## Pen for OS/2 Device Driver Reference

[prev][next][parent][TOC]

### Finger Offset

You can improve the finger selection ability by offsetting the OS/2 pointer so it remains visible and appears to be pointing at the tip of the finger, instead of underneath the finger.

The figure, "Digitizer Coordinate Systems", shows a finger with a y- coordinate offset. If the offset were just added to the locator position, there would be a region on the bottom of the screen that could not be selected. To compensate for this, a slide region is used for this part of the screen. Gradually removing the offset in this region makes the entire region selectable.

Offsets are set through a device object and managed through the Pen for OS/ 2 system extension. The category 91 Set Locator Offset IOCtl informs the pen device driver of the change when the variable changes through the Pen for OS/2 system.