## Presentation Device Driver Reference for OS/2

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### GrePolyShortLine - Parameters

hdc (HDC) - input Device context handle.

psl (PSHORTLINE) - input Pointer to SHORTLINE structure.

The shortlines are defined in a list of linked SHORTLINE structures:

slh SHORTLINEHEADER structure:

ulStyle Line style.
ulFormat Line format.
ptlStart (X,Y) position of start (the start position is included in the line).
ptlStop (X,Y) position of end (the end position is not included in the line ).
lxLeft Left edge of bounding rectangle.
lxRight Right edge of bounding rectangle.
pslhNext Pointer to next shortline.
pslhPrev Pointer to previous shortline.

The boundaries of the rectangle are inclusive at the start points of the lines, and exclusive at the stop points regardless of the direction.

This structure is a discrete representation of a curve that starts at point (x0,y0) and ends at point (x1,y1). For each of the (y1-y0+1) rows, there is exactly one X value contained in the X array. The final point in the series is not drawn.

ax Steps. This is an array of X-coordinates in absolute values. There is one coordinate value for each shortline.

pInstance (PVOID) - input Pointer to instance data.

lFunction (ULONG) - input High-order WORD=flags; low-order WORD= NGrePolyShortLine.

rc (LONG) - returns Return Code.

On completion, the handling routine must return an integer (cHits) indicating, where appropriate, whether correlation hits were detected:

GPI_OK Successful
GPI_HITS Successful with correlate hit (returned by display drivers when the correlate flag is ON, and a hit is detected)
GPI_ERROR Error

Possible Errors Detected: When an error is detected, the handling routine must call WinSetErrorInfo to post the condition. Error codes for conditions that the handling routine is expected to check include:

PMERR_BITMAP_NOT_SELECTED
PMERR_COORDINATE_OVERFLOW
PMERR_DEV_FUNC_NOT_INSTALLED
PMERR_HDC_BUSY
PMERR_INV_COLOR_DATA
PMERR_INV_COLOR_INDEX
PMERR_INV_COORD_SPACE
PMERR_INV_HDC
PMERR_INV_IN_AREA
PMERR_INV_IN_PATH
PMERR_INV_LENGTH_OR_COUNT
PMERR_INV_PICK_APERTURE_POSN

Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.