From 882c4d67a6bdc0e48105bf4b13572dff7d0ab4eb Mon Sep 17 00:00:00 2001
From: MarekSpodBiedry <73122968+MarekSpodBiedry@users.noreply.github.com>
Date: Sat, 10 Oct 2026 18:26:11 +0200
Subject: [PATCH] Keep dimension text rotation when saving DXF (#78) (#153)

---
 crates/io/src/dxf_write.rs |  5 ++++-
 crates/io/src/tests.rs     | 15 +++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/crates/io/src/dxf_write.rs b/crates/io/src/dxf_write.rs
index a145103..0650a51 100644
--- a/crates/io/src/dxf_write.rs
+++ b/crates/io/src/dxf_write.rs
@@ -562,6 +562,9 @@ fn entity(w: &mut W, d: &Drawing, e: &Entity, owner: &str, paper: bool, cx: &Ctx
                 w.s(1, &dm.text);
             }
             w.s(3, &dm.style);
+            if dm.text_rotation != 0.0 {
+                w.f(53, dm.text_rotation.to_degrees());
+            }
             match dm.kind {
                 DimKind::Linear { rotation } => {
                     w.s(100, "AcDbAlignedDimension");
@@ -819,7 +822,7 @@ fn dim_block_entities(d: &Drawing, dm: &Dimension, layer: &str) -> Vec<Entity> {
                 height: style.text_height * style.scale.max(1e-9),
                 width: 0.0,
                 attach: 5,
-                rotation: 0.0,
+                rotation: g.text_angle,
                 style: style.text_style.clone(),
                 contents: g.value.clone(),
                 line_spacing: 1.0,
diff --git a/crates/io/src/tests.rs b/crates/io/src/tests.rs
index 48ababa..9f11318 100644
--- a/crates/io/src/tests.rs
+++ b/crates/io/src/tests.rs
@@ -1272,3 +1272,18 @@ fn attdef_prompt_survives_dxf_roundtrip() {
         .collect();
     assert_eq!(prompts, vec!["Enter value", ""]);
 }
+
+#[test]
+fn dimension_text_rotation_roundtrips() {
+    let mut d = Drawing::new_imperial();
+    let mut dm = dim(DimKind::Linear { rotation: 0.0 }, Vec3::ZERO, Vec3::new(10.0, 0.0, 0.0));
+    dm.text_rotation = 30.0_f64.to_radians();
+    let h = d.add(&Space::Model, Common::default(), EntityKind::Dimension(dm.clone())).unwrap();
+    let back = roundtrip(&d);
+    let EntityKind::Dimension(x) = &back.entity(h).unwrap().kind else { panic!("dimension expected") };
+    assert!((x.text_rotation - dm.text_rotation).abs() < 1e-9, "got {}", x.text_rotation);
+    // The anonymous block that renders the reopened dimension carries the same text angle.
+    let b = x.block.as_deref().and_then(|n| back.block(n)).expect("dimension block");
+    let rot = b.entities.iter().find_map(|e| if let EntityKind::MText(t) = &e.kind { Some(t.rotation) } else { None });
+    assert!(rot.is_some_and(|r| (r - dm.text_rotation).abs() < 1e-9), "block text rotation {rot:?}");
+}