'As we spend more and more of our time staring at the screens of movies, televisions, computers, and handheld devices—"windows" full of moving images, texts, and icons—how the world is framed has become as important as what is in the frame. In The Virtual Window, Anne Friedberg examines the window as metaphor, as architectural component, and as an opening to the dematerialized reality we see on the screen.
In De pictura (1435), Leon Battista Alberti famously instructed painters to consider the frame of the painting as an open window. Taking Alberti's metaphor as her starting point, Friedberg tracks shifts in the perspectival paradigm as she gives us histories of the architectural window, developments in glass and transparency, and the emerging apparatuses of photography, cinema, television, and digital imaging. Single-point perspective—Alberti's metaphorical window—has long been challenged by modern painting, modern architecture, and moving-image technologies.'
(http://mitpress.mit.edu/catalog/item/default.asp?tid=10780&t...

'Leon Battista Alberti concepisce la visione come una figura piramidale nel cui vertice si trova l'occhio e i cui lati sono formati dalle linee che partono dai contorni dell'oggetto guardato (vedi figura sopra). Secondo questa immagine geometrica il dipinto su cui riportare l'immagine è come una finestra che si trova tra l'occhio e l'oggetto osservato e sulla cui superficie è possibile riportare l'immagine stessa dell'oggetto. E' evidente che se questo oggetto si allontana dall'occhio la sua immagine riportata sulla finestra sarà più piccola.'
(http://didascienze.formazione.unimib.it/Lucevisione/pittura/...


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Note added at 22 mins (2012-09-14 12:42:54 GMT)
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More about the window metaphor here,
http://www.uni-muenster.de/EuropeanPopularScience/win-sample...
"During the flowering of the Renaissance the term ‘window metaphor’ became associated with Leon Battista Alberti, who, based on the theory of perspective originated by the paintings and drawings of Filippo Brunelleschi, in 1435 published his famed ‘De Pictura’. This was the first theoretical and critical account ‘on how to paint’ in an aesthetically attractive and visually convincing way."