fix(task-22): headless named views are written as plan views and restore carries the orientation

ezdxf's VIEW default is direction=(1, 1, 1) — an isometric view — so every
named view the headless engine wrote to disk was oblique while the tool
claimed to store the plan window of center/height; AutoCAD restored it in
that DCS. view_named_save now writes direction (0,0,1), target (0,0,0) and
view_twist 0 explicitly. view_named_restore copies direction/target/twist
from the VIEW into the *Active VPORT instead of flattening a foreign
oblique view to plan, reading the attributes the way the file carries them
(ezdxf forces those tags on export). Measured live on AutoCAD 2026:
Views.Add already creates a plan view, so the COM path only gains a note.

Tests: the VIEW entry and the reopened DXF assert 11/21/31 = 0/0/1 and the
target; a hand-built oblique, twisted VIEW restores its orientation into
the VPORT and a tool-saved view puts it back on plan.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd

backends/com_backend.py

@@ -1662,6 +1662,9 @@ class ComBackend(AutoCADBackend):
             view = self._com_view(doc, clean)
             replaced = view is not None
             if view is None:
+                # Measured (AutoCAD 2026): Views.Add creates a plan view —
+                # Direction (0, 0, 1), Target (0, 0, 0) — so unlike ezdxf's
+                # VIEW default of (1, 1, 1) nothing has to be forced here.
                 view = doc.Views.Add(clean)
             view.Center = _av([cx, cy])
             view.Height = float(h)

backends/ezdxf_backend.py

@@ -2576,7 +2576,22 @@ class EzdxfBackend(AutoCADBackend):
             stored = existing.dxf.name if replaced else clean
             if replaced:
                 doc.views.remove(stored)
-            doc.views.add(stored, dxfattribs={"center": (cx, cy, 0.0), "height": h, "width": w})
+            # The tool stores a plan window. ezdxf's VIEW default is
+            # direction=(1, 1, 1) — an isometric view — so the orientation must
+            # be written explicitly or AutoCAD restores the entry oblique and
+            # reads ``center`` in that DCS. Measured: the VPORT default is plan,
+            # which is why a save→restore round trip alone never shows it.
+            doc.views.add(
+                stored,
+                dxfattribs={
+                    "center": (cx, cy, 0.0),
+                    "height": h,
+                    "width": w,
+                    "direction": (0.0, 0.0, 1.0),
+                    "target": (0.0, 0.0, 0.0),
+                    "view_twist": 0.0,
+                },
+            )
             self._mark_dirty()
             return {
                 "ok": True,
@@ -2610,6 +2625,14 @@ class EzdxfBackend(AutoCADBackend):
             vport.dxf.height = h
             if h > 0:
                 vport.dxf.aspect_ratio = w / h
+            # The orientation travels with the window: a foreign drawing's
+            # VIEW may be oblique or twisted, and flattening it to a plan view
+            # of the same center would be a silent lie. The attribute read
+            # mirrors what the file carries: ezdxf forces these tags on export,
+            # so an unset direction is (1, 1, 1) on disk as well as here.
+            vport.dxf.direction = tuple(view.dxf.direction)
+            vport.dxf.target = tuple(view.dxf.target)
+            vport.dxf.view_twist = float(view.dxf.view_twist)
             self._mark_dirty()
             return {
                 "ok": True,

tests/test_views_ucs.py

@@ -106,6 +106,57 @@ async def test_view_replace_restore_and_list(backend):
     assert "BAD" not in backend._doc.views
 
 
+async def test_view_is_written_as_a_plan_view_on_disk(backend, tmp_path):
+    """ezdxf's VIEW default is ``direction=(1, 1, 1)`` — an isometric view. The
+    tool stores the plan window of ``center``/``height``, so the entry must
+    say so explicitly (DXF 11/21/31, 12/22/32 and 50) or AutoCAD restores it
+    oblique and reads ``center`` in that DCS."""
+    await backend.entity_create_line(0, 0, 100, 50)
+    await backend.view_named_save("OVERALL")
+    view = backend._doc.views.get("OVERALL")
+    assert tuple(view.dxf.direction) == (0.0, 0.0, 1.0)
+    assert tuple(view.dxf.target) == (0.0, 0.0, 0.0)
+    assert view.dxf.view_twist == 0.0
+
+    import ezdxf
+
+    path = tmp_path / "views.dxf"
+    await backend.drawing_save_as(str(path))
+    reopened = ezdxf.readfile(str(path)).views.get("OVERALL")
+    assert tuple(reopened.dxf.direction) == (0.0, 0.0, 1.0)
+    assert tuple(reopened.dxf.target) == (0.0, 0.0, 0.0)
+    assert tuple(reopened.dxf.center)[:2] == (50.0, 25.0)
+
+
+async def test_view_restore_carries_the_orientation_into_the_vport(backend):
+    """A foreign drawing's VIEW may be oblique or twisted; restoring it must
+    not silently flatten it to a plan view of the same center."""
+    backend._doc.views.add(
+        "ISO",
+        dxfattribs={
+            "center": (5.0, 6.0, 0.0),
+            "height": 20.0,
+            "width": 30.0,
+            "direction": (1.0, 1.0, 1.0),
+            "target": (1.0, 2.0, 3.0),
+            "view_twist": 15.0,
+        },
+    )
+    result = await backend.view_named_restore("iso")
+    assert result["name"] == "ISO" and result["center"] == [5.0, 6.0]
+    (vport,) = backend._doc.viewports.get("*Active")
+    assert tuple(vport.dxf.direction) == (1.0, 1.0, 1.0)
+    assert tuple(vport.dxf.target) == (1.0, 2.0, 3.0)
+    assert vport.dxf.view_twist == 15.0
+    # ...and restoring a view the tool saved puts the VPORT back on plan.
+    await backend.view_named_save("PLAN", center=[0, 0], height=10)
+    await backend.view_named_restore("PLAN")
+    (vport,) = backend._doc.viewports.get("*Active")
+    assert tuple(vport.dxf.direction) == (0.0, 0.0, 1.0)
+    assert tuple(vport.dxf.target) == (0.0, 0.0, 0.0)
+    assert vport.dxf.view_twist == 0.0
+
+
 # ── headless: UCS ───────────────────────────────────────────────────────────