Examining Pen Data

The following functions enable an application to examine, directly modify, or retrieve information from an HPENDATA object:

These three functions work in tandem. Together, they enable an application to directly read an HPENDATA block in memory.
Use these functions with caution and only for reading pen data. Do not attempt to write into an HPENDATA block.
BeginEnumStrokes returns a far pointer to the HPENDATA memory block within the global heap.
GetPenDataStroke retrieves pointers to point data within the HPENDATA. Although an HPENDATA block no longer prefaces strokes with STROKEINFO structures, GetPenDataStroke can retrieve a STROKEINFO structure corresponding to any stroke within the block.
When the application has finished with the memory block, it must call EndEnumStrokes. This unlocks the block in the global heap and invalidates the pointers returned by GetPenDataStroke. For this reason, an application must not use the pointers once it has called EndEnumStrokes.
Retrieves summary information from the pen data memory block. It is superseded by the GetPenDataAttributes function to some extent.
Provides enhanced versions of some of the capabilities of GetPenDataInfo. It also provides additional detailed information taken from the HPENDATA block. For example, GetPenDataAttributes can return
  • The total number of points in the HPENDATA
  • The total number of strokes
  • The time the HPENDATA was created
  • The device sampling rate
Retrieve or set information about a given stroke in an HPENDATA object. For example, these functions can get or set
  • The pen state (up or down) for a stroke
  • The ink color and width
  • The absolute time the stroke occurred
Retrieve or set information about all strokes in an HPENDATA object that share a given class. For all such strokes, these functions can get or set:
  • The ink color and width.
  • The user value.
  • The number of entries in the stroke table.
Determines whether a given point lies near the line of a stroke. The function accepts a threshold value that describes a square region around the given point on the tablet or screen. If a stroke in an HPENDATA block passes through the square, this function reports a "hit." HitTestPenData considers only points with a pen-down state.

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