perf: cache expensive layout values

src/ui/main-window/ThumbnailTitleView.swift

@@ -2,6 +2,7 @@ import Cocoa
 
 class ThumbnailTitleView: NSTextField {
     private var currentWidth: CGFloat = -1
+    private var widthConstraint: NSLayoutConstraint?
 
     convenience init(font: NSFont) {
         self.init(labelWithString: "")
@@ -21,15 +22,13 @@ class ThumbnailTitleView: NSTextField {
         guard currentWidth != width else { return }
         currentWidth = width
         frame.size.width = width
-        // TODO: NSTextField does some internal magic, and ends up with constraints.
-        // we can't use addOrUpdateConstraint for some reason, otherwise it will only actually apply after the UI is shown twice
-        // i tried everything and ended up removing all constraints then adding a fresh one. This seems to work
-        let toRemove = constraints.filter {
-            ($0.firstItem as? NSView) === self && $0.firstAttribute == .width ||
-                ($0.secondItem as? NSView) === self && $0.secondAttribute == .width
+        if let widthConstraint {
+            widthConstraint.constant = width
+        } else {
+            let constraint = widthAnchor.constraint(equalToConstant: width)
+            constraint.isActive = true
+            widthConstraint = constraint
         }
-        toRemove.forEach { removeConstraint($0) }
-        widthAnchor.constraint(equalToConstant: width).isActive = true
     }
 
     override func mouseMoved(with event: NSEvent) {

src/ui/main-window/ThumbnailView.swift

@@ -4,6 +4,7 @@ class ThumbnailView: FlippedView {
     static let noOpenWindowToolTip = NSLocalizedString("App is running but has no open window", comment: "")
     // when calculating the width of a nstextfield, somehow we need to add this suffix to get the correct width
     static let extraTextForPadding = "lmnopqrstuvw"
+
     var window_: Window?
     var thumbnail = LightImageView(withTransparencyChecks: true)
     var appIcon = LightImageView()
@@ -310,7 +311,7 @@ class ThumbnailView: FlippedView {
             }
         }
         let xPosition = -leftOffset
-        let height = label.fittingSize.height
+        let height = ThumbnailsView.layoutCache.labelHeight
         let yPosition = hStackView.frame.origin.y + hStackView.frame.height + Appearance.intraCellPadding * 2
         label.frame = NSRect(x: xPosition, y: yPosition, width: effectiveLabelWidth, height: height)
         label.setWidth(effectiveLabelWidth)
@@ -379,7 +380,7 @@ class ThumbnailView: FlippedView {
             assignIfDifferent(&hStackView.frame.size, NSSize(width: appIcon.frame.width, height: appIcon.frame.height))
         } else {
             assignIfDifferent(&vStackView.frame.size, NSSize(width: frame.width, height: frame.height))
-            assignIfDifferent(&hStackView.frame.size, NSSize(width: frame.width - Appearance.edgeInsetsSize * 2, height: max(appIcon.frame.height, label.fittingSize.height)))
+            assignIfDifferent(&hStackView.frame.size, NSSize(width: frame.width - Appearance.edgeInsetsSize * 2, height: max(appIcon.frame.height, ThumbnailsView.layoutCache.labelHeight)))
             let labelWidth = hStackView.frame.width - appIcon.frame.width - Appearance.appIconLabelSpacing - indicatorsSpace()
             label.setWidth(labelWidth)
         }
@@ -391,12 +392,12 @@ class ThumbnailView: FlippedView {
             assignIfDifferent(&appIcon.frame.origin.x, App.shared.userInterfaceLayoutDirection == .leftToRight
                 ? 0
                 : hStackView.frame.width - appIcon.frame.width)
-            let iconWidth = windowIndicatorIcons.first!.fittingSize.width
+            let iconWidth = ThumbnailsView.layoutCache.iconWidth
             var indicatorSpace = CGFloat(0)
             for icon in windowIndicatorIcons {
                 if !icon.isHidden {
                     indicatorSpace += iconWidth
-                    icon.centerFrameInParent(y: true)
+                    assignIfDifferent(&icon.frame.origin.y, ((hStackView.frame.height - ThumbnailsView.layoutCache.iconHeight) / 2).rounded())
                     assignIfDifferent(&icon.frame.origin.x, App.shared.userInterfaceLayoutDirection == .leftToRight
                         ? hStackView.frame.width - indicatorSpace
                         : indicatorSpace - iconWidth)
@@ -406,7 +407,7 @@ class ThumbnailView: FlippedView {
             assignIfDifferent(&label.frame.origin.x, App.shared.userInterfaceLayoutDirection == .leftToRight
                 ? appIcon.frame.maxX + Appearance.appIconLabelSpacing
                 : hStackView.frame.width - appIcon.frame.width - Appearance.appIconLabelSpacing - labelWidth)
-            label.centerFrameInParent(y: true)
+            assignIfDifferent(&label.frame.origin.y, ((hStackView.frame.height - ThumbnailsView.layoutCache.labelHeight) / 2).rounded())
         }
         if Preferences.appearanceStyle == .thumbnails {
             assignIfDifferent(&thumbnail.frame.origin, NSPoint(x: Appearance.edgeInsetsSize, y: hStackView.frame.maxY + Appearance.intraCellPadding))
@@ -438,8 +439,8 @@ class ThumbnailView: FlippedView {
         // we set dockLabelIcon origin, without checking if .isHidden
         // This is because its updated async. We need it positioned correctly always
         let (offsetX, offsetY) = dockLabelOffset()
-        assignIfDifferent(&dockLabelIcon.frame.origin.x, appIcon.frame.maxX - (dockLabelIcon.fittingSize.width * offsetX).rounded())
-        assignIfDifferent(&dockLabelIcon.frame.origin.y, appIcon.frame.maxY - (dockLabelIcon.fittingSize.height * offsetY).rounded())
+        assignIfDifferent(&dockLabelIcon.frame.origin.x, appIcon.frame.maxX - (ThumbnailsView.layoutCache.dockLabelSize.width * offsetX).rounded())
+        assignIfDifferent(&dockLabelIcon.frame.origin.y, appIcon.frame.maxY - (ThumbnailsView.layoutCache.dockLabelSize.height * offsetY).rounded())
     }
 
     /// positioning the dock label is messy because it's an NSTextField so it's visual size doesn't match what we can through APIs
@@ -469,8 +470,7 @@ class ThumbnailView: FlippedView {
     }
 
     private func indicatorsSpace() -> CGFloat {
-        let iconWidth = windowIndicatorIcons.first!.fittingSize.width
-        return CGFloat(windowIndicatorIcons.filter { !$0.isHidden }.count) * iconWidth
+        return CGFloat(windowIndicatorIcons.filter { !$0.isHidden }.count) * ThumbnailsView.layoutCache.iconWidth
     }
 
     private func getAppOrAndWindowTitle() -> String {

src/ui/main-window/ThumbnailsView.swift

@@ -8,11 +8,22 @@ class ThumbnailsView {
     static var recycledViews = [ThumbnailView]()
     static var thumbnailsWidth = CGFloat(0.0)
     static var thumbnailsHeight = CGFloat(0.0)
+    static var layoutCache = LayoutCache()
 
     init() {
         updateBackgroundView()
         // TODO: think about this optimization more
         (1...20).forEach { _ in ThumbnailsView.recycledViews.append(ThumbnailView()) }
+        Self.updateCachedSizes()
+    }
+
+    static func updateCachedSizes() {
+        guard let firstView = ThumbnailsView.recycledViews.first else { return }
+        layoutCache.labelHeight = firstView.label.fittingSize.height
+        let iconFittingSize = firstView.windowIndicatorIcons.first!.fittingSize
+        layoutCache.iconWidth = iconFittingSize.width
+        layoutCache.iconHeight = iconFittingSize.height
+        layoutCache.dockLabelSize = firstView.dockLabelIcon.fittingSize
     }
 
     func updateBackgroundView() {
@@ -39,6 +50,7 @@ class ThumbnailsView {
         for i in 0..<ThumbnailsView.recycledViews.count {
             ThumbnailsView.recycledViews[i] = ThumbnailView()
         }
+        Self.updateCachedSizes()
     }
 
     static func highlight(_ indexInRecycledViews: Int) {
@@ -116,7 +128,7 @@ class ThumbnailsView {
     }
 
     private func layoutThumbnailViews(_ widthMax: CGFloat) -> (CGFloat, CGFloat, CGFloat, [Int])? {
-        let labelHeight = ThumbnailsView.recycledViews.first!.label.fittingSize.height
+        let labelHeight = Self.layoutCache.labelHeight
         let height = ThumbnailView.height(labelHeight)
         let isLeftToRight = App.shared.userInterfaceLayoutDirection == .leftToRight
         let startingX = isLeftToRight ? Appearance.interCellPadding : widthMax - Appearance.interCellPadding
@@ -247,6 +259,13 @@ class ThumbnailsView {
             }
         }
     }
+
+    struct LayoutCache {
+        var labelHeight = CGFloat(0)
+        var iconWidth = CGFloat(0)
+        var iconHeight = CGFloat(0)
+        var dockLabelSize = NSSize.zero
+    }
 }
 
 class ScrollView: NSScrollView {