Mercurial > sdl-ios-xcode
view docs/html/guideeventexamples.html @ 816:428f688f2ad2
Date: Fri, 13 Feb 2004 17:03:16 +0100
From: Max Horn
Subject: Modifier key fix
The internal modifier state can get out of sync with reality. To
trigger this, do for example this:
1) Launch an SDL app
2) Alt-click on the desktop (this will hide the SDL app).
3) Bring the SDL app back to the front
4) SDL will still think alt is pressed (and as such will treat left
clicks like middle clicks). If you press and release alt, it'll be fine
again.
The attached patch cures this by rechecking the modifier state whenever
we process an event.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Fri, 13 Feb 2004 17:57:16 +0000 |
parents | 355632dca928 |
children |
line wrap: on
line source
<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 <stdio.h> #include <stdlib.h> #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->type == SDL_QUIT) && boycott ) { printf("Quit event filtered out -- try again.\n"); boycott = 0; return(0); } if ( event->type == SDL_MOUSEMOTION ) { printf("Mouse moved to (%d,%d)\n", event->motion.x, event->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) < 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(&event) >= 0 ) { switch (event.type) { case SDL_ACTIVEEVENT: { if ( event.active.state & 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 >