eGalax touchscreen calibration

[Markamc]

The equation is,

m_mouseX = g_graphicsContext.GetWidth() - (int)(((float)levt.value) * (calib_x_fact)) - calib_x_d;
1280 - ((Touch screen values) * -0.666) - 1280
and for 1080 1920 - ((Touch screen values) * -0.666) - 1920

If you change the overscan though in config.txt or video calibration, this constant g_graphicsContext.GetWidth() effects the calibration values, so you can alter the last value to change the offset back to corner of screen.

hope this makes sense