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advantage of the eager interpretation process over
the lazy one: indeed, the user limits the ambigui-
ties, which makes the system more robust and
more efficient, increasing its user-friendliness and
its usability. The system is also faster because it
only has to find the sequence of rules to apply on
the last hand-drawn stroke.
Figure 11. Selection and moving mechanisms:
Example on a quarter-note
Selection
Selected
elements
dot
Selection
gesture
Moving
gesture
the elements exactly in the rectangles. To lighten
the editing area, a context is visible provided that
it is not already filled with an element. Thus, as
presented on Figure 10, it is possible to switch
between a
novice mode
, in which empty contexts
are visible, and an
expert mode
, in which they are
not. It is also possible to show only the contexts
that are near the pen position, once again to lighten
the editing area: it corresponds to a
contextual
mode
. The experience shows that this last mode
seems to be the most user-friendly because it
allows to only focus on potentially interesting
structural contexts according to the pen position.
The authors would like to note that the filled-note
head structural contexts presented on Figure 10
correspond to those declared in the
FilledNote
interpretation rule defined in Table 2.
Graphical functions also make it possible to
display the neatly retranscribed symbols and/or
handwritten strokes, as presented for instance in
Figure 12 and Figure 13. Moreover, a document
can be constituted of as many pages as possible;
it is then, for instance, possible to switch form
one page to another. Some classical functions,
such as zooming in or out, displaying an outline
of some of the pages of the composed document
or printing, are also already available.
a set of graphical functions and
pen-Based editing functions
The last component of the system is a set of
graphical and pen-based editing functions: it
deals with the human-computer interaction. In
this section, we present these functions that are
independent of the domain of the documents that
are drawn, more in detail. Their principle is to
enable the user to draw
graphical gestures
, which
are not interpreted by the system as drawings
of symbols, but as editing actions. Although we
have developed our own graphical and pen-based
editing functions, this component is not the main
contribution of our method, because other authors
have proposed similar functions (Lank, 2003).
Graphical Functions
Graphical functions correspond to the way the
system displays its messages to the user. Their
main functionality is the display of the results of
the analysis process, i.e., the neatly retranscribed
symbols, directly as the user is drawing his docu-
ment. They exploit graphical information, such as
images of these symbols, which are externalized
of the system because they are dependent of the
domain of the documents.
Graphical functions also propose solutions to
guide the user in the drawing process. Indeed,
to help him to have reference marks, rectangles
giving an indication of the document structural
contexts that are generated in DCC blocks can
be displayed. We would like to note that whereas
these displayed rectangles are strict, structural
contexts are not: the user does not have to draw
Editing Functions
Editing functions correspond to the way the user
expresses his requests to the system thanks to pen
interaction. Concerned functions can be divided
into two main categories, on the one hand the
document functions
that involve the management
of the document, and on the other hand the
ele-
ment functions
that involve the modification of
the document elements.
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