    if sublines.is_empty() {
+        sublines.push(Vec::new());
+    }
+    sublines
+}
+
+fn line_total_width(
+    atoms: &[LayoutAtom],
+    entity_h: f32,
+    base_wf: f32,
+    base_font: &str,
+    line_start_x: f32,
+    indent_left: f32,
+    tab_stops: &[TabStop],
+) -> f32 {
+    let mut x = line_start_x;
+    for atom in atoms {
+        match atom.kind {
+            AtomKind::Tab => {
+                x = next_tab_position(x, tab_stops, indent_left, entity_h);
+            }
+            _ => x += atom_width(atom, entity_h, base_wf, base_font),
+        }
+    }
+    x - line_start_x
+}
+
+fn resolve_inline_color(c: &InlineColor) -> Option<[f32; 3]> {
+    match c {
+        InlineColor::Aci(idx) => {
+            aci_to_rgb(*idx).map(|(r, g, b)| [r as f32 / 255.0, g as f32 / 255.0, b as f32 / 255.0])
+        }
+        InlineColor::True(rgb) => Some(*rgb),
+    }
+}
+
+/// Wrap a run's glyph text with MTEXT decoration markers so cxf's
+/// `tessellate_text_run` emits the underline / overline / strikethrough
+/// strokes for us — keeps decoration geometry in one place rather than
+/// duplicating the y-position constants.
+fn decorated(text: &str, state: &RunState) -> String {
+    if !(state.underline || state.overline || state.strike) {
+        return text.to_string();
+    }
+    let mut s = String::with_capacity(text.len() + 6);
+    if state.underline {
+        s.push_str("\\L");
+    }
+    if state.overline {
+        s.push_str("\\O");
+    }
+    if state.strike {
+        s.push_str("\\K");
+    }
+    s.push_str(text);
+    if state.underline {
+        s.push_str("\\l");
+    }
+    if state.overline {
+        s.push_str("\\o");
+    }
+    if state.strike {
+        s.push_str("\\k");
+    }
+    s
+}
+
 fn to_truck(t: &MText, document: &acadrust::CadDocument) -> TruckEntity {
     let resolved_style = resolve_text_style(&t.style, document);
-    let font_name = resolved_style.font_name;
-    let font = cxf::get_font(&font_name);
-    // MText has no entity-level width/oblique override (those are MText format
-    // codes \W and \Q inside the value string, handled by `strip_mtext_codes`).
-    // Default rendering inherits both from the style. `is_backward` flips the
-    // width-factor sign so text reads right-to-left.
-    let base_wf = resolved_style.width_factor.max(0.01);
-    let style_width_factor = if resolved_style.is_backward { -base_wf } else { base_wf };
-    let style_oblique = resolved_style.oblique_angle;
-    let plain = strip_mtext_codes(&t.value);
-    let explicit_lines = split_mtext_lines(&plain);
-    let lines: Vec<String> = if t.rectangle_width > 0.0 {
-        // Measurement uses the magnitude only; the sign on style_width_factor
-        // is a render-time mirror flag, not a width scalar.
-        let scale = t.height as f32 / 9.0 * style_width_factor.abs();
-        let max_w = t.rectangle_width as f32;
-        explicit_lines
+    let base_font_name = resolved_style.font_name.clone();
+    let base_font = cxf::get_font(&base_font_name);
+    let base_wf_abs = resolved_style.width_factor.max(0.01);
+    let base_wf = if resolved_style.is_backward { -base_wf_abs } else { base_wf_abs };
+    let base_oblique = resolved_style.oblique_angle;
+    let entity_h = t.height as f32;
+    let rect_w = t.rectangle_width as f32;
+
+    // ── 1. Parse ────────────────────────────────────────────────────────────
+    let paragraphs = parse_mtext_paragraphs(&t.value, entity_h);
+
+    // ── 2. Atomise + wrap each paragraph into sub-lines ─────────────────────
+    struct SubLine {
+        atoms: Vec<LayoutAtom>,
+        align: Option<ParagraphAlign>,
+        indent_first: f32,
+        indent_left: f32,
+        indent_right: f32,
+        tab_stops: Vec<TabStop>,
+        is_first_in_paragraph: bool,
+    }
+
+    let mut sub_lines: Vec<SubLine> = Vec::new();
+    for para in &paragraphs {
+        // Flatten runs into atoms.
+        let mut atoms: Vec<LayoutAtom> = Vec::new();
+        for run in &para.runs {
+            match &run.kind {
+                MTextRunKind::Glyphs(text) => {
+                    let mut word = String::new();
+                    for ch in text.chars() {
+                        if ch == ' ' || ch == '\u{00A0}' {
+                            if !word.is_empty() {
+                                atoms.push(LayoutAtom {
+                                    kind: AtomKind::Word(std::mem::take(&mut word)),
+                                    state: run.state.clone(),
+                                });
+                            }
+                            atoms.push(LayoutAtom {
+                                kind: AtomKind::Space,
+                                state: run.state.clone(),
+                            });
+                        } else {
+                            word.push(ch);
+                        }
+                    }
+                    if !word.is_empty() {
+                        atoms.push(LayoutAtom {
+                            kind: AtomKind::Word(word),
+                            state: run.state.clone(),
+                        });
+                    }
+                }
+                MTextRunKind::Tab => {
+                    atoms.push(LayoutAtom {
+                        kind: AtomKind::Tab,
+                        state: run.state.clone(),
+                    });
+                }
+            }
+        }
+
+        // Trim leading + trailing Space atoms — the legacy renderer dropped
+        // edge whitespace via `String::trim()` after `strip_mtext_codes`, so
+        // line_w / cursor_start agree on what counts as the paragraph's
+        // visible content. Without this, a paragraph that ends with a stray
+        // space measures wider than it draws and centering / right-alignment
+        // appears off by half a space-width.
+        let first_word = atoms
             .iter()
-            .flat_map(|line| word_wrap(line, max_w, scale, font))
-            .collect()
-    } else {
-        explicit_lines
-    };
-    let n_lines = lines.len().max(1) as f32;
+            .position(|a| !matches!(a.kind, AtomKind::Space))
+            .unwrap_or(atoms.len());
+        atoms.drain(..first_word);
+        while matches!(atoms.last().map(|a| &a.kind), Some(AtomKind::Space)) {
+            atoms.pop();
+        }
+
+        let wrapped = wrap_paragraph(
+            atoms,
+            rect_w,
+            para.indent_first,
+            para.indent_left,
+            para.indent_right,
+            &para.tab_stops,
+            entity_h,
+            base_wf,
+            &base_font_name,
+        );
+        for (idx, atoms) in wrapped.into_iter().enumerate() {
+            sub_lines.push(SubLine {
+                atoms,
+                align: para.align,
+                indent_first: para.indent_first,
+                indent_left: para.indent_left,
+                indent_right: para.indent_right,
+                tab_stops: para.tab_stops.clone(),
+                is_first_in_paragraph: idx == 0,
+            });
+        }
+    }
+    if sub_lines.is_empty() {
+        sub_lines.push(SubLine {
+            atoms: Vec::new(),
+            align: None,
+            indent_first: 0.0,
+            indent_left: 0.0,
+            indent_right: 0.0,
+            tab_stops: Vec::new(),
+            is_first_in_paragraph: true,
+        });
+    }
+
+    // ── 3. Block geometry (line spacing, attachment, rotation) ──────────────
+    let n_lines = sub_lines.len().max(1) as f32;
     let ls_factor = if t.line_spacing_factor > 0.0 {
         t.line_spacing_factor as f32
     } else {
         1.0
     };
-    // AutoCAD DXF code 44 is a multiplier on the *default* baseline-to-baseline
-    // distance, which is 5/3 × text_height (≈ 1.667).  factor = 1.0 → single
-    // spacing, factor = 2.0 → double spacing, etc.
-    let line_h = t.height as f32 * ls_factor * (5.0 / 3.0) * font.line_spacing;
-    let h = t.height as f32;
-    // CXF glyphs sit on the baseline (y=0) and extend UP by `h` (cap height).
-    // Block top   = line-0 baseline + h
-    // Block bottom = last-line baseline = line-0 baseline − (n_lines−1)·line_h
-    //
-    // v_offset is the Y of line-0 baseline relative to the insertion point, so:
-    //   Top    attachment → block top    at insertion → v_offset = −h
-    //   Bottom attachment → block bottom at insertion → v_offset = (n_lines−1)·line_h
-    //   Middle attachment → block center at insertion → midpoint of the two above
+    // DXF code 44 — multiplier on the *default* baseline-to-baseline gap,
+    // which AutoCAD defines as 5/3 × text height (≈ 1.667). 1.0 → single
+    // spacing, 2.0 → double, etc.
+    let line_h = entity_h * ls_factor * (5.0 / 3.0) * base_font.line_spacing;
+    let h = entity_h;
+    // CXF glyphs sit on the baseline (y=0) and extend UP by `h`. v_offset
+    // is the Y of the first sub-line's baseline relative to the insertion
+    // point; pick it from the attachment-point's vertical anchor:
+    //   Top    → block top    at insertion → v_offset = −h
+    //   Bottom → block bottom at insertion → v_offset = (n−1) · line_h
+    //   Middle → midpoint of the two above
     let v_offset = match t.attachment_point {
         AttachmentPoint::TopLeft | AttachmentPoint::TopCenter | AttachmentPoint::TopRight => -h,
         AttachmentPoint::MiddleLeft
@@ -128,7 +429,7 @@ fn to_truck(t: &MText, document: &acadrust::CadDocument) -> TruckEntity {
         | AttachmentPoint::BottomCenter
         | AttachmentPoint::BottomRight => (n_lines - 1.0) * line_h,
     };
-    let h_anchor = match t.attachment_point {
+    let attach_h_anchor: f32 = match t.attachment_point {
         AttachmentPoint::TopCenter
         | AttachmentPoint::MiddleCenter
         | AttachmentPoint::BottomCenter => 0.5,
@@ -137,8 +438,8 @@ fn to_truck(t: &MText, document: &acadrust::CadDocument) -> TruckEntity {
         }
         _ => 0.0,
     };
+    let box_left = -attach_h_anchor * rect_w;
     let vertical_text = matches!(t.drawing_direction, DrawingDirection::TopToBottom);
-    // is_upside_down flips the text 180° around the insertion point.
     let rot = if resolved_style.is_upside_down {
         t.rotation as f32 + std::f32::consts::PI
     } else {
@@ -149,41 +450,138 @@ fn to_truck(t: &MText, document: &acadrust::CadDocument) -> TruckEntity {
     let ins_y = t.insertion_point.y;
     let insertion = Vec3::new(ins_x as f32, ins_y as f32, t.insertion_point.z as f32);
     let mut all_strokes: Vec<TextStroke> = Vec::new();
-    for (i, line) in lines.iter().enumerate() {
+
+    // ── 4. Render each sub-line ─────────────────────────────────────────────
+    for (i, sub) in sub_lines.iter().enumerate() {
         let li = i as f32;
-        // Compute line offset as f32 (small relative values), apply to f64 insertion point.
-        let (small_x, small_y) = if vertical_text {
-            let col_offset = li * t.height as f32 * 1.2;
+        let (line_base_x, line_base_y) = if vertical_text {
+            let col_offset = li * entity_h * 1.2;
             (
                 col_offset * cos_r + v_offset * (-sin_r),
                 col_offset * sin_r + v_offset * cos_r,
             )
         } else {
-            let line_y = -(li * line_h) + v_offset;
-            (line_y * (-sin_r), line_y * cos_r)
+            let ly = -(li * line_h) + v_offset;
+            (ly * (-sin_r), ly * cos_r)
         };
-        let line_w = if h_anchor > 0.0 {
-            let scale = t.height as f32 / 9.0 * style_width_factor.abs();
-            measure_mtext_chars(line, scale, font)
+
+        // Paragraph-content area: [content_left, content_right] relative to
+        // insertion point. With rect_w == 0 we have no box, so fall back to
+        // anchoring at the insertion point (legacy behaviour).
+        let content_left = if rect_w > 0.0 {
+            box_left + if sub.is_first_in_paragraph { sub.indent_first } else { sub.indent_left }
         } else {
             0.0
         };
-        let h_shift = -line_w * h_anchor;
-        let origin: [f64; 2] = [
-            ins_x + (small_x + h_shift * cos_r) as f64,
-            ins_y + (small_y + h_shift * sin_r) as f64,
-        ];
-        let strokes = cxf::tessellate_text_ex(
-            [0.0, 0.0],
-            t.height as f32,
-            rot,
-            style_width_factor,
-            style_oblique,
-            &font_name,
-            line,
+        let content_right = if rect_w > 0.0 {
+            box_left + rect_w - sub.indent_right
+        } else {
+            0.0
+        };
+
+        // Effective horizontal anchor for this sub-line: paragraph alignment
+        // (when explicitly set inline) wins, otherwise inherit from the
+        // entity attachment.
+        let line_anchor: f32 = match sub.align {
+            Some(ParagraphAlign::Left)
+            | Some(ParagraphAlign::Justify)
+            | Some(ParagraphAlign::Distribute) => 0.0,
+            Some(ParagraphAlign::Center) => 0.5,
+            Some(ParagraphAlign::Right) => 1.0,
+            None => attach_h_anchor,
+        };
+
+        let line_w = line_total_width(
+            &sub.atoms,
+            entity_h,
+            base_wf,
+            &base_font_name,
+            0.0,
+            sub.indent_left,
+            &sub.tab_stops,
         );
-        all_strokes.push(TextStroke { strokes, origin });
+
+        // Cursor X (relative to insertion point, pre-rotation) where the
+        // first atom starts. With a box: lay the line inside the paragraph
+        // content area at `line_anchor`. Without a box: anchor the line at
+        // the insertion point using the entity's attachment.
+        let cursor_start = if rect_w > 0.0 {
+            let content_w = (content_right - content_left).max(0.0);
+            content_left + (content_w - line_w) * line_anchor
+        } else if line_anchor > 0.0 {
+            -line_w * line_anchor
+        } else {
+            0.0
+        };
+
+        // Line's tallest run height (for valign offsets).
+        let line_max_h = sub
+            .atoms
+            .iter()
+            .map(|a| a.state.height_mul * entity_h)
+            .fold(entity_h, f32::max);
+
+        // Walk atoms left → right, emitting one TextStroke per Word atom.
+        let mut cursor_x = cursor_start;
+        for atom in &sub.atoms {
+            match &atom.kind {
+                AtomKind::Word(text) => {
+                    // Per-atom render parameters (composed with style baseline).
+                    let run_h = atom.state.height_mul * entity_h;
+                    let signed_wf = base_wf.signum() * atom.state.width_mul * base_wf.abs();
+                    let oblique = base_oblique + atom.state.oblique_rad;
+                    let font_name = resolve_font(&atom.state, &base_font_name);
+                    let tracking = atom.state.tracking;
+                    let valign_dy = match atom.state.valign {
+                        1 => (line_max_h - run_h) * 0.5,
+                        2 => line_max_h - run_h,
+                        _ => 0.0,
+                    };
+                    let color = atom.state.color.as_ref().and_then(resolve_inline_color);
+                    let body = decorated(text, &atom.state);
+
+                    // Translate (cursor_x, valign_dy) into world space at this
+                    // sub-line's baseline.
+                    let lx = cursor_x;
+                    let ly = valign_dy;
+                    let world_dx = lx * cos_r - ly * sin_r;
+                    let world_dy = lx * sin_r + ly * cos_r;
+                    let origin: [f64; 2] = [
+                        ins_x + (line_base_x + world_dx) as f64,
+                        ins_y + (line_base_y + world_dy) as f64,
+                    ];
+                    let strokes = cxf::tessellate_text_run(
+                        [0.0, 0.0],
+                        run_h,
+                        rot,
+                        signed_wf,
+                        oblique,
+                        tracking,
+                        font_name,
+                        &body,
+                    );
+                    all_strokes.push(TextStroke {
+                        strokes,
+                        origin,
+                        color,
+                    });
+                    cursor_x += measure_word(text, &atom.state, entity_h, base_wf, &base_font_name);
+                }
+                AtomKind::Space => {
+                    cursor_x += measure_space(&atom.state, entity_h, base_wf, &base_font_name);
+                }
+                AtomKind::Tab => {
+                    cursor_x = next_tab_position(
+                        cursor_x,
+                        &sub.tab_stops,
+                        sub.indent_left,
+                        entity_h,
+                    );
+                }
+            }
+        }
     }
+
     TruckEntity {
         object: TruckObject::Text(all_strokes),
         snap_pts: vec![(insertion, SnapHint::Insertion)],

src/entities/text.rs

@@ -141,7 +141,7 @@ fn to_truck(t: &Text, document: &acadrust::CadDocument) -> TruckEntity {
         &t.value,
     );
     TruckEntity {
-        object: TruckObject::Text(vec![TextStroke { strokes, origin }]),
+        object: TruckObject::Text(vec![TextStroke { strokes, origin, color: None }]),
         snap_pts: vec![(snap_pt, SnapHint::Insertion)],
         tangent_geoms: vec![],
         key_vertices: vec![],

src/entities/text_support.rs

@@ -176,6 +176,542 @@ pub fn resolve_dxf_special_chars(s: &str) -> String {
     out
 }
 
+// ──────────────────────────────────────────────────────────────────────────
+// Rich MTEXT parser — full inline format-code coverage
+//
+// Recognised codes (DXF MTEXT inline):
+//   Escapes:  \\  \{  \}  \~  \t  \P  \n  \N  \U+XXXX  \u+XXXX
+//   Toggles:  \L\l  \O\o  \K\k  (underline / overline / strike)
+//   State:    \H<v>[x];  \W<v>[x];  \Q<v>;  \T<v>[x];  \A<n>;
+//             \C<aci>;   \c<rgb>;
+//             \f<name>|b<0/1>|i<0/1>|c<n>|p<n>;   \F<file>;
+//             \M+<n>;    \X   \S<u><sep><l>;
+//   Paragraph: \p[xi<v>,l<v>,r<v>,q[lcrjd],t<positions>,s<v>...];
+//   Scope:    { ... }   push/pop full state
+// ──────────────────────────────────────────────────────────────────────────
+
+/// Paragraph alignment encoded inline via `\p...q[lcrjd]...;`.
+/// `Justify` / `Distribute` render as `Left` (full inter-word redistribution
+/// is not implemented in the stroke renderer).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum ParagraphAlign {
+    Left,
+    Center,
+    Right,
+    Justify,
+    Distribute,
+}
+
+/// Inline colour override (`\C` ACI or `\c` 24-bit true colour). Resolved to
+/// linear RGB at render time via the document's ACI table.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum InlineColor {
+    Aci(u8),
+    True([f32; 3]),
+}
+
+/// Tab-stop alignment kind (from `\pt<L|C|R><pos>` entries).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum TabKind {
+    Left,
+    Center,
+    Right,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct TabStop {
+    pub position: f32,
+    pub kind: TabKind,
+}
+
+/// Per-run formatting state. All fields are multipliers / overrides relative
+/// to the entity-level defaults; the renderer composes them with the resolved
+/// text style at draw time.
+#[derive(Clone, Debug, PartialEq)]
+pub struct RunState {
+    /// Multiplier on entity text height (`\H<v>x;` → ×v; `\H<v>;` → v / entity_h)
+    pub height_mul: f32,
+    /// Multiplier on the (signed) style width-factor (`\W<v>;` → set, `\Wx;` → ×)
+    pub width_mul: f32,
+    /// Absolute oblique angle override in radians (`\Q<deg>;`)
+    pub oblique_rad: f32,
+    /// Tracking multiplier on `font.letter_spacing` (`\T<v>;`)
+    pub tracking: f32,
+    /// Vertical alignment of the run within its line box (0=baseline / 1=center
+    /// / 2=top). Mainly used for fractions and superscript-like layout (`\A`).
+    pub valign: u8,
+    /// Font-name override, `None` ⇒ inherit the resolved style font.
+    pub font: Option<String>,
+    /// Colour override, `None` ⇒ inherit entity colour.
+    pub color: Option<InlineColor>,
+    pub underline: bool,
+    pub overline: bool,
+    pub strike: bool,
+}
+
+impl Default for RunState {
+    fn default() -> Self {
+        Self {
+            height_mul: 1.0,
+            width_mul: 1.0,
+            oblique_rad: 0.0,
+            tracking: 1.0,
+            valign: 0,
+            font: None,
+            color: None,
+            underline: false,
+            overline: false,
+            strike: false,
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub enum MTextRunKind {
+    /// Renderable glyph text (DXF specials resolved, decoration markers stripped).
+    Glyphs(String),
+    /// `\t` — jump the cursor to the next tab stop (or default tab interval).
+    Tab,
+}
+
+#[derive(Clone, Debug)]
+pub struct MTextRun {
+    pub kind: MTextRunKind,
+    pub state: RunState,
+}
+
+/// One paragraph of MTEXT after parsing. Each line is a sequence of runs that
+/// share text content + a snapshot of formatting state, plus paragraph-level
+/// layout (alignment, indents, tab stops). `\P` / `\n` / `\N` start a new
+/// line; paragraph properties carry forward until the next `\p...;` block.
+#[derive(Clone, Debug, Default)]
+pub struct MTextLine {
+    pub runs: Vec<MTextRun>,
+    pub align: Option<ParagraphAlign>,
+    pub indent_first: f32,
+    pub indent_left: f32,
+    pub indent_right: f32,
+    pub tab_stops: Vec<TabStop>,
+}
+
+impl MTextLine {
+    /// Concatenated glyph text across all runs (decorations / tabs ignored).
+    /// Useful for callers that only need an unstyled string (search, hit-test
+    /// previews, fallback paths).
+    pub fn plain_text(&self) -> String {
+        let mut s = String::new();
+        for r in &self.runs {
+            if let MTextRunKind::Glyphs(t) = &r.kind {
+                s.push_str(t);
+            }
+        }
+        s
+    }
+
+    pub fn is_blank(&self) -> bool {
+        self.runs.iter().all(|r| match &r.kind {
+            MTextRunKind::Glyphs(t) => t.trim().is_empty(),
+            MTextRunKind::Tab => false,
+        })
+    }
+}
+
+#[derive(Clone, Debug, Default)]
+struct ParagraphProps {
+    align: Option<ParagraphAlign>,
+    indent_first: f32,
+    indent_left: f32,
+    indent_right: f32,
+    tab_stops: Vec<TabStop>,
+}
+
+/// Parse a `\p...;` body. Comma-separated tokens, each with a single-letter
+/// kind prefix. Unknown tokens are skipped — anything we don't understand is
+/// silently dropped rather than poisoning the rest of the paragraph.
+fn parse_paragraph_block(body: &str, props: &mut ParagraphProps) {
+    // The legacy AutoCAD writer prefixes the block with a redundant `x`; skip
+    // it so it doesn't confuse the kind matcher.
+    let body = body.strip_prefix('x').unwrap_or(body);
+    for token in body.split(',') {
+        let token = token.trim();
+        let mut chars = token.chars();
+        let Some(kind) = chars.next() else { continue };
+        let rest: String = chars.collect();
+        match kind {
+            'q' | 'Q' => {
+                let sel = rest.chars().next().map(|c| c.to_ascii_lowercase());
+                props.align = match sel {
+                    Some('l') => Some(ParagraphAlign::Left),
+                    Some('c') => Some(ParagraphAlign::Center),
+                    Some('r') => Some(ParagraphAlign::Right),
+                    Some('j') => Some(ParagraphAlign::Justify),
+                    Some('d') => Some(ParagraphAlign::Distribute),
+                    _ => props.align,
+                };
+            }
+            'i' => {
+                if let Ok(v) = rest.parse::<f32>() {
+                    props.indent_first = v;
+                }
+            }
+            'l' => {
+                if let Ok(v) = rest.parse::<f32>() {
+                    props.indent_left = v;
+                }
+            }
+            'r' => {
+                if let Ok(v) = rest.parse::<f32>() {
+                    props.indent_right = v;
+                }
+            }
+            't' => {
+                // Tab list. Each entry may be prefixed with L / C / R to
+                // pick the tab kind; default is Left. The remainder is the
+                // position in drawing units.
+                props.tab_stops.clear();
+                for entry in rest.split(',') {
+                    let entry = entry.trim();
+                    if entry.is_empty() {
+                        continue;
+                    }
+                    let (kind, num_str) = match entry.chars().next() {
+                        Some(c @ ('L' | 'l')) => (TabKind::Left, &entry[c.len_utf8()..]),
+                        Some(c @ ('C' | 'c')) => (TabKind::Center, &entry[c.len_utf8()..]),
+                        Some(c @ ('R' | 'r')) => (TabKind::Right, &entry[c.len_utf8()..]),
+                        _ => (TabKind::Left, entry),
+                    };
+                    if let Ok(p) = num_str.parse::<f32>() {
+                        props.tab_stops.push(TabStop { position: p, kind });
+                    }
+                }
+            }
+            's' => {} // space-before — affects line spacing; ignored for now
+            _ => {}
+        }
+    }
+}
+
+/// Parse an unsigned 24-bit true-colour value into linear-ish [r,g,b] floats.
+/// AutoCAD packs `\c` as a 24-bit decimal: high byte = R, mid = G, low = B.
+fn parse_true_color(s: &str) -> Option<InlineColor> {
+    let n: u32 = s.trim().parse().ok()?;
+    let r = ((n >> 16) & 0xFF) as f32 / 255.0;
+    let g = ((n >> 8) & 0xFF) as f32 / 255.0;
+    let b = (n & 0xFF) as f32 / 255.0;
+    Some(InlineColor::True([r, g, b]))
+}
+
+/// Parse `\H` / `\W` / `\T` value. Returns `(value, is_relative)`; a trailing
+/// `x` marks a multiplier on the current state, otherwise the value is the
+/// absolute target (interpreted by the caller against entity defaults).
+fn parse_scalar_with_x_suffix(body: &str) -> Option<(f32, bool)> {
+    let body = body.trim();
+    let (num, is_rel) = if let Some(stripped) = body.strip_suffix('x').or_else(|| body.strip_suffix('X')) {
+        (stripped, true)
+    } else {
+        (body, false)
+    };
+    Some((num.trim().parse::<f32>().ok()?, is_rel))
+}
+
+/// Flush the glyph buffer as a `Glyphs` run on `line` using a snapshot of
+/// `state`. Resolves DXF `%%x` specials (degree / diameter / `%%nnn` literal
+/// unicode) so the renderer sees fully decoded text.
+fn flush_glyph_buf(line: &mut MTextLine, buf: &mut String, state: &RunState) {
+    if buf.is_empty() {
+        return;
+    }
+    let text = resolve_dxf_special_chars(&std::mem::take(buf));
+    line.runs.push(MTextRun {
+        kind: MTextRunKind::Glyphs(text),
+        state: state.clone(),
+    });
+}
+
+/// Walk the MTEXT value string and produce one [`MTextLine`] per visible
+/// paragraph (after stripping leading / trailing blank lines, as the legacy
+/// `split_mtext_lines` does). Every inline format code listed in the module
+/// header is recognised; unknown semicolon-terminated codes are stripped
+/// silently so future / vendor-specific extensions don't pollute the text.
+///
+/// `entity_height` is needed to translate absolute `\H<v>;` declarations into
+/// the height-multiplier representation carried in [`RunState`]; pass the
+/// MTEXT entity's `height` field.
+pub fn parse_mtext_paragraphs(s: &str, entity_height: f32) -> Vec<MTextLine> {
+    let mut lines: Vec<MTextLine> = Vec::new();
+    let mut current = MTextLine::default();
+    let mut buf = String::new();
+    let mut state = RunState::default();
+    let mut state_stack: Vec<RunState> = Vec::new();
+    let mut props = ParagraphProps::default();
+    // No props_stack — paragraph props persist across braces by design.
+    let entity_height = entity_height.max(1e-6);
+
+    let mut chars = s.chars().peekable();
+
+    let read_until_semi = |chars: &mut std::iter::Peekable<std::str::Chars>| -> String {
+        let mut out = String::new();
+        for c in chars.by_ref() {
+            if c == ';' {
+                break;
+            }
+            out.push(c);
+        }
+        out
+    };
+
+    while let Some(ch) = chars.next() {
+        match ch {
+            '\\' => match chars.peek().copied() {
+                // ── Line / paragraph break ────────────────────────────────
+                Some('P') | Some('n') | Some('N') => {
+                    chars.next();
+                    flush_glyph_buf(&mut current, &mut buf, &state);
+                    current.align = props.align;
+                    current.indent_first = props.indent_first;
+                    current.indent_left = props.indent_left;
+                    current.indent_right = props.indent_right;
+                    current.tab_stops = props.tab_stops.clone();
+                    lines.push(std::mem::take(&mut current));
+                }
+                // ── Whitespace literals ───────────────────────────────────
+                Some('~') => {
+                    chars.next();
+                    buf.push('\u{00A0}'); // nbsp — treated as a regular space by the wrap pass
+                }
+                Some('t') => {
+                    chars.next();
+                    flush_glyph_buf(&mut current, &mut buf, &state);
+                    current.runs.push(MTextRun {
+                        kind: MTextRunKind::Tab,
+                        state: state.clone(),
+                    });
+                }
+                // ── Unicode by hex code point ────────────────────────────
+                Some('U') | Some('u') => {
+                    chars.next();
+                    if chars.peek() == Some(&'+') {
+                        chars.next();
+                        let mut hex = String::with_capacity(6);
+                        for _ in 0..6 {
+                            match chars.peek() {
+                                Some(&c) if c.is_ascii_hexdigit() => {
+                                    hex.push(chars.next().unwrap());
+                                }
+                                _ => break,
+                            }
+                        }
+                        if chars.peek() == Some(&';') {
+                            chars.next();
+                        }
+                        if let Ok(n) = u32::from_str_radix(&hex, 16) {
+                            if let Some(c) = char::from_u32(n) {
+                                buf.push(c);
+                                continue;
+                            }
+                        }
+                    } else {
+                        // Bare `\U` / `\u` — strip to next `;`
+                        let _ = read_until_semi(&mut chars);
+                    }
+                }
+                // ── Stacked text \S<u><sep><l>; ──────────────────────────
+                Some('S') | Some('s') => {
+                    chars.next();
+                    let mut upper = String::new();
+                    let mut lower = String::new();
+                    let mut sep = '/';
+                    let mut in_lower = false;
+                    for c in chars.by_ref() {
+                        if c == ';' {
+                            break;
+                        }
+                        if !in_lower && (c == '/' || c == '^' || c == '#') {
+                            sep = c;
+                            in_lower = true;
+                        } else if in_lower {
+                            lower.push(c);
+                        } else {
+                            upper.push(c);
+                        }
+                    }
+                    buf.push_str(&upper);
+                    if !lower.is_empty() {
+                        buf.push(if sep == '#' { '/' } else { sep });
+                        buf.push_str(&lower);
+                    }
+                }
+                // ── Decoration toggles (state, not markers) ──────────────
+                Some('L') => { chars.next(); flush_glyph_buf(&mut current, &mut buf, &state); state.underline = true; }
+                Some('l') => { chars.next(); flush_glyph_buf(&mut current, &mut buf, &state); state.underline = false; }
+                Some('O') => { chars.next(); flush_glyph_buf(&mut current, &mut buf, &state); state.overline = true; }
+                Some('o') => { chars.next(); flush_glyph_buf(&mut current, &mut buf, &state); state.overline = false; }
+                Some('K') => { chars.next(); flush_glyph_buf(&mut current, &mut buf, &state); state.strike = true; }
+                Some('k') => { chars.next(); flush_glyph_buf(&mut current, &mut buf, &state); state.strike = false; }
+                // ── Literal backslash / braces ───────────────────────────
+                Some('\\') => { chars.next(); buf.push('\\'); }
+                Some('{') | Some('}') => { buf.push(chars.next().unwrap()); }
+                // ── Paragraph props ──────────────────────────────────────
+                Some('p') => {
+                    chars.next();
+                    let body = read_until_semi(&mut chars);
+                    parse_paragraph_block(&body, &mut props);
+                }
+                // ── Height ───────────────────────────────────────────────
+                Some('H') => {
+                    chars.next();
+                    let body = read_until_semi(&mut chars);
+                    if let Some((v, is_rel)) = parse_scalar_with_x_suffix(&body) {
+                        flush_glyph_buf(&mut current, &mut buf, &state);
+                        if is_rel {
+                            state.height_mul *= v;
+                        } else {
+                            state.height_mul = v / entity_height;
+                        }
+                    }
+                }
+                // ── Width factor ─────────────────────────────────────────
+                Some('W') => {
+                    chars.next();
+                    let body = read_until_semi(&mut chars);
+                    if let Some((v, is_rel)) = parse_scalar_with_x_suffix(&body) {
+                        flush_glyph_buf(&mut current, &mut buf, &state);
+                        if is_rel {
+                            state.width_mul *= v;
+                        } else {
+                            state.width_mul = v;
+                        }
+                    }
+                }
+                // ── Oblique angle (degrees → radians) ────────────────────
+                Some('Q') => {
+                    chars.next();
+                    let body = read_until_semi(&mut chars);
+                    if let Ok(deg) = body.trim().parse::<f32>() {
+                        flush_glyph_buf(&mut current, &mut buf, &state);
+                        state.oblique_rad = deg.to_radians();
+                    }
+                }
+                // ── Tracking ─────────────────────────────────────────────
+                Some('T') => {
+                    chars.next();
+                    let body = read_until_semi(&mut chars);
+                    if let Some((v, is_rel)) = parse_scalar_with_x_suffix(&body) {
+                        flush_glyph_buf(&mut current, &mut buf, &state);
+                        if is_rel {
+                            state.tracking *= v;
+                        } else {
+                            state.tracking = v;
+                        }
+                    }
+                }
+                // ── Vertical alignment ───────────────────────────────────
+                Some('A') => {
+                    chars.next();
+                    let body = read_until_semi(&mut chars);
+                    if let Ok(n) = body.trim().parse::<u8>() {
+                        flush_glyph_buf(&mut current, &mut buf, &state);
+                        state.valign = n.min(2);
+                    }
+                }
+                // ── ACI colour ───────────────────────────────────────────
+                Some('C') => {
+                    chars.next();
+                    let body = read_until_semi(&mut chars);
+                    if let Ok(n) = body.trim().parse::<u32>() {
+                        flush_glyph_buf(&mut current, &mut buf, &state);
+                        state.color = Some(InlineColor::Aci(n.min(255) as u8));
+                    }
+                }
+                // ── True colour ──────────────────────────────────────────
+                Some('c') => {
+                    chars.next();
+                    let body = read_until_semi(&mut chars);
+                    if let Some(col) = parse_true_color(&body) {
+                        flush_glyph_buf(&mut current, &mut buf, &state);
+                        state.color = Some(col);
+                    }
+                }
+                // ── Font (name + b/i/c/p flags) ──────────────────────────
+                Some('f') | Some('F') => {
+                    chars.next();
+                    let body = read_until_semi(&mut chars);
+                    // First `|`-separated field is the font name / file stem.
+                    let name = body.split('|').next().unwrap_or("").trim();
+                    if !name.is_empty() {
+                        flush_glyph_buf(&mut current, &mut buf, &state);
+                        // Strip extension if `\F` passed a file path.
+                        let stem = name
+                            .rsplit(['/', '\\'])
+                            .next()
+                            .unwrap_or(name)
+                            .split('.')
+                            .next()
+                            .unwrap_or(name);
+                        state.font = Some(stem.to_string());
+                    }
+                }
+                // ── Multibyte / codepage marker — strip silently ─────────
+                Some('M') => {
+                    chars.next();
+                    let _ = read_until_semi(&mut chars);
+                }
+                // ── Dimension MTEXT paragraph-end marker — strip silently
+                Some('X') => {
+                    chars.next();
+                }
+                // ── Unknown single-letter escape ─────────────────────────
+                Some(_) => {
+                    chars.next();
+                }
+                None => {}
+            },
+            // Scope push / pop — braces scope *character* state (font,
+            // colour, height, decorations, …). Paragraph properties
+            // (`\p...;`) are intentionally NOT scoped: AutoCAD treats them
+            // as paragraph-level layout that persists across braces, and
+            // real-world files routinely wrap inline `\pxqc;` inside a
+            // `{\fArial;…}` block while expecting the alignment to apply
+            // to the whole paragraph.
+            '{' => {
+                state_stack.push(state.clone());
+            }
+            '}' => {
+                if let Some(prev) = state_stack.pop() {
+                    flush_glyph_buf(&mut current, &mut buf, &state);
+                    state = prev;
+                }
+            }
+            '\r' => {}
+            '\n' => {
+                flush_glyph_buf(&mut current, &mut buf, &state);
+                current.align = props.align;
+                current.indent_first = props.indent_first;
+                current.indent_left = props.indent_left;
+                current.indent_right = props.indent_right;
+                current.tab_stops = props.tab_stops.clone();
+                lines.push(std::mem::take(&mut current));
+            }
+            other => buf.push(other),
+        }
+    }
+    flush_glyph_buf(&mut current, &mut buf, &state);
+    current.align = props.align;
+    current.indent_first = props.indent_first;
+    current.indent_left = props.indent_left;
+    current.indent_right = props.indent_right;
+    current.tab_stops = props.tab_stops.clone();
+    lines.push(current);
+
+    let start = lines.iter().position(|l| !l.is_blank()).unwrap_or(0);
+    let end = lines
+        .iter()
+        .rposition(|l| !l.is_blank())
+        .map(|i| i + 1)
+        .unwrap_or(0);
+    lines[start..end].to_vec()
+}
+
 pub fn strip_mtext_codes(s: &str) -> String {
     let mut out = String::with_capacity(s.len());
     let mut chars = s.chars().peekable();

src/entities/tolerance.rs

@@ -244,7 +244,7 @@ impl TruckConvertible for Tolerance {
         let origin = [self.insertion_point.x, self.insertion_point.y];
 
         Some(TruckEntity {
-            object: TruckObject::Text(vec![TextStroke { strokes, origin }]),
+            object: TruckObject::Text(vec![TextStroke { strokes, origin, color: None }]),
             snap_pts: vec![(snap_pt, SnapHint::Insertion)],
             tangent_geoms: vec![],
             key_vertices: vec![],

src/scene/acad_to_truck.rs

@@ -10,9 +10,15 @@ use crate::scene::wire_model::{SnapHint, TangentGeom};
 /// One group of glyph strokes with its world-space origin stored in f64.
 /// Strokes are in glyph-local space (origin = [0,0]) so that the large
 /// world offset can be subtracted with f64 precision in tessellate.rs.
+///
+/// `color`, when set, overrides the entity colour for just this group — used
+/// by MTEXT inline `\C` / `\c` per-run colour. Strokes sharing the same
+/// (color, None) override are merged into one WireModel downstream; runs with
+/// distinct colours emit their own WireModel.
 pub struct TextStroke {
     pub strokes: Vec<Vec<[f32; 2]>>,
     pub origin: [f64; 2],
+    pub color: Option<[f32; 3]>,
 }
 
 #[allow(dead_code)]

src/scene/block_cache.rs

@@ -401,9 +401,32 @@ fn tessellate_sub_local(
     // Pass `local_offset` as the f64 world-offset so tessellate subtracts it
     // before casting to f32 — same precision-preservation trick used for
     // top-level entities, applied per-defn.
-    let wire = tessellate::tessellate(
+    //
+    // tessellate() may emit multiple WireModels for a single sub-entity (e.g.
+    // MTEXT with inline `\C` / `\c` colour switches splits one entity into
+    // one wire per colour group). The block-defn cache stores a single
+    // LocalWire per sub-entity, so we fold the wires into one — points get
+    // concatenated with NaN separators, the primary colour comes from the
+    // first wire. Per-segment colour is lost inside cached block defns; for
+    // top-level MTEXT outside blocks the colour split is preserved via the
+    // hot path in `tessellate_entity`.
+    let mut wires_out = tessellate::tessellate(
         doc, h, sub, false, sub_color, pat_len, pat, lw_px, local_offset, anno_scale,
     );
+    if wires_out.is_empty() {
+        return None;
+    }
+    let mut wire = wires_out.remove(0);
+    for extra in wires_out {
+        if !wire.points.is_empty() && !extra.points.is_empty() {
+            wire.points.push([f32::NAN, f32::NAN, f32::NAN]);
+        }
+        wire.points.extend(extra.points);
+        wire.key_vertices.extend(extra.key_vertices);
+        wire.snap_pts.extend(extra.snap_pts);
+        wire.tangent_geoms.extend(extra.tangent_geoms);
+        wire.fill_tris.extend(extra.fill_tris);
+    }
 
     if wire.points.len() > 100_000 {
         return None;

src/scene/cxf.rs

@@ -226,6 +226,33 @@ pub fn tessellate_text_ex(
     oblique_angle: f32,
     font_name: &str,
     text: &str,
+) -> Vec<Vec<[f32; 2]>> {
+    tessellate_text_run(
+        origin,
+        height,
+        rotation,
+        width_factor,
+        oblique_angle,
+        1.0,
+        font_name,
+        text,
+    )
+}
+
+/// Like [`tessellate_text_ex`] but takes a `tracking` multiplier applied to
+/// the per-glyph `letter_spacing` advance. `tracking = 1.0` keeps the legacy
+/// behaviour; MTEXT's `\T<v>;` inline code routes here so per-run character
+/// spacing scales independently of the width factor.
+#[allow(clippy::too_many_arguments)]
+pub fn tessellate_text_run(
+    origin: [f32; 2],
+    height: f32,
+    rotation: f32,
+    width_factor: f32,
+    oblique_angle: f32,
+    tracking: f32,
+    font_name: &str,
+    text: &str,
 ) -> Vec<Vec<[f32; 2]>> {
     if text.is_empty() || height <= 0.0 {
         return vec![];
@@ -388,7 +415,7 @@ pub fn tessellate_text_ex(
                         }
                     } else {
                         // Partial digit sequence — advance as unknown glyph and move on
-                        cursor_x += (6.0 + font.letter_spacing) * wf;
+                        cursor_x += (6.0 + font.letter_spacing * tracking) * wf;
                         continue;
                     }
                 }
@@ -417,11 +444,11 @@ pub fn tessellate_text_ex(
                             .collect(),
                     );
                 }
-                cursor_x += (glyph.advance + font.letter_spacing) * wf;
+                cursor_x += (glyph.advance + font.letter_spacing * tracking) * wf;
             }
             None => {
                 warn_missing_glyph(font_name, render_ch);
-                cursor_x += (6.0 + font.letter_spacing) * wf;
+                cursor_x += (6.0 + font.letter_spacing * tracking) * wf;
             }
         }
     }

src/scene/mod.rs

@@ -4777,7 +4777,7 @@ fn tessellate_entity(
         } else {
             (0.0_f32, [0.0f32; 8])
         };
-        let mut wire = tessellate::tessellate(
+        let mut wires = tessellate::tessellate(
             document,
             h,
             e,
@@ -4789,8 +4789,11 @@ fn tessellate_entity(
             world_offset,
             1.0,
         );
-        wire.aabb = entity_aabb(e, world_offset);
-        return vec![wire];
+        let ab = entity_aabb(e, world_offset);
+        for w in &mut wires {
+            w.aabb = ab;
+        }
+        return wires;
     }
 
     let (entity_color, pattern_length, pattern, line_weight_px, aci) =
@@ -5066,7 +5069,7 @@ fn tessellate_entity(
                 let sub_aabb = entity_aabb(&sub, world_offset);
                 let sub_pattern_length = sub_pattern_length * pslt_factor;
                 let sub_pattern = sub_pattern.map(|v| v * pslt_factor);
-                let mut wire = tessellate::tessellate(
+                let mut wires = tessellate::tessellate(
                     document,
                     h,
                     &sub,
@@ -5078,10 +5081,12 @@ fn tessellate_entity(
                     world_offset,
                     anno_scale,
                 );
-                wire.name = h.value().to_string();
-                wire.aci = sub_aci;
-                wire.aabb = sub_aabb;
-                vec![wire]
+                for w in &mut wires {
+                    w.name = h.value().to_string();
+                    w.aci = sub_aci;
+                    w.aabb = sub_aabb;
+                }
+                wires
             })
             .collect();
         append_insert_attribute_wires(
@@ -5219,7 +5224,7 @@ fn tessellate_entity(
         }
     }
 
-    let mut base = tessellate::tessellate(
+    let mut bases = tessellate::tessellate(
         document,
         h,
         e,
@@ -5231,28 +5236,37 @@ fn tessellate_entity(
         world_offset,
         anno_scale,
     );
-    base.aci = aci;
-    base.aabb = aabb;
+    for b in &mut bases {
+        b.aci = aci;
+        b.aabb = aabb;
+    }
 
+    // Complex linetypes (with embedded shapes / text) expand the *base*
+    // polyline along its tangent. Text-type entities never have a complex
+    // linetype assigned, so we only consult the first wire here — multi-wire
+    // returns come exclusively from MTEXT colour splits which can't trigger
+    // this path.
     if let Some(clt) = crate::linetypes::complex_lt(lt_name) {
-        let mut wires = complex_lt::apply_along(
-            &base.name,
-            &base.points,
-            clt,
-            (lt_scale * pslt_factor).max(1e-4),
-            entity_color,
-            sel,
-            base.line_weight_px,
-        );
-        if !wires.is_empty() {
-            for w in &mut wires {
-                w.aabb = aabb;
+        if let Some(base) = bases.first() {
+            let mut wires = complex_lt::apply_along(
+                &base.name,
+                &base.points,
+                clt,
+                (lt_scale * pslt_factor).max(1e-4),
+                entity_color,
+                sel,
+                base.line_weight_px,
+            );
+            if !wires.is_empty() {
+                for w in &mut wires {
+                    w.aabb = aabb;
+                }
+                return wires;
             }
-            return wires;
         }
     }
 
-    vec![base]
+    bases
 }
 
 /// Build the 4 OBB corners (CCW: bl, br, tr, tl) of a Text / MText entity
@@ -5565,7 +5579,7 @@ fn append_insert_attribute_wires(
             sub_color
         };
         let sub_aabb = entity_aabb(&attr_entity, world_offset);
-        let mut wire = tessellate::tessellate(
+        let mut attr_wires = tessellate::tessellate(
             document,
             insert_handle,
             &attr_entity,
@@ -5579,10 +5593,12 @@ fn append_insert_attribute_wires(
         );
         // Use the INSERT's handle so selection / picking groups attribute
         // text with the parent insert instead of treating it as a stray text.
-        wire.name = insert_handle.value().to_string();
-        wire.aci = sub_aci;
-        wire.aabb = sub_aabb;
-        wires.push(wire);
+        for w in &mut attr_wires {
+            w.name = insert_handle.value().to_string();
+            w.aci = sub_aci;
+            w.aabb = sub_aabb;
+        }
+        wires.extend(attr_wires);
     }
 }
 

src/scene/tessellate.rs

@@ -112,7 +112,7 @@ pub fn tessellate(
     line_weight_px: f32,
     world_offset: [f64; 3],
     anno_scale: f32,
-) -> WireModel {
+) -> Vec<WireModel> {
     let color = if selected {
         WireModel::SELECTED
     } else {
@@ -145,7 +145,7 @@ pub fn tessellate(
     // MultiLeader is handled by scene/mod.rs since it emits multiple WireModels
     // (leader, text, frame, fill) with distinct colors.
     if let EntityType::Leader(leader) = entity {
-        return tessellate_leader_single(
+        return vec![tessellate_leader_single(
             document,
             handle,
             leader,
@@ -154,74 +154,141 @@ pub fn tessellate(
             line_weight_px,
             world_offset,
             anno_scale,
-        );
+        )];
     }
 
     // ── Try the truck path first ───────────────────────────────────────────
     if let Some(te) = convert(entity, document) {
         match te.object {
             // ── Text / MText: pre-tessellated glyph strokes ───────────────
+            //
+            // Strokes are pre-grouped by world origin (one TextStroke per
+            // line / per run / per fragment), each carrying an optional
+            // colour override produced by MTEXT inline `\C` / `\c`. We bin
+            // groups by override colour and emit one WireModel per bin so a
+            // single MTEXT can hand back N colour-distinct wires when the
+            // value mixes inline colours.
             TruckObject::Text(stroke_groups) => {
-                // Each TextStroke keeps its strokes in glyph-local space and
-                // its world origin as f64.  Subtract world_offset in f64 before
-                // casting to f32 so large UTM coordinates don't crush precision.
                 let [ox, oy, oz] = world_offset;
                 let elev = entity_z(entity) - oz as f32;
 
-                let mut points: Vec<[f32; 3]> = Vec::new();
-                let mut first = true;
-                // Annotation scale: scale glyph strokes relative to the text
-                // insertion point (first group's origin) so multi-line MText
-                // lines spread apart correctly as well as growing in size.
+                // anno_scale anchors at the first group's origin so multi-line
+                // MText lines spread apart correctly as they grow.
                 let ref_origin = stroke_groups
                     .first()
                     .map(|g| g.origin)
                     .unwrap_or([0.0, 0.0]);
                 let ref_lx = (ref_origin[0] - ox) as f32;
                 let ref_ly = (ref_origin[1] - oy) as f32;
+
+                // Selection forces a single uniform colour — never split.
+                let split_by_color = !selected;
+
+                // Bins: key = Some(rgb) or None (= inherit entity colour).
+                // Preserve insertion order so wire-emit ordering tracks the
+                // original glyph stream (useful for stable hit-test indexing).
+                let mut bins: Vec<(Option<[f32; 3]>, Vec<[f32; 3]>)> = Vec::new();
+                let mut bin_first: Vec<bool> = Vec::new();
+                let find_or_make =
+                    |key: Option<[f32; 3]>, bins: &mut Vec<(Option<[f32; 3]>, Vec<[f32; 3]>)>, firsts: &mut Vec<bool>| -> usize {
+                        if let Some(i) = bins.iter().position(|(k, _)| *k == key) {
+                            i
+                        } else {
+                            bins.push((key, Vec::new()));
+                            firsts.push(true);
+                            bins.len() - 1
+                        }
+                    };
+
                 for group in &stroke_groups {
                     let lx = (group.origin[0] - ox) as f32;
                     let ly = (group.origin[1] - oy) as f32;
                     let slx = (lx - ref_lx) * anno_scale + ref_lx;
                     let sly = (ly - ref_ly) * anno_scale + ref_ly;
+                    let bin_key = if split_by_color { group.color } else { None };
+                    let bi = find_or_make(bin_key, &mut bins, &mut bin_first);
+                    let pts = &mut bins[bi].1;
                     for stroke in &group.strokes {
                         if stroke.len() < 2 {
                             continue;
                         }
-                        if !first && !points.is_empty() {
-                            points.push([f32::NAN, f32::NAN, f32::NAN]);
+                        if !bin_first[bi] && !pts.is_empty() {
+                            pts.push([f32::NAN, f32::NAN, f32::NAN]);
                         }
-                        first = false;
+                        bin_first[bi] = false;
                         for &[x, y] in stroke {
-                            points.push([x * anno_scale + slx, y * anno_scale + sly, elev]);
+                            pts.push([x * anno_scale + slx, y * anno_scale + sly, elev]);
                         }
                     }
                 }
 
                 let snap_pts = offset_snap_pts(te.snap_pts, world_offset);
-                let [ox, oy, oz] = world_offset;
                 let key_vertices: Vec<[f32; 3]> = te
                     .key_vertices
                     .into_iter()
                     .map(|[x, y, z]| [(x - ox) as f32, (y - oy) as f32, (z - oz) as f32])
                     .collect();
-                return WireModel {
-                    name,
-                    points,
-                    color,
-                    selected,
-                    pattern_length: 0.0,
-                    pattern: [0.0; 8],
-                    line_weight_px,
-                    snap_pts,
-                    tangent_geoms: te.tangent_geoms,
-                    aci: 0,
-                    key_vertices,
-                    aabb: WireModel::UNBOUNDED_AABB,
-                    plinegen: true,
-                    vp_scissor: None,
-                    fill_tris: vec![],
-                };
+
+                // Empty input (no glyphs) → emit a single empty wire so the
+                // entity still has a hit-test target via snap_pts.
+                if bins.is_empty() {
+                    return vec![WireModel {
+                        name,
+                        points: Vec::new(),
+                        color,
+                        selected,
+                        pattern_length: 0.0,
+                        pattern: [0.0; 8],
+                        line_weight_px,
+                        snap_pts,
+                        tangent_geoms: te.tangent_geoms,
+                        aci: 0,
+                        key_vertices,
+                        aabb: WireModel::UNBOUNDED_AABB,
+                        plinegen: true,
+                        vp_scissor: None,
+                        fill_tris: vec![],
+                    }];
+                }
+
+                let bin_count = bins.len();
+                let mut out: Vec<WireModel> = Vec::with_capacity(bin_count);
+                for (idx, (override_rgb, pts)) in bins.into_iter().enumerate() {
+                    let wire_color = match override_rgb {
+                        Some([r, g, b]) => [r, g, b, color[3]],
+                        None => color,
+                    };
+                    // Snap points and key vertices belong to the entity as a
+                    // whole — attach them only to the first emitted wire so
+                    // pickers / hover don't double-count.
+                    let (snap, keys, tangents) = if idx == 0 {
+                        (
+                            snap_pts.clone(),
+                            key_vertices.clone(),
+                            te.tangent_geoms.clone(),
+                        )
+                    } else {
+                        (Vec::new(), Vec::new(), Vec::new())
+                    };
+                    out.push(WireModel {
+                        name: name.clone(),
+                        points: pts,
+                        color: wire_color,
+                        selected,
+                        pattern_length: 0.0,
+                        pattern: [0.0; 8],
+                        line_weight_px,
+                        snap_pts: snap,
+                        tangent_geoms: tangents,
+                        aci: 0,
+                        key_vertices: keys,
+                        aabb: WireModel::UNBOUNDED_AABB,
+                        plinegen: true,
+                        vp_scissor: None,
+                        fill_tris: vec![],
+                    });
+                }
+                return out;
             }
 
             // ── Standard topology objects ─────────────────────────────────
@@ -239,7 +306,7 @@ pub fn tessellate(
                                 [(kx - ox) as f32, (ky - oy) as f32, (kz - oz) as f32]
                             })
                             .collect();
-                        return WireModel {
+                        return vec![WireModel {
                             name,
                             points: vec![
                                 [x - s, y, z],
@@ -260,7 +327,7 @@ pub fn tessellate(
                             plinegen: true,
                             vp_scissor: None,
                             fill_tris: vec![],
-                        };
+                        }];
                     }
                     _ => {}
                 }
@@ -275,7 +342,7 @@ pub fn tessellate(
                         .into_iter()
                         .map(|[x, y, z]| [(x - ox) as f32, (y - oy) as f32, (z - oz) as f32])
                         .collect();
-                    return WireModel {
+                    return vec![WireModel {
                         name,
                         points,
                         color,
@@ -291,7 +358,7 @@ pub fn tessellate(
                         plinegen: true,
                         vp_scissor: None,
                         fill_tris: vec![],
-                    };
+                    }];
                 }
             }
 
@@ -304,7 +371,7 @@ pub fn tessellate(
                         .into_iter()
                         .map(|[x, y, z]| [(x - ox) as f32, (y - oy) as f32, (z - oz) as f32])
                         .collect();
-                    return WireModel {
+                    return vec![WireModel {
                         name,
                         points,
                         color,
@@ -320,7 +387,7 @@ pub fn tessellate(
                         plinegen: true,
                         vp_scissor: None,
                         fill_tris: vec![],
-                    };
+                    }];
                 }
             }
 
@@ -351,7 +418,7 @@ pub fn tessellate(
                     .into_iter()
                     .map(|[x, y, z]| [(x - ox) as f32, (y - oy) as f32, (z - oz) as f32])
                     .collect();
-                return WireModel {
+                return vec![WireModel {
                     name,
                     points: local_pts,
                     color,
@@ -367,7 +434,7 @@ pub fn tessellate(
                     plinegen: true,
                     vp_scissor: None,
                     fill_tris,
-                };
+                }];
             }
 
             TruckObject::SegmentedLines(points) => {
@@ -388,7 +455,7 @@ pub fn tessellate(
                     .into_iter()
                     .map(|[x, y, z]| [(x - ox) as f32, (y - oy) as f32, (z - oz) as f32])
                     .collect();
-                return WireModel {
+                return vec![WireModel {
                     name,
                     points: local_pts,
                     color,
@@ -404,7 +471,7 @@ pub fn tessellate(
                     vp_scissor: None,
                     aabb: WireModel::UNBOUNDED_AABB,
                     fill_tris: vec![],
-                };
+                }];
             }
 
             TruckObject::Volume(_) => {
@@ -427,14 +494,14 @@ pub fn tessellate(
                     let sp = Vec3::new((p.x - ox) as f32, (p.y - oy) as f32, (p.z - oz) as f32);
                     wm.snap_pts.push((sp, SnapHint::Insertion));
                 }
-                return wm;
+                return vec![wm];
             }
         }
     }
 
     // ── Legacy fallback for Viewport and other unhandled types ────────────
     let (points, snap_pts, tangent_geoms, key_vertices) = legacy_geometry(entity, world_offset);
-    WireModel {
+    vec![WireModel {
         name,
         points,
         color,
@@ -450,7 +517,7 @@ pub fn tessellate(
         plinegen: true,
         vp_scissor: None,
         fill_tris: vec![],
-    }
+    }]
 }
 
 pub fn tessellate_dimension(
@@ -1539,7 +1606,7 @@ pub fn tessellate_multileader(
             for sub in synth_ins.explode_from_document(document) {
                 let normalized =
                     crate::modules::home::modify::explode::normalize_insert_entity(sub);
-                let mut wire = tessellate(
+                let mut sub_wires = tessellate(
                     document,
                     handle,
                     &normalized,
@@ -1551,8 +1618,10 @@ pub fn tessellate_multileader(
                     world_offset,
                     1.0,
                 );
-                wire.name = name.clone();
-                wires.push(wire);
+                for w in &mut sub_wires {
+                    w.name = name.clone();
+                }
+                wires.extend(sub_wires);
             }
             // Block attributes attached to the multileader — render each as
             // its own attribute entity at WCS location like INSERT does.