Screen area setting.

[serge-rgb]

[Edit: Clarity. Also, I had said something about EasyTab not working with multiple monitors, which wasn't true! EasyTab was working, but setting the whole monitor as the output area. ]

This implements support for screen area mapping, which means not setting the SysOrg and SysExt variables in LogContext.

Looking at lines 895 and 896 of the PR:

       Point.x = EasyTab->ScreenOriginX + Packet.pkX / EasyTab->ScreenAreaRatioX;
       Point.y = EasyTab->ScreenOriginY + Packet.pkY / EasyTab->ScreenAreaRatioY;

when before it was:

        Point.x = Packet.pkX;
        Point.y = Packet.pkY;

This should work as before when the feature is not being used.

• On a single monitor config, ScreenOrigin(X|Y) should be 0.
• When the feature is disabled, SysExt(X|Y) will be equal to CoordRange(X|Y), so ScreenAreaRatio(X|Y) will be 1.

I tested it on my machine enabling only one monitor and toggling the feature, but please test it if you choose to merge this :)

The feature works as expected with Milton compared with other programs that support it (Krita, Mischief, Gimp) but I have only tried it out with Milton. Maybe test it with Papaya first?

Finally, requesting code review :)

[serge-rgb]

Replying to say Don't merge this! Just got this bug report. Tracked it down to find out that the culprit is the ScreenAreaRatio, which doesn't work as expected when Windows has its scaling level above 100%. GetSystemMetrics gets the scaled resolution while the Wacom Driver gets the real resolution..

[serge-rgb]

Reopening until I'm certain it's not an easy fix