NAME¶
gii_pmove_event - LibGII pointer movement events
SYNOPSIS¶
#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;
DESCRIPTION¶
The
gii_pmove_event structure is used to report change of pointer
position. Depending on the event type, the values are either absolute or
relative.
GENERATED EVENTS¶
This structure is used for
evPtrRelative and
evPtrAbsolute events.
STRUCTURE MEMBERS¶
The
gii_pmove_event structure describes pointer (mice, etc.) motion in
terms of the
x,
y,
z coordinates and the
wheel
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
evPtrRelative or
evPtrAbsolute,
respectively.
LibGII does not attempt to interpolate or keep track of the
current
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.
EXAMPLES¶
Input handling for applications expecting absolute pointer position:
{
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 */
}
SEE ALSO¶
gii_event(3)