fix(dimension): grip menu Above Dim Line places text by the style, not a 1-unit nudge

It moved the text a fixed drawing unit off the line and then another unit
up, wrong at any real scale. It now sets DIMTAD = Above on the dimension
and lets the automatic layout place the text.

Fixes #543

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/update/command.rs

@@ -1934,6 +1934,14 @@ pub(super) fn on_tab_close(&mut self, idx: usize) -> Task<Message> {
                 } else {
                     None
                 };
+                if matches!(item.action, GripMenuAction::AboveDimLine) {
+                    crate::entities::dim_override::set_property(
+                        &mut self.tabs[i].scene.document,
+                        popup.handle,
+                        "dim_text_pos_vert",
+                        "Above",
+                    );
+                }
                 if let Some(entity) = self.tabs[i].scene.document.get_entity_mut(popup.handle) {
                     entity.apply_grip_menu(popup.grip_id, item.action);
                 }

src/entities/dimension.rs

@@ -1111,32 +1111,6 @@ fn dimension_line_grip_position(dim: &Dimension) -> Option<DVec3> {
     Some((p1 + p2) * 0.5)
 }
 
-fn above_dimension_text_position(dim: &Dimension) -> Option<DVec3> {
-    if let Some((vertex, start, end, radius)) = angular_dimension_frame(dim) {
-        let angle = (start + end) * 0.5;
-        let direction = DVec3::new(angle.cos() as f64, angle.sin() as f64, 0.0);
-        return Some(
-            DVec3::new(vertex.x as f64, vertex.y as f64, vertex.z as f64)
-                + direction * (radius as f64 + 1.0),
-        );
-    }
-    let center = dimension_line_grip_position(dim)?;
-    let (ax, ay) = match dim {
-        Dimension::Linear(d) => (d.rotation.cos(), d.rotation.sin()),
-        Dimension::Aligned(d) => {
-            let dx = d.second_point.x - d.first_point.x;
-            let dy = d.second_point.y - d.first_point.y;
-            let length = (dx * dx + dy * dy).sqrt();
-            if length <= 1e-12 {
-                return None;
-            }
-            (dx / length, dy / length)
-        }
-        _ => return Some(center + DVec3::Y),
-    };
-    Some(center + DVec3::new(-ay, ax, 0.0))
-}
-
 impl Grippable for Dimension {
     fn grips(&self) -> Vec<GripDef> {
         // Auto-placed dimensions carry a zero text_middle_point sentinel; put
@@ -1489,12 +1463,13 @@ impl Grippable for Dimension {
                 base.flip_arrow1 = !base.flip_arrow1;
                 base.flip_arrow2 = !base.flip_arrow2;
             }
+            // The caller sets DIMTAD = Above as an override; the text goes
+            // back to automatic placement so DIMGAP and the text height set
+            // how far above the line it sits, at any drawing scale. (#543)
             A::AboveDimLine if grip_id == text_grip => {
-                if let Some(point) = above_dimension_text_position(self) {
+                let b = self.base_mut();
-                    let base = self.base_mut();
+                b.text_middle_point = Vector3::new(0.0, 0.0, 0.0);
-                    base.text_middle_point = Vector3::new(point.x, point.y + 1.0, point.z);
+                b.text_user_positioned = false;
-                    base.text_user_positioned = true;
-                }
             }
             _ => {}
         }