wmnotify/src/xevents.c

   1 /*
   2  * xevents.c -- handling X events, and detecting single-click and double-click
   3  *              mouse events.
   4  *
   5  * Copyright (C) 2009 Hugo Villeneuve <hugo@hugovil.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
  20  */
  21
  22 #if HAVE_CONFIG_H
  23 #  include "config.h"
  24 #endif
  25
  26 #include <unistd.h>
  27 #include <stdlib.h>
  28 #include <stdio.h>
  29 #include <fcntl.h>
  30 #include <errno.h>
  31 #include <signal.h>
  32 #include <time.h>
  33 #include <pthread.h>
  34 #include <sys/types.h>
  35 #include <X11/Xlib.h>
  36
  37 #include "common.h"
  38 #include "dockapp.h"
  39 #include "xevents.h"
  40
  41
  42 /* Maximum time between mouse double-clicks, in milliseconds */
  43 #define DOUBLE_CLICK_MAX_INTERVAL_MS 250
  44
  45
  46 /* Function pointers to handle single and double mouse click events. */
  47 static void (*SingleClickCallback)( void ) = NULL;
  48
  49 static void (*DoubleClickCallback)( void ) = NULL;
  50
  51
  52 void
  53 AudibleBeep( void )
  54 {
  55   /* The specified volume is relative to the base volume for the keyboard.
  56      To change the base volume of the keyboard, use XChangeKeyboardControl(). */
  57   (void) XBell( dockapp.display, 100 ); /* Volume = 100% */
  58 }
  59
  60
  61 /* This function must be called at the beginning of your program to initialize
  62    the function pointers to handle single and double click mouse events. */
  63 void
  64 ProcessXlibEventsInit( void (*single_click_callback)( void ),
  65                        void (*double_click_callback)( void ) )
  66 {
  67   int status;
  68
  69   /* This must be called before any other XLib functions. */
  70   status = XInitThreads();
  71   if( status == 0 ) {
  72     fprintf( stderr, "%s: XInitThreads() initialization failed\n", PACKAGE );
  73     ErrorLocation( __FILE__, __LINE__ );
  74     exit( EXIT_FAILURE );
  75   }
  76
  77   SingleClickCallback = single_click_callback;
  78   DoubleClickCallback = double_click_callback;
  79 }
  80
  81
  82 /* Processing of X events */
  83 void
  84 ProcessXlibEvents( void )
  85 {
  86   bool quit = false;
  87   bool button1_pressed = false;
  88   bool check_for_double_click = false;
  89   XEvent Event;
  90
  91   while( quit == false ) {
  92     if( ( check_for_double_click != false ) &&
  93         ( XPending( dockapp.display ) == 0 ) ) {
  94       /* If no other button 1 events are received after the delay, then it is a
  95          single-click mouse event. */
  96       if( SingleClickCallback != NULL ) {
  97         (*SingleClickCallback)();
  98       }
  99
 100       check_for_double_click = false;
 101     }
 102     /* XNextEvent is a blocking call: it will return only when an event is
 103        ready to be processed, thus freeing the CPU for other tasks when no
 104        events are available. */
 105     (void) XNextEvent( dockapp.display, &Event );
 106     switch( Event.type ) {
 107     case Expose:
 108       /* Window was uncovered... */
 109       RedrawWindow();
 110       break;
 111     case DestroyNotify:
 112       /* Window was killed... */
 113       /* Is this necessary ? */
 114       (void) XCloseDisplay( dockapp.display );
 115       quit = true;
 116       break;
 117     case ClientMessage:
 118       /* Doesn't seem to work... */
 119       printf( "Client message received...\n" );
 120       break;
 121     case ButtonPress:
 122       if( Event.xbutton.button == Button1 ) {
 123         /* Mouse LEFT button pressed. */
 124         button1_pressed = true;
 125       }
 126       break;
 127     case ButtonRelease:
 128       if( Event.xbutton.button == Button1 ) {
 129         /* Mouse LEFT button released. */
 130         if( button1_pressed != false ) {
 131           /* We act only when the button is released */
 132           if( check_for_double_click != false ) {
 133             /* Double-click */
 134             if( DoubleClickCallback != NULL ) {
 135               (*DoubleClickCallback)();
 136             }
 137             check_for_double_click = false;
 138           }
 139           else {
 140             (void) usleep( DOUBLE_CLICK_MAX_INTERVAL_MS * 1000 );
 141             check_for_double_click = true;
 142           }
 143         }
 144       }
 145       break;
 146     }
 147   } /* end while */
 148 }