How to get the double click time setting on various platforms.
DRAFT of 2024-03-11
John Nagle


Windows:

    GetDoubleClickTime function (winuser.h)

    https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getdoubleclicktime


MacOS:

    NSTimeInterval doubleClickInterval = [NSEvent doubleClickInterval];

    https://stackoverflow.com/questions/12354923/how-can-i-read-the-mac-osxs-double-click-duration-programmatically

    class var doubleClickInterval: TimeInterval { get }

    https://developer.apple.com/documentation/appkit/nsevent/1528384-doubleclickinterval

Linux:

    Gnome: 
        Default is 400ms.
        
        Ubuntu: There's now a standard way to set the double click delay via the UI.
        Settings->Accessability->Pointing and Clicking->Double click delay
   
        The source for the Gnome Settings program is here:
        https://gitlab.gnome.org/GNOME/gnome-control-center
   
        Documetation is vague on how that works. See
        https://discourse.gnome.org/t/what-should-i-use-to-get-the-double-click-time/6998
        
    KDE:
   
        Ref: https://forum.kde.org/viewtopic.php%3Ft=153755.html
   
        DoubleClickInterval

        in the KDE section of ~/.config/kdeglobals
        
        Format is
        
           DoubleClickInterval=500
           
        Unit is milliseconds.
        
Browser/WASM

    ?
    
Android

    Double click considered nonstandard.
   
Egui:

    It's a constant in Egui.
    
    https://github.com/emilk/egui/blob/00a399b2f7eae6bcbe968bdaa7bb77689043bba2/crates/egui/src/input_state.rs#L18
    const MAX_DOUBLE_CLICK_DELAY: f64 = 0.3; // TODO(emilk): move to settings