fix: layout is now correct; also removed layout preferences for now

alt-tab-macos/api-wrappers/CGWindow.swift

@@ -22,12 +22,6 @@ extension CGWindow {
         return layer() == 0
     }
 
-    // workaround: some apps like chrome use a window to implement the search popover
-    func isReasonablyBig() -> Bool {
-        let windowBounds = CGRect(dictionaryRepresentation: bounds()!)!
-        return windowBounds.width > Preferences.minimumWindowSize && windowBounds.height > Preferences.minimumWindowSize
-    }
-
     func id() -> CGWindowID? {
         return value(kCGWindowNumber, CGWindowID.self)
     }

alt-tab-macos/logic/Preferences.swift

@@ -3,11 +3,35 @@ import Cocoa
 import Carbon.HIToolbox.Events
 
 class Preferences {
+    // the following constant are not exposed as preferences but may be in the future, probably through macro preferences
+    static let windowMaterial = NSVisualEffectView.Material.dark
+    static let iconSize = CGFloat(32)
+    static let fontColor = NSColor.white
+    static let fontHeight = CGFloat(15)
+    static let font = NSFont.systemFont(ofSize: fontHeight)
+    static let windowPadding = CGFloat(23)
+    static let cellPadding = CGFloat(5)
+    static let fontIconSize = CGFloat(20)
+    static let maxScreenUsage = CGFloat(0.8)
+    static let minCellsPerRow = CGFloat(4)
+    static let maxCellsPerRow = CGFloat(6)
+    static let nCellsRows = CGFloat(4)
+
+    static let themeMacro = MacroPreferenceHelper<(CGFloat, CGFloat, CGFloat, NSColor, NSColor)>([
+        MacroPreference(" macOS", (0, 5, 20, .clear, NSColor(red: 0, green: 0, blue: 0, alpha: 0.3))),
+        MacroPreference("❖ Windows 10", (2, 0, 0, .white, .clear))
+    ])
+    static let metaKeyMacro = MacroPreferenceHelper<([Int], NSEvent.ModifierFlags)>([
+        MacroPreference("⌥ option", ([kVK_Option, kVK_RightOption], .option)),
+        MacroPreference("⌃ control", ([kVK_Control, kVK_RightControl], .control)),
+        MacroPreference("⌘ command", ([kVK_Command, kVK_RightCommand], .command))
+    ])
+    static let showOnScreenMacro = MacroPreferenceHelper<ShowOnScreenPreference>([
+        MacroPreference("Main screen", ShowOnScreenPreference.MAIN),
+        MacroPreference("Screen including mouse", ShowOnScreenPreference.MOUSE),
+    ])
+
     static var defaults: [String: String] = [
-        "maxScreenUsage": "80",
-        "maxThumbnailsPerRow": "4",
-        "iconSize": "32",
-        "fontHeight": "15",
         "tabKeyCode": String(kVK_Tab),
         "metaKey": metaKeyMacro.macros[0].label,
         "windowDisplayDelay": "0",
@@ -16,21 +40,9 @@ class Preferences {
         "hideSpaceNumberLabels": String(false)
     ]
     static var rawValues = [String: String]()
-    static var minimumWindowSize = CGFloat(200)
-    static var emptyThumbnailWidth = CGFloat(200)
-    static var emptyThumbnailHeight = CGFloat(emptyThumbnailWidth * 9 / 16)
-    static var fontColor = NSColor.white
-    static var windowMaterial = NSVisualEffectView.Material.dark
-    static var windowPadding = CGFloat(23)
-    static var interItemPadding = CGFloat(4)
-    static var fontIconSize = CGFloat(20)
-    static var cellPadding = CGFloat(6)
+
     static var cellBorderWidth: CGFloat?
     static var cellCornerRadius: CGFloat?
-    static var maxScreenUsage: CGFloat?
-    static var maxThumbnailsPerRow: CGFloat?
-    static var iconSize: CGFloat?
-    static var fontHeight: CGFloat?
     static var tabKeyCode: UInt16?
     static var highlightBorderColor: NSColor?
     static var highlightBackgroundColor: NSColor?
@@ -38,22 +50,8 @@ class Preferences {
     static var metaModifierFlag: NSEvent.ModifierFlags?
     static var windowDisplayDelay: DispatchTimeInterval?
     static var windowCornerRadius: CGFloat?
-    static var font: NSFont?
     static var showOnScreen: ShowOnScreenPreference?
-    static var hideSpaceNumberLabels = false
-    static var themeMacro = MacroPreferenceHelper<(CGFloat, CGFloat, CGFloat, NSColor, NSColor)>([
-        MacroPreference(" macOS", (0, 5, 20, .clear, NSColor(red: 0, green: 0, blue: 0, alpha: 0.3))),
-        MacroPreference("❖ Windows 10", (2, 0, 0, .white, .clear))
-    ])
-    static var metaKeyMacro = MacroPreferenceHelper<([Int], NSEvent.ModifierFlags)>([
-        MacroPreference("⌥ option", ([kVK_Option, kVK_RightOption], .option)),
-        MacroPreference("⌃ control", ([kVK_Control, kVK_RightControl], .control)),
-        MacroPreference("⌘ command", ([kVK_Command, kVK_RightCommand], .command))
-    ])
-    static var showOnScreenMacro = MacroPreferenceHelper<ShowOnScreenPreference>([
-        MacroPreference("Main screen", ShowOnScreenPreference.MAIN),
-        MacroPreference("Screen including mouse", ShowOnScreenPreference.MOUSE),
-    ])
+    static var hideSpaceNumberLabels: Bool?
 
     private static let defaultsFile = fileFromPreferencesFolder("alt-tab-macos-defaults.json")
     private static let userFile = fileFromPreferencesFolder("alt-tab-macos.json")
@@ -85,15 +83,6 @@ class Preferences {
 
     static func updateAndValidateFromString(_ valueName: String, _ value: String) throws {
         switch valueName {
-        case "maxScreenUsage":
-            maxScreenUsage = try CGFloat(CGFloat(value).orThrow() / 100)
-        case "maxThumbnailsPerRow":
-            maxThumbnailsPerRow = try CGFloat(value).orThrow()
-        case "iconSize":
-            iconSize = try CGFloat(value).orThrow()
-        case "fontHeight":
-            fontHeight = try CGFloat(value).orThrow()
-            font = NSFont.systemFont(ofSize: fontHeight!)
         case "tabKeyCode":
             tabKeyCode = try UInt16(value).orThrow()
         case "metaKey":

alt-tab-macos/logic/Screen.swift

@@ -13,18 +13,6 @@ class Screen {
         return NSScreen.screens.first { NSMouseInRect(NSEvent.mouseLocation, $0.frame, false) }
     }
 
-    static func thumbnailMaxSize(_ screen: NSScreen) -> NSSize {
-        let frame = screen.visibleFrame
-        let width = (frame.width * Preferences.maxScreenUsage! - Preferences.windowPadding * 2) / Preferences.maxThumbnailsPerRow! - Preferences.interItemPadding
-        let height = width * (frame.height / frame.width)
-        return NSSize(width: width, height: height)
-    }
-
-    static func thumbnailPanelMaxSize(_ screen: NSScreen) -> NSSize {
-        let frame = screen.visibleFrame
-        return NSSize(width: frame.width * Preferences.maxScreenUsage!, height: frame.height * Preferences.maxScreenUsage!)
-    }
-
     static func repositionPanel(_ window: NSWindow, _ screen: NSScreen, _ alignment: VerticalAlignment) {
         let screenFrame = screen.visibleFrame
         let panelFrame = window.frame

alt-tab-macos/ui/Cell.swift

@@ -7,7 +7,7 @@ typealias MouseMovedCallback = (Cell) -> Void
 class Cell: NSCollectionViewItem {
     var thumbnail = NSImageView()
     var appIcon = NSImageView()
-    var label = CellTitle(Preferences.fontHeight!)
+    var label = CellTitle(Preferences.fontHeight)
     var minimizedIcon = FontIcon(FontIcon.sfSymbolCircledMinusSign, Preferences.fontIconSize, .white)
     var hiddenIcon = FontIcon(FontIcon.sfSymbolCircledDotSign, Preferences.fontIconSize, .white)
     var spaceIcon = FontIcon(FontIcon.sfSymbolCircledNumber0, Preferences.fontIconSize, .white)
@@ -20,7 +20,13 @@ class Cell: NSCollectionViewItem {
         let vStackView = makeVStackView(hStackView)
         let shadow = Cell.makeShadow(.gray)
         thumbnail.shadow = shadow
+        thumbnail.wantsLayer = true
+        thumbnail.layer!.backgroundColor = NSColor.blue.cgColor
         appIcon.shadow = shadow
+        appIcon.wantsLayer = true
+        appIcon.layer!.backgroundColor = NSColor.green.cgColor
+        vStackView.wantsLayer = true
+        vStackView.layer!.backgroundColor = NSColor.gray.cgColor
         view = vStackView
     }
 
@@ -39,21 +45,22 @@ class Cell: NSCollectionViewItem {
         }
     }
 
-    func updateWithNewContent(_ element: Window, _ mouseDownCallback: @escaping MouseDownCallback, _ mouseMovedCallback: @escaping MouseMovedCallback, _ screen: NSScreen) {
+    func updateRecycledCellWithNewContent(_ element: Window, _ mouseDownCallback: @escaping MouseDownCallback, _ mouseMovedCallback: @escaping MouseMovedCallback, _ screen: NSScreen) {
         window = element
         thumbnail.image = element.thumbnail
-        let (width, height) = Cell.computeDownscaledSize(element.thumbnail, screen)
-        thumbnail.image?.size = NSSize(width: width, height: height)
-        thumbnail.frame.size = NSSize(width: width, height: height)
+        let thumbnailSize = Cell.thumbnailSize(element.thumbnail, screen)
+        thumbnail.image?.size = thumbnailSize
+        thumbnail.frame.size = thumbnailSize
         appIcon.image = element.icon
-        appIcon.image?.size = NSSize(width: Preferences.iconSize!, height: Preferences.iconSize!)
-        appIcon.frame.size = NSSize(width: Preferences.iconSize!, height: Preferences.iconSize!)
+        let appIconSize = NSSize(width: Preferences.iconSize, height: Preferences.iconSize)
+        appIcon.image?.size = appIconSize
+        appIcon.frame.size = appIconSize
         label.string = element.title
         // workaround: setting string on NSTextView change the font (most likely a Cocoa bug)
-        label.font = Preferences.font!
+        label.font = Preferences.font
         hiddenIcon.isHidden = !window!.isHidden
         minimizedIcon.isHidden = !window!.isMinimized
-        spaceIcon.isHidden = element.spaceIndex == nil || Spaces.isSingleSpace || Preferences.hideSpaceNumberLabels
+        spaceIcon.isHidden = element.spaceIndex == nil || Spaces.isSingleSpace || Preferences.hideSpaceNumberLabels!
         if !spaceIcon.isHidden {
             if element.isOnAllSpaces {
                 spaceIcon.setStar()
@@ -61,8 +68,8 @@ class Cell: NSCollectionViewItem {
                 spaceIcon.setNumber(UInt32(element.spaceIndex!))
             }
         }
-        let fontIconWidth = CGFloat([minimizedIcon, hiddenIcon, spaceIcon].filter { !$0.isHidden }.count) * (Preferences.fontIconSize + Preferences.interItemPadding)
-        label.textContainer!.size.width = thumbnail.frame.width - Preferences.iconSize! - Preferences.interItemPadding - fontIconWidth
+        let fontIconWidth = CGFloat([minimizedIcon, hiddenIcon, spaceIcon].filter { !$0.isHidden }.count) * (Preferences.fontIconSize + Preferences.cellPadding)
+        label.textContainer!.size.width = view.frame.width - Preferences.iconSize - Preferences.cellPadding * 3 - fontIconWidth
         self.mouseDownCallback = mouseDownCallback
         self.mouseMovedCallback = mouseMovedCallback
         if view.trackingAreas.count > 0 {
@@ -71,20 +78,6 @@ class Cell: NSCollectionViewItem {
         view.addTrackingArea(NSTrackingArea(rect: view.bounds, options: [.mouseMoved, .activeAlways], owner: self, userInfo: nil))
     }
 
-    static func computeDownscaledSize(_ image: NSImage?, _ screen: NSScreen) -> (Int, Int) {
-        if let image_ = image {
-            let imageRatio = image_.size.width / image_.size.height
-            let thumbnailMaxSize = Screen.thumbnailMaxSize(screen)
-            let thumbnailWidth = Int(floor(thumbnailMaxSize.height * imageRatio))
-            if thumbnailWidth <= Int(thumbnailMaxSize.width) {
-                return (thumbnailWidth, Int(thumbnailMaxSize.height))
-            } else {
-                return (Int(thumbnailMaxSize.width), Int(floor(thumbnailMaxSize.width / imageRatio)))
-            }
-        }
-        return (Int(Preferences.emptyThumbnailWidth), Int((Preferences.emptyThumbnailHeight)))
-    }
-
     static func makeShadow(_ color: NSColor) -> NSShadow {
         let shadow = NSShadow()
         shadow.shadowColor = color
@@ -95,7 +88,9 @@ class Cell: NSCollectionViewItem {
 
     private func makeHStackView() -> NSStackView {
         let hStackView = NSStackView()
-        hStackView.spacing = Preferences.interItemPadding
+        hStackView.spacing = Preferences.cellPadding
+        label.wantsLayer = true
+        label.layer!.backgroundColor = NSColor.brown.cgColor
         hStackView.setViews([appIcon, label, hiddenIcon, minimizedIcon, spaceIcon], in: .leading)
         return hStackView
     }
@@ -109,8 +104,37 @@ class Cell: NSCollectionViewItem {
         vStackView.layer!.borderColor = .clear
         vStackView.edgeInsets = NSEdgeInsets(top: Preferences.cellPadding, left: Preferences.cellPadding, bottom: Preferences.cellPadding, right: Preferences.cellPadding)
         vStackView.orientation = .vertical
-        vStackView.spacing = Preferences.interItemPadding
+        vStackView.spacing = Preferences.cellPadding
         vStackView.setViews([hStackView, thumbnail], in: .leading)
         return vStackView
     }
+
+    static func widthMax(_ screen: NSScreen) -> CGFloat {
+        return ThumbnailsPanel.widthMax(screen) / Preferences.minCellsPerRow - Preferences.cellPadding
+    }
+
+    static func widthMin(_ screen: NSScreen) -> CGFloat {
+        return ThumbnailsPanel.widthMax(screen) / Preferences.maxCellsPerRow - Preferences.cellPadding
+    }
+
+    static func height(_ screen: NSScreen) -> CGFloat {
+        return ThumbnailsPanel.heightMax(screen) / Preferences.nCellsRows - Preferences.cellPadding
+    }
+
+    static func width(_ image: NSImage?, _ screen: NSScreen) -> CGFloat {
+        return max(thumbnailSize(image, screen).width + Preferences.cellPadding * 2, ThumbnailsPanel.widthMin(screen))
+    }
+
+    static func thumbnailSize(_ image: NSImage?, _ screen: NSScreen) -> NSSize {
+        let thumbnailWidthMin = Cell.widthMin(screen) - Preferences.cellPadding * 2
+        let thumbnailHeightMax = Cell.height(screen) - Preferences.cellPadding * 3 - Preferences.iconSize
+        let thumbnailWidthMax = Cell.widthMax(screen) - Preferences.cellPadding * 2
+        guard let image = image else { return NSSize(width: thumbnailWidthMin, height: thumbnailHeightMax) }
+        let imageRatio = image.size.width / image.size.height
+        let thumbnailRatio = thumbnailWidthMax / thumbnailHeightMax
+        if thumbnailRatio > imageRatio {
+            return NSSize(width: image.size.width * thumbnailHeightMax / image.size.height, height: thumbnailHeightMax)
+        }
+        return NSSize(width: thumbnailWidthMax, height: image.size.height * thumbnailWidthMax / image.size.width)
+    }
 }

alt-tab-macos/ui/CollectionViewCenterFlowLayout.swift

@@ -4,10 +4,9 @@ class CollectionViewCenterFlowLayout: NSCollectionViewFlowLayout {
     var currentScreen: NSScreen?
 
     override func layoutAttributesForElements(in rect: CGRect) -> [NSCollectionViewLayoutAttributes] {
-        let attributes = super.layoutAttributesForElements(in: rect)
-        if attributes.isEmpty {
-            return attributes
-        }
+        let attributes_ = super.layoutAttributesForElements(in: rect)
+        guard !attributes_.isEmpty else { return attributes_ }
+        let attributes = NSArray(array: attributes_, copyItems: true) as! [NSCollectionViewLayoutAttributes]
         var currentRow: [NSCollectionViewLayoutAttributes] = []
         var currentRowY = CGFloat(0)
         var currentRowWidth = CGFloat(0)
@@ -15,35 +14,38 @@ class CollectionViewCenterFlowLayout: NSCollectionViewFlowLayout {
         var currentRowMaxY = CGFloat(0)
         var widestRow = CGFloat(0)
         var totalHeight = CGFloat(0)
-        attributes.enumerated().forEach {
-            let isNewRow = abs($1.frame.origin.y - currentRowY) > Screen.thumbnailMaxSize(currentScreen!).height
+        for (index, attribute) in attributes.enumerated() {
+            let isNewRow = abs(attribute.frame.origin.y - currentRowY) > Cell.height(currentScreen!)
             if isNewRow {
-                computeOriginXForAllItems(currentRowWidth - minimumInteritemSpacing, previousRowMaxY, currentRow)
+                computeOriginXForAllItems(currentRowWidth - Preferences.cellPadding, previousRowMaxY, currentRow)
                 currentRow.removeAll()
-                currentRowY = $1.frame.origin.y
+                currentRowY = attribute.frame.origin.y
                 currentRowWidth = 0
-                previousRowMaxY += currentRowMaxY + minimumLineSpacing
+                previousRowMaxY += currentRowMaxY + Preferences.cellPadding
                 currentRowMaxY = 0
             }
-            currentRow.append($1)
-            currentRowWidth += $1.frame.size.width + minimumInteritemSpacing
+            currentRow.append(attribute)
+            currentRowWidth += attribute.frame.size.width + Preferences.cellPadding
             widestRow = max(widestRow, currentRowWidth)
-            currentRowMaxY = max(currentRowMaxY, $1.frame.size.height)
-            if $0 == attributes.count - 1 {
-                computeOriginXForAllItems(currentRowWidth - minimumInteritemSpacing, previousRowMaxY, currentRow)
+            currentRowMaxY = max(currentRowMaxY, attribute.frame.size.height)
+            if index == attributes.count - 1 {
+                computeOriginXForAllItems(currentRowWidth - Preferences.cellPadding, previousRowMaxY, currentRow)
                 totalHeight = previousRowMaxY + currentRowMaxY
             }
         }
-        collectionView!.setFrameSize(NSSize(width: widestRow - minimumInteritemSpacing, height: totalHeight))
+        let newWidth = widestRow - Preferences.cellPadding
+        collectionView!.bounds.origin.x = (collectionView!.frame.size.width - newWidth) / 2
+        collectionView!.frame.size.width = newWidth
+        collectionView!.frame.size.height = totalHeight
         return attributes
     }
 
-    func computeOriginXForAllItems(_ currentRowWidth: CGFloat, _ previousRowMaxHeight: CGFloat, _ currentRow: [NSCollectionViewLayoutAttributes]) {
-        var marginLeft = floor((collectionView!.frame.size.width - currentRowWidth) / 2)
-        currentRow.forEach {
-            $0.frame.origin.x = marginLeft
-            $0.frame.origin.y = previousRowMaxHeight
-            marginLeft += $0.frame.size.width + minimumInteritemSpacing
+    private func computeOriginXForAllItems(_ currentRowWidth: CGFloat, _ previousRowMaxHeight: CGFloat, _ currentRow: [NSCollectionViewLayoutAttributes]) {
+        var marginLeft = (collectionView!.frame.size.width - currentRowWidth) / 2
+        for attribute in currentRow {
+            attribute.frame.origin.x = marginLeft
+            attribute.frame.origin.y = previousRowMaxHeight
+            marginLeft += attribute.frame.size.width + Preferences.cellPadding
         }
     }
 }

alt-tab-macos/ui/PreferencesWindow.swift

@@ -82,10 +82,6 @@ class PreferencesWindow: NSWindow, NSWindowDelegate {
             makeLabelWithInput("Tab key", rawName: "tabKeyCode", width: 33, suffixText: "KeyCodes Reference", suffixUrl: "https://eastmanreference.com/complete-list-of-applescript-key-codes", validator: tabKeyCodeValidator),
             makeHorizontalSeparator(),
             makeLabelWithDropdown("Theme", rawName: "theme", values: Preferences.themeMacro.labels),
-            makeLabelWithSlider("Max screen usage", rawName: "maxScreenUsage", minValue: 10, maxValue: 100, numberOfTickMarks: 0, unitText: "%"),
-            makeLabelWithSlider("Max thumbnails per row", rawName: "maxThumbnailsPerRow", minValue: 3, maxValue: 16, numberOfTickMarks: 0),
-            makeLabelWithSlider("Apps icon size", rawName: "iconSize", minValue: 12, maxValue: 64, numberOfTickMarks: 0, unitText: "px"),
-            makeLabelWithSlider("Window font size", rawName: "fontHeight", minValue: 12, maxValue: 64, numberOfTickMarks: 0, unitText: "px"),
             makeLabelWithCheckbox("Hide space number labels", rawName: "hideSpaceNumberLabels"),
             makeHorizontalSeparator(),
             makeLabelWithSlider("Window apparition delay", rawName: "windowDisplayDelay", minValue: 0, maxValue: 2000, numberOfTickMarks: 0, unitText: "ms"),

alt-tab-macos/ui/ThumbnailsPanel.swift

@@ -2,7 +2,7 @@ import Cocoa
 
 class ThumbnailsPanel: NSPanel, NSCollectionViewDataSource, NSCollectionViewDelegate, NSCollectionViewDelegateFlowLayout {
     var backgroundView: NSVisualEffectView?
-    var collectionView_: NSCollectionView!
+    var collectionView: NSCollectionView!
     var app: App?
     let cellId = NSUserInterfaceItemIdentifier("Cell")
     var currentScreen: NSScreen?
@@ -21,7 +21,7 @@ class ThumbnailsPanel: NSPanel, NSCollectionViewDataSource, NSCollectionViewDele
         titleVisibility = .hidden
         styleMask.remove(.titled)
         backgroundColor = .clear
-        collectionView_ = makeCollectionView()
+        collectionView = makeCollectionView()
         backgroundView = makeBackgroundView()
         contentView!.addSubview(backgroundView!)
         // highest level possible; this allows the app to go on top of context menus
@@ -41,7 +41,8 @@ class ThumbnailsPanel: NSPanel, NSCollectionViewDataSource, NSCollectionViewDele
         backgroundView.state = .active
         backgroundView.wantsLayer = true
         backgroundView.layer!.cornerRadius = Preferences.windowCornerRadius!
-        backgroundView.addSubview(collectionView_)
+        backgroundView.layer!.backgroundColor = .white
+        backgroundView.addSubview(collectionView)
         return backgroundView
     }
 
@@ -49,62 +50,67 @@ class ThumbnailsPanel: NSPanel, NSCollectionViewDataSource, NSCollectionViewDele
         let collectionView_ = NSCollectionView()
         collectionView_.dataSource = self
         collectionView_.delegate = self
-        collectionView_.collectionViewLayout = makeLayout()
-        collectionView_.backgroundColors = [.clear]
+        collectionView_.collectionViewLayout = CollectionViewCenterFlowLayout()
+        collectionView_.backgroundColors = [.yellow]
         collectionView_.isSelectable = true
         collectionView_.allowsMultipleSelection = false
         collectionView_.register(Cell.self, forItemWithIdentifier: cellId)
         return collectionView_
     }
 
-    func makeLayout() -> CollectionViewCenterFlowLayout {
-        let layout = CollectionViewCenterFlowLayout()
-        layout.estimatedItemSize = NSSize(width: Preferences.emptyThumbnailWidth, height: Preferences.emptyThumbnailHeight)
-        layout.minimumInteritemSpacing = 5
-        layout.minimumLineSpacing = 5
-        return layout
-    }
-
     func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {
         return Windows.list.count
     }
 
     func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {
         let item = collectionView.makeItem(withIdentifier: cellId, for: indexPath) as! Cell
-        item.updateWithNewContent(Windows.list[indexPath.item], app!.focusSelectedWindow, app!.thumbnailsPanel!.highlightCell, currentScreen!)
+        item.updateRecycledCellWithNewContent(Windows.list[indexPath.item], app!.focusSelectedWindow, app!.thumbnailsPanel!.highlightCell, currentScreen!)
         return item
     }
 
     func collectionView(_ collectionView: NSCollectionView, layout collectionViewLayout: NSCollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> NSSize {
-        if indexPath.item < Windows.list.count {
-            let (width, height) = Cell.computeDownscaledSize(Windows.list[indexPath.item].thumbnail, currentScreen!)
-            return NSSize(width: CGFloat(width) + Preferences.cellPadding * 2, height: CGFloat(height) + max(Preferences.fontHeight!, Preferences.iconSize!) + Preferences.interItemPadding + Preferences.cellPadding * 2)
-        }
-        return .zero
+        guard indexPath.item < Windows.list.count else { return .zero }
+        return NSSize(width: Cell.width(Windows.list[indexPath.item].thumbnail, currentScreen!), height: Cell.height(currentScreen!))
     }
 
     func highlightCell() {
-        collectionView_.deselectAll(nil)
-        collectionView_!.selectItems(at: [IndexPath(item: Windows.focusedWindowIndex, section: 0)], scrollPosition: .top)
+        collectionView.deselectAll(nil)
+        collectionView.selectItems(at: [IndexPath(item: Windows.focusedWindowIndex, section: 0)], scrollPosition: .top)
     }
 
     func highlightCell(_ cell: Cell) {
-        let newIndex = collectionView_.indexPath(for: cell)!
+        let newIndex = collectionView.indexPath(for: cell)!
         if Windows.focusedWindowIndex != newIndex.item {
-            collectionView_!.selectItems(at: [newIndex], scrollPosition: .top)
-            collectionView_!.deselectItems(at: [IndexPath(item: Windows.focusedWindowIndex, section: 0)])
+            collectionView.selectItems(at: [newIndex], scrollPosition: .top)
+            collectionView.deselectItems(at: [IndexPath(item: Windows.focusedWindowIndex, section: 0)])
             Windows.focusedWindowIndex = newIndex.item
         }
     }
 
-    func refreshCollectionView(_ currentScreen: NSScreen, _ uiWorkShouldBeDone: Bool) {
-        if uiWorkShouldBeDone { self.currentScreen = currentScreen }
-        if uiWorkShouldBeDone { (collectionView_.collectionViewLayout as! CollectionViewCenterFlowLayout).currentScreen = currentScreen }
-        if uiWorkShouldBeDone { collectionView_!.setFrameSize(Screen.thumbnailPanelMaxSize(currentScreen)) }
-        if uiWorkShouldBeDone { collectionView_!.reloadData() }
-        if uiWorkShouldBeDone { collectionView_!.layoutSubtreeIfNeeded() }
-        if uiWorkShouldBeDone { setContentSize(NSSize(width: collectionView_!.frame.size.width + Preferences.windowPadding * 2, height: collectionView_!.frame.size.height + Preferences.windowPadding * 2)) }
+    func refreshCollectionView(_ screen: NSScreen, _ uiWorkShouldBeDone: Bool) {
+        if uiWorkShouldBeDone { self.currentScreen = screen }
+        if uiWorkShouldBeDone { (collectionView.collectionViewLayout as! CollectionViewCenterFlowLayout).currentScreen = screen }
+        if uiWorkShouldBeDone { collectionView.setFrameSize(NSSize(width: ThumbnailsPanel.widthMax(screen), height: ThumbnailsPanel.heightMax(screen))) }
+        if uiWorkShouldBeDone { collectionView.reloadData() }
+        if uiWorkShouldBeDone { collectionView.layoutSubtreeIfNeeded() }
+        if uiWorkShouldBeDone { setContentSize(NSSize(width: collectionView.frame.size.width + Preferences.windowPadding * 2, height: collectionView.frame.size.height + Preferences.windowPadding * 2)) }
         if uiWorkShouldBeDone { backgroundView!.setFrameSize(frame.size) }
-        if uiWorkShouldBeDone { collectionView_!.setFrameOrigin(NSPoint(x: Preferences.windowPadding, y: Preferences.windowPadding)) }
+        if uiWorkShouldBeDone { collectionView.setFrameOrigin(NSPoint(x: Preferences.windowPadding, y: Preferences.windowPadding)) }
+    }
+
+    static func widthMax(_ screen: NSScreen) -> CGFloat {
+        return screen.frame.width * Preferences.maxScreenUsage - Preferences.windowPadding * 2
+    }
+
+    static func heightMax(_ screen: NSScreen) -> CGFloat {
+        return screen.frame.height * Preferences.maxScreenUsage - Preferences.windowPadding * 2
+    }
+
+    static func widthMin(_ screen: NSScreen) -> CGFloat {
+        return Cell.widthMin(screen) - Preferences.windowPadding * 2
+    }
+
+    static func heightMin(_ screen: NSScreen) -> CGFloat {
+        return Cell.height(screen) - Preferences.windowPadding * 2
     }
 }