.TH "gii_pmove_event" 3 "2006-12-30" "libgii-1.0.x" GGI
.SH NAME
\fBgii_pmove_event\fR : LibGII pointer movement events
.SH SYNOPSIS
.nb
.nf
#include <ggi/events.h>

typedef struct gii_pmove_event {

    COMMON_DATA;

    int32_t  x, y;           /* absolute/relative position   */
    int32_t  z, wheel;

} gii_pmove_event;
.fi

.SH DESCRIPTION
The \fBgii_pmove_event\fR structure is used to report change of pointer
position. Depending on the event type, the values are either absolute
or relative.
.SH GENERATED EVENTS
This structure is used for \fBevPtrRelative\fR and \fBevPtrAbsolute\fR events.
.SH STRUCTURE MEMBERS
The \fBgii_pmove_event\fR structure describes pointer (mice, etc.) motion
in terms of the \fBx\fR, \fBy\fR, \fBz\fR coordinates and the \fBwheel\fR values of
the device.  The motion described may be relative (offset from the
current location) or absolute (a specific location on the 'screen'),
depending on whether the event is of type \fBevPtrRelative\fR or
\fBevPtrAbsolute\fR, respectively.

LibGII does not attempt to interpolate or keep track of the \fIcurrent\fR
pointer position.  (This is the application's responsibility.)  LibGII
may also report both relative and absolute pointer motion for the same
input, which may happen when the mouse is being emulated using a
keyboard on an input/target that is normally reports absolute motion.
.SH EXAMPLES
Input handling for applications expecting absolute pointer position:

.nb
.nf
{
    static int mousex,mousey;

    ggiEventPoll(vis, emKey|emPointer, NULL);
    events = ggiEventsQueued(vis, emKey|emPointer);

    while (events--) {
        ggiEventRead(vis, &event, emKey|emPointer);

        switch(event.any.type) {
        case evPtrButtonPress:
                switch(event.pbutton.button) {
                case GII_PBUTTON_FIRST:
                    do_something_as_appropriate(mousex,mousey);
                    break;
                case GII_PBUTTON_SECOND:
                    /* ... */
                }
                break;
        case evPtrButtonRelease:
            /* ... if needed ... */
            break;
        case evPtrAbsolute:
            mousex = event.pmove.x;
            mousey = event.pmove.y;
            break;
        case evPtrRelative:
            mousex += event.pmove.x;
            mousey += event.pmove.y;
            break;
        }

        /* Constrain mouse in any case */
        if (mousex < 0) mousex = 0;
        if (mousey < 0) mousey = 0;
        if (mousex > xmax) mousex = xmax;
        if (mousey > ymax) mousey = ymax;

    } /* while */
}
.fi

.SH SEE ALSO
\f(CWgii_event(3)\fR