[sdl_omap.git] / docs / html / guideeventexamples.html

<HTML
><HEAD
><TITLE
>Event Examples</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
"><LINK
REL="HOME"
TITLE="SDL Library Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="Examples"
HREF="guideexamples.html"><LINK
REL="PREVIOUS"
TITLE="Examples"
HREF="guideexamples.html"><LINK
REL="NEXT"
TITLE="Audio Examples"
HREF="guideaudioexamples.html"></HEAD
><BODY
CLASS="SECT1"
BGCOLOR="#FFF8DC"
TEXT="#000000"
LINK="#0000ee"
VLINK="#551a8b"
ALINK="#ff0000"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>SDL Library Documentation</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="guideexamples.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
>Chapter 4. Examples</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="guideaudioexamples.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="GUIDEEVENTEXAMPLES"
></A
>Event Examples</H1
><P
></P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN375"
></A
>Filtering and Handling Events</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>#include &#60;stdio.h&#62;
#include &#60;stdlib.h&#62;

#include "SDL.h"

/* This function may run in a separate event thread */
int FilterEvents(const SDL_Event *event) {
    static int boycott = 1;

    /* This quit event signals the closing of the window */
    if ( (event-&#62;type == SDL_QUIT) &#38;&#38; boycott ) {
        printf("Quit event filtered out -- try again.\n");
        boycott = 0;
        return(0);
    }
    if ( event-&#62;type == SDL_MOUSEMOTION ) {
        printf("Mouse moved to (%d,%d)\n",
                event-&#62;motion.x, event-&#62;motion.y);
        return(0);    /* Drop it, we've handled it */
    }
    return(1);
}

int main(int argc, char *argv[])
{
    SDL_Event event;

    /* Initialize the SDL library (starts the event loop) */
    if ( SDL_Init(SDL_INIT_VIDEO) &#60; 0 ) {
        fprintf(stderr,
                "Couldn't initialize SDL: %s\n", SDL_GetError());
        exit(1);
    }

    /* Clean up on exit, exit on window close and interrupt */
    atexit(SDL_Quit);

    /* Ignore key events */
    SDL_EventState(SDL_KEYDOWN, SDL_IGNORE);
    SDL_EventState(SDL_KEYUP, SDL_IGNORE);

    /* Filter quit and mouse motion events */
    SDL_SetEventFilter(FilterEvents);

    /* The mouse isn't much use unless we have a display for reference */
    if ( SDL_SetVideoMode(640, 480, 8, 0) == NULL ) {
        fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n",
                        SDL_GetError());
        exit(1);
    }

    /* Loop waiting for ESC+Mouse_Button */
    while ( SDL_WaitEvent(&#38;event) &#62;= 0 ) {
        switch (event.type) {
            case SDL_ACTIVEEVENT: {
                if ( event.active.state &#38; SDL_APPACTIVE ) {
                    if ( event.active.gain ) {
                        printf("App activated\n");
                    } else {
                        printf("App iconified\n");
                    }
                }
            }
            break;
                    
            case SDL_MOUSEBUTTONDOWN: {
                Uint8 *keys;

                keys = SDL_GetKeyState(NULL);
                if ( keys[SDLK_ESCAPE] == SDL_PRESSED ) {
                    printf("Bye bye...\n");
                    exit(0);
                }
                printf("Mouse button pressed\n");
            }
            break;

            case SDL_QUIT: {
                printf("Quit requested, quitting.\n");
                exit(0);
            }
            break;
        }
    }
    /* This should never happen */
    printf("SDL_WaitEvent error: %s\n", SDL_GetError());
    exit(1);
}</PRE
></P
></DIV
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="guideexamples.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="guideaudioexamples.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Examples</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="guideexamples.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Audio Examples</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
Commit	Line	Data
e14743d1	1	<HTML
	2	><HEAD
	3	><TITLE
	4	>Event Examples</TITLE
	5	><META
	6	NAME="GENERATOR"
	7	CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
	8	"><LINK
	9	REL="HOME"
	10	TITLE="SDL Library Documentation"
	11	HREF="index.html"><LINK
	12	REL="UP"
	13	TITLE="Examples"
	14	HREF="guideexamples.html"><LINK
	15	REL="PREVIOUS"
	16	TITLE="Examples"
	17	HREF="guideexamples.html"><LINK
	18	REL="NEXT"
	19	TITLE="Audio Examples"
	20	HREF="guideaudioexamples.html"></HEAD
	21	><BODY
	22	CLASS="SECT1"
	23	BGCOLOR="#FFF8DC"
	24	TEXT="#000000"
	25	LINK="#0000ee"
	26	VLINK="#551a8b"
	27	ALINK="#ff0000"
	28	><DIV
	29	CLASS="NAVHEADER"
	30	><TABLE
	31	SUMMARY="Header navigation table"
	32	WIDTH="100%"
	33	BORDER="0"
	34	CELLPADDING="0"
	35	CELLSPACING="0"
	36	><TR
	37	><TH
	38	COLSPAN="3"
	39	ALIGN="center"
	40	>SDL Library Documentation</TH
	41	></TR
	42	><TR
	43	><TD
	44	WIDTH="10%"
	45	ALIGN="left"
	46	VALIGN="bottom"
	47	><A
	48	HREF="guideexamples.html"
	49	ACCESSKEY="P"
	50	>Prev</A
	51	></TD
	52	><TD
	53	WIDTH="80%"
	54	ALIGN="center"
	55	VALIGN="bottom"
	56	>Chapter 4. Examples</TD
	57	><TD
	58	WIDTH="10%"
	59	ALIGN="right"
	60	VALIGN="bottom"
	61	><A
	62	HREF="guideaudioexamples.html"
	63	ACCESSKEY="N"
	64	>Next</A
65	></TD
66	></TR
67	></TABLE
68	><HR
69	ALIGN="LEFT"
70	WIDTH="100%"></DIV
71	><DIV
72	CLASS="SECT1"
73	><H1
74	CLASS="SECT1"
75	><A
76	NAME="GUIDEEVENTEXAMPLES"
77	></A
78	>Event Examples</H1
79	><P
80	></P
81	><DIV
82	CLASS="SECT2"
83	><H2
84	CLASS="SECT2"
85	><A
86	NAME="AEN375"
87	></A
88	>Filtering and Handling Events</H2
89	><P
90	><PRE
91	CLASS="PROGRAMLISTING"
92	>#include <stdio.h>
93	#include <stdlib.h>
94
95	#include "SDL.h"
96
97	/* This function may run in a separate event thread */
98	int FilterEvents(const SDL_Event *event) {
99	static int boycott = 1;
100
101	/* This quit event signals the closing of the window */
102	if ( (event->type == SDL_QUIT) && boycott ) {
103	printf("Quit event filtered out -- try again.\n");
104	boycott = 0;
105	return(0);
106	}
107	if ( event->type == SDL_MOUSEMOTION ) {
108	printf("Mouse moved to (%d,%d)\n",
109	event->motion.x, event->motion.y);
110	return(0); /* Drop it, we've handled it */
111	}
112	return(1);
113	}
114
115	int main(int argc, char *argv[])
116	{
117	SDL_Event event;
118
119	/* Initialize the SDL library (starts the event loop) */
120	if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
121	fprintf(stderr,
122	"Couldn't initialize SDL: %s\n", SDL_GetError());
123	exit(1);
124	}
125
126	/* Clean up on exit, exit on window close and interrupt */
127	atexit(SDL_Quit);
128
129	/* Ignore key events */
130	SDL_EventState(SDL_KEYDOWN, SDL_IGNORE);
131	SDL_EventState(SDL_KEYUP, SDL_IGNORE);
132
133	/* Filter quit and mouse motion events */
134	SDL_SetEventFilter(FilterEvents);
135
136	/* The mouse isn't much use unless we have a display for reference */
137	if ( SDL_SetVideoMode(640, 480, 8, 0) == NULL ) {
138	fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n",
139	SDL_GetError());
140	exit(1);
141	}
142
143	/* Loop waiting for ESC+Mouse_Button */
144	while ( SDL_WaitEvent(&event) >= 0 ) {
145	switch (event.type) {
146	case SDL_ACTIVEEVENT: {
147	if ( event.active.state & SDL_APPACTIVE ) {
148	if ( event.active.gain ) {
149	printf("App activated\n");
150	} else {
151	printf("App iconified\n");
152	}
153	}
154	}
155	break;
156
157	case SDL_MOUSEBUTTONDOWN: {
158	Uint8 *keys;
159
160	keys = SDL_GetKeyState(NULL);
161	if ( keys[SDLK_ESCAPE] == SDL_PRESSED ) {
162	printf("Bye bye...\n");
163	exit(0);
164	}
165	printf("Mouse button pressed\n");
166	}
167	break;
168
169	case SDL_QUIT: {
170	printf("Quit requested, quitting.\n");
171	exit(0);
172	}
173	break;
174	}
175	}
176	/* This should never happen */
177	printf("SDL_WaitEvent error: %s\n", SDL_GetError());
178	exit(1);
179	}</PRE
180	></P
181	></DIV
182	></DIV
183	><DIV
184	CLASS="NAVFOOTER"
185	><HR
186	ALIGN="LEFT"
187	WIDTH="100%"><TABLE
188	SUMMARY="Footer navigation table"
189	WIDTH="100%"
190	BORDER="0"
191	CELLPADDING="0"
192	CELLSPACING="0"
193	><TR
194	><TD
195	WIDTH="33%"
196	ALIGN="left"
197	VALIGN="top"
198	><A
199	HREF="guideexamples.html"
200	ACCESSKEY="P"
201	>Prev</A
202	></TD
203	><TD
204	WIDTH="34%"
205	ALIGN="center"
206	VALIGN="top"
207	><A
208	HREF="index.html"
209	ACCESSKEY="H"
210	>Home</A
211	></TD
212	><TD
213	WIDTH="33%"
214	ALIGN="right"
215	VALIGN="top"
216	><A
217	HREF="guideaudioexamples.html"
218	ACCESSKEY="N"
219	>Next</A
220	></TD
221	></TR
222	><TR
223	><TD
224	WIDTH="33%"
225	ALIGN="left"
226	VALIGN="top"
227	>Examples</TD
228	><TD
229	WIDTH="34%"
230	ALIGN="center"
231	VALIGN="top"
232	><A
233	HREF="guideexamples.html"
234	ACCESSKEY="U"
235	>Up</A
236	></TD
237	><TD
238	WIDTH="33%"
239	ALIGN="right"
240	VALIGN="top"
241	>Audio Examples</TD
242	></TR
243	></TABLE
244	></DIV
245	></BODY
246	></HTML
247	>