After some experiments i am back to motif.

now i have some strange results. it would be nice if someone could tell me what is going on.

I have a drawing area widget and for testing i draw a line from upper right to lower left,

When i resize the window are the first reported coordinates are as expected. all other are rubbish.

void exposeCB(Widget w, XtPointer clientdata,XtPointer calldata)
{
puts(__func__);
XGCValues values;
int width,height,depth; /* Dimension */
GC gc;

XtVaGetValues(w,
XmNforeground,&values.foreground,
XmNbackground,&values.background,
NULL);
gc=XtGetGC(w, GCForeground|GCBackground,&values);

width=0;height=0;
XtVaGetValues(w,
XmNwidth,&width,
XmNheight,&height,
XmNdepth,&depth,
NULL);

XDrawLine(XtDisplay(w),
XtWindow(w) , /* drawable */
gc,
0,0,
width,height);

printf("%d %d\n",height,width);
}