Fix Fl_Overlay_Window for Cairo.

FL/Fl.H

@@ -1040,7 +1040,7 @@ public:
 public:
 
   // Cairo support API
-  static cairo_t * cairo_make_current(Fl_Window* w);
+  static cairo_t * cairo_make_current(Fl_Window* wi, Window w = 0);
    /** when FLTK_HAVE_CAIRO is defined and cairo_autolink_context() is true, 
       any current window dc is linked to a current context.
       This is not the default, because it may not be necessary

FL/Fl_Overlay_Window.H

@@ -45,15 +45,10 @@
   overlay will blink if you change the image in the window.
 */
 class FL_EXPORT Fl_Overlay_Window : public Fl_Double_Window {
-  friend class _Fl_Overlay;
   virtual void draw_overlay() = 0;
-  Fl_Window *overlay_;
 public:
-  void show();
   void flush();
-  void hide();
-  void resize(int,int,int,int);
-  ~Fl_Overlay_Window();
+  virtual ~Fl_Overlay_Window();
   int can_do_overlay();
   void redraw_overlay();
   /**
@@ -63,13 +58,12 @@ public:
     will choose them.
   */
   Fl_Overlay_Window(int W, int H, const char *l=0)
-    : Fl_Double_Window(W,H,l) {overlay_ = 0; force_doublebuffering_=1; image(0); }
+    : Fl_Double_Window(W,H,l) { force_doublebuffering_=1; image(0); }
    /**
     See Fl_Overlay_Window::Fl_Overlay_Window(int W, int H, const char *l=0)
   */
  Fl_Overlay_Window(int X, int Y, int W, int H, const char *l=0)
-    : Fl_Double_Window(X,Y,W,H,l) {overlay_ = 0; force_doublebuffering_=1; image(0); }
-  void show(int a, char **b) {Fl_Double_Window::show(a,b);}
+    : Fl_Double_Window(X,Y,W,H,l) { force_doublebuffering_=1; image(0); }
 };
 
 #endif

src/Fl_Cairo.cxx

@@ -57,10 +57,11 @@ static Window real_xid;
 static int W, H;
 
 cairo_t * 
-Fl::cairo_make_current(Fl_Window* wi) {
+Fl::cairo_make_current(Fl_Window* wi, Window w ) {
     if (!wi) return NULL; // Precondition
 
-    Window w = wi->i->other_xid ? wi->i->other_xid : wi->i->xid;
+    if ( ! w )
+      w =  wi->i->other_xid ? wi->i->other_xid : wi->i->xid;
 
     if ( ( fl_cairo_context && fl_cairo_context == wi->i->cc ) &&
          w && w == real_xid && 

src/Fl_Overlay_Window.cxx

@@ -42,15 +42,6 @@
 #include <FL/fl_draw.H>
 #include <FL/x.H>
 
-void Fl_Overlay_Window::show() {
-  Fl_Double_Window::show();
-  if (overlay_ && overlay_ != this) overlay_->show();
-}
-
-void Fl_Overlay_Window::hide() {
-  Fl_Double_Window::hide();
-}
-
 void Fl_Overlay_Window::flush() {
 #ifdef BOXX_BUGS
   if (overlay_ && overlay_ != this && overlay_->shown()) {
@@ -61,15 +52,17 @@ void Fl_Overlay_Window::flush() {
     return;
   }
 #endif
-  int erase_overlay = (damage()&FL_DAMAGE_OVERLAY) | (overlay_ == this);
+  int erase_overlay = (damage()&FL_DAMAGE_OVERLAY);
   clear_damage((uchar)(damage()&~FL_DAMAGE_OVERLAY));
   Fl_Double_Window::flush(erase_overlay);
-  if (overlay_ == this) draw_overlay();
-}
-
-void Fl_Overlay_Window::resize(int X, int Y, int W, int H) {
-  Fl_Double_Window::resize(X,Y,W,H);
-  if (overlay_ && overlay_!=this) overlay_->resize(0,0,w(),h());
+  Fl_X* myi = Fl_X::i(this);
+#if FLTK_HAVE_CAIRO
+      Fl::cairo_make_current( this, myi->xid );
+#endif
+      draw_overlay();
+#if FLTK_HAVE_CAIRO
+      Fl::cairo_make_current( this, myi->other_xid );
+#endif
 }
 
 /**
@@ -89,7 +82,6 @@ int Fl_Overlay_Window::can_do_overlay() {return 0;}
   calling show().
 */
 void Fl_Overlay_Window::redraw_overlay() {
-  overlay_ = this;
   clear_damage((uchar)(damage()|FL_DAMAGE_OVERLAY));
   Fl::damage(FL_DAMAGE_CHILD);
 }