Drop the grey level, and settle on black

Preview/PreviewApp.swift

@@ -16,7 +16,7 @@ import AppKit
 ///     NecoSaverPreview --snapshot out.png --cats 5  # override the saved cat count
 ///     NecoSaverPreview --snapshot out.png --speed 4 # override the saved speed
 ///     NecoSaverPreview --snapshot out.png --picture pic.png # override the backdrop
-///     NecoSaverPreview --snapshot out.png --grey    # ... or leave the grey showing
+///     NecoSaverPreview --snapshot out.png --no-picture # ... or leave the black
 ///     NecoSaverPreview --snapshot out.png --options # render the Options sheet instead
 ///
 /// `--size` is in points; snapshots are written at 2x, as on a Retina display.
@@ -123,7 +123,7 @@ enum PreviewApp {
         if let picture = options.picture {
             settings.picturePath = picture
         }
-        if options.grey {
+        if options.noPicture {
             settings.pictureEnabled = false
         }
 
@@ -217,7 +217,7 @@ private struct Options {
     var cats: Int?
     var speed: Double?
     var picture: String?
-    var grey = false
+    var noPicture = false
 
     init(_ arguments: some Sequence<String>) throws {
         var explicitSize = false
@@ -228,8 +228,8 @@ private struct Options {
                 showOptions = true
             case "--preview":
                 isPreview = true
-            case "--grey":
-                grey = true
+            case "--no-picture":
+                noPicture = true
             case "--snapshot", "--frames", "--size", "--cats", "--speed", "--picture":
                 let raw = try Self.value(after: argument, from: &iterator)
                 try set(argument, to: raw, explicitSize: &explicitSize)

README.md

@@ -17,8 +17,7 @@ random point instead of the pointer.
 | Cats | 1 | 1–8 | Cats on screen. Each one wanders on its own. |
 | Size | 64 pt | 32–192 pt | How big the cat is drawn. Walking speed and the size of the mess scale with it. |
 | Speed | 1.00× | 0.2–3.0 | |
-| Picture | on, your wallpaper | | The picture the cats walk on, by path. Type one, or press `Choose…`. Turn it off, or empty the field, for the grey. |
-| Grey level | 0% | 0–100% | The colour behind the cats when no picture is drawn, either by choice or because the path could not be read. |
+| Picture | on, your wallpaper | | The picture the cats walk on, by path. Type one, or press `Choose…`. Turn it off, or empty the field, for a plain black screen. |
 | Paw prints | on | | Dropped while running; fade out after 12 s. |
 | Scratch marks | on | | Dropped while the cat works its claws; fade out after 20 s. |
 

Sources/ConfigureSheetController.swift

@@ -86,7 +86,6 @@ final class ConfigureSheetController: NSObject {
         let integer: (Double) -> String = { String(Int($0.rounded())) }
         let multiplier: (Double) -> String = { String(format: "%.2f×", $0) }
         let points: (Double) -> String = { String(format: "%.0f pt", $0 * Double(Sprites.width)) }
-        let percent: (Double) -> String = { String(format: "%.0f%%", $0 * 100) }
         let settings = NecoSaverSettings.self
 
         return [
@@ -100,11 +99,6 @@ final class ConfigureSheetController: NSObject {
                     describe: multiplier, read: { $0.speed },
                     write: { $0.speed = $1 }),
             makePictureRow(),
-            // Named for what it does. It is the whole backdrop only when no
-            // picture is drawn, so "Background" would overstate it.
-            makeRow(title: "Grey level:", control: makeSlider(range: settings.backgroundRange),
-                    describe: percent, read: { $0.background },
-                    write: { $0.background = $1 }),
             makeCheckboxRow(title: "Paw prints", read: { $0.pawsEnabled },
                             write: { $0.pawsEnabled = $1 }),
             makeCheckboxRow(title: "Scratch marks", read: { $0.scratchEnabled },

Sources/Litter.swift

@@ -32,7 +32,7 @@ final class LitterField {
     /// How much bigger than Neco's own cat these marks belong to (Tuning.unit), so
     /// the mess grows with the sprite.
     var unit: CGFloat = 1
-    /// Mark colour, picked against the background by the engine.
+    /// Mark colour, picked against the backdrop by the engine.
     var ink: NSColor = .black
 
     private var marks: [Mark] = []

Sources/NecoSaverEngine.swift

@@ -11,7 +11,7 @@ final class NecoSaverEngine {
 
     /// The desktop picture to sit the cats on. Supplied by the host rather than
     /// read here: the wallpaper is per display, and only the view knows which
-    /// display it landed on. Left nil, the backdrop is `settings.background`.
+    /// display it landed on. Left nil, the backdrop is plain black.
     var wallpaper: Wallpaper? {
         didSet { configureLitter() }
     }
@@ -91,7 +91,7 @@ final class NecoSaverEngine {
         if let backdrop {
             backdrop.draw(in: rect, context: context)
         } else {
-            context.setFillColor(NSColor(calibratedWhite: settings.background, alpha: 1).cgColor)
+            context.setFillColor(NSColor.black.cgColor)
             context.fill(rect)
         }
 
@@ -112,7 +112,7 @@ final class NecoSaverEngine {
         Tuning(scale: settings.size, speedFactor: settings.speed)
     }
 
-    /// The picture to sit the cats on, if one was supplied. Nil leaves the grey:
+    /// The picture to sit the cats on, if one was supplied. Nil leaves the black:
     /// either it was asked for, or nothing could be read.
     private var backdrop: Wallpaper? {
         settings.pictureEnabled ? wallpaper : nil
@@ -124,7 +124,7 @@ final class NecoSaverEngine {
         litter.unit = tuning.unit
         // Dark marks vanish on a dark backdrop and vice versa, so the ink takes the
         // opposite end from whatever the floor turns out to be.
-        let floor = backdrop.map { $0.brightness(in: bounds) } ?? CGFloat(settings.background)
+        let floor = backdrop.map { $0.brightness(in: bounds) } ?? 0
         litter.ink = NSColor(calibratedWhite: floor < 0.5 ? 0.9 : 0.1, alpha: 1)
     }
 }

Sources/NecoSaverSettings.swift

@@ -16,15 +16,11 @@ struct NecoSaverSettings: Equatable {
     /// size Neco itself uses.
     var size: Double
     var speed: Double
-    /// Background grey level, 0 = black ... 1 = white. The cat is black ink on a
-    /// white body, so it reads at either end; the litter marks flip to suit. Used
-    /// whenever no picture is drawn, either by choice or because none could be read.
-    var background: Double
-    /// Draw `picturePath` behind the cats rather than the flat grey.
+    /// Draw `picturePath` behind the cats rather than the plain black.
     var pictureEnabled: Bool
     /// The picture to draw. Seeded once with the desktop's wallpaper (see
     /// `seedPicturePath`), an ordinary saved value from then on; empty, or naming
-    /// a file that cannot be read, leaves the grey showing.
+    /// a file that cannot be read, leaves the black showing.
     var picturePath: String
     var pawsEnabled: Bool
     var scratchEnabled: Bool
@@ -33,7 +29,6 @@ struct NecoSaverSettings: Equatable {
         catCount: 1,
         size: 2.0,
         speed: 1.0,
-        background: 0.0,
         pictureEnabled: true,
         picturePath: "",
         pawsEnabled: true,
@@ -43,13 +38,11 @@ struct NecoSaverSettings: Equatable {
     static let catCountRange = 1 ... 8
     static let sizeRange = 1.0 ... 6.0
     static let speedRange = 0.2 ... 3.0
-    static let backgroundRange = 0.0 ... 1.0
 
     private enum Key {
         static let catCount = "catCount"
         static let size = "size"
         static let speed = "speed"
-        static let background = "background"
         static let pictureEnabled = "pictureEnabled"
         static let picturePath = "picturePath"
         static let pawsEnabled = "pawsEnabled"
@@ -62,7 +55,6 @@ struct NecoSaverSettings: Equatable {
             Key.catCount: standard.catCount,
             Key.size: standard.size,
             Key.speed: standard.speed,
-            Key.background: standard.background,
             Key.pictureEnabled: standard.pictureEnabled,
             Key.picturePath: standard.picturePath,
             Key.pawsEnabled: standard.pawsEnabled,
@@ -79,7 +71,6 @@ struct NecoSaverSettings: Equatable {
             catCount: catCountRange.clamping(store.integer(forKey: Key.catCount)),
             size: sizeRange.clamping(store.double(forKey: Key.size)),
             speed: speedRange.clamping(store.double(forKey: Key.speed)),
-            background: backgroundRange.clamping(store.double(forKey: Key.background)),
             pictureEnabled: store.bool(forKey: Key.pictureEnabled),
             picturePath: store.string(forKey: Key.picturePath) ?? standard.picturePath,
             pawsEnabled: store.bool(forKey: Key.pawsEnabled),
@@ -99,7 +90,7 @@ struct NecoSaverSettings: Equatable {
     /// Fills in the picture on first run, when nothing has been chosen yet: the
     /// desktop's own wallpaper stands in, and is written down. From then on it is
     /// an ordinary saved value — changing the wallpaper later leaves the backdrop
-    /// alone, and clearing the field leaves the grey.
+    /// alone, and clearing the field leaves the black.
     mutating func seedPicturePath(with path: String) {
         guard picturePath.isEmpty, !path.isEmpty, let store = Self.store else { return }
         picturePath = path
@@ -112,7 +103,6 @@ struct NecoSaverSettings: Equatable {
         store.set(catCount, forKey: Key.catCount)
         store.set(size, forKey: Key.size)
         store.set(speed, forKey: Key.speed)
-        store.set(background, forKey: Key.background)
         store.set(pictureEnabled, forKey: Key.pictureEnabled)
         store.set(picturePath, forKey: Key.picturePath)
         store.set(pawsEnabled, forKey: Key.pawsEnabled)

Sources/NecoSaverView.swift

@@ -76,7 +76,7 @@ final class NecoSaverView: ScreenSaverView {
     }
 
     /// Reads a picture only when one is going to be drawn — decoding one costs
-    /// several megabytes that a grey backdrop has no use for.
+    /// several megabytes that a black backdrop has no use for.
     private func loadWallpaper() {
         engine.wallpaper = Wallpaper.matching(engine.settings, on: window?.screen)
     }

Sources/Wallpaper.swift

@@ -7,15 +7,15 @@ import AppKit
 /// (plus `com.apple.security.assets.pictures.read-only`), so a picture anywhere on
 /// disk opens with no bookmark and no panel. Everything here degrades to `nil`
 /// rather than throwing — a path can name a file that has moved, or a video — and
-/// the engine falls back to a plain grey.
+/// the engine falls back to plain black.
 @MainActor
 struct Wallpaper {
     private let image: NSImage
     private let scaling: NSImageScaling
     private let allowsClipping: Bool
     private let fillColor: NSColor
 
-    /// The picture the settings ask for, or nil to leave the grey showing.
+    /// The picture the settings ask for, or nil to leave the black showing.
     static func matching(_ settings: NecoSaverSettings, on screen: NSScreen?) -> Wallpaper? {
         guard settings.pictureEnabled else { return nil }
         return picture(atPath: settings.picturePath, on: screen)