--- HELLO.C START ---
/*
HelloX.C
========
(c) Copyright Paul Griffiths 1999
Email: paulgriffiths@cwcom.net
"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;
int x, y;
unsigned int width, height;
unsigned int border_width;
char * window_name = "Hello, X Window System!";
char * icon_name = "HelloX";
/* Display variables */
char * display_name = NULL;
unsigned int display_width, display_height;
/* 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);
/* Set initial window size and position, and create it */
x = y = 0;
width = display_width / 3;
height = display_width / 3;
win = XCreateSimpleWindow(display, RootWindow(display, screen_num),
x, y, width, height, border_width,
BlackPixel(display, screen_num),
WhitePixel(display, screen_num));
/* 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 = 200;
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 = "hellox";
XSetWMProperties(display, win, &windowName, &iconName, argv, argc,
size_hints, wm_hints, class_hints);
/* 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);
XSetForeground(display, gc, BlackPixel(display, screen_num));
/* Display Window */
XMapWindow(display, win);
/* 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;
/* 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;
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 ButtonPress: /* Fall through */
case KeyPress:
/* Clean up and exit */
XUnloadFont(display, font_info->fid);
XFreeGC(display, gc);
XCloseDisplay(display);
exit(EXIT_SUCCESS);
}
}
return EXIT_SUCCESS; /* We shouldn't get here */
}
--- HELLO.C END ---
--- Makefile START ---
HelloX: HelloX.o
gcc -o HelloX HelloX.o -Wall -L/usr/X11R6/lib -lX11
HelloX.o: HelloX.c
gcc -o HelloX.o HelloX.c -c -ansi -pedantic -Wall
--- Makefile END --- |