2.cpp

unix/linux下面X-Windows的开发示例代码

#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xos.h>
#include <X11/Xatom.h>

#define DUMP_ERR printf

static void draw(Display *display,Window win,GC gc,int width,int height);

int main()
{
Display *display;
int screennum;
int width;
int height;
Atom protocols;

const char *strdraw = “hello world”;

Window win;
GC gc;

display = XOpenDisplay(NULL);
if( !display ){
DUMP_ERR(”call XOpenDisplay(%s) fail\n”,XDisplayName(NULL));
return 1;
}

// get default screen
screennum = DefaultScreen(display);
width = DisplayWidth(display,screennum)/2;
height = DisplayHeight(display,screennum)/2;

// create window
win = XCreateSimpleWindow(display,
RootWindow(display,screennum),
0,0,width,height,3,
BlackPixel(display,screennum),
WhitePixel(display,screennum));

//增加这个代码是捕获程序退出事件
protocols = XInternAtom(display, “WM_DELETE_WINDOW”, True);
XSetWMProtocols(display, win, &protocols, 1);

// select event
XSelectInput(display,win,
ExposureMask|KeyPressMask
|ButtonPressMask|StructureNotifyMask);

// create gc
{
unsigned long valuemask = 0;
XGCValues values;
gc = XCreateGC(display,win,valuemask,&values);
}

// show window
XMapWindow(display,win);

// event loop
while(1){
XEvent event;
XNextEvent(display,&event);

switch(event.type){
case Expose: // expose window
if( event.xexpose.count != 0) break;
draw(display,win,gc,width,height);
//XDrawString(display,win,gc,10,10,
//strdraw,strlen(strdraw));
break;

case ConfigureNotify: // when the window’s size change
width = event.xconfigure.width;
height = event.xconfigure.height;
break;
case ClientMessage :
if(event.xclient.data.l[0] == protocols){
DUMP_ERR(”recv destroy notify\n”);
XFreeGC(display,gc);
XDestroyWindow(display, win);
XCloseDisplay(display);
}
return 0;

default:
break;
}
}
}
// 使用changeGC修改属性的代码 只有valuemask被设置的属性才会根据XCGValues里面的值进行修改
static void set_gc_values(Di