/* HelloX.C "Hello, World!", X Window System style. */ #include #include #include #include #include #include #include /* Global variables */ Display * display; int screen_num; static char * appname; /* main() function */ int main( int argc, char * argv[] ) { /* Window variables */ Window win, root_window; int x, y; unsigned int width, height; unsigned int border_width; char * window_name = "Xlib Example"; char * icon_name = "Xlib Example"; /* Mouse-keyboard variables */ int xM, yM; int bufferlength = 64; char buffer[65]; KeySym keysym; /* Display variables */ char * display_name = NULL; unsigned int display_width, display_height; unsigned long white_pixel, black_pixel; /* Color variables */ Colormap colorMap; /* color map to use for allocating colors. */ XColor red, blue; /* used for allocation of the given color map entries. */ /* Miscellaneous X variables */ XSizeHints * size_hints; XWMHints * wm_hints; XClassHint * class_hints; XTextProperty windowName, iconName; XEvent report; XFontStruct * font_info; XGCValues values; GC gc; appname = argv[0]; /* Allocate memory for our structures */ if ( !( size_hints = XAllocSizeHints() ) || !( wm_hints = XAllocWMHints() ) || !( class_hints = XAllocClassHint() ) ) { fprintf(stderr, "%s: couldn't allocate memory.\n", appname); exit(EXIT_FAILURE); } /* Connect to X server */ if ( (display = XOpenDisplay(display_name)) == NULL ) { fprintf(stderr, "%s: couldn't connect to X server %s\n", appname, display_name); exit(EXIT_FAILURE); } /* Get screen size from display structure macro */ screen_num = DefaultScreen(display); display_width = DisplayWidth(display, screen_num); display_height = DisplayHeight(display, screen_num); root_window = RootWindow(display, screen_num); /* find the ID of the root window of the screen. */ white_pixel = WhitePixel(display, screen_num); /* find the value of a white pixel on this screen. */ black_pixel = BlackPixel(display, screen_num); /* find the value of a black pixel on this screen. */ /* Set initial window size, position and border, and create it */ x = y = 100; width = display_width/2; height = display_height/2; border_width = 2; /* create a simple window, as a direct child of the screen's */ /* root window. Use the screen's white color as the background */ /* color of the window. Place the new window's top-left corner */ /* at the given 'x,y' coordinates. */ win = XCreateSimpleWindow(display, root_window, x, y, width, height, border_width, white_pixel,white_pixel); /* Set hints for window manager before mapping window */ if ( XStringListToTextProperty(&window_name, 1, &windowName) == 0 ) { fprintf(stderr, "%s: structure allocation for windowName failed.\n", appname); exit(EXIT_FAILURE); } if ( XStringListToTextProperty(&icon_name, 1, &iconName) == 0 ) { fprintf(stderr, "%s: structure allocation for iconName failed.\n", appname); exit(EXIT_FAILURE); } size_hints->flags = PPosition | PSize | PMinSize; size_hints->min_width = 100; size_hints->min_height = 100; wm_hints->flags = StateHint | InputHint; wm_hints->initial_state = NormalState; wm_hints->input = True; class_hints->res_name = appname; class_hints->res_class = "xlib_example"; XSetWMProperties(display, win, &windowName, &iconName, argv, argc, size_hints, wm_hints, class_hints); /* Display Window */ XMapWindow(display, win); /* Choose which events we want to handle */ XSelectInput(display, win, ExposureMask | KeyPressMask | ButtonPressMask | StructureNotifyMask); /* Load a font called "9x15" */ if ( (font_info = XLoadQueryFont(display, "9x15")) == NULL ) { fprintf(stderr, "%s: cannot open 9x15 font.\n", appname); exit(EXIT_FAILURE); } /* Create graphics context */ gc = XCreateGC(display, win, 0, &values); XSetFont(display, gc, font_info->fid); XSetBackground(display, gc, white_pixel); /* get access to the screen's color map. */ colorMap = DefaultColormap(display, screen_num); /* allocate the set of colors we will want to use for the drawing. */ if (! XAllocNamedColor(display, colorMap, "red", &red, &red)) { fprintf(stderr, "XAllocNamedColor - failed to allocated 'red' color.\n"); exit(1); } if (! XAllocNamedColor(display, colorMap, "blue", &blue, &blue)) { fprintf(stderr, "XAllocNamedColor - failed to allocated 'blue' color.\n"); exit(1); } /* Enter event loop */ while ( 1 ) { static char * message = "Hello, X Window System!"; static int length; static int font_height; static int msg_x, msg_y; XNextEvent(display, &report); switch ( report.type ) { case Expose: if ( report.xexpose.count != 0 ) break; /* Redraw window */ /* Output message centrally in window */ length = XTextWidth(font_info, message, strlen(message)); msg_x = (width - length) / 2; font_height = font_info->ascent + font_info->descent; msg_y = (height + font_height) / 2; /* draw the message in a red color. */ XSetForeground(display, gc, red.pixel); XDrawString(display, win, gc, msg_x, msg_y, message, strlen(message)); break; case ConfigureNotify: /* Store new window width & height */ width = report.xconfigure.width; height = report.xconfigure.height; break; case KeyPress: length = XLookupString(&report.xkey, buffer, bufferlength, &keysym, NULL ); /* if press 'q', quit... */ if(keysym == 'q'){ /* Clean up and exit */ printf("Quiting...\n"); XUnloadFont(display, font_info->fid); XFreeGC(display, gc); XCloseDisplay(display); exit(EXIT_SUCCESS); } break; case ButtonPress: xM = report.xbutton.x; yM = report.xbutton.y; switch (report.xbutton.button) { case Button1: /* draw the point in a black color. */ XSetForeground(display, gc, black_pixel); XDrawPoint(display, win, gc, xM, yM); break; case Button2: case Button3: break; } default: /* unknown event type - ignore it. */ break; } } return EXIT_SUCCESS; /* We shouldn't get here */ }