Hello, You could try the Virtual Magnifying Glass:
http://sourceforge.net/projects/magnifier If you enlarge the glass enougth, it will cover the entire screen. The software is created with Lazarus Component Library, which can be recompiled with many different underlying widgetsets. The default underlying widgetset is Gtk 2, but you can recompile it for Qt 4 if that´s a necessity (or native windows api, or wince api, or mac os x carbon, but that´s another story) -- Felipe Monteiro de Carvalho
