Windows 8 tablets are one of an increasing range of devices to feature a dual input screen, capable of identifying finger touch and pressure-sensitive pen input in the same glass screen. The technology is made by Wacom who have a pedigree in digitising and pressure-sensitive tablets and screens used in the graphic arts.
Unlike Wacom's high-end digitising pads, however, the screen based digitising technology does not recognise the pen position precisely, paticularly in corners and along edges of the screen, and requires calibration to minimise this effect. Microsoft includes a utility to do this which provides a default grid of points across and down the screen. Users who want to fine-tune their screen can use the same utility via the command line to create a grid with a large number of points.
Here's an example of the command and its arguments:
tabcal lincal novalidate XGridPts=2,20,200,855,1720,1810,1900,1918
YGridPts=2,20,200,540,880,1060,1078
The XGridPoints and YGridPoints arguments are a comma-separated list of points on screen at which a grid point will be defined within the calibration utility.
The utility I've written will create this command for you based on your screen size and positions of lines from the edges of the screen. The application defaults to settings for the Microsoft Surface
Pro and includes a series of screen points I've found useful for its screen.
You can change the series by creating a comma separated list of points up to half of your screen's width resolution. Any points beyond that point will be discarded when calculating the command.
The utility will create a command and copy it to the clipboard. Open a command window or paste this command into the Start > File > Run... dialog box to execute it.