I know that in the Duplicate mode(Win + P), the display contents of the two monitors are exactly the same. Even through EnumDisplayMonitors or GetSystemMetrics(SM_CMONITORS), only one monitor information can be obtained.
I currently have this requirement. In the Duplicate mode, only a green mask is displayed on one of the monitors for matting.
If you use a semi-transparent green window, both monitors will display this green mask (after all, it is in Duplicate mode).
I tried to modify the color temperature of one of the monitors (SetMonitorRedGreenOrBlueGain), but not all monitors support it.
Is there any solution? Thank you.