[macos][swift4]Switch and Display DisplayMode command and StatusBar Menu app

cg-hidden.h

#include <stdio.h>
#include <stdlib.h>
#include <CoreGraphics/CoreGraphics.h>

// https://github.com/robbertkl/ResolutionMenu/blob/master/Resolution%20Menu/DisplayModeMenuItem.m
// CoreGraphics DisplayMode struct used in private APIs
typedef struct {
  uint32_t modeNumber;
  uint32_t flags;
  uint32_t width;
  uint32_t height;
  uint32_t depth;
  uint8_t unknown[170];
  uint16_t freq;
  uint8_t more_unknown[16];
  float density;
} CGSDisplayMode;
// CoreGraphics private APIs with support for scaled (retina) display modes
void CGSGetCurrentDisplayMode(CGDirectDisplayID display, int* modeNum);
void CGSConfigureDisplayMode(
  CGDisplayConfigRef config, CGDirectDisplayID display, int modeNum);
void CGSGetNumberOfDisplayModes(CGDirectDisplayID display, int* nModes);
void CGSGetDisplayModeDescriptionOfLength(
  CGDirectDisplayID display, int idx, CGSDisplayMode* mode, int length);

DisplayMode.swift

#!/usr/bin/env swift -import-objc-header cg-hidden.h
// $ swiftc -import-objc-header cg-hidden.h DisplayMode.swift
import Foundation
import CoreFoundation
import CoreGraphics

let display = CGMainDisplayID()
let count = UnsafeMutablePointer<Int32>.allocate(capacity: 1)
defer {count.deallocate()}
CGSGetNumberOfDisplayModes(display, count);

let argv = CommandLine.arguments
if argv.count == 2 {
    guard let modeNum = Int32(argv[1]) else {
        fputs("mode num should be integer but: \(argv[1])\n", stderr)
        exit(1)
    }
    if modeNum < 0 || count.pointee <= modeNum {
        fputs("mode num should be in 0-\(count.pointee - 1) but: \(argv[1])\n", stderr)
        exit(1)
    }
    let config = UnsafeMutablePointer<CGDisplayConfigRef?>.allocate(capacity: 1)
    defer {config.deallocate()}
    CGBeginDisplayConfiguration(config)
    CGSConfigureDisplayMode(config.pointee, display, modeNum)
    CGCompleteDisplayConfiguration(config.pointee, CGConfigureOption.permanently)
}

let current = UnsafeMutablePointer<Int32>.allocate(capacity: 1)
defer {current.deallocate()}
CGSGetCurrentDisplayMode(display, current);
let dmode = UnsafeMutablePointer<CGSDisplayMode>.allocate(capacity: 1)
defer {dmode.deallocate()}
let size = Int32(MemoryLayout<CGSDisplayMode>.size)
for i in 0 ..< count.pointee {
    CGSGetDisplayModeDescriptionOfLength(display, i, dmode, size)
    let mark = i == current.pointee ? "(current)" : ""
    print(String(format: "mode %2d: %5d x %-5d \(mark)",
                 i, dmode.pointee.width, dmode.pointee.height))
}

DisplayModeSwitcher.swift

#!/usr/bin/env swift -import-objc-header cg-hidden.h
// DisplayMode switcher on StatrusBar (for swift4)
// $ swiftc -import-objc-header cg-hidden.h DisplayModeSwitcher.swift
import Cocoa

let monoText = NSFont.monospacedDigitSystemFont(ofSize: NSFont.systemFontSize, weight: .regular)
let attrsT: [NSAttributedString.Key: Any] = [.font: monoText]
let attrsS: [NSAttributedString.Key: Any] = [.font: monoText, .expansion: 0.8]
func resolution(_ id: String, _ w: String, _ h: String, _ mark: String) -> NSAttributedString {
    let parts = [(String(repeating: " ", count: 3 - id.count), attrsS), ("\(id): ", attrsT),
                 (String(repeating: " ", count: 5 - w.count), attrsS), ("\(w) x \(h)", attrsT),
                 (String(repeating: " ", count: 5 - h.count), attrsS), (mark, attrsT)]
    let title = NSMutableAttributedString()
    for (text, attrs) in parts {title.append(NSAttributedString(string: text, attributes: attrs))}
    return title
}

class Main: NSObject, NSMenuDelegate {
    func menuWillOpen(_ menu: NSMenu) {
        menu.removeAllItems()
        let display = CGMainDisplayID()
        let count = UnsafeMutablePointer<Int32>.allocate(capacity: 1)
        defer {count.deallocate()}
        CGSGetNumberOfDisplayModes(display, count)
        let current = UnsafeMutablePointer<Int32>.allocate(capacity: 1)
        defer {current.deallocate()}
        CGSGetCurrentDisplayMode(display, current)

        let dmode = UnsafeMutablePointer<CGSDisplayMode>.allocate(capacity: 1)
        defer {dmode.deallocate()}
        let size = Int32(MemoryLayout<CGSDisplayMode>.size)
        let items = (0 ..< count.pointee).map {(i) -> NSMenuItem in
            CGSGetDisplayModeDescriptionOfLength(display, i, dmode, size)
            let mark = i == current.pointee ? "\u{2713}" : ""
            let mi = NSMenuItem()
            mi.attributedTitle = resolution(
              "\(i)", "\(dmode.pointee.width)", "\(dmode.pointee.height)",  "\(mark)")
            mi.target = self
            mi.action = #selector(self.switchMode(_:))
            mi.tag = Int(i)
            return mi
        }
        for item in items {menu.addItem(item)}

        menu.addItem(NSMenuItem.separator())
        let terminate = #selector(NSApplication.shared.terminate) 
        menu.addItem(withTitle: "Quit", action: terminate, keyEquivalent: "")
    }

    @objc func switchMode(_ sender: NSMenuItem) {
        let display = CGMainDisplayID()
        let config = UnsafeMutablePointer<CGDisplayConfigRef?>.allocate(capacity: 1)
        defer {config.deallocate()}
        CGBeginDisplayConfiguration(config)
        CGSConfigureDisplayMode(config.pointee, display, Int32(sender.tag))
        CGCompleteDisplayConfiguration(config.pointee, CGConfigureOption.permanently)
    }
}
let main = Main()


NSApplication.loadApplication()
let menu = NSMenu()
menu.delegate = main
let statusItem = NSStatusBar.system.statusItem(withLength: -1)
statusItem.button?.title = "\u{1F5A5}"
//statusItem.button?.title = "\u{1F4BB}"
statusItem.menu = menu
NSApplication.shared.run()

icon.svg

Info.plist.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>CFBundleInfoDictionaryVersion</key>
  <string>6.0</string>
  <key>CFBundlePackageType</key>
  <string>APPL</string>
  <key>CFBundleDevelopmentRegion</key>
  <string>en</string>
  <key>CFBundleExecutable</key>
  <string>%name%</string>
  <key>CFBundleIdentifier</key>
  <string>%id%</string>
  <key>CFBundleIconFile</key>
  <string>%name%.icns</string>
  <key>CFBundleName</key>
  <string>%name%</string>
  <key>CFBundleShortVersionString</key>
  <string>1.0</string>
  <key>CFBundleVersion</key>
  <string>1</string>
  <key>LSUIElement</key>
  <true/>
</dict>
</plist>

makeappbundle.sh

#!/bin/bash

if [ "$(which convert)" == "" ] ; then
    echo "[Abort] Please install imagemagick"
    exit 1
fi

namespace=bellbind
name=DisplayModeSwitcher
svg=icon.svg
id="$namespace.$name"

#NOTE: Prepare your certificate in "Keychain Access"
#cert=bellbind

# build bin
cd $(dirname $0)
swiftopts="-import-objc-header cg-hidden.h"
swiftc $swiftopts "$name.swift"

# build icns from svg
iconset="$name.iconset"
png="$svg.png"
opts="-fuzz 15% -transparent white"
mkdir -p "$iconset"
qlmanage -t -s 1024 -o . "$svg"
convert "$png" $opts -resize 16x16 "$iconset/icon_16x16.png"
convert "$png" $opts -resize 32x32 "$iconset/icon_16x16@2x.png"
convert "$png" $opts -resize 32x32 "$iconset/icon_32x32.png"
convert "$png" $opts -resize 64x64 "$iconset/icon_32x32@2x.png"
convert "$png" $opts -resize 128x128 "$iconset/icon_128x128.png"
convert "$png" $opts -resize 256x256 "$iconset/icon_128x128@2x.png"
convert "$png" $opts -resize 256x256 "$iconset/icon_256x256.png"
convert "$png" $opts -resize 512x512 "$iconset/icon_256x256@2x.png"
convert "$png" $opts -resize 512x512 "$iconset/icon_512x512.png"
convert "$png" $opts -resize 1024x1024 "$iconset/icon_512x512@2x.png"
iconutil -c icns "$iconset"

# build app bundle
app="$name.app"
mkdir -p "$app/Contents/MacOS"
mkdir -p "$app/Contents/Resources"
sed -e "s/%name%/$name/g;s/%id%/$id/g" Info.plist.xml > "$app/Contents/Info.plist"
cp "$name" "$app/Contents/MacOS"
cp "$name.icns" "$app/Contents/Resources"

# cleanup
rm -r "$name.iconset"
rm "$name" "$name.icns" "$png"

# codesign
if [ "$cert" ] ; then
    codesign -s "$cert" "$app"
fi

# make dmg
mkdir -p dmg/
cp -a "$app" dmg/
( cd dmg ; ln -s /Applications/ )
hdiutil create -srcfolder dmg -volname "$name" "$name.dmg"
rm -rf dmg/

• C commandline with hidden API: https://gist.github.com/bellbind/27220148ea752335259dfce63f43bd5d
• StatusBar app with standard API: https://gist.github.com/bellbind/b69f6ef133f0ad5266ff40be2001aecc