8.1.3 Probe

It is sometimes the case that the area touched on the screen is larger than the size of small expression details. Moreover, those details are obscured by the touching finger. Together, these effects can make it difficult to perform selection.

Probe displays cross hairs over the current selection. The cross hairs act as a surrogate point for touch and drag which can thus occur at any location elsewhere on the display. The cross hairs are removed when touch is released.

Because the touch position can be anywhere on the screen, the touching finger no longer obscures the expression. As well, the drag speed is reduced before being applied to the selection-point motion. This allows finer control over the selection point and makes it easier to achieve pixel accuracy even on small high-resolution screens.