Metatrader Application Window Width

I need to determine the MetaTrader Application Window Width (not the Chart Width).
The Chart Width I can get with CHART_WIDTH_IN_PIXELS ,
but how do I get the width of the application window?

You can extract the info from here: https://www.mql5.com/en/articles/1903

Basically, you would use Windows API functions to get the metrics of any window in the system.