feat(wm): add threshold-based layout_options_rules for workspaces

Adds layout_options_rules to workspace configuration, allowing
layout_options to dynamically change based on container count. Uses the
same threshold semantics as layout_rules: when container count >=
threshold, the highest matching rule fully replaces the base
layout_options.

docs/common-workflows/layout-ratios.md

@@ -172,6 +172,71 @@ consistently to all splits of that type throughout the layout. Additional values
 - Unspecified ratios default to sharing the remaining space equally
 - You only need to specify the ratios you want to customize; trailing values can be omitted
 
+## Layout Options Rules
+
+You can dynamically change `layout_options` based on the number of containers on a workspace
+using `layout_options_rules`. This uses the same threshold-based logic as `layout_rules`:
+when the container count is greater than or equal to a threshold, the highest matching
+threshold's options are used.
+
+Rules **fully replace** the base `layout_options` when they match. If no rule matches, the
+base `layout_options` is used.
+
+### Configuration
+
+```json
+{
+  "monitors": [
+    {
+      "workspaces": [
+        {
+          "name": "main",
+          "layout": "VerticalStack",
+          "layout_options": {
+            "column_ratios": [0.6],
+            "row_ratios": [0.4]
+          },
+          "layout_options_rules": {
+            "3": { "column_ratios": [0.55] },
+            "5": { "column_ratios": [0.3, 0.3, 0.3], "row_ratios": [0.5] }
+          }
+        }
+      ]
+    }
+  ]
+}
+```
+
+In the example above:
+
+| Container Count | Effective `layout_options` |
+|-----------------|---------------------------|
+| 1-2 | Base: `column_ratios: [0.6]`, `row_ratios: [0.4]` |
+| 3-4 | Rule "3": `column_ratios: [0.55]` (no row_ratios, no scrolling, no grid) |
+| 5+ | Rule "5": `column_ratios: [0.3, 0.3, 0.3]`, `row_ratios: [0.5]` |
+
+Rules can include any field that `layout_options` supports: `column_ratios`, `row_ratios`,
+`scrolling`, and `grid`. When a rule matches, it completely replaces the base options. Fields
+not specified in the matching rule default to their standard defaults (not the base
+`layout_options` values).
+
+### Example: Scrolling Layout with Dynamic Columns
+
+```json
+{
+  "layout": "Scrolling",
+  "layout_options": {
+    "scrolling": { "columns": 2 }
+  },
+  "layout_options_rules": {
+    "4": { "scrolling": { "columns": 3 } },
+    "7": { "scrolling": { "columns": 4 } }
+  }
+}
+```
+
+This increases the visible scrolling columns as more windows are added.
+
 ## Progressive Ratio Behavior
 
 Ratios are applied progressively as windows are added. For example, with `row_ratios: [0.3, 0.5]` in a VerticalStack:

komorebi-layouts/src/default_layout.rs

@@ -420,370 +420,5 @@ impl DefaultLayout {
 }
 
 #[cfg(test)]
-mod tests {
+#[path = "default_layout_tests.rs"]
-    use super::*;
+mod tests;
-
-    // Helper to create LayoutOptions with column ratios
-    fn layout_options_with_column_ratios(ratios: &[f32]) -> LayoutOptions {
-        let mut arr = [None; MAX_RATIOS];
-        for (i, &r) in ratios.iter().take(MAX_RATIOS).enumerate() {
-            arr[i] = Some(r);
-        }
-        LayoutOptions {
-            scrolling: None,
-            grid: None,
-            column_ratios: Some(arr),
-            row_ratios: None,
-        }
-    }
-
-    // Helper to create LayoutOptions with row ratios
-    fn layout_options_with_row_ratios(ratios: &[f32]) -> LayoutOptions {
-        let mut arr = [None; MAX_RATIOS];
-        for (i, &r) in ratios.iter().take(MAX_RATIOS).enumerate() {
-            arr[i] = Some(r);
-        }
-        LayoutOptions {
-            scrolling: None,
-            grid: None,
-            column_ratios: None,
-            row_ratios: Some(arr),
-        }
-    }
-
-    // Helper to create LayoutOptions with both column and row ratios
-    fn layout_options_with_ratios(column_ratios: &[f32], row_ratios: &[f32]) -> LayoutOptions {
-        let mut col_arr = [None; MAX_RATIOS];
-        for (i, &r) in column_ratios.iter().take(MAX_RATIOS).enumerate() {
-            col_arr[i] = Some(r);
-        }
-        let mut row_arr = [None; MAX_RATIOS];
-        for (i, &r) in row_ratios.iter().take(MAX_RATIOS).enumerate() {
-            row_arr[i] = Some(r);
-        }
-        LayoutOptions {
-            scrolling: None,
-            grid: None,
-            column_ratios: Some(col_arr),
-            row_ratios: Some(row_arr),
-        }
-    }
-
-    mod deserialize_ratios_tests {
-        use super::*;
-
-        #[test]
-        fn test_deserialize_valid_ratios() {
-            let json = r#"{"column_ratios": [0.3, 0.4, 0.2]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            assert_eq!(ratios[0], Some(0.3));
-            assert_eq!(ratios[1], Some(0.4));
-            assert_eq!(ratios[2], Some(0.2));
-            assert_eq!(ratios[3], None);
-            assert_eq!(ratios[4], None);
-        }
-
-        #[test]
-        fn test_deserialize_clamps_values_to_min() {
-            // Values below MIN_RATIO should be clamped
-            let json = r#"{"column_ratios": [0.05]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            assert_eq!(ratios[0], Some(MIN_RATIO)); // Clamped to 0.1
-        }
-
-        #[test]
-        fn test_deserialize_clamps_values_to_max() {
-            // Values above MAX_RATIO should be clamped
-            let json = r#"{"column_ratios": [0.95]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            // 0.9 is the max, so it should be clamped
-            assert!(ratios[0].unwrap() <= MAX_RATIO);
-        }
-
-        #[test]
-        fn test_deserialize_truncates_when_sum_exceeds_one() {
-            // Sum of ratios should not reach 1.0
-            // [0.5, 0.4] = 0.9, then 0.3 would make it 1.2, so it should be truncated
-            let json = r#"{"column_ratios": [0.5, 0.4, 0.3]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            assert_eq!(ratios[0], Some(0.5));
-            assert_eq!(ratios[1], Some(0.4));
-            // Third ratio should be truncated because 0.5 + 0.4 + 0.3 >= 1.0
-            assert_eq!(ratios[2], None);
-        }
-
-        #[test]
-        fn test_deserialize_truncates_at_max_ratios() {
-            // More than MAX_RATIOS values should be truncated
-            let json = r#"{"column_ratios": [0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            // Only MAX_RATIOS (5) values should be stored
-            for item in ratios.iter().take(MAX_RATIOS) {
-                assert_eq!(*item, Some(0.1));
-            }
-        }
-
-        #[test]
-        fn test_deserialize_empty_array() {
-            let json = r#"{"column_ratios": []}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            for item in ratios.iter().take(MAX_RATIOS) {
-                assert_eq!(*item, None);
-            }
-        }
-
-        #[test]
-        fn test_deserialize_null() {
-            let json = r#"{"column_ratios": null}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-            assert!(opts.column_ratios.is_none());
-        }
-
-        #[test]
-        fn test_deserialize_row_ratios() {
-            let json = r#"{"row_ratios": [0.3, 0.5]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.row_ratios.unwrap();
-            assert_eq!(ratios[0], Some(0.3));
-            assert_eq!(ratios[1], Some(0.5));
-            assert_eq!(ratios[2], None);
-        }
-    }
-
-    mod serialize_ratios_tests {
-        use super::*;
-
-        #[test]
-        fn test_serialize_ratios_compact() {
-            let opts = layout_options_with_column_ratios(&[0.3, 0.4]);
-            let json = serde_json::to_string(&opts).unwrap();
-
-            // Should serialize ratios as compact array without trailing nulls in the ratios array
-            assert!(json.contains("0.3") && json.contains("0.4"));
-        }
-
-        #[test]
-        fn test_serialize_none_ratios() {
-            let opts = LayoutOptions {
-                scrolling: None,
-                grid: None,
-                column_ratios: None,
-                row_ratios: None,
-            };
-            let json = serde_json::to_string(&opts).unwrap();
-
-            // None values should serialize as null or be omitted
-            assert!(!json.contains("["));
-        }
-
-        #[test]
-        fn test_roundtrip_serialization() {
-            let original = layout_options_with_column_ratios(&[0.3, 0.4, 0.2]);
-            let json = serde_json::to_string(&original).unwrap();
-            let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
-
-            assert_eq!(original.column_ratios, deserialized.column_ratios);
-        }
-
-        #[test]
-        fn test_serialize_row_ratios() {
-            let opts = layout_options_with_row_ratios(&[0.3, 0.5]);
-            let json = serde_json::to_string(&opts).unwrap();
-
-            assert!(json.contains("row_ratios"));
-            assert!(json.contains("0.3") && json.contains("0.5"));
-        }
-
-        #[test]
-        fn test_roundtrip_row_ratios() {
-            let original = layout_options_with_row_ratios(&[0.4, 0.3]);
-            let json = serde_json::to_string(&original).unwrap();
-            let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
-
-            assert_eq!(original.row_ratios, deserialized.row_ratios);
-            assert!(original.column_ratios.is_none());
-        }
-
-        #[test]
-        fn test_roundtrip_both_ratios() {
-            let original = layout_options_with_ratios(&[0.3, 0.4], &[0.5, 0.3]);
-            let json = serde_json::to_string(&original).unwrap();
-            let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
-
-            assert_eq!(original.column_ratios, deserialized.column_ratios);
-            assert_eq!(original.row_ratios, deserialized.row_ratios);
-        }
-    }
-
-    mod ratio_constants_tests {
-        use super::*;
-
-        #[test]
-        fn test_constants_valid_ranges() {
-            const {
-                assert!(MIN_RATIO > 0.0);
-                assert!(MIN_RATIO < MAX_RATIO);
-                assert!(MAX_RATIO < 1.0);
-                assert!(DEFAULT_RATIO >= MIN_RATIO && DEFAULT_RATIO <= MAX_RATIO);
-                assert!(
-                    DEFAULT_SECONDARY_RATIO >= MIN_RATIO && DEFAULT_SECONDARY_RATIO <= MAX_RATIO
-                );
-                assert!(MAX_RATIOS >= 1);
-            }
-        }
-
-        #[test]
-        fn test_default_ratio_is_half() {
-            assert_eq!(DEFAULT_RATIO, 0.5);
-        }
-
-        #[test]
-        fn test_max_ratios_is_five() {
-            assert_eq!(MAX_RATIOS, 5);
-        }
-    }
-
-    mod layout_options_tests {
-        use super::*;
-
-        #[test]
-        fn test_layout_options_default_values() {
-            let json = r#"{}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            assert!(opts.scrolling.is_none());
-            assert!(opts.grid.is_none());
-            assert!(opts.column_ratios.is_none());
-            assert!(opts.row_ratios.is_none());
-        }
-
-        #[test]
-        fn test_layout_options_with_all_fields() {
-            let json = r#"{
-                "scrolling": {"columns": 3},
-                "grid": {"rows": 2},
-                "column_ratios": [0.3, 0.4],
-                "row_ratios": [0.5]
-            }"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            assert!(opts.scrolling.is_some());
-            assert_eq!(opts.scrolling.unwrap().columns, 3);
-            assert!(opts.grid.is_some());
-            assert_eq!(opts.grid.unwrap().rows, 2);
-            assert!(opts.column_ratios.is_some());
-            assert!(opts.row_ratios.is_some());
-        }
-    }
-
-    mod default_layout_tests {
-        use super::*;
-
-        #[test]
-        fn test_cycle_next_covers_all_layouts() {
-            let start = DefaultLayout::BSP;
-            let mut current = start;
-            let mut visited = vec![current];
-
-            loop {
-                current = current.cycle_next();
-                if current == start {
-                    break;
-                }
-                assert!(
-                    !visited.contains(&current),
-                    "Cycle contains duplicate: {:?}",
-                    current
-                );
-                visited.push(current);
-            }
-
-            // Should have visited all layouts
-            assert_eq!(visited.len(), 9); // 9 layouts total
-        }
-
-        #[test]
-        fn test_cycle_previous_is_inverse_of_next() {
-            // Note: cycle_previous has some inconsistencies in the current implementation
-            // This test documents the expected behavior for most layouts
-            let layouts_with_correct_inverse = [
-                DefaultLayout::Columns,
-                DefaultLayout::Rows,
-                DefaultLayout::VerticalStack,
-                DefaultLayout::HorizontalStack,
-                DefaultLayout::UltrawideVerticalStack,
-                DefaultLayout::Grid,
-                DefaultLayout::RightMainVerticalStack,
-            ];
-
-            for layout in layouts_with_correct_inverse {
-                let next = layout.cycle_next();
-                assert_eq!(
-                    next.cycle_previous(),
-                    layout,
-                    "cycle_previous should be inverse of cycle_next for {:?}",
-                    layout
-                );
-            }
-        }
-
-        #[test]
-        fn test_leftmost_index_standard_layouts() {
-            assert_eq!(DefaultLayout::BSP.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::Columns.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::Rows.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::VerticalStack.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::HorizontalStack.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::Grid.leftmost_index(5), 0);
-        }
-
-        #[test]
-        fn test_leftmost_index_ultrawide() {
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(1), 0);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(2), 1);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(5), 1);
-        }
-
-        #[test]
-        fn test_leftmost_index_right_main() {
-            assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(1), 0);
-            assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(2), 1);
-            assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(5), 1);
-        }
-
-        #[test]
-        fn test_rightmost_index_standard_layouts() {
-            assert_eq!(DefaultLayout::BSP.rightmost_index(5), 4);
-            assert_eq!(DefaultLayout::Columns.rightmost_index(5), 4);
-            assert_eq!(DefaultLayout::Rows.rightmost_index(5), 4);
-            assert_eq!(DefaultLayout::VerticalStack.rightmost_index(5), 4);
-        }
-
-        #[test]
-        fn test_rightmost_index_right_main() {
-            assert_eq!(DefaultLayout::RightMainVerticalStack.rightmost_index(1), 0);
-            assert_eq!(DefaultLayout::RightMainVerticalStack.rightmost_index(5), 0);
-        }
-
-        #[test]
-        fn test_rightmost_index_ultrawide() {
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(1), 0);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(2), 0);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(3), 2);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(5), 4);
-        }
-    }
-}

komorebi-layouts/src/default_layout_tests.rs

@@ -0,0 +1,435 @@
+use super::*;
+
+// Helper to create LayoutOptions with column ratios
+fn layout_options_with_column_ratios(ratios: &[f32]) -> LayoutOptions {
+    let mut arr = [None; MAX_RATIOS];
+    for (i, &r) in ratios.iter().take(MAX_RATIOS).enumerate() {
+        arr[i] = Some(r);
+    }
+    LayoutOptions {
+        scrolling: None,
+        grid: None,
+        column_ratios: Some(arr),
+        row_ratios: None,
+    }
+}
+
+// Helper to create LayoutOptions with row ratios
+fn layout_options_with_row_ratios(ratios: &[f32]) -> LayoutOptions {
+    let mut arr = [None; MAX_RATIOS];
+    for (i, &r) in ratios.iter().take(MAX_RATIOS).enumerate() {
+        arr[i] = Some(r);
+    }
+    LayoutOptions {
+        scrolling: None,
+        grid: None,
+        column_ratios: None,
+        row_ratios: Some(arr),
+    }
+}
+
+// Helper to create LayoutOptions with both column and row ratios
+fn layout_options_with_ratios(column_ratios: &[f32], row_ratios: &[f32]) -> LayoutOptions {
+    let mut col_arr = [None; MAX_RATIOS];
+    for (i, &r) in column_ratios.iter().take(MAX_RATIOS).enumerate() {
+        col_arr[i] = Some(r);
+    }
+    let mut row_arr = [None; MAX_RATIOS];
+    for (i, &r) in row_ratios.iter().take(MAX_RATIOS).enumerate() {
+        row_arr[i] = Some(r);
+    }
+    LayoutOptions {
+        scrolling: None,
+        grid: None,
+        column_ratios: Some(col_arr),
+        row_ratios: Some(row_arr),
+    }
+}
+
+mod deserialize_ratios_tests {
+    use super::*;
+
+    #[test]
+    fn test_deserialize_valid_ratios() {
+        let json = r#"{"column_ratios": [0.3, 0.4, 0.2]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        assert_eq!(ratios[0], Some(0.3));
+        assert_eq!(ratios[1], Some(0.4));
+        assert_eq!(ratios[2], Some(0.2));
+        assert_eq!(ratios[3], None);
+        assert_eq!(ratios[4], None);
+    }
+
+    #[test]
+    fn test_deserialize_clamps_values_to_min() {
+        // Values below MIN_RATIO should be clamped
+        let json = r#"{"column_ratios": [0.05]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        assert_eq!(ratios[0], Some(MIN_RATIO)); // Clamped to 0.1
+    }
+
+    #[test]
+    fn test_deserialize_clamps_values_to_max() {
+        // Values above MAX_RATIO should be clamped
+        let json = r#"{"column_ratios": [0.95]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        // 0.9 is the max, so it should be clamped
+        assert!(ratios[0].unwrap() <= MAX_RATIO);
+    }
+
+    #[test]
+    fn test_deserialize_truncates_when_sum_exceeds_one() {
+        // Sum of ratios should not reach 1.0
+        // [0.5, 0.4] = 0.9, then 0.3 would make it 1.2, so it should be truncated
+        let json = r#"{"column_ratios": [0.5, 0.4, 0.3]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        assert_eq!(ratios[0], Some(0.5));
+        assert_eq!(ratios[1], Some(0.4));
+        // Third ratio should be truncated because 0.5 + 0.4 + 0.3 >= 1.0
+        assert_eq!(ratios[2], None);
+    }
+
+    #[test]
+    fn test_deserialize_truncates_at_max_ratios() {
+        // More than MAX_RATIOS values should be truncated
+        let json = r#"{"column_ratios": [0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        // Only MAX_RATIOS (5) values should be stored
+        for item in ratios.iter().take(MAX_RATIOS) {
+            assert_eq!(*item, Some(0.1));
+        }
+    }
+
+    #[test]
+    fn test_deserialize_empty_array() {
+        let json = r#"{"column_ratios": []}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        for item in ratios.iter().take(MAX_RATIOS) {
+            assert_eq!(*item, None);
+        }
+    }
+
+    #[test]
+    fn test_deserialize_null() {
+        let json = r#"{"column_ratios": null}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+        assert!(opts.column_ratios.is_none());
+    }
+
+    #[test]
+    fn test_deserialize_row_ratios() {
+        let json = r#"{"row_ratios": [0.3, 0.5]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.row_ratios.unwrap();
+        assert_eq!(ratios[0], Some(0.3));
+        assert_eq!(ratios[1], Some(0.5));
+        assert_eq!(ratios[2], None);
+    }
+}
+
+mod serialize_ratios_tests {
+    use super::*;
+
+    #[test]
+    fn test_serialize_ratios_compact() {
+        let opts = layout_options_with_column_ratios(&[0.3, 0.4]);
+        let json = serde_json::to_string(&opts).unwrap();
+
+        // Should serialize ratios as compact array without trailing nulls in the ratios array
+        assert!(json.contains("0.3") && json.contains("0.4"));
+    }
+
+    #[test]
+    fn test_serialize_none_ratios() {
+        let opts = LayoutOptions {
+            scrolling: None,
+            grid: None,
+            column_ratios: None,
+            row_ratios: None,
+        };
+        let json = serde_json::to_string(&opts).unwrap();
+
+        // None values should serialize as null or be omitted
+        assert!(!json.contains("["));
+    }
+
+    #[test]
+    fn test_roundtrip_serialization() {
+        let original = layout_options_with_column_ratios(&[0.3, 0.4, 0.2]);
+        let json = serde_json::to_string(&original).unwrap();
+        let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
+
+        assert_eq!(original.column_ratios, deserialized.column_ratios);
+    }
+
+    #[test]
+    fn test_serialize_row_ratios() {
+        let opts = layout_options_with_row_ratios(&[0.3, 0.5]);
+        let json = serde_json::to_string(&opts).unwrap();
+
+        assert!(json.contains("row_ratios"));
+        assert!(json.contains("0.3") && json.contains("0.5"));
+    }
+
+    #[test]
+    fn test_roundtrip_row_ratios() {
+        let original = layout_options_with_row_ratios(&[0.4, 0.3]);
+        let json = serde_json::to_string(&original).unwrap();
+        let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
+
+        assert_eq!(original.row_ratios, deserialized.row_ratios);
+        assert!(original.column_ratios.is_none());
+    }
+
+    #[test]
+    fn test_roundtrip_both_ratios() {
+        let original = layout_options_with_ratios(&[0.3, 0.4], &[0.5, 0.3]);
+        let json = serde_json::to_string(&original).unwrap();
+        let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
+
+        assert_eq!(original.column_ratios, deserialized.column_ratios);
+        assert_eq!(original.row_ratios, deserialized.row_ratios);
+    }
+}
+
+mod ratio_constants_tests {
+    use super::*;
+
+    #[test]
+    fn test_constants_valid_ranges() {
+        const {
+            assert!(MIN_RATIO > 0.0);
+            assert!(MIN_RATIO < MAX_RATIO);
+            assert!(MAX_RATIO < 1.0);
+            assert!(DEFAULT_RATIO >= MIN_RATIO && DEFAULT_RATIO <= MAX_RATIO);
+            assert!(DEFAULT_SECONDARY_RATIO >= MIN_RATIO && DEFAULT_SECONDARY_RATIO <= MAX_RATIO);
+            assert!(MAX_RATIOS >= 1);
+        }
+    }
+
+    #[test]
+    fn test_default_ratio_is_half() {
+        assert_eq!(DEFAULT_RATIO, 0.5);
+    }
+
+    #[test]
+    fn test_max_ratios_is_five() {
+        assert_eq!(MAX_RATIOS, 5);
+    }
+}
+
+mod layout_options_tests {
+    use super::*;
+
+    #[test]
+    fn test_layout_options_default_values() {
+        let json = r#"{}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        assert!(opts.scrolling.is_none());
+        assert!(opts.grid.is_none());
+        assert!(opts.column_ratios.is_none());
+        assert!(opts.row_ratios.is_none());
+    }
+
+    #[test]
+    fn test_layout_options_with_all_fields() {
+        let json = r#"{
+            "scrolling": {"columns": 3},
+            "grid": {"rows": 2},
+            "column_ratios": [0.3, 0.4],
+            "row_ratios": [0.5]
+        }"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        assert!(opts.scrolling.is_some());
+        assert_eq!(opts.scrolling.unwrap().columns, 3);
+        assert!(opts.grid.is_some());
+        assert_eq!(opts.grid.unwrap().rows, 2);
+        assert!(opts.column_ratios.is_some());
+        assert!(opts.row_ratios.is_some());
+    }
+}
+
+mod default_layout_tests {
+    use super::*;
+
+    #[test]
+    fn test_cycle_next_covers_all_layouts() {
+        let start = DefaultLayout::BSP;
+        let mut current = start;
+        let mut visited = vec![current];
+
+        loop {
+            current = current.cycle_next();
+            if current == start {
+                break;
+            }
+            assert!(
+                !visited.contains(&current),
+                "Cycle contains duplicate: {:?}",
+                current
+            );
+            visited.push(current);
+        }
+
+        // Should have visited all layouts
+        assert_eq!(visited.len(), 9); // 9 layouts total
+    }
+
+    #[test]
+    fn test_cycle_previous_is_inverse_of_next() {
+        // Note: cycle_previous has some inconsistencies in the current implementation
+        // This test documents the expected behavior for most layouts
+        let layouts_with_correct_inverse = [
+            DefaultLayout::Columns,
+            DefaultLayout::Rows,
+            DefaultLayout::VerticalStack,
+            DefaultLayout::HorizontalStack,
+            DefaultLayout::UltrawideVerticalStack,
+            DefaultLayout::Grid,
+            DefaultLayout::RightMainVerticalStack,
+        ];
+
+        for layout in layouts_with_correct_inverse {
+            let next = layout.cycle_next();
+            assert_eq!(
+                next.cycle_previous(),
+                layout,
+                "cycle_previous should be inverse of cycle_next for {:?}",
+                layout
+            );
+        }
+    }
+
+    #[test]
+    fn test_leftmost_index_standard_layouts() {
+        assert_eq!(DefaultLayout::BSP.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::Columns.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::Rows.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::VerticalStack.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::HorizontalStack.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::Grid.leftmost_index(5), 0);
+    }
+
+    #[test]
+    fn test_leftmost_index_ultrawide() {
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(1), 0);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(2), 1);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(5), 1);
+    }
+
+    #[test]
+    fn test_leftmost_index_right_main() {
+        assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(1), 0);
+        assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(2), 1);
+        assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(5), 1);
+    }
+
+    #[test]
+    fn test_rightmost_index_standard_layouts() {
+        assert_eq!(DefaultLayout::BSP.rightmost_index(5), 4);
+        assert_eq!(DefaultLayout::Columns.rightmost_index(5), 4);
+        assert_eq!(DefaultLayout::Rows.rightmost_index(5), 4);
+        assert_eq!(DefaultLayout::VerticalStack.rightmost_index(5), 4);
+    }
+
+    #[test]
+    fn test_rightmost_index_right_main() {
+        assert_eq!(DefaultLayout::RightMainVerticalStack.rightmost_index(1), 0);
+        assert_eq!(DefaultLayout::RightMainVerticalStack.rightmost_index(5), 0);
+    }
+
+    #[test]
+    fn test_rightmost_index_ultrawide() {
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(1), 0);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(2), 0);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(3), 2);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(5), 4);
+    }
+}
+
+mod layout_options_rules_tests {
+    use super::*;
+
+    #[test]
+    fn test_hashmap_deserialization_ratios_only() {
+        // layout_options_rules entries with only ratios
+        // Note: ratios must sum to < 1.0 to avoid truncation by validate_ratios
+        let json = r#"{
+            "2": {"column_ratios": [0.7]},
+            "3": {"column_ratios": [0.55]},
+            "5": {"column_ratios": [0.3, 0.3, 0.3]}
+        }"#;
+        let rules: std::collections::HashMap<usize, LayoutOptions> =
+            serde_json::from_str(json).unwrap();
+        assert_eq!(rules.len(), 3);
+        assert_eq!(rules[&2].column_ratios.unwrap()[0], Some(0.7));
+        assert_eq!(rules[&3].column_ratios.unwrap()[0], Some(0.55));
+        let r5 = rules[&5].column_ratios.unwrap();
+        assert_eq!(r5[0], Some(0.3));
+        assert_eq!(r5[1], Some(0.3));
+        assert_eq!(r5[2], Some(0.3));
+        // No scrolling/grid in these entries
+        assert!(rules[&2].scrolling.is_none());
+        assert!(rules[&2].grid.is_none());
+    }
+
+    #[test]
+    fn test_hashmap_deserialization_full_options() {
+        // layout_options_rules entries with full options including scrolling/grid
+        let json = r#"{
+            "2": {"column_ratios": [0.7], "scrolling": {"columns": 3}},
+            "5": {"column_ratios": [0.3, 0.3, 0.3], "grid": {"rows": 2}}
+        }"#;
+        let rules: std::collections::HashMap<usize, LayoutOptions> =
+            serde_json::from_str(json).unwrap();
+        assert_eq!(rules.len(), 2);
+        assert_eq!(rules[&2].scrolling.unwrap().columns, 3);
+        assert!(rules[&2].grid.is_none());
+        assert!(rules[&5].scrolling.is_none());
+        assert_eq!(rules[&5].grid.unwrap().rows, 2);
+    }
+
+    #[test]
+    fn test_rule_entry_with_all_fields() {
+        let json = r#"{
+            "column_ratios": [0.6, 0.3],
+            "scrolling": {"columns": 4, "center_focused_column": true},
+            "grid": {"rows": 2},
+            "row_ratios": [0.5]
+        }"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+        let col = opts.column_ratios.unwrap();
+        assert_eq!(col[0], Some(0.6));
+        assert_eq!(col[1], Some(0.3));
+        let row = opts.row_ratios.unwrap();
+        assert_eq!(row[0], Some(0.5));
+        assert_eq!(opts.scrolling.unwrap().columns, 4);
+        assert_eq!(opts.scrolling.unwrap().center_focused_column, Some(true));
+        assert_eq!(opts.grid.unwrap().rows, 2);
+    }
+
+    #[test]
+    fn test_rule_entry_empty_object_gives_defaults() {
+        let json = r#"{}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+        assert!(opts.column_ratios.is_none());
+        assert!(opts.row_ratios.is_none());
+        assert!(opts.scrolling.is_none());
+        assert!(opts.grid.is_none());
+    }
+}

komorebi/src/state.rs

@@ -253,6 +253,7 @@ impl From<&WindowManager> for State {
                             layout: workspace.layout.clone(),
                             layout_options: workspace.layout_options,
                             layout_rules: workspace.layout_rules.clone(),
+                            layout_options_rules: workspace.layout_options_rules.clone(),
                             work_area_offset_rules: workspace.work_area_offset_rules.clone(),
                             layout_flip: workspace.layout_flip,
                             workspace_padding: workspace.workspace_padding,

komorebi/src/static_config.rs

@@ -215,6 +215,12 @@ pub struct WorkspaceConfig {
     /// Layout-specific options
     #[serde(skip_serializing_if = "Option::is_none")]
     pub layout_options: Option<LayoutOptions>,
+    /// Threshold-based layout options rules in the format of threshold => options.
+    /// When container count >= threshold, the highest matching threshold's options
+    /// fully replace the base `layout_options`.
+    /// This follows the same threshold logic as `layout_rules`.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub layout_options_rules: Option<HashMap<usize, LayoutOptions>>,
     /// END OF LIFE FEATURE: Custom Layout
     #[deprecated(note = "End of life feature")]
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -342,6 +348,11 @@ impl From<&Workspace> for WorkspaceConfig {
                 );
                 value.layout_options
             },
+            layout_options_rules: if value.layout_options_rules.is_empty() {
+                None
+            } else {
+                Some(value.layout_options_rules.iter().copied().collect())
+            },
             #[allow(deprecated)]
             custom_layout: value
                 .workspace_config

komorebi/src/workspace.rs

@@ -61,6 +61,10 @@ pub struct Workspace {
     pub layout: Layout,
     pub layout_options: Option<LayoutOptions>,
     pub layout_rules: Vec<(usize, Layout)>,
+    /// Threshold-based layout options rules (container_count >= threshold -> use these options).
+    /// Sorted by threshold ascending at load time.
+    #[serde(default)]
+    pub layout_options_rules: Vec<(usize, LayoutOptions)>,
     pub work_area_offset_rules: Vec<(usize, Rect)>,
     pub layout_flip: Option<Axis>,
     pub workspace_padding: Option<i32>,
@@ -119,6 +123,7 @@ impl Default for Workspace {
             layout: Layout::Default(DefaultLayout::BSP),
             layout_options: None,
             layout_rules: vec![],
+            layout_options_rules: vec![],
             work_area_offset_rules: vec![],
             layout_flip: None,
             workspace_padding: Option::from(DEFAULT_WORKSPACE_PADDING.load(Ordering::SeqCst)),
@@ -251,12 +256,25 @@ impl Workspace {
         self.layout_flip = config.layout_flip;
         self.floating_layer_behaviour = config.floating_layer_behaviour;
         self.wallpaper = config.wallpaper.clone();
+
+        // Load layout options directly (LayoutOptions is used in both config and runtime)
         self.layout_options = config.layout_options;
 
+        // Load threshold-based layout options rules, sorted by threshold ascending
+        self.layout_options_rules = if let Some(rules) = &config.layout_options_rules {
+            let mut sorted_rules: Vec<(usize, LayoutOptions)> =
+                rules.iter().map(|(t, o)| (*t, *o)).collect();
+            sorted_rules.sort_by_key(|(t, _)| *t);
+            sorted_rules
+        } else {
+            vec![]
+        };
+
         tracing::debug!(
-            "Workspace '{}' loaded layout_options: {:?}",
+            "Workspace '{}' loaded layout_options: {:?}, layout_options_rules: {} entries",
             self.name.as_deref().unwrap_or("unnamed"),
-            self.layout_options
+            self.layout_options,
+            self.layout_options_rules.len(),
         );
 
         self.workspace_config = Some(config.clone());
@@ -584,10 +602,34 @@ impl Workspace {
             } else if let Some(window) = &mut self.maximized_window {
                 window.maximize();
             } else if !self.containers().is_empty() {
-                tracing::debug!(
+                // Compute effective layout options:
-                    "Workspace '{}' update() - self.layout_options before calculate: {:?}",
+                //   1. If layout_options_rules has a matching threshold (container_count >= threshold),
-                    self.name.as_deref().unwrap_or("unnamed"),
+                //      use the highest matching threshold's options (full replacement)
+                //   2. Otherwise, use the workspace base layout_options
+                let effective_layout_options = if !self.layout_options_rules.is_empty() {
+                    let container_count = self.containers().len();
+                    let mut matched = None;
+                    for (threshold, opts) in &self.layout_options_rules {
+                        if container_count >= *threshold {
+                            matched = Some(*opts);
+                        }
+                    }
+                    // If a rule matched, use it entirely (replaces base layout_options)
+                    if matched.is_some() {
+                        matched
+                    } else {
+                        self.layout_options
+                    }
+                } else {
                     self.layout_options
+                };
+
+                tracing::debug!(
+                    "Workspace '{}' update() - effective_layout_options: {:?} (base: {:?}, rules: {})",
+                    self.name.as_deref().unwrap_or("unnamed"),
+                    effective_layout_options,
+                    self.layout_options,
+                    self.layout_options_rules.len(),
                 );
                 let mut layouts = self.layout.as_boxed_arrangement().calculate(
                     &adjusted_work_area,
@@ -598,7 +640,7 @@ impl Workspace {
                     self.layout_flip,
                     &self.resize_dimensions,
                     self.focused_container_idx(),
-                    self.layout_options,
+                    effective_layout_options,
                     &self.latest_layout,
                 );
 

schema.bar.json

@@ -9683,6 +9683,26 @@
             }
           ]
         },
+        "layout_options_rules": {
+          "description": "Threshold-based layout options rules (container_count >= threshold -> use these options).\nSorted by threshold ascending at load time.",
+          "type": "array",
+          "default": [],
+          "items": {
+            "type": "array",
+            "maxItems": 2,
+            "minItems": 2,
+            "prefixItems": [
+              {
+                "type": "integer",
+                "format": "uint",
+                "minimum": 0
+              },
+              {
+                "$ref": "#/$defs/LayoutOptions"
+              }
+            ]
+          }
+        },
         "layout_rules": {
           "type": "array",
           "items": {
@@ -9985,6 +10005,19 @@
             }
           ]
         },
+        "layout_options_rules": {
+          "description": "Threshold-based layout options rules in the format of threshold => options.\nWhen container count >= threshold, the highest matching threshold's options\nfully replace the base `layout_options`.\nThis follows the same threshold logic as `layout_rules`.",
+          "type": [
+            "object",
+            "null"
+          ],
+          "additionalProperties": false,
+          "patternProperties": {
+            "^\\d+$": {
+              "$ref": "#/$defs/LayoutOptions"
+            }
+          }
+        },
         "layout_rules": {
           "description": "Layout rules in the format of threshold => layout",
           "type": [

schema.json

@@ -4214,6 +4214,19 @@
             }
           ]
         },
+        "layout_options_rules": {
+          "description": "Threshold-based layout options rules in the format of threshold => options.\nWhen container count >= threshold, the highest matching threshold's options\nfully replace the base `layout_options`.\nThis follows the same threshold logic as `layout_rules`.",
+          "type": [
+            "object",
+            "null"
+          ],
+          "additionalProperties": false,
+          "patternProperties": {
+            "^\\d+$": {
+              "$ref": "#/$defs/LayoutOptions"
+            }
+          }
+        },
         "layout_rules": {
           "description": "Layout rules in the format of threshold => layout",
           "type": [