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.TH "GET STROKE 3" 3P "29 February 1991"
.SH NAME
GET STROKE 3 \- retrieve the
\s-2STROKE\s+2
event in the \s-2PHIGS\s+2 current event report
.IX "Event Input Mode" "GET STROKE 3"
.IX "Input Modes" "GET STROKE 3"
.IX "Stroke Input Devices" "GET STROKE 3"
.SH SYNOPSIS
.SS C Syntax
.ft B
.ta 1.25i 3i
.nf
void
pget_stroke3 ( view_ind, stroke )
Pint	*view_ind;	\fI\s-2OUT\s+2 view index\fP
Ppoint_list3	*stroke;	\fI\s-2OUT\s+2 stroke\fP
.fi
.ft R
.SS Required PHIGS Operating States
(PHOP, WSOP, *, *)
.SH DESCRIPTION
.SS Purpose
\s-2GET STROKE 3\s+2 retrieves the current event report from the \s-2PHIGS\s+2
state list when the event report contains a \s-2STROKE\s+2 event.
.LP
A \s-2STROKE\s+2 event consists of a list of World Coordinate
(\s-2WC\s+2) points and a view_index.
The points correspond to positions on the workstation selected by the
operator.
The view_index is the index of the view used to transform
those positions to World Coordinates.
.SS C Output Parameters
.IP \fIview_ind\fP
\s-2PHIGS\s+2 sets the variable pointed to by \fIview_ind\fP to
the index of the view representation used to transform
the \s-2NPC\s+2 stroke positions to \s-2WC\s+2 points.
.IP \fIstroke\fP
\s-2PHIGS\s+2 copies the number and list of stroke points selected by
the operator to the variable pointed to by \fIstroke\fP.
Ppoint_list3 is defined in phigs.h as follows:
.sp .4
.ta .5i +\w'Ppoint3     'u +\w'num_points;     'u
.nf
typedef struct {
.sp .2
	Pint	num_points;	/* number of Ppoint3s in the list */
	Ppoint3	*points;	/* list of points */
.sp .2
} Ppoint_list3;
.sp
.fi
.IP
\fInum_points\fP is the number of points in \fIpoints\fP.
.IP
\fIpoints\fP is the array of Ppoint3 structures specifying the
points in \s-2WC\s+2.
\fBThis array must be allocated by the calling program
and the array pointer assigned to this field before calling this
function.\fP
The array must be at least as large as the buffer of the
\s-2STROKE\s+2 device that generated the event.
This buffer size is set when the device is initialized.
Ppoint3 is defined in phigs.h as follows:
.sp .4
.ta .5i +\w'Pfloat     'u +\w'x;     'u
.nf
typedef struct {
.sp .2
	Pfloat	x;	/* x coordinate */
	Pfloat	y;	/* y coordinate */
	Pfloat	z;	/* z coordinate */
.sp .2
} Ppoint3;
.fi
.SS Execution
\s-2GET STROKE 3\s+2 retrieves the \s-2STROKE\s+2
event from the current event report in the \s-2PHIGS\s+2 state list.
.LP
When an input device in \s-2EVENT\s+2 mode is triggered by the operator,
an event report is added to the input event queue.
The event report contains the identity and current measure of the triggering
device.
\s-2AWAIT EVENT\s+2 moves the measure of the oldest event in the input queue
to the current event report in the \s-2PHIGS\s+2 state list.
If the event was a \s-2STROKE\s+2 event,
\s-2GET STROKE 3\s+2 or \s-2GET STROKE\s+2 is used to
retrieve the event from the current event report.
The \s-2STROKE\s+2 positions are computed by mapping the \s-2DC\s+2
workstation positions selected by the operator to  \s-2WC\s+2 points.
The workstation transform is used to transform the \s-2DC\s+2
positions to \s-2NPC\s+2 positions prior to transforming them to
\s-2WC\s+2.
See \s-2INITIALIZE LOCATOR 3\s+2 and
\s-2SET VIEW TRANSFORMATION INPUT PRIORITY\s+2 for a
description of how \s-2PHIGS\s+2 determines the view representation to use
to map the \s-2NPC\s+2 positions to \s-2WC\s+2.
.LP
See \s-2INITIALIZE STROKE 3\s+2 for a description of the available
\s-2STROKE\s+2 devices and how their measure values are determined.
.SH ERRORS
.IP 003
Ignoring function, function requires state (\s-2PHOP, WSOP, *, *\s+2)
.IP 259
Ignoring function, the input device class of the current input report
does not match the class being requested
.SH SEE ALSO
.nf
.IP
.ta 0.5i
.SM "INITIALIZE STROKE 3 (3P)"
.SM "AWAIT EVENT (3P)"
.SM "SET VIEW TRANSFORMATION INPUT PRIORITY (3P)"
.SM "GET STROKE (3P)"
.fi
