Geoscience Reference
In-Depth Information
not all commands need to have an associated shortcut. However, as QGIS
requires a large number of frequently used commands, we developed a
new mechanism called Relative Finger-Counts. It makes it possible to
select menus items that do not have a dedicated FC shortcut by first select-
ing a neighboring item that has a shortcut, then moving the right hand up
or down before releasing it from the table surface. This is shown in
figure
6
where “Save Project As” is reached by first selecting “Save Project”, and
then moving fingers to the North.
Another improvement is Contextual Finger-Count shortcuts. By double
tapping on an interactive element (e.g. a building on a map), a pop-up
window is opened and the user can select its properties such as symbols,
by performing FC shortcuts in this window. The pop-up is large enough to
contain 10 fingers. Hence, users can not only select up to 75 items of the
global menubar system but also change the properties of interactive
elements by performing multi-touch gestures.
Figure 6:
Saving projects in QGIS-MT
Direct manipulation
. Some commands require direct manipulation: the
user must not only select a command but also set one or several values inter-
actively. FC shortcuts allow to do both in the same gesture. For instance,
the “Select Features” command requires the definition of a selection zone.
The user first presses 2 left hand fingers and 1 right hand finger to activate
this command (
Figure 7
), then directly moves his fingers on the screen to
set the position of the selection zone corners, and only releases them when
the correct position is obtained. This feature avoids using modes and the
many errors they tend to provoke (Raskin 2000).
