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C H A P T E R 1 0
Recognition: Advanced Topics
Using Advanced Topics in Recognition
10-9
Creating a recConfig Frame
10
For any view that is to use a
recConfig
frame, you must supply a
recConfig
slot, usually by defining it in your view's template. The frame in your view's
recConfig
slot must be modifiable; that is, it must be RAM-based. When your
view template supplies a
recConfig
frame, the view system builds a RAM-based
recConfig
frame along with the view--you need not do anything more to cause
the view to use the
recConfig
frame.
To create your own
recConfig
frame at run time, you need to call the
PrepRecConfig
function to create a RAM-based
recConfig
frame that the
system can use. Although you could obtain similar results by cloning a
recConfig
frame that your view template defines, using the
PrepRecConfig
function is more efficient:
The
PrepRecConfig
function creates a smaller frame than that obtained by
cloning your view template's
recConfig
frame.
The frame that the
PrepRecConfig
function returns can be used as it is by the
recognition system. Any other frame that you place in the view's
recConfig
slot is used by the system to create the
recConfig
frame actually used by the
view, with the result being the creation of two frames in RAM rather than just one.
Consistent use of this function to create
recConfig
frames saves RAM by
permitting similar
recConfig
frames to share the same frame map.
A function similar to the
PrepRecConfig
function, the
BuildRecConfig
function, is provided for debugging use. Do not use the
BuildRecConfig
function to create your RAM-based
recConfig
frame. The argument to the
BuildRecConfig
function is the view itself, rather than its
recConfig
frame.
This function builds an appropriate
recConfig
frame for the specified view,
regardless of whether the view defines one. The system does not use the
recConfig
frame that this function returns, however--as stated previously, this
frame is for debugging use only.
IMPORTANT
The contents of the
inputMask
slot in the view's
recConfig
frame must match the input mask (the recognition-related bits)
provided by the view's
viewFlags
slot. For more information on
this slot and others that the
recConfig
frame may contain, see
"protoRecConfig" (page 8-36) in Newton Programmer's
Reference
.
You can base your
recConfig
frame on one of the system-supplied
recConfig
frames by simply placing the appropriate constant in your view template's
recConfig
slot. Alternatively, you can place in this slot a frame that uses its
_proto
slot to reference one of the system-supplied
recConfig
frames. A third
way to define a
recConfig
frame is to supply all necessary values yourself. The
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