AddStroke function

Adds an ink stroke to the RecognizerContext.

Syntax


HRESULT WINAPI AddStroke(
         HRECOCONTEXT       hrc,
   const PACKET_DESCRIPTION *pPacketDesc,
         ULONG              cbPacket,
   const BYTE               *pPacket,
   const XFORM              *pxForm
);

Parameters

hrc

The handle to the recognizer context.

pPacketDesc

Describes the contents of the packets. The description must match the contents of the packets in pPacket. If NULL, this function uses the GetPreferredPacketDescription function.

cbPacket

Size, in bytes, of the pPacket buffer.

pPacket

Array of packets that contain tablet space coordinates.

pxForm

Describes the transform that can be applied to ink to transform it from tablet space into ink space. A recognizer may choose to ignore this transform and implement their own ink rotation algorithms. These recognizers should still return properties calculated in the lattice data relative to this transform.

Return value

This function can return one of these values.

Return codeDescription
S_OK

Success.

E_POINTER

One of the parameters is an invalid pointer.

E_OUTOFMEMORY

Unable to allocate memory to complete the operation.

TPC_E_INVALID_PACKET_DESCRIPTION

The packet description does not contain the necessary information for the packet to be considered valid. For example, it does not include a GUID_X or GUID_Y property.

TPC_E_OUT_OF_ORDER_CALL

The call to the method was made out of order.

E_FAIL

An unspecified error occurred.

E_INVALIDARG

An invalid argument was received.

 

Remarks

The recognizer must return properties such as Baseline in ink space coordinates rather than tablet coordinates.

It is recommended that your recognizer place a limit on the number of strokes per context and/or the points allowed in a given stroke. Limit input to 1024 strokes per context and 32767 points per stroke.

Strokes with zero points are not allowed. You should return E_FAIL in such a case.

Requirements

Minimum supported client

Windows XP Tablet PC Edition [desktop apps only]

Minimum supported server

None supported

Header

Recapis.h

See also

PACKET_DESCRIPTION Structure
GetPreferredPacketDescription

 

 

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