const char *get_vardir(void) { return "."; }
 
 
-static enum { mode_all=03, mode_screenshot=01, mode_analyse=02 }
-    o_mode= mode_all;
+static enum {
+  mf_findwindow=    01,
+  mf_screenshot=    02,
+  mf_analyse=       04,
+  
+  mode_findwindow=  01,
+  mode_screenshot=  03,
+  mode_analyse=     04,
+
+  mode_all=         07,
+} o_mode= mode_all;
+
 static char *o_screenshots_fn;
 static int o_single_page;
 
   int r;
 
   while ((arg=*++argv)) {
-    if (!strcmp(arg,"--screenshot-only"))
+    if (!strcmp(arg,"--find-window-only"))
+      o_mode= mode_findwindow;
+    else if (!strcmp(arg,"--screenshot-only"))
       o_mode= mode_screenshot;
     else if (!strcmp(arg,"--analyse-only"))
       o_mode= mode_analyse;
     eassert(r>=0);  eassert(o_screenshots_fn);
   }
 
-  if (o_mode & mode_screenshot) {
+  if (o_mode & mf_findwindow) {
     screenshot_startup();
     find_yppclient_window();
+  }
+  if (o_mode & mf_screenshot) {
     screenshots_file= fopen(o_screenshots_fn, "w"); eassert(screenshots_file);
     if (o_single_page)
       take_one_screenshot();
     screenshots_file= fopen(o_screenshots_fn, "r"); eassert(screenshots_file);
     read_screenshots();
   }
-  if (o_mode & mode_analyse) {
+  if (o_mode & mf_analyse) {
     analyse();
     //output_tsv();
   }
 
 /*----- debugging arrangements, rather contingent -----*/
 
 #define DEBUG_FLAG_LIST                                \
-   DF(ocr)                                     \
+   DF(findypp)                                 \
+   DF(pages)                                   \
    DF(rect)                                    \
-   DF(callout)                                 \
-   DF(pages)
+   DF(ocr)                                     \
+   DF(callout)
 
 enum {
 #define DF(f) dbg__shift_##f,
 
 const char *get_vardir(void);
 
-#define DEBUG_DEFINE_DEBUGF(f)                                         \
-  static void vdebugf(const char *fmt, va_list al) {                   \
-    if (DEBUGP(f))                                                     \
+#define DEBUG_DEFINE_SOME_DEBUGF(fl,funcf)                             \
+  static void v##funcf(const char *fmt, va_list al) {                  \
+    if (DEBUGP(fl))                                                    \
       vfprintf(debug,fmt,al);                                          \
   }                                                                    \
-  static void debugf(const char *fmt, ...) {                           \
-    va_list al;  va_start(al,fmt);  vdebugf(fmt,al);  va_end(al);      \
+  static void funcf(const char *fmt, ...) {                            \
+    va_list al;  va_start(al,fmt);  v##funcf(fmt,al);  va_end(al);     \
   }
 
+#define DEBUG_DEFINE_DEBUGF(fl) DEBUG_DEFINE_SOME_DEBUGF(fl,debugf)
+
 #endif /*OCR_H*/
 
 CanonImage *page_images[MAX_PAGES];
 int npages;
 
+char *ocean, *pirate;
+
 static XWindowAttributes attr;
 static Window id;
 static Display *disp;
   id= wul;
 }
 
+DEBUG_DEFINE_SOME_DEBUGF(findypp,debugfind)
+
 void find_yppclient_window(void) {
+  Window root, gotroot, gotparent;
+  int screen, r;
+  int nfound=0;
+  
   if (id) return;
-  eassert(!"finding client window NYI");
+  
+  static const char prefix[]= "Puzzle Pirates - ";
+  static const char onthe[]= " on the ";
+  static const char suffix[]= " ocean";
+#define S(x) (sizeof((x))-1)
+
+  Atom wm_name= XInternAtom(disp,"WM_NAME",True);
+  eassert(wm_name != None);
+
+  for (screen=0; screen<ScreenCount(disp); screen++) {
+    debugfind("FINDYPP screen %d\n", screen);
+    root= RootWindow(disp,screen);
+    unsigned int nchildren1;
+    Window *children1=0;
+
+    r= XQueryTree(disp,root,
+                 &gotroot,&gotparent,
+                 &children1,&nchildren1);
+    eassert(r);
+    debugfind("FINDYPP screen %d nchildren1=%d\n", screen, nchildren1);
+
+    int i;
+    for (i=0; i<nchildren1; i++) {
+      Window w1= children1[i];
+      unsigned int nchildren2;
+      Window *children2=0;
+
+      r= XQueryTree(disp,w1,
+                   &gotroot,&gotparent,
+                   &children2,&nchildren2);
+      eassert(r);
+      debugfind("FINDYPP screen %d c1[%2d]=0x%08lx nchildren2=%d\n",
+               screen, i, (unsigned long)w1, nchildren2);
+
+      int j;
+      for (j=-1; j<(int)nchildren2; j++) {
+       Window w2= j<0 ? w1 : children2[j];
+       debugfind("FINDYPP screen %d c1[%2d]=0x%08lx c2[%2d]=0x%08lx",
+                 screen, i, (unsigned long)w1, j, (unsigned long)w2);
+
+       int gotfmt;
+       Atom gottype;
+       unsigned long len, gotbytesafter;
+       char *title;
+       unsigned char *gottitle=0;
+       r= XGetWindowProperty(disp,w2, wm_name,0,512, False,
+                             AnyPropertyType,&gottype, &gotfmt, &len,
+                             &gotbytesafter, &gottitle);
+       eassert(!r);
+       title= (char*)gottitle;
+
+       if (DEBUGP(findypp)) {
+         debugfind(" gf=%d len=%lu gba=%lu \"", gotfmt,len,gotbytesafter);
+         char *p;
+         for (p=title; p < title+len; p++) {
+           char c= *p;
+           if (c>=' ' && c<=126) fputc(c,debug);
+           else fprintf(debug,"\\x%02x",c & 0xff);
+         }
+         fputs("\": ",debug);
+       }
+
+#define REQUIRE(pred)                                                     \
+        if (!(pred)) { debugfind(" failed test  %s\n", #pred); continue; } \
+        else
+
+       REQUIRE( gottype!=None );
+       REQUIRE( len );
+       REQUIRE( gotfmt==8 );
+
+       REQUIRE( len >= S(prefix) + 1 + S(onthe) + 1 + S(suffix) );
+
+       char *spc1= strchr(  title        + S(prefix), ' ');  REQUIRE(spc1);
+       char *spc2= strrchr((title + len) - S(suffix), ' ');  REQUIRE(spc2);
+
+       REQUIRE( (title + len) - spc1  >= S(onthe)  + S(suffix) );
+       REQUIRE(  spc2         - title >= S(prefix) + S(onthe) );
+
+       REQUIRE( !memcmp(title,                   prefix, S(prefix)) );
+       REQUIRE( !memcmp(title + len - S(suffix), suffix, S(suffix))  );
+       REQUIRE( !memcmp(spc1,                    onthe,  S(onthe))  );
+
+#define ASSIGN(what, start, end) do {                                  \
+       r= asprintf(&what, "%.*s", end - start, start);  eassert(r>0);  \
+     }while(0)
+       ASSIGN(ocean,  title + S(prefix),  spc1);
+       ASSIGN(pirate, spc1 + S(onthe),   (title + len) - S(suffix));
+
+       debugfind(" YES!\n");
+       id= w2;
+       nfound++;
+      }
+      if (children2) XFree(children2);
+    }
+    if (children1) XFree(children1);
+  }
+  eassert(nfound==1);
 }