void frm_main::Paint(Draw& w) {
  Size sz = GetSize();
  ImageBuffer ib(scroll.GetViewSize());
  BufferPainter sw(ib, MODE_ANTIALIASED);
 
  sw.Co(); // Enable MT.
  sw.Clear(White());
  _icons_paint(sw, scroll.Get().x, scroll.Get().y, render_everything);
  sw.Finish(); // Join.

  w.DrawImage(0, 0, ib);
}

void frm_main::Run()
{
	OpenMain();
	while(IsOpen()) {
		Ctrl::ProcessEvents();
		Sleep(1); // can be dynamically set to adapt to workload...
	}
}

void frm_main::_icons_paint2(Draw& w, int x_offset, int y_offset, bool _render_everything)
{
  rect_f visible = rect_f(scroll.x, scroll.y, GetSize().cx, GetSize().cy);
  for(auto it = icons_zorder.rbegin(); it != icons_zorder.rend() ; it++) {
    icon_t* icon = *it;
    rect_f ricon;

    ricon = icon->get_bounds();

    if(_render_everything || ricon.intersects(visible)) {
      w.Clip(GetSize());
      icon->icon_paint2(w, x_offset, y_offset);
      w.End();
    }
  }
}

TIMING Paint          : 834.63 ms -  2.74 ms (835.00 ms / 305 ), min:  2.00 ms, max:  4.00 ms, nesting: 0 - 305

void frm_main::Paint(Draw& w) {
  Size sz = GetSize();
  w.DrawRect(sz, Yellow()); // System draw, background = yellow.
  ImageBuffer ib(sz);
  BufferPainter bp(ib, MODE_ANTIALIASED);
  bp.Clear(RGBAZero());     // Buffer now has transparent background.

  _icons_paint(bp, scroll.Get().x, scroll.Get().y, allow_scaling, render_everything);
	
  if(show_overlay) {
    _paint_overlay(bp);
  }

  SetSurface(w, 0, 0, sz.cx, sz.cy, ~ib); // You need to use SetSurface to directly paint buffer content here (this is optimized for systemdraw (possibly faster than usual image drawing) ...
}