feat: windows on mouse screen, implements lwouis#28

- adds a new Preference to use the main screen (keyboard focus) or mouse location screen
- honors that preference for thumbnail generation and display of all panels
- increases the Preferences version
- widens PreferencesPanel width and input sizing to allow 3 characters, issue lwouis#59 minimal adjustment

alt-tab-macos/logic/Preferences.swift

@@ -2,17 +2,23 @@ import Foundation
 import Cocoa
 import Carbon.HIToolbox.Events
 
+enum ShowOnScreenPreference {
+    case MAIN
+    case MOUSE
+}
+
 class Preferences {
     static var defaults: [String: String] = [
-        "version": "2", // bump this anytime the dictionary is changed
+        "version": "3", // bump this anytime the dictionary is changed
         "maxScreenUsage": "80",
         "maxThumbnailsPerRow": "4",
         "iconSize": "32",
         "fontHeight": "15",
         "tabKeyCode": String(kVK_Tab),
         "metaKey": metaKeyMacro.macros[0].label,
         "windowDisplayDelay": "0",
-        "theme": themeMacro.macros[0].label
+        "theme": themeMacro.macros[0].label,
+        "showOnScreen": showOnScreenMacro.macros[0].label
     ]
     static var rawValues = [String: String]()
     static var thumbnailMaxWidth: CGFloat = 200
@@ -37,6 +43,7 @@ class Preferences {
     static var windowDisplayDelay: DispatchTimeInterval?
     static var windowCornerRadius: CGFloat?
     static var font: NSFont?
+    static var showOnScreen: ShowOnScreenPreference?
     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))
@@ -46,6 +53,10 @@ class Preferences {
         MacroPreference("⌃ control", ([kVK_Control, kVK_RightControl], .control)),
         MacroPreference("⌘ command", ([kVK_Command, kVK_RightCommand], .command))
     ])
+    static var showOnScreenMacro = MacroPreferenceHelper<(ShowOnScreenPreference)>([
+        MacroPreference("with keyboard focus", (ShowOnScreenPreference.MAIN)),
+        MacroPreference("with mouse pointer", (ShowOnScreenPreference.MOUSE)),
+    ])
 
     private static let defaultsFile = fileFromPreferencesFolder("alt-tab-macos-defaults.json")
     private static let userFile = fileFromPreferencesFolder("alt-tab-macos.json")
@@ -89,6 +100,9 @@ class Preferences {
             highlightBackgroundColor = p.preferences.4
         case "windowDisplayDelay":
             windowDisplayDelay = DispatchTimeInterval.milliseconds(try Int(value).orThrow())
+        case "showOnScreen":
+            let p = try showOnScreenMacro.labelToMacro[value].orThrow()
+            showOnScreen = p.preferences
         default:
             throw "Tried to update an unknown preference: '\(valueName)' = '\(value)'"
         }

alt-tab-macos/logic/Screen.swift

@@ -14,9 +14,23 @@ class Screen {
 
     static func updateThumbnailMaxSize() -> Void {
         if Preferences.thumbnailMaxWidth == 200 && Preferences.thumbnailMaxHeight == 200 {
-            let main = NSScreen.main!.frame
+            let screenFrame = getPreferredScreen().frame
             Preferences.thumbnailMaxWidth = (NSScreen.main!.frame.size.width * Preferences.maxScreenUsage! - Preferences.windowPadding * 2) / Preferences.maxThumbnailsPerRow! - Preferences.interItemPadding
-            Preferences.thumbnailMaxHeight = Preferences.thumbnailMaxWidth * (main.height / main.width)
+            Preferences.thumbnailMaxHeight = Preferences.thumbnailMaxWidth * (screenFrame.height / screenFrame.width)
         }
     }
+
+    static func getPreferredScreen() -> NSScreen {
+        switch Preferences.showOnScreen! {
+        case .MOUSE:
+            return getScreenWithMouse() ?? NSScreen.main!; // .main as fail-safe
+        default: // no case for .MAIN since its currently the same as default case
+            return NSScreen.main!;
+        }
+    }
+
+    // https://stackoverflow.com/a/49624487/4767781
+    static func getScreenWithMouse() -> NSScreen? {
+        return NSScreen.screens.first { NSMouseInRect(NSEvent.mouseLocation, $0.frame, false) }
+    }
 }

alt-tab-macos/ui/Application.swift

@@ -61,11 +61,13 @@ class Application: NSApplication, NSApplicationDelegate, NSWindowDelegate {
     }
 
     @objc func showCenteredPreferencesPanel() {
-        showCenteredPanel(preferencesPanel!)
+        showCenteredFrontPanel(preferencesPanel!)
     }
 
-    func showCenteredPanel(_ panel: NSPanel) {
-        panel.center()
+    func showCenteredFrontPanel(_ panel: NSPanel, _ screenOverride: NSScreen? = nil) {
+        let preferredScreen = screenOverride ?? Screen.getPreferredScreen() // use optional provided screen or determine it just in time
+        let centerPosition = NSPoint(x: preferredScreen.visibleFrame.midX - panel.frame.width / 2, y: preferredScreen.visibleFrame.midY - panel.frame.height / 2)
+        panel.setFrameOrigin(centerPosition)
         panel.makeKeyAndOrderFront(nil)
         Application.shared.arrangeInFront(nil)
     }
@@ -109,11 +111,12 @@ class Application: NSApplication, NSApplicationDelegate, NSWindowDelegate {
                 return
             }
             selectedOpenWindow = cellWithStep(step)
+            let preferredScreen = Screen.getPreferredScreen() // we want the thumbnail computation and panel display use the same screen (in case mouse movements switching screens etc.)
             var workItem: DispatchWorkItem!
             workItem = DispatchWorkItem {
-                if !workItem.isCancelled { self.thumbnailsPanel!.computeThumbnails() }
+                if !workItem.isCancelled { self.thumbnailsPanel!.computeThumbnails(preferredScreen) }
                 if !workItem.isCancelled { self.thumbnailsPanel!.highlightCellAt(step) }
-                if !workItem.isCancelled { self.showCenteredPanel(self.thumbnailsPanel!) }
+                if !workItem.isCancelled { self.showCenteredFrontPanel(self.thumbnailsPanel!, preferredScreen) }
             }
             workItems.append(workItem)
             DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + Preferences.windowDisplayDelay!, execute: workItem)

alt-tab-macos/ui/PreferencesPanel.swift

@@ -15,6 +15,7 @@ class PreferencesPanel: NSPanel, NSTextViewDelegate {
     var windowDisplayDelay: NSTextView?
     var metaKey: NSPopUpButton?
     var theme: NSPopUpButton?
+    var showOnScreen: NSPopUpButton?
     var inputsMap = [NSTextView: String]()
 
     override init(contentRect: NSRect, styleMask style: StyleMask, backing backingStoreType: BackingStoreType, defer flag: Bool) {
@@ -34,14 +35,15 @@ class PreferencesPanel: NSPanel, NSTextViewDelegate {
             makeLabelWithInput(\PreferencesPanel.iconSize, "Apps icon size (px)", "iconSize"),
             makeLabelWithInput(\PreferencesPanel.fontHeight, "Font size (px)", "fontHeight"),
             makeLabelWithInput(\PreferencesPanel.windowDisplayDelay, "Window apparition delay (ms)", "windowDisplayDelay"),
+            makeLabelWithDropdown(\PreferencesPanel.showOnScreen, "Show on Screen", "showOnScreen", Preferences.showOnScreenMacro.labels)
         ]
     }
 
     private func makeGridView(_ rows: [[NSView]], _ warningLabel: BaseLabel) -> NSGridView {
         let gridView = NSGridView(views: rows)
         gridView.setContentHuggingPriority(.defaultLow, for: .horizontal)
         gridView.setContentHuggingPriority(.defaultLow, for: .vertical)
-        gridView.widthAnchor.constraint(greaterThanOrEqualToConstant: 360).isActive = true
+        gridView.widthAnchor.constraint(greaterThanOrEqualToConstant: 380).isActive = true
         gridView.addRow(with: [warningLabel, NSGridCell.emptyContentView])
         gridView.mergeCells(inHorizontalRange: NSRange(location: 0, length: 2), verticalRange: NSRange(location: gridView.numberOfRows - 1, length: 1))
         return gridView
@@ -61,7 +63,7 @@ class PreferencesPanel: NSPanel, NSTextViewDelegate {
         input.delegate = self
         input.font = Preferences.font
         input.string = Preferences.rawValues[rawName]!
-        input.widthAnchor.constraint(equalToConstant: 32).isActive = true
+        input.widthAnchor.constraint(equalToConstant: 40).isActive = true
         self[keyPath: keyPath] = input
         inputsMap[input] = rawName
         return [label, input]
@@ -86,6 +88,8 @@ class PreferencesPanel: NSPanel, NSTextViewDelegate {
                 try! Preferences.updateAndValidateFromString("theme", popUpButton.titleOfSelectedItem!)
             case metaKey:
                 try! Preferences.updateAndValidateFromString("metaKey", popUpButton.titleOfSelectedItem!)
+            case showOnScreen:
+                try! Preferences.updateAndValidateFromString("showOnScreen", popUpButton.titleOfSelectedItem!)
             default:
                 throw "Tried to update an unknown popUpButton: '\(popUpButton)' = '\(popUpButton.titleOfSelectedItem!)'"
             }

alt-tab-macos/ui/ThumbnailsPanel.swift

@@ -91,8 +91,9 @@ class ThumbnailsPanel: NSPanel, NSCollectionViewDataSource, NSCollectionViewDele
         }
     }
 
-    func computeThumbnails() {
-        let maxSize = NSSize(width: NSScreen.main!.frame.width * Preferences.maxScreenUsage!, height: NSScreen.main!.frame.height * Preferences.maxScreenUsage!)
+    func computeThumbnails(_ screenOverride: NSScreen? = nil) {
+        let preferredScreen = screenOverride ?? Screen.getPreferredScreen() // use optional provided screen or determine it just in time
+        let maxSize = NSSize(width: preferredScreen.frame.width * Preferences.maxScreenUsage!, height: preferredScreen.frame.height * Preferences.maxScreenUsage!)
         collectionView_!.setFrameSize(maxSize)
         collectionView_!.collectionViewLayout!.invalidateLayout()
         collectionView_!.reloadData()