Activeで指定したウィンドウを半透明に

# 必要なuser32.dllのメソッドを定義
Add-Type @"
    using System;
    using System.Runtime.InteropServices;
    public class User32 {
        [DllImport("user32.dll", SetLastError = true)]
        public static extern IntPtr GetForegroundWindow();

        [DllImport("user32.dll", SetLastError = true)]
        public static extern int GetWindowLong(IntPtr hWnd, int nIndex);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool SetLayeredWindowAttributes(IntPtr hwnd, uint crKey, byte bAlpha, uint dwFlags);
    }
"@ -ErrorAction Stop

# 定数の設定
$GWL_EXSTYLE = -20
$WS_EX_LAYERED = 0x80000
$LWA_ALPHA = 0x2

# アクティブなウィンドウのハンドルを取得
$activeWindowHandle = [User32]::GetForegroundWindow()

# 現在のウィンドウの拡張スタイルを取得
$currentStyle = [User32]::GetWindowLong($activeWindowHandle, $GWL_EXSTYLE)

# レイヤードスタイルを設定
[User32]::SetWindowLong($activeWindowHandle, $GWL_EXSTYLE, $currentStyle -bor $WS_EX_LAYERED)

# 透明度を設定 (0: 完全に透明, 255: 不透明)
# 例えば、128を設定すると半透明になります。
$opacity = 128
[User32]::SetLayeredWindowAttributes($activeWindowHandle, 0, [byte]$opacity, $LWA_ALPHA)

Write-Output "The transparency of the active window has been set to $opacity."