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Apple Newton Programmer’s Newton 2.0 (for Newton 2.0) User Manual

Page 379

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C H A P T E R 1 0

Recognition: Advanced Topics

About Advanced Topics in Recognition

10-3

On the other hand, if the view does not supply a

recConfig

frame, the recognition

system builds one based on the set of view flags enabled for that view, the contents
of its

dictionaries

slot (if present) and any recognition-related user preferences

that may apply. Thus, every view that performs recognition is eventually associated
with a

recConfig

frame that the system uses to perform setup tasks when the

view is opened.

Note that the

recConfig

frame actually used to configure recognition is the one

that the system builds, not the one that you supply. The

recConfig

frame that

you supply is referenced by the

_proto

slot of the

recConfig

frame that the

system builds.

The

recConfig

frame built by the system is passed to a

recognition area

, which is

an object used internally by the system to describe the recognition characteristics
of one or more views. Because similar views can share an area, the use of
recognition areas minimizes the reconfiguration of the recognition system required
to respond to changes in views on the screen.

A small number of recognition areas are kept in a cache. You can change the
recognition behavior of a view dynamically by specifying new recognition settings
and invalidating the area cache. The next time the view accepts input, the system
builds a new recognition area reflecting its currently-specified recognition behavior
and the dictionaries it is to use for recognition.

In addition to providing an efficient and flexible means of configuring the
recognition system programmatically,

recConfig

frames provide support for

future expansion of the recognition system. The

recConfig

frame allows

applications to specify recognition configurations in a uniform way that is not
dependent on the use of any particular recognizer engine. Although the Newton
platform currently supports only its built-in recognizers, future versions of the
system may permit the use of third-party recognizer engines.

The system provides several standard

recConfig

frames that can be placed in your

view’s

recConfig

slot or used as a starting point for building your own

recConfig

frames. For descriptions of system-supplied

recConfig

frames, see

“System-Supplied recConfig Frames” (page 8-18) in Newton Programmer’s
Reference
.

In summary, the recognition behavior that a view exhibits is ultimately determined
by a combination of the following values:

values inherited from the system’s user configuration data.

values in the view’s

viewFlags

and

entryFlags

slots.

values in the view’s

dictionaries

slot when the

vCustomDictionaries

flag is set.

values specified by an optional

recToggle

view, which may override values

inherited from user configuration data or supply additional values.