Xlib: Does XGetWindowAttributes always return 1x1?

Question

I would like to have the width and height of the current focal window. Window selection works like a charm, while height and width always return 1.

#include <X11/Xlib.h>
#include <stdio.h>

int main(int argc, char *argv[])
{
    Display *display;
    Window focus;
    XWindowAttributes attr;
    int revert;

    display = XOpenDisplay(NULL);
    XGetInputFocus(display, &focus, &revert);
    XGetWindowAttributes(display, focus, &attr);
    printf("[0x%x] %d x %d\n", (unsigned)focus, attr.width, attr.height);

    return 0;
}

This is not a "real" window, but the current active component (for example, a text field or a button?). And why should it have a size of 1x1 anyway? If so, how can I get the main window of the application containing this control? So ... view of the top-level window, the topmost window, except for the root window.

PS: I do not know if this is really important; I am using Ubuntu 10.04 32 and 64 bit.

Answer 1

- . GTK, , "" , 1x1, , . GNOME, GTK ().

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, , XQueryTree - .

:

#include <X11/Xlib.h>
#include <stdio.h>
#include <stdlib.h>

/*
Returns the parent window of "window" (i.e. the ancestor of window
that is a direct child of the root, or window itself if it is a direct child).
If window is the root window, returns window.
*/
Window get_toplevel_parent(Display * display, Window window)
{
     Window parent;
     Window root;
     Window * children;
     unsigned int num_children;

     while (1) {
         if (0 == XQueryTree(display, window, &root,
                   &parent, &children, &num_children)) {
             fprintf(stderr, "XQueryTree error\n");
             abort(); //change to whatever error handling you prefer
         }
         if (children) { //must test for null
             XFree(children);
         }
         if (window == root || parent == root) {
             return window;
         }
         else {
             window = parent;
         }
     }
}

int main(int argc, char *argv[])
{
    Display *display;
    Window focus, toplevel_parent_of_focus;
    XWindowAttributes attr;
    int revert;

    display = XOpenDisplay(NULL);
    XGetInputFocus(display, &focus, &revert);
    toplevel_parent_of_focus = get_toplevel_parent(display, focus);
    XGetWindowAttributes(display, toplevel_parent_of_focus, &attr);
    printf("[0x%x] %d x %d\n", (unsigned)toplevel_parent_of_focus, 
       attr.width, attr.height);

    return 0;
}