Recognition: Advanced Topics

Using Advanced Topics in Recognition

Sketch ink, like shapes, is displayed only in views based on the

clEditView

class. As a rule of thumb, consider sketch ink and ink text to be mutually exclusive
when configuring recognition in views; for best results, configure your input view
to recognize only one of these two data types.

Views based on the

clEditView

class handle sketch ink and ink text automatically.

For other views, the system invokes the view's

ViewInkWordScript

or

ViewRawInkScript

method when ink arrives. For more details, see the

descriptions of these methods in Newton Programmer's Reference.

The system-supplied

ROM_rcInkOrText

constant provides a ready-to-use

recConfig

frame that allows views based on the

clParagraphView

class to

contain ink text in addition to normal text. To use this

recConfig

frame to create

a view that supports ink text, you'll need to take the following steps:

Create a view template that protos from the

clParagraphView

class.

In your view template, create a

recConfig

slot that holds the

ROM_rcInkOrText

constant. For more information, see "Creating a recConfig

Frame" beginning on page 10-9.

Provide a

protoRecToggle

view that allows the user to choose text or ink

text settings; if your application provides a status bar, you need to provide the

recToggle

view as one of its children. For more information, see "Creating

the recToggle View" beginning on page 10-19.

Provide a

_recogSettings

slot at an appropriate position in the

recToggle

view's

_parent

chain. For more information see "Creating the _recogSettings

Slot" beginning on page 10-20.

Normally, the input view tries to recognize input using all currently enabled
recognizers. If no recognizers are enabled or if recognition fails for some reason--
for example, due to messy input or some sort of error--then the view system
converts the input strokes into ink. The

doInkWordRecognition

slot in the

input view's

recConfig

frame specifies the kind of ink that the system creates

from the input strokes.

When the

doInkWordRecognition

slot holds a non-

nil

value, the system

returns ink text; when this slot holds the

nil

value, the system returns sketch ink.

This slot is described fully in "protoRecConfig" (page 8-36) in Newton
Programmer's Reference. Table 10-1 on page 10-12 summarizes the kinds of data
returned by the recognition system when recognition fails in an edit view or
paragraph view that is controlled by a

recToggle

view.

Note that when the input view is set to recognize shapes, the smoothed and cleaned
up ink that is returned may be ink text but is more likely to be a curve shape. Aside
from the failure of shape recognition, the only time raw ink is returned to the view
is when its associated

recToggle

is set to "Sketches".