fix(text): keep text anchors in f64 and honour space advance

Single-line TEXT and ATTRIB/ATTDEF cast the insertion/alignment point to
f32 before computing the stroke origin. At large coordinates (UTM ~4.5M)
the f32 ulp is ~0.5, snapping text baselines onto a coarse grid so
adjacent rows collapse onto each other and overlap. Keep the anchor in
f64 throughout.

Horizontal alignment now uses the pen advance box [0, advance] instead of
the inked min_x/max_x, so leading/trailing spaces keep their width and
space-aligned columns no longer shift. text_local_bounds returns
TextLocalBounds { ink_min, ink_max, advance }.

TABLE laid out its whole grid in an f32 world frame; switch to a local
f32 frame plus an f64 base added at the widening step, fixing cell-text
baseline snap and the i32 overflow in the border-dedup keys.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/entities/attribute.rs

@@ -255,17 +255,19 @@ fn build_attr_truck(input: AttrTextInputs<'_>, document: &acadrust::CadDocument)
             oblique_angle,
         );
         let (anchor_local_x, anchor_local_y) =
-            if let Some(([min_x, min_y], [max_x, max_y])) = bounds {
+            if let Some(b) = bounds {
+                // Horizontal anchor uses the pen advance box so leading /
+                // trailing spaces keep their width.
                 let ax = match input.horizontal_alignment {
-                    AHA::Left => min_x,
+                    AHA::Left => 0.0,
-                    AHA::Center | AHA::Middle => (min_x + max_x) * 0.5,
+                    AHA::Center | AHA::Middle => b.advance * 0.5,
-                    AHA::Right | AHA::Aligned | AHA::Fit => max_x,
+                    AHA::Right | AHA::Aligned | AHA::Fit => b.advance,
                 };
                 let ay = match input.vertical_alignment {
                     AVA::Baseline => 0.0,
-                    AVA::Bottom => min_y,
+                    AVA::Bottom => b.ink_min[1],
-                    AVA::Middle => (min_y + max_y) * 0.5,
+                    AVA::Middle => (b.ink_min[1] + b.ink_max[1]) * 0.5,
-                    AVA::Top => max_y,
+                    AVA::Top => b.ink_max[1],
                 };
                 (ax, ay)
             } else {

src/entities/table.rs

@@ -22,7 +22,17 @@ impl TruckConvertible for Table {
             return None;
         }
 
-        let origin = v3(&self.insertion_point);
+        // Lay the table out in a local frame with the origin at zero. The world
+        // insertion point is added back as f64 at the widening step below, so
+        // large coordinates (UTM etc.) keep full precision instead of snapping
+        // onto the coarse f32 grid — which would collide cell-text baselines and
+        // overflow the integer border-dedup keys.
+        let base = [
+            self.insertion_point.x,
+            self.insertion_point.y,
+            self.insertion_point.z,
+        ];
+        let origin = Vec3::ZERO;
         let h_raw = v3(&self.horizontal_direction);
         let h = if h_raw.length_squared() > 1e-10 {
             h_raw.normalize()
@@ -298,22 +308,22 @@ impl TruckConvertible for Table {
             }
         }
 
-        // Table currently does its layout in glam::Vec3 (f32). The world_offset
+        // The layout above is in a local f32 frame (small magnitudes). Widen to
-        // subtraction in tessellate.rs needs f64, so widen at the boundary —
+        // f64 and add the world insertion so the absolute position carries full
-        // precision is already limited by the f32 math above (separate fix-up).
+        // precision; tessellate.rs then applies world_offset.
         let pts_f64: Vec<[f64; 3]> = pts
             .into_iter()
             .map(|[x, y, z]| {
                 if x.is_nan() {
                     [f64::NAN, f64::NAN, f64::NAN]
                 } else {
-                    [x as f64, y as f64, z as f64]
+                    [x as f64 + base[0], y as f64 + base[1], z as f64 + base[2]]
                 }
             })
             .collect();
         Some(TruckEntity {
             object: TruckObject::Lines(pts_f64),
-            snap_pts: vec![(origin, SnapHint::Insertion)],
+            snap_pts: vec![(v3(&self.insertion_point), SnapHint::Insertion)],
             tangent_geoms: vec![],
             key_vertices: vec![],
             fill_tris: vec![],

src/entities/text.rs

@@ -87,15 +87,19 @@ fn to_truck(t: &Text, document: &acadrust::CadDocument) -> TruckEntity {
     } else {
         resolved_style.oblique_angle
     };
-    let anchor = match (
+    // Anchor stays f64: large coordinates (UTM etc.) lose ~0.5 units of
+    // precision when cast to f32, which snaps text baselines onto a coarse
+    // grid and makes adjacent rows collide. Only the small local offsets
+    // below are computed in f32.
+    let anchor: [f64; 2] = match (
         &t.horizontal_alignment,
         &t.vertical_alignment,
         &t.alignment_point,
     ) {
-        (HA::Aligned | HA::Middle | HA::Fit, _, Some(a)) => [a.x as f32, a.y as f32],
+        (HA::Aligned | HA::Middle | HA::Fit, _, Some(a)) => [a.x, a.y],
-        (HA::Center | HA::Right, _, Some(a)) => [a.x as f32, a.y as f32],
+        (HA::Center | HA::Right, _, Some(a)) => [a.x, a.y],
-        (_, VA::Bottom | VA::Middle | VA::Top, Some(a)) => [a.x as f32, a.y as f32],
+        (_, VA::Bottom | VA::Middle | VA::Top, Some(a)) => [a.x, a.y],
-        _ => [t.insertion_point.x as f32, t.insertion_point.y as f32],
+        _ => [t.insertion_point.x, t.insertion_point.y],
     };
     // Strip %%u/%%o for bounds (they add no width); resolve %%d/%%c/%%p for correct advance.
     let value_for_bounds = resolve_dxf_special_chars(&t.value);
@@ -106,17 +110,20 @@ fn to_truck(t: &Text, document: &acadrust::CadDocument) -> TruckEntity {
         width_factor,
         oblique_angle,
     );
-    let (anchor_local_x, anchor_local_y) = if let Some(([min_x, min_y], [max_x, max_y])) = bounds {
+    let (anchor_local_x, anchor_local_y) = if let Some(b) = bounds {
+        // Horizontal anchor uses the pen advance box [0, advance] so leading /
+        // trailing spaces keep their width instead of snapping to the inked glyphs.
         let ax = match t.horizontal_alignment {
-            HA::Left => min_x,
+            HA::Left => 0.0,
-            HA::Center | HA::Middle => (min_x + max_x) * 0.5,
+            HA::Center | HA::Middle => b.advance * 0.5,
-            HA::Right | HA::Aligned | HA::Fit => max_x,
+            HA::Right | HA::Aligned | HA::Fit => b.advance,
         };
+        // Vertical anchor uses the inked extent (cap / baseline geometry).
         let ay = match t.vertical_alignment {
             VA::Baseline => 0.0,
-            VA::Bottom => min_y,
+            VA::Bottom => b.ink_min[1],
-            VA::Middle => (min_y + max_y) * 0.5,
+            VA::Middle => (b.ink_min[1] + b.ink_max[1]) * 0.5,
-            VA::Top => max_y,
+            VA::Top => b.ink_max[1],
         };
         (ax, ay)
     } else {
@@ -125,7 +132,7 @@ fn to_truck(t: &Text, document: &acadrust::CadDocument) -> TruckEntity {
     let (cos_r, sin_r) = (rotation.cos() as f64, rotation.sin() as f64);
     // Keep origin as f64 — large coordinates (UTM etc.) must not be cast to
     // f32 here; world_offset subtraction happens later in tessellate.rs.
-    let anchor_f64 = [anchor[0] as f64, anchor[1] as f64];
+    let anchor_f64 = anchor;
     let origin: [f64; 2] = [
         anchor_f64[0] - (anchor_local_x as f64 * cos_r - anchor_local_y as f64 * sin_r),
         anchor_f64[1] - (anchor_local_x as f64 * sin_r + anchor_local_y as f64 * cos_r),

src/entities/text_support.rs

@@ -55,13 +55,24 @@ pub fn resolve_text_style(style_name: &str, document: &CadDocument) -> ResolvedT
     }
 }
 
+pub struct TextLocalBounds {
+    /// Inked extent (glyph strokes only) — drives vertical alignment, where
+    /// the cap / baseline geometry is what matters.
+    pub ink_min: [f32; 2],
+    pub ink_max: [f32; 2],
+    /// Pen advance along the baseline, including leading / trailing spaces and
+    /// inter-glyph spacing. Drives horizontal alignment so spaces in the string
+    /// keep their width instead of collapsing to the first / last inked glyph.
+    pub advance: f32,
+}
+
 pub fn text_local_bounds(
     font_name: &str,
     text: &str,
     height: f32,
     width_factor: f32,
     oblique_angle: f32,
-) -> Option<([f32; 2], [f32; 2])> {
+) -> Option<TextLocalBounds> {
     if text.is_empty() || height <= 0.0 {
         return None;
     }
@@ -101,8 +112,16 @@ pub fn text_local_bounds(
         }
     }
 
+    // Pen advance is measured at the baseline, so oblique shear (which skews x
+    // only by gy) does not enter it. Valid even for an all-space string.
+    let advance = cursor_x * scale * wf;
+
     if min_x.is_finite() && min_y.is_finite() && max_x.is_finite() && max_y.is_finite() {
-        Some(([min_x, min_y], [max_x, max_y]))
+        Some(TextLocalBounds {
+            ink_min: [min_x, min_y],
+            ink_max: [max_x, max_y],
+            advance,
+        })
     } else {
         None
     }