Samsung SUR40 with Microsoft PixelSense hardware exposes throught the Surface SDK 2.0 the
This property represents the ratio between 96 dot per inch (DPI) and the logical DPI
used by Microsoft Surface units. Using this transform, 96 pixels will result in one real
inch on Microsoft Surface displays.
The LogicalDpiX and LogicalDpiY properties are also exposed. These return the
number of pixels that show as one inch on a Surface device.
These properties allow people to write applications where a UIElement will have the
same physical display size, no matter what type of Surface device is used. These
properties help design applications that have content that is properly sized, no matter
the screen dimension or resolution. For instance, a keyboard should come up the same
size no matter what hardware is used.
Emember that not all displays expose the real size of a pixel, in that case the default 96 DPI
is assumed for that type of hardware.