This function allows you to select the event types which you want returned from the specified window. The event_mask can be a bitwise OR of multiple events.
| Type | Name | Description |
|---|---|---|
| GR_WINDOW_ID | wid | The ID of the window to receive events on. |
| GR_EVENT_MASK | eventmask | A bitmask that specifies the events that should be sent from the window. |
Example 2-1. Using GrSelectEvents()
#include <stdio.h>
#define MWINCLUDECOLORS
#include "microwin/nano-X.h"
GR_WINDOW_ID wid;
GR_GC_ID gc;
void event_handler (GR_EVENT *event);
int main (void)
{
if (GrOpen() < 0)
{
fprintf (stderr, "GrOpen failed");
exit (1);
}
gc = GrNewGC();
GrSetGCUseBackground (gc, GR_FALSE);
GrSetGCForeground (gc, RED);
wid = GrNewWindowEx (GR_WM_PROPS_APPFRAME |
GR_WM_PROPS_CAPTION |
GR_WM_PROPS_CLOSEBOX,
"Hello Window",
GR_ROOT_WINDOW_ID,
50, 50, 200, 100, WHITE);
GrSelectEvents (wid, GR_EVENT_MASK_EXPOSURE |
GR_EVENT_MASK_CLOSE_REQ);
GrMapWindow (wid);
GrMainLoop (event_handler);
}
void event_handler (GR_EVENT *event)
{
switch (event->type)
{
case GR_EVENT_TYPE_EXPOSURE:
GrText (wid, gc, 50, 50,
"Hello World", -1, GR_TFASCII);
break;
case GR_EVENT_TYPE_CLOSE_REQ:
GrClose();
exit (0);
}
} |