Optimizations for when Fl_Tree is a container of FLTK widgets.

o Don't draw FLTK widgets outside tree's viewport.
   o Added tree-as-container.cxx example program, demos tree 
     w/50k tree items each with 6 widgets (300k total)



git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@9356 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

examples/Makefile

@@ -22,6 +22,7 @@ ALL = howto-add_fd-and-popen$(EXEEXT) \
       textdisplay-with-colors$(EXEEXT) \
       texteditor-simple$(EXEEXT) \
       tree-simple$(EXEEXT) \
+      tree-as-container$(EXEEXT) \
       wizard-simple$(EXEEXT)
 
 # default target -- build everything

examples/tree-as-container.cxx

@@ -0,0 +1,90 @@
+//
+// "$Id$"
+//
+//	Fl_Tree as a container of FLTK widgets. - erco 04/15/2012
+//
+// Copyright 2010,2012 Greg Ercolano.
+// Copyright 1998-2010 by Bill Spitzak and others.
+//
+// This library is free software. Distribution and use rights are outlined in
+// the file "COPYING" which should have been included with this file.  If this
+// file is missing or damaged, see the license at:
+//
+//     http://www.fltk.org/COPYING.php
+//
+// Please report all bugs and problems on the following page:
+//
+//     http://www.fltk.org/str.php
+//
+#include <stdio.h>
+#include <FL/Fl.H>
+#include <FL/Fl_Double_Window.H>
+#include <FL/Fl_Tree.H>
+#include <FL/Fl_Group.H>
+#include <FL/Fl_Input.H>
+
+#define MAX_ROWS     80000
+#define MAX_FIELDS   5
+#define FIELD_WIDTH  70
+#define FIELD_HEIGHT 25
+
+class MyData : public Fl_Group {
+    Fl_Input *fields[MAX_FIELDS];
+public:
+    MyData(int X,int Y,int W,int H) : Fl_Group(X,Y,W,H) {
+	static int colors[MAX_FIELDS] = {
+	    0xffffdd00, 0xffdddd00, 0xddffff00, 0xddffdd00, 0xddddff00
+	};
+        for ( int t=0; t<MAX_FIELDS; t++ ) {
+	    fields[t] = new Fl_Input(X+t*FIELD_WIDTH,Y,FIELD_WIDTH,H);
+	    fields[t]->color(colors[t]);
+	}
+	end();
+    }
+    void SetData(int col, const char *val) {
+        if ( col >= 0 && col < MAX_FIELDS )
+	    fields[col]->value(val);
+    }
+};
+
+int main(int argc, char *argv[]) {
+  Fl_Double_Window *win = new Fl_Double_Window(450, 400, "Tree As FLTK Widget Container");
+  win->begin();
+  {
+    // Create the tree
+    Fl_Tree *tree = new Fl_Tree(10, 10, win->w()-20, win->h()-20);
+    tree->showroot(0);				// don't show root of tree
+    // Add some regular text nodes
+    tree->add("Foo/Bar/001");
+    tree->add("Foo/Bar/002");
+    tree->add("Foo/Bla/Aaa");
+    tree->add("Foo/Bla/Bbb");
+    // Add items to the 'Data' node
+    for ( int t=0; t<MAX_ROWS; t++ ) {
+        // Add item to tree
+        static char s[80];
+	sprintf(s, "FLTK Widgets/%d", t);
+	Fl_Tree_Item *item = tree->add(s);
+	// Reconfigure item to be an FLTK widget (MyData)
+	tree->begin();
+	{
+	    MyData *data = new MyData(0,0,FIELD_WIDTH*MAX_FIELDS, FIELD_HEIGHT);
+	    item->widget(data);
+	    // Initialize widget data
+	    for ( int c=0; c<MAX_FIELDS; c++ ) {
+		sprintf(s, "%d-%d", t,c);
+	        data->SetData(c,s);
+	    }
+	}
+	tree->end();
+    }
+  }
+  win->end();
+  win->resizable(win);
+  win->show(argc, argv);
+  return(Fl::run());
+}
+
+//
+// End of "$Id$".
+//

src/Fl_Tree.cxx

@@ -125,6 +125,7 @@ Fl_Tree::~Fl_Tree() {
 
 /// Standard FLTK event handler for this widget.
 int Fl_Tree::handle(int e) {
+  if (e == FL_NO_EVENT) return(0);		// XXX: optimize to prevent slow resizes on large trees!
   int ret = 0;
   // Developer note: Fl_Browser_::handle() used for reference here..
   // #include <FL/names.h>	// for event debugging
@@ -400,7 +401,26 @@ void Fl_Tree::draw() {
   }
   // Draw children
   fl_push_clip(cx,cy,cw-(_vscroll->visible()?_vscroll->w():0),ch);
-  Fl_Group::draw_children();	// draws any FLTK children set via Fl_Tree::widget()
+  // Similar to Fl_Group::draw(), but optimized to ignore drawing
+  // items outside the viewport.
+  // TODO: Suggest Fl_Group::draw() do this if clip_children() is enabled.
+  {
+    Fl_Widget*const* a = Fl_Group::array();
+    if (damage() & ~FL_DAMAGE_CHILD) { // redraw the entire thing:
+      for (int i=Fl_Group::children(); i--;) {
+	Fl_Widget& o = **a++;
+	if ( (o.y()+o.h()) < y() || (o.y() > (y()+h())) ) continue;
+	Fl_Group::draw_child(o);
+	Fl_Group::draw_outside_label(o);
+      }
+    } else {	// only redraw the children that need it:
+      for (int i=Fl_Group::children(); i--;) {
+	Fl_Widget& o = **a++;
+	if ( (o.y()+o.h()) < y() || (o.y() > (y()+h())) ) continue;
+	Fl_Group::update_child(o);
+      }
+    }
+  }
   fl_pop_clip();
   draw_child(*_vscroll);	// draw scroll last
 }