feat(ribbon): add layer isolation tools

Closes #589

assets/icons/layers/layiso.svg

@@ -0,0 +1,18 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="64" height="64">
+  <!-- Muted surrounding layers -->
+  <line x1="2" y1="5" x2="22" y2="5"
+        stroke="#777777" stroke-width="2.25" stroke-linecap="round"
+        stroke-dasharray="3 3"/>
+  <line x1="2" y1="19" x2="22" y2="19"
+        stroke="#777777" stroke-width="2.25" stroke-linecap="round"
+        stroke-dasharray="3 3"/>
+  <!-- The selected layer remains visible -->
+  <line x1="2" y1="12" x2="22" y2="12"
+        stroke="#4cc9f0" stroke-width="2.25" stroke-linecap="round"/>
+  <circle cx="12" cy="12" r="2.5"
+          fill="#4cc9f0" stroke="#e0e0e0" stroke-width="1.25"/>
+  <!-- Focus brackets -->
+  <path d="M6 9V7H9 M15 7H18V9 M18 15V17H15 M9 17H6V15"
+        fill="none" stroke="#f0c040" stroke-width="1.75"
+        stroke-linecap="round" stroke-linejoin="round"/>
+</svg>

assets/icons/layers/layuniso.svg

@@ -0,0 +1,13 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="64" height="64">
+  <!-- Restored layer stack -->
+  <line x1="2" y1="5" x2="22" y2="5"
+        stroke="#e0e0e0" stroke-width="2.25" stroke-linecap="round"/>
+  <line x1="2" y1="12" x2="22" y2="12"
+        stroke="#4cc9f0" stroke-width="2.25" stroke-linecap="round"/>
+  <line x1="2" y1="19" x2="22" y2="19"
+        stroke="#e0e0e0" stroke-width="2.25" stroke-linecap="round"/>
+  <!-- Outward arrows indicate restoring the isolated layers -->
+  <path d="M8 9L5 6L2 9 M16 15L19 18L22 15"
+        fill="none" stroke="#f0c040" stroke-width="1.75"
+        stroke-linecap="round" stroke-linejoin="round"/>
+</svg>

src/modules/draw/layers/layiso.rs

@@ -0,0 +1,12 @@
+use crate::modules::{IconKind, ModuleEvent, ToolDef};
+
+pub fn tool() -> ToolDef {
+    ToolDef {
+        id: "LAYISO",
+        label: "Isolate Layer",
+        icon: IconKind::Svg(include_bytes!(
+            "../../../../assets/icons/layers/layiso.svg"
+        )),
+        event: ModuleEvent::Command("LAYISO".to_string()),
+    }
+}

src/modules/draw/layers/layuniso.rs

@@ -0,0 +1,12 @@
+use crate::modules::{IconKind, ModuleEvent, ToolDef};
+
+pub fn tool() -> ToolDef {
+    ToolDef {
+        id: "LAYUNISO",
+        label: "Unisolate Layers",
+        icon: IconKind::Svg(include_bytes!(
+            "../../../../assets/icons/layers/layuniso.svg"
+        )),
+        event: ModuleEvent::Command("LAYUNISO".to_string()),
+    }
+}

src/modules/draw/layers/mod.rs

@@ -1,9 +1,11 @@
 pub(super) mod color;
 pub(super) mod layfrz;
+pub(super) mod layiso;
 pub(super) mod laylck;
 pub(super) mod layoff;
 pub(super) mod layon;
 pub(super) mod laythw;
+pub(super) mod layuniso;
 pub(super) mod layulk;
 pub(super) mod make_current;
 pub mod match_layer;

src/modules/draw/mod.rs

@@ -34,7 +34,8 @@ impl CadModule for DrawModule {
         use draw::{arc, circle, ellipse, hatch, line, polyline, shapes};
         use groups::{group, ungroup};
         use layers::{
-            layfrz, laylck, layoff, layon, laythw, layulk, make_current, match_layer, panel,
+            layfrz, layiso, laylck, layoff, layon, laythw, layulk, layuniso, make_current,
+            match_layer, panel,
         };
         use modify::{
             array, copy, delete, explode, fillet, mirror, offset, rotate, scale, stretch,
@@ -182,12 +183,14 @@ impl CadModule for DrawModule {
                                 layfrz::tool(),
                                 laylck::tool(),
                                 make_current::tool(),
+                                layiso::tool(),
                             ],
                             row3: vec![
                                 layon::tool(),
                                 laythw::tool(),
                                 layulk::tool(),
                                 match_layer::tool(),
+                                layuniso::tool(),
                             ],
                         },
                     ],

src/ui/ribbon/widgets.rs

@@ -613,10 +613,17 @@ pub(super) fn render_large<'a>(
                     *id, *icon, None, items, *default, active_tool, open_dd, last_cmd,
                     dim,
                 )
-            }
+        }
 
         RibbonItem::LayerComboGroup { row2, row3 } => {
-            const COMBO_W: f32 = LARGE_W * 2.5;
+            const TOOL_BUTTON_W: f32 = 26.0;
+            const TOOL_SPACING: f32 = 2.0;
+            const GROUP_PADDING: f32 = 8.0;
+            let tool_count = row2.len().max(row3.len()) as f32;
+            let tools_w = tool_count * TOOL_BUTTON_W
+                + (tool_count - 1.0).max(0.0) * TOOL_SPACING
+                + GROUP_PADDING;
+            let combo_w = (LARGE_W * 2.5).max(tools_w);
 
             let info = layer_infos.iter().find(|l| l.name == active_layer);
             let lc = info.map(|l| l.color).unwrap_or(Color::WHITE);
@@ -641,8 +648,15 @@ pub(super) fn render_large<'a>(
                 .width(12)
                 .height(12);
 
-            const ICONS_USED: f32 = 14.0 + 14.0 + 14.0 + 12.0 + 10.0 + 5.0 * 4.0 + 16.0 + 16.0;
-            let name_w = (COMBO_W - ICONS_USED).max(40.0);
+            const FIXED_COMBO_W: f32 =
+                14.0 * 3.0 + 12.0 + 9.0 + 4.0 * 4.0 + 8.0 * 2.0;
+            let name_w = (combo_w - FIXED_COMBO_W).max(24.0);
+            // About 6 px per glyph at 11 px. The dropdown itself keeps the
+            // complete layer name available; only its closed ribbon label is
+            // shortened to preserve the fixed row height.
+            let name_budget = ((name_w / 6.0) as usize).max(4);
+            let active_layer_label =
+                crate::ui::text_util::elide(active_layer, name_budget);
 
             let combo_btn = button(
                 row![
@@ -650,7 +664,7 @@ pub(super) fn render_large<'a>(
                     freeze_icon,
                     lock_icon,
                     swatch,
-                    container(text(active_layer).size(11))
+                    container(text(active_layer_label).size(11))
                         .width(name_w)
                         .clip(true),
                     icons::themed_arrow_down(9.0),
@@ -710,7 +724,7 @@ pub(super) fn render_large<'a>(
                 .spacing(3)
                 .align_x(iced::Left),
             )
-            .width(Length::Fixed(COMBO_W))
+            .width(Length::Fixed(combo_w))
             .height(Fill)
             .align_y(iced::Center)
             .padding(Padding {