ColorGuard — fix the MECHREVO / AiStone Control Center colour-mode LUT bug

中文用户请先看 使用说明.txt —— 傻瓜式逐步操作说明（解压 → 解除锁定 → 捕获曲线 → 开启守护 → 常见问题）。

A ~15 KB WinForms utility that keeps the display gamma ramp (LUT) in sync with the colour mode of MECHREVO's Control Center (AiStone GamingCenter2), because the Control Center itself stopped doing it in version 5.56.60.34.

With Windows 11 Auto color management (ACM) enabled, switching the colour mode in Control Center (原色域 / Default <-> sRGB) updates the ICC profile association but does not rewrite the display gamma ramp (LUT):

Measured on a test unit (RTX 5060 Laptop, internal panel):

LUT sum in Default mode : 22,835,221
LUT sum after switching to sRGB : 22,835,221   <-- identical, nothing was written
Expected for sRGB (identity ramp) : 25,165,440

The old workaround — toggling "colour management" off/on in the Control Center — used to force a ramp rewrite. In 5.56.60.34 that code path is gone, so the workaround no longer works.

• Watches HKLM\SOFTWARE\OEM\GamingCenter2 with RegNotifyChangeKeyValue (event driven — 0 % CPU idle).
• When the Control Center profile changes, it writes the correct ramp:
  • sRGB → identity ramp (let ACM do the gamut transform),
  • Default / 原色域 → the curve captured on this machine.
• Then re-asserts it a few times over 0.4 s to converge with the OS/ACM handover.
• Logs every action with millisecond timestamps to ColorGuard.log.

Measured reaction time: 3–8 ms (registry notification → ramp written).

It never autostarts and has no background service: you launch it and press 开启守护 / Enable guard. Closing the window stops it.

• Windows 10 / 11, .NET Framework 4.x (present on virtually every Windows install)
• MECHREVO (or any other AiStone-based) Control Center, i.e. the registry key HKLM\SOFTWARE\OEM\GamingCenter2 must exist
• Windows "Auto color management" enabled (required for the sRGB side to make sense)

On other brands the registry key is missing — the tool then simply does nothing.

build.cmd

or

%windir%\Microsoft.NET\Framework64\v4.0.30319\csc.exe /nologo /optimize+ ^
  /target:winexe /reference:System.Windows.Forms.dll /reference:System.Drawing.dll ^
  /out:dist\ColorGuard.exe src\ColorGuard.cs

No SDK, no NuGet, no Visual Studio needed.

The published build deliberately contains no machine-specific curve; both modes default to identity. Calibrate once per machine:

1. Start ColorGuard.exe.
2. Control Center → 原色域 / Default; make sure the picture looks correct → press 捕获当前曲线 (capture) → writes profile-default.ramp next to the exe.
3. Control Center → sRGB; make sure the picture looks correct → press 捕获当前曲线 again → writes profile-srgb.ramp.
4. Press 开启守护 / Enable guard.

Capture only when the picture in that mode is already correct — you are recording the ramp that is currently active. If a mode is broken at that moment you would store the broken curve.

The profiles are plain text (768 numbers) and can be copied, backed up or replaced freely. If profile-srgb.ramp is absent, identity is used (correct when ACM is on).

• Switching modes still shows a 0.1–0.3 s transition flash (sometimes a colour-noise or warm tint). That comes from the Control Center + Windows ACM applying their changes asynchronously — it happens with this tool disabled as well. The tool only guarantees that the final state is correct. To avoid the flash entirely, stay in one mode.
• If a future Control Center version starts writing the LUT again, disable this tool.
• Use at your own risk; it only calls GetDeviceGammaRamp / SetDeviceGammaRamp and reads one registry key.

src/ColorGuard.cs        single-file C# source (WinForms)
build.cmd                one-command build with csc
docs/root-cause.md       measurements and reasoning behind the fix
profile-default.ramp     (generated) captured Default-mode ramp
profile-srgb.ramp        (generated) captured sRGB ramp
ColorGuard.log           (generated) action log

问题：机械革命控制中心 5.56.60.34 在切换色域（原色域 ⇄ sRGB）时只改 ICC 关联、不重写显示器伽马曲线。 Default.icm 自带 vcgt（所以原色域正常）；sRGB.icm 没有 vcgt、只有 MHC2，它的校色本应由 Windows ACM 在合成阶段完成 —— 结果 OS 在做 sRGB 变换、显示器下却还压着原色域的旧曲线， 两者叠加就出现偏暗 + 彩噪。旧版可用的"色彩管理关→开"招数在新版失效。

本工具：事件驱动监听 HKLM\SOFTWARE\OEM\GamingCenter2，档位一变就写正确曲线 （sRGB → 恒等；原色域 → 本机捕获的曲线），响应 3–8 ms；不自启、手动开关、关窗即停。

用法：打开 exe → 在"原色域"确认画面正常后点【捕获当前曲线】→ 切"sRGB"确认正常后再点一次 → 点【开启守护】。发布的版本不含任何机器专属曲线，必须自己捕获一次。

限制：只适用于 AiStone 系控制中心（机械革命等）；切换瞬间 0.1–0.3 s 的过渡闪烁由控制中心与 Windows ACM 的异步切换造成，本工具无法消除（关掉本工具同样存在），它只保证最终状态正确。

MIT — see LICENSE.

背景：v1.0 存在一个实际踩到的坑 —— 在"画面还不正常"时点了【捕获当前曲线】， 会把错误的曲线存成该档位的"正确曲线"，守护据此判定"已正确"而不再纠正，画面持续异常。

v1.1 新增三道防线：

1. 捕获时拒绝张冠李戴：当前档位是 sRGB 但屏幕仍在使用原色域曲线（或反之）→ 直接拒绝捕获并提示等待画面刷新。
2. sRGB 档捕获非恒等曲线要二次确认：正常 sRGB 档应由系统按 ICC 校正、屏幕 LUT 保持恒等；偏离时弹窗要求确认。
3. 启动自检自动修复：若 profile-srgb.ramp 与 profile-default.ramp 完全重合（误捕获的典型特征）→ 自动把 sRGB 恢复为恒等曲线，旧文件备份，日志留痕。

另：每次捕获前自动备份 .bak-时间，日志记录前后曲线总和，误操作可回溯。

已在真实机器上实测：模拟"把 default 复制成 srgb"的误捕获，程序启动后自动恢复恒等并写入 self-check: ... restored identity。