Show wall cursor gizmos outside edit mode + axis previews

Four concerns that together make the cursor-anchored gizmos
(extend_x_gizmo, extend_z_gizmo, split_gizmo on GizmoWallEdition)
fully functional and visually informative without entering parametric
edit mode first:

* Drop the props.is_editing gate in _update_cursor_gizmos. The three
  bound operators (bim.extend_wall_to_cursor,
  bim.extend_wall_height_to_cursor, bim.split_wall_at_cursor) already
  poll on wall-selected and commit any pending wall edit before
  acting, so single-click without entering edit mode is now the
  canonical flow. Matches gizmos-8088's always-on behaviour.

* Register GizmoWallEdition instances in a per-region weakref map
  (_active_instances) populated at setup_element_specific_gizmos
  time. The WallGizmoPreviewDecorator dereferences this map to read
  live is_highlight state off the cursor icons. Without the
  registration its _cursor_icon_hovered always returned False and
  the hover-gated GPU previews silently never drew. Mirrors the
  same pattern already in place on GizmoWallJoinIntersection.

* Add post-operator resync to all three cursor operators
  (_maybe_resync_wall_props_from_ifc for the single-wall split /
  extend-height paths, _resync_walls_after_mutation for the
  selection-wide extend-X path). Without this, props.length /
  props.height stayed stale after the operator ran, so the
  orientation flips _apply_wall_extend_flips computes from
  cursor_local vs wall dimensions kept using the pre-extend values
  until the next selection change. Matches gizmos-8088's pattern.

* Hover-gated GPU previews per icon:

  - extend-X: filled Z=0 floor quads spanning the wall's offset to
    offset+thickness Y band, visible from plan view without side-
    view clutter. Grow case (cursor beyond either endpoint): one
    green decorator_color_selected quad over the extension. Shrink
    case (cursor inside extent): green quad for the portion that
    REMAINS + red decorator_color_error quad for the portion the
    operator REMOVES.

  - extend-Z: vertical lines at the cursor's projected X in the
    wall's y=0 reference-line plane. Grow case (cursor above wall
    top): one green segment from z=height to z=cursor.z. Shrink
    case: green from z=0 to z=cursor.z (REMAINS) + red from
    z=cursor.z to z=height (REMOVES).

  - split: one red vertical line at the cursor's projected X from
    base to wall top — the cut plane.

  Quads use QUAD_ALPHA=0.25 so the underlying wall body stays
  visible.

* New module-level _fill_quads_alpha helper next to
  _stroke_lines_alpha, plus a per-decorator _fill convenience method
  and a _wall_floor_quad corner builder.

Modal-active gizmo hiding (is_gizmo_hidden_by_modal) is preserved.

Generated with the assistance of an AI coding tool.

src/bonsai/bonsai/bim/module/model/decorator.py

@@ -2069,6 +2069,47 @@ def _stroke_lines_alpha(
     gpu.state.blend_set("NONE")
 
 
+def _fill_quads_alpha(
+    context: bpy.types.Context,
+    quads: list[
+        tuple[
+            tuple[float, float, float],
+            tuple[float, float, float],
+            tuple[float, float, float],
+            tuple[float, float, float],
+        ]
+    ],
+    color_rgb: tuple[float, float, float],
+    alpha: float,
+) -> None:
+    """Render ``quads`` (each a 4-tuple of world-space corner verts in CCW
+    order) as one TRIS batch with two triangles per quad. Companion to
+    ``_stroke_lines_alpha`` for filled previews."""
+    if not quads:
+        return
+    verts: list[tuple[float, float, float]] = []
+    indices: list[tuple[int, int, int]] = []
+    for quad in quads:
+        if len(quad) != 4:
+            continue
+        base = len(verts)
+        verts.extend(tuple(v) for v in quad)
+        indices.append((base, base + 1, base + 2))
+        indices.append((base, base + 2, base + 3))
+    if not tool.Blender.validate_shader_batch_data(verts, indices):
+        return
+    region = getattr(context, "region", None)
+    if region is None:
+        return
+    shader = gpu.shader.from_builtin("UNIFORM_COLOR")
+    shader.bind()
+    shader.uniform_float("color", (*color_rgb, alpha))
+    batch = batch_for_shader(shader, "TRIS", {"pos": verts}, indices=indices)
+    gpu.state.blend_set("ALPHA")
+    batch.draw(shader)
+    gpu.state.blend_set("NONE")
+
+
 class WallFilletPreviewDecorator(tool.Blender.ViewportDecorator):
     """GPU preview lines for the wall-fillet flow.
 
@@ -2543,6 +2584,9 @@ class WallGizmoPreviewDecorator(tool.Blender.ViewportDecorator):
 
     LINE_WIDTH = 1.5
     LINE_ALPHA = 0.8
+    # Semi-transparent so the wall body and surrounding geometry stay visible
+    # under the preview quads.
+    QUAD_ALPHA = 0.25
 
     def draw_lines(self, context: bpy.types.Context) -> None:
         if not tool.Blender.are_viewport_gizmos_enabled():
@@ -2563,6 +2607,38 @@ class WallGizmoPreviewDecorator(tool.Blender.ViewportDecorator):
     ) -> None:
         _stroke_lines_alpha(context, segments, color_rgb, self.LINE_WIDTH, self.LINE_ALPHA)
 
+    def _fill(
+        self,
+        context: bpy.types.Context,
+        quads: list[
+            tuple[
+                tuple[float, float, float],
+                tuple[float, float, float],
+                tuple[float, float, float],
+                tuple[float, float, float],
+            ]
+        ],
+        color_rgb: tuple[float, float, float],
+    ) -> None:
+        _fill_quads_alpha(context, quads, color_rgb, self.QUAD_ALPHA)
+
+    @staticmethod
+    def _wall_floor_quad(mw: Matrix, x0: float, x1: float, y0: float, y1: float) -> tuple[
+        tuple[float, float, float],
+        tuple[float, float, float],
+        tuple[float, float, float],
+        tuple[float, float, float],
+    ]:
+        """4 world-space corners of a Z=0 wall-local rectangle, CCW when
+        viewed from +Z. Used for top-down floor-projection quads so the
+        extend / split previews stay legible from plan view."""
+        return (
+            tuple(mw @ Vector((x0, y0, 0.0))),
+            tuple(mw @ Vector((x1, y0, 0.0))),
+            tuple(mw @ Vector((x1, y1, 0.0))),
+            tuple(mw @ Vector((x0, y1, 0.0))),
+        )
+
     def _draw_join_preview(self, context: bpy.types.Context, prefs: Any) -> None:
         """Render four preview lines per wall pair — two at each wall's base
         Z, two at each wall's top Z — extending each axis to the projected
@@ -2710,11 +2786,18 @@ class WallGizmoPreviewDecorator(tool.Blender.ViewportDecorator):
         return active
 
     def _draw_cursor_extend_preview(self, context: bpy.types.Context, prefs: Any) -> None:
-        """Render the extend-X preview line only while the cursor-anchored
-        extend-X icon gizmo is hovered. The line runs from the wall's nearer
-        axis endpoint to the cursor's projected X on the wall axis, both
-        clamped to wall-local Y=0 Z=0 so the line stays on the wall's floor
-        edge regardless of cursor Z."""
+        """Hover-gated floor-plane preview for the extend-X icon. Quads sit
+        on the Z=0 plane spanning the wall's ``offset`` to
+        ``offset + thickness`` Y band so the operator's effect reads from
+        plan view without side-view clutter:
+
+        - **Cursor outside ``[anchor_x, anchor_x+length]`` (grow)**: one
+          green ``decorator_color_selected`` quad over the extension
+          (nearer endpoint → cursor X).
+        - **Cursor inside the wall extent (shrink)**: green quad for the
+          portion that REMAINS (cursor X → farther endpoint) + red
+          ``decorator_color_error`` quad for the portion the operator
+          REMOVES (nearer endpoint → cursor X)."""
         active = self._active_layer2_wall_for_gizmo_preview(context, prefs)
         if active is None:
             return
@@ -2727,21 +2810,35 @@ class WallGizmoPreviewDecorator(tool.Blender.ViewportDecorator):
             return
         anchor_x = geom.get("anchor_x", 0.0)
         length = geom.get("length", 0.0)
-        if length <= 0:
+        offset = geom.get("offset", 0.0)
+        thickness = geom.get("thickness", 0.0)
+        if length <= 0 or thickness <= 0:
             return
         mw = active.matrix_world
         cursor_local = mw.inverted() @ context.scene.cursor.location
+        y_floor_0 = offset
+        y_floor_1 = offset + thickness
         start_x = anchor_x
         end_x = anchor_x + length
+        keep_color = tuple(prefs.decorator_color_selected[:3])
         nearest_x = start_x if abs(cursor_local.x - start_x) < abs(cursor_local.x - end_x) else end_x
-        start_world = mw @ Vector((nearest_x, 0.0, 0.0))
-        end_world = mw @ Vector((cursor_local.x, 0.0, 0.0))
-        if (end_world - start_world).length < 1e-6:
+
+        def emit(x0: float, x1: float, color: tuple[float, float, float]) -> None:
+            if abs(x1 - x0) < 1e-6:
+                return
+            lo, hi = (x0, x1) if x0 < x1 else (x1, x0)
+            self._fill(context, [self._wall_floor_quad(mw, lo, hi, y_floor_0, y_floor_1)], color)
+
+        if start_x < cursor_local.x < end_x:
+            remove_color = tuple(prefs.decorator_color_error[:3])
+            farthest_x = end_x if nearest_x == start_x else start_x
+            emit(nearest_x, cursor_local.x, remove_color)
+            emit(cursor_local.x, farthest_x, keep_color)
             return
-        self._stroke(context, [(tuple(start_world), tuple(end_world))], tuple(prefs.decorator_color_selected[:3]))
+        emit(nearest_x, cursor_local.x, keep_color)
 
     def _draw_cursor_split_preview(self, context: bpy.types.Context, prefs: Any) -> None:
-        """Render one line at the cursor's projected X, from wall base to wall top
+        """Render one red line at the cursor's projected X, from wall base to wall top
         along the wall's local Z — the cut plane the split operator would commit.
         Hover-gated on the split icon; coloured with the destructive-action warning
         red to match the icon's own hover signal."""
@@ -2769,9 +2866,18 @@ class WallGizmoPreviewDecorator(tool.Blender.ViewportDecorator):
         self._stroke(context, [(tuple(bottom_world), tuple(top_world))], tuple(prefs.decorator_color_error[:3]))
 
     def _draw_cursor_extend_z_preview(self, context: bpy.types.Context, prefs: Any) -> None:
-        """Render one preview line at the cursor's projected X on the wall axis,
-        from the wall base to the gizmo's local Z — the new total height the
-        extend-Z operator would commit. Hover-gated on the extend-Z icon."""
+        """Hover-gated vertical-line preview for the extend-Z icon at the
+        cursor's projected X on the wall axis (y=0 reference-line plane).
+
+        Two cases by cursor Z relative to the wall's current height:
+
+        - **Cursor Z above the wall top (grow)**: one green
+          ``decorator_color_selected`` segment from z=height to z=cursor.z
+          (the new vertical material).
+        - **Cursor Z inside ``(0, height)`` (shrink)**: two segments —
+          green from z=0 to z=cursor.z (the portion that REMAINS), red
+          ``decorator_color_error`` from z=cursor.z to z=height (the
+          portion the operator REMOVES)."""
         active = self._active_layer2_wall_for_gizmo_preview(context, prefs)
         if active is None:
             return
@@ -2793,6 +2899,17 @@ class WallGizmoPreviewDecorator(tool.Blender.ViewportDecorator):
             return
         if abs(cursor_local.z - height) < 1e-6:
             return
-        base_world = mw @ Vector((cursor_local.x, 0.0, 0.0))
-        top_world = mw @ Vector((cursor_local.x, 0.0, cursor_local.z))
-        self._stroke(context, [(tuple(base_world), tuple(top_world))], tuple(prefs.decorator_color_selected[:3]))
+        keep_color = tuple(prefs.decorator_color_selected[:3])
+        cursor_x = cursor_local.x
+
+        def stroke(z0: float, z1: float, color: tuple[float, float, float]) -> None:
+            a = mw @ Vector((cursor_x, 0.0, z0))
+            b = mw @ Vector((cursor_x, 0.0, z1))
+            self._stroke(context, [(tuple(a), tuple(b))], color)
+
+        if cursor_local.z > height:
+            stroke(height, cursor_local.z, keep_color)
+            return
+        remove_color = tuple(prefs.decorator_color_error[:3])
+        stroke(0.0, cursor_local.z, keep_color)
+        stroke(cursor_local.z, height, remove_color)

src/bonsai/bonsai/bim/module/model/wall.py

@@ -2011,6 +2011,13 @@ class GizmoWallEdition(bpy.types.GizmoGroup, gizmo.BaseParametricGizmoGroup):
             (0, 0, 1),
         )
 
+    # Per-region weakref map populated in ``setup_element_specific_gizmos``.
+    # The ``WallGizmoPreviewDecorator`` dereferences this each draw to read
+    # live ``is_highlight`` state off the cursor icons (extend-X / extend-Z
+    # / split) in the same region it's currently drawing in, so the GPU
+    # axis-preview lines only render while the matching icon is hovered.
+    _active_instances: ClassVar["dict[int, weakref.ReferenceType[GizmoWallEdition]]"] = {}
+
     # Row layout: validate / cancel / baseline-triplet / rotate / array.
     # Wall has no ``cycle_type_operator``, so the cycle slot collapses and
     # the baseline triplet takes the cycle X position (0.87). Rotate
@@ -2073,6 +2080,8 @@ class GizmoWallEdition(bpy.types.GizmoGroup, gizmo.BaseParametricGizmoGroup):
             highlight_color,
         )
         self.setup_pen_row_toggle_openings_icon()
+        if context.region is not None:
+            type(self)._active_instances[context.region.as_pointer()] = weakref.ref(self)
 
     def _refresh_element_specific(self, context: bpy.types.Context, mw: Matrix, props: "BIMWallProperties") -> None:
         """Position cursor-anchored gizmos and the wall-specific icon-row extras."""
@@ -2087,6 +2096,14 @@ class GizmoWallEdition(bpy.types.GizmoGroup, gizmo.BaseParametricGizmoGroup):
         """Position the cursor-anchored icons (extend-X / extend-Z / split) on the wall
         axis at the cursor's projected X.
 
+        Always visible when a parametric wall is selected — not gated on edit
+        mode. The three operators (``bim.extend_wall_to_cursor`` /
+        ``bim.extend_wall_height_to_cursor`` / ``bim.split_wall_at_cursor``)
+        all poll on wall-selected and commit any pending wall edit before
+        acting, so single-click without entering edit mode is the canonical
+        flow. The ``WallGizmoPreviewDecorator`` keeps the viewport clean by
+        only drawing the action's guide line on hover.
+
         Two branches by view orientation:
 
         - **Non-top-down**: world-Z stacking. Each icon sits at the Z its
@@ -2101,10 +2118,6 @@ class GizmoWallEdition(bpy.types.GizmoGroup, gizmo.BaseParametricGizmoGroup):
         if not hasattr(self, "split_gizmo"):
             return
         all_gizmos = (self.extend_x_gizmo, self.extend_z_gizmo, self.split_gizmo)
-        if not props.is_editing:
-            for gz in all_gizmos:
-                gz.hide = True
-            return
         cursor_world = context.scene.cursor.location
         cursor_local = mw.inverted() @ cursor_world
         in_range = props.anchor_x < cursor_local.x < props.anchor_x + props.length
@@ -2252,9 +2265,11 @@ class SplitWallAtCursor(bpy.types.Operator, tool.Ifc.Operator):
     def _execute(self, context: bpy.types.Context) -> set[str]:
         # Applies any pending wall edit first so the split operates on the committed
         # geometry rather than the draft preview box.
-        if _commit_active_wall_edit_if_any(context) is None:
+        obj = _commit_active_wall_edit_if_any(context)
+        if obj is None:
             return {"CANCELLED"}
         bpy.ops.bim.split_wall()
+        _maybe_resync_wall_props_from_ifc(obj)
         return {"FINISHED"}
 
 
@@ -2282,6 +2297,7 @@ class ExtendWallToCursor(bpy.types.Operator, tool.Ifc.Operator):
             tool.Model,
             context.scene.cursor.location,
         )
+        _resync_walls_after_mutation(tool.Blender.get_selected_objects())
         return {"FINISHED"}
 
 
@@ -2313,6 +2329,7 @@ class ExtendWallHeightToCursor(bpy.types.Operator, tool.Ifc.Operator):
             return {"CANCELLED"}
         with bpy.context.temp_override(active_object=obj, selected_objects=[obj]):
             bpy.ops.bim.change_extrusion_depth(depth=new_height)
+        _maybe_resync_wall_props_from_ifc(obj)
         return {"FINISHED"}