Align Niri viewport fitting by window mode

Extract shared mode-aware viewport fitting for normal, maximized, and fullscreen columns. Use the parent monitor area for maximized columns, working area plus gaps for normal columns, and anchor fullscreen columns at offset zero.

Route focus, resize, center, gesture, new-window, and workspace move paths through the shared fitting helper so keyboard and gesture snapping agree. Add regression coverage for mode-aware offsets and inset working-area centering.

Author: Barut

Sources/OmniWM/Core/Controller/NiriLayoutHandler.swift

@@ -596,7 +596,10 @@ enum NiriWindowMoveResult {
                         motion: motion,
                         animate: false,
                         centerMode: settings.centerFocusedColumn,
-                        alwaysCenterSingleColumn: settings.alwaysCenterSingleColumn
+                        alwaysCenterSingleColumn: settings.alwaysCenterSingleColumn,
+                        scale: pass.engine.displayScale(in: pass.wsId),
+                        workingArea: pass.insetFrame,
+                        viewFrame: pass.monitor.frame
                     )
                 }
             } else if let newCol = pass.engine.column(of: newNode),

Sources/OmniWM/Core/Controller/WorkspaceNavigationHandler.swift

@@ -820,12 +820,13 @@ final class WorkspaceNavigationHandler {
             {
                 targetState.selectedNodeId = movedNode.id
                 let gap = CGFloat(controller.workspaceManager.gaps)
+                let workingFrame = controller.insetWorkingFrame(for: monitor)
                 engine.ensureSelectionVisible(
                     node: movedNode,
                     in: target.id,
                     motion: controller.motionPolicy.snapshot(),
                     state: &targetState,
-                    workingFrame: monitor.visibleFrame,
+                    workingFrame: workingFrame,
                     gaps: gap
                 )
             }
@@ -935,12 +936,13 @@ final class WorkspaceNavigationHandler {
                 targetState.selectedNodeId = movedNode.id
 
                 let gap = CGFloat(controller.workspaceManager.gaps)
+                let workingFrame = controller.insetWorkingFrame(for: monitor)
                 engine.ensureSelectionVisible(
                     node: movedNode,
                     in: targetWsId,
                     motion: controller.motionPolicy.snapshot(),
                     state: &targetState,
-                    workingFrame: monitor.visibleFrame,
+                    workingFrame: workingFrame,
                     gaps: gap
                 )
             }

Sources/OmniWM/Core/Layout/Niri/NiriLayoutEngine+InteractiveMove.swift

@@ -45,7 +45,10 @@ extension NiriLayoutEngine {
             motion: motion,
             animate: false,
             centerMode: settings.centerFocusedColumn,
-            alwaysCenterSingleColumn: settings.alwaysCenterSingleColumn
+            alwaysCenterSingleColumn: settings.alwaysCenterSingleColumn,
+            scale: displayScale(in: workspaceId),
+            workingArea: workingFrame,
+            viewFrame: monitorForWorkspace(workspaceId)?.frame
         )
 
         return true

Sources/OmniWM/Core/Layout/Niri/NiriLayoutEngine+ViewportCommands.swift

@@ -17,16 +17,21 @@ extension NiriLayoutEngine {
 
         cancelInteractiveResize(for: columns[activeIndex], in: workspaceId)
 
+        let scale = displayScale(in: workspaceId)
+        let viewFrame = monitorForWorkspace(workspaceId)?.frame
         let targetOffset = state.computeCenteredOffset(
             columnIndex: activeIndex,
             columns: columns,
             gap: gaps,
-            viewportWidth: workingFrame.width
+            viewportWidth: workingFrame.width,
+            workingArea: workingFrame,
+            viewFrame: viewFrame,
+            scale: scale
         )
         state.animateToOffset(
             targetOffset,
             motion: motion,
-            scale: displayScale(in: workspaceId)
+            scale: scale
         )
         return true
     }
@@ -52,16 +57,25 @@ extension NiriLayoutEngine {
         let activeIndex = state.activeColumnIndex.clamped(to: 0 ... (columns.count - 1))
         state.activeColumnIndex = activeIndex
 
+        let scale = displayScale(in: workspaceId)
+        let viewFrame = monitorForWorkspace(workspaceId)?.frame
+        let areas = state.normalizedFittingAreas(
+            viewportSpan: workingFrame.width,
+            workingArea: workingFrame,
+            viewFrame: viewFrame,
+            scale: scale
+        )
         let viewStart = state.targetViewPosPixels(columns: columns, gap: gaps)
-        let viewportWidth = workingFrame.width
+        let workingStart = areas.origin(of: areas.working)
+        let viewportWidth = areas.span(of: areas.working)
 
         var widthTaken: CGFloat = 0
         var leftmostColumnX: CGFloat?
         var activeColumnX: CGFloat?
 
         for (idx, column) in columns.enumerated() {
             let columnX = state.columnX(at: idx, columns: columns, gap: gaps)
-            if columnX < viewStart + gaps {
+            if columnX < viewStart + workingStart + gaps {
                 continue
             }
 
@@ -70,7 +84,7 @@ extension NiriLayoutEngine {
             }
 
             let width = column.cachedWidth
-            if viewStart + viewportWidth < columnX + width + gaps {
+            if viewStart + workingStart + viewportWidth < columnX + width + gaps {
                 break
             }
 
@@ -86,9 +100,8 @@ extension NiriLayoutEngine {
         cancelInteractiveResize(for: columns[activeIndex], in: workspaceId)
 
         let freeSpace = viewportWidth - widthTaken + gaps
-        let newViewStart = leftmostColumnX - freeSpace / 2
+        let newViewStart = leftmostColumnX - freeSpace / 2 - workingStart
         let targetOffset = newViewStart - activeColumnX
-        let scale = displayScale(in: workspaceId)
 
         state.animateToOffset(
             targetOffset,
@@ -105,7 +118,9 @@ extension NiriLayoutEngine {
             sizeKeyPath: \.cachedWidth,
             centerMode: settings.centerFocusedColumn,
             alwaysCenterSingleColumn: settings.alwaysCenterSingleColumn,
-            scale: scale
+            scale: scale,
+            workingArea: workingFrame,
+            viewFrame: viewFrame
         )
 
         return true

Sources/OmniWM/Core/Layout/Niri/NiriNavigation.swift

@@ -199,6 +199,7 @@ extension NiriLayoutEngine {
         }
 
         let scale = displayScale(in: workspaceId)
+        let viewFrame = monitorForWorkspace(workspaceId)?.frame
         let oldActivePos = previousActiveContainerPosition
             ?? state.containerPosition(
                 at: state.activeColumnIndex,
@@ -227,7 +228,10 @@ extension NiriLayoutEngine {
             alwaysCenterSingleColumn: settings.alwaysCenterSingleColumn,
             animationConfig: animationConfig,
             fromContainerIndex: prevIdx,
-            scale: scale
+            scale: scale,
+            workingArea: workingFrame,
+            viewFrame: viewFrame,
+            orientation: orientation
         )
 
         state.selectionProgress = 0.0

Sources/OmniWM/Core/Layout/Niri/ViewportState+ColumnTransitions.swift

@@ -8,7 +8,10 @@ extension ViewportState {
         gap: CGFloat,
         viewportWidth: CGFloat,
         motion: MotionSnapshot,
-        animate: Bool = false
+        animate: Bool = false,
+        workingArea: CGRect? = nil,
+        viewFrame: CGRect? = nil,
+        scale: CGFloat = 2.0
     ) {
         guard !columns.isEmpty else { return }
         let clampedIndex = index.clamped(to: 0 ... (columns.count - 1))
@@ -23,7 +26,10 @@ extension ViewportState {
             columnIndex: clampedIndex,
             columns: columns,
             gap: gap,
-            viewportWidth: viewportWidth
+            viewportWidth: viewportWidth,
+            workingArea: workingArea,
+            viewFrame: viewFrame,
+            scale: scale
         )
 
         if animate {
@@ -47,7 +53,9 @@ extension ViewportState {
         centerMode: CenterFocusedColumn,
         alwaysCenterSingleColumn: Bool = false,
         fromColumnIndex: Int? = nil,
-        scale: CGFloat = 2.0
+        scale: CGFloat = 2.0,
+        workingArea: CGRect? = nil,
+        viewFrame: CGRect? = nil
     ) {
         guard !columns.isEmpty else { return }
         let clampedIndex = newIndex.clamped(to: 0 ... (columns.count - 1))
@@ -71,7 +79,9 @@ extension ViewportState {
             centerMode: centerMode,
             alwaysCenterSingleColumn: alwaysCenterSingleColumn,
             fromColumnIndex: fromColumnIndex ?? prevActiveColumn,
-            scale: scale
+            scale: scale,
+            workingArea: workingArea,
+            viewFrame: viewFrame
         )
 
         let pixel: CGFloat = 1.0 / max(scale, 1.0)
@@ -105,7 +115,10 @@ extension ViewportState {
         alwaysCenterSingleColumn: Bool = false,
         animationConfig: SpringConfig? = nil,
         fromContainerIndex: Int? = nil,
-        scale: CGFloat = 2.0
+        scale: CGFloat = 2.0,
+        workingArea: CGRect? = nil,
+        viewFrame: CGRect? = nil,
+        orientation: Monitor.Orientation = .horizontal
     ) {
         guard !containers.isEmpty, containerIndex >= 0, containerIndex < containers.count else { return }
 
@@ -124,7 +137,10 @@ extension ViewportState {
             centerMode: centerMode,
             alwaysCenterSingleColumn: alwaysCenterSingleColumn,
             fromContainerIndex: fromContainerIndex,
-            scale: scale
+            scale: scale,
+            workingArea: workingArea,
+            viewFrame: viewFrame,
+            orientation: orientation
         )
 
         if abs(targetOffset - stationaryOffset) <= pixelEpsilon {