--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2010-09-09  Shai Ayal  <shaiay@users.sourceforge.net>
+
+	* gl2ps-renderer.cc: Renders to a previously opened fid.
+	* gl2ps-renderer.h: Ditto.
+	* DLD-FUNCTIONS/fltk_backend.cc: print now accepts fid instead
+	of filename to use with above change
+
 2010-09-07  Jaroslav Hajek  <highegg@gmail.com>
 
 	* DLD-FUNCTIONS/__magick_read__.cc (maybe_initialize_magick): New

--- a/src/DLD-FUNCTIONS/fltk_backend.cc
+++ b/src/DLD-FUNCTIONS/fltk_backend.cc
@@ -87,7 +87,7 @@
 public:
   OpenGL_fltk (int xx, int yy, int ww, int hh, double num)
     : Fl_Gl_Window (xx, yy, ww, hh, 0), number (num), renderer (),
-      in_zoom (false), zoom_box (),  print_filename ()
+      in_zoom (false), zoom_box (),  print_fid (-1)
   {
     // Ask for double buffering and a depth buffer.
     mode (FL_DEPTH | FL_DOUBLE);
@@ -105,9 +105,9 @@
   bool zoom (void) { return in_zoom; }
   void set_zoom_box (const Matrix& zb) { zoom_box = zb; }
   
-  void print (const std::string& filename, const std::string& term)
+  void print (const int fid, const std::string& term)
   {
-    print_filename  = filename;
+    print_fid  = fid;
     print_term  = term;
   }
 
@@ -118,7 +118,7 @@
   // (x1,y1,x2,y2)
   Matrix zoom_box;
 
-  std::string print_filename;
+  int print_fid;
   std::string print_term;
 
   void setup_viewport (int ww, int hh)
@@ -136,11 +136,11 @@
         setup_viewport (w (), h ());
       }
 
-    if (! print_filename.empty ())
+    if ( print_fid > 0 )
       {
-        opengl_renderer *rend = new glps_renderer (print_filename, print_term);
+        opengl_renderer *rend = new glps_renderer (print_fid, print_term);
         rend->draw (gh_manager::lookup (number));
-        print_filename = "";
+        print_fid = -1;
         delete rend;
       }
     else
@@ -338,9 +338,9 @@
   // FIXME -- this could change.
   double number (void) { return fp.get___myhandle__ ().value (); }
 
-  void print (const std::string& fname, const std::string& term)
+  void print (const int fid, const std::string& term)
   {
-    canvas->print (fname, term);
+    canvas->print (fid, term);
 
     // Print immediately so the output file will exist when the drawnow
     // command is done.
@@ -958,10 +958,10 @@
     return get_size (hnd2idx (gh));
   }
 
-  static void print (const graphics_handle& gh , const std::string& filename,  const std::string& term)
+  static void print (const graphics_handle& gh , const int fid,  const std::string& term)
   {
     if (instance_ok ())
-      instance->do_print (hnd2idx(gh), filename, term);
+      instance->do_print (hnd2idx(gh), fid, term);
   }
 
 private:
@@ -1060,12 +1060,12 @@
     return sz;
   }
 
-  void do_print (int idx, const std::string& filename,  const std::string& term)
+  void do_print (int idx, const int fid,  const std::string& term)
   {
     wm_iterator win;
     if ((win = windows.find (idx)) != windows.end ())
       {
-        win->second->print (filename, term);
+        win->second->print (fid, term);
       }
   }
 
@@ -1228,8 +1228,15 @@
                      const std::string& file, bool /*mono*/,
                      const std::string& /*debug_file*/) const 
   { 
-    figure_manager::print (go.get_handle (), file, term);
-    redraw_figure (go);
+    int fid;
+    std::istringstream istr (file);
+    if (istr >> fid)
+      {
+        figure_manager::print (go.get_handle (), fid, term);
+        redraw_figure (go);
+      }
+    else
+      error ("fltk_backend: filename should be fid");
   }
 
   Matrix get_canvas_size (const graphics_handle& fh) const

--- a/src/gl2ps-renderer.cc
+++ b/src/gl2ps-renderer.cc
@@ -43,7 +43,7 @@
     {
       in_draw = true;
 
-      FILE *fp = fopen (filename.c_str (), "wb");
+      FILE *fp = fdopen (fid, "wb");
       GLint buffsize = 0, state = GL2PS_OVERFLOW;
       GLint viewport[4];
 
@@ -74,7 +74,7 @@
                            | GL2PS_NO_BLENDING | GL2PS_OCCLUSION_CULL
                            | GL2PS_BEST_ROOT | gl2ps_text), 
                           GL_RGBA, 0, NULL, 0, 0, 0,
-                          buffsize, fp, filename.c_str () );
+                          buffsize, fp, "" );
 
           opengl_renderer::draw (go);
           state = gl2psEndPage ();

--- a/src/gl2ps-renderer.h
+++ b/src/gl2ps-renderer.h
@@ -31,8 +31,8 @@
 glps_renderer : public opengl_renderer
 {
 public:
-  glps_renderer (const std::string& _filename, const std::string& _term) 
-    : opengl_renderer () , filename (_filename), term (_term) { }
+  glps_renderer (const int _fid, const std::string& _term) 
+    : opengl_renderer () , fid (_fid), term (_term) { }
 
   ~glps_renderer (void) { }
 
@@ -74,7 +74,7 @@
   }
 
 private:
-  std::string filename;
+  int fid;
   caseless_str term;
   double fontsize;
   std::string fontname;