property h_offset : 2
property y_offset : 44
property window_count : count of window
property larghezza_schermo : 1260
property window_width : larghezza_schermo / window_count
property window_height : 800
property window_gutter : 4

tell application "Finder"
try

if the window_count is not greater than 1 then error number -128
repeat with x from 1 to 4
if x is 1 then
set the position of window x to {h_offset, y_offset}
else
set the position of window x to {h_offset + window_width * (x - 1) + window_gutter, y_offset}
end if
copy the bounds of window x to {h1, v1, h2, v2}
set the bounds of window x to {h1, v1, h1 + window_width, v1 + window_height}

end repeat
on error error_message number error_number
if the error_number is not -128 then
beep
display dialog error_message buttons {"Cancel"} default button 1
end if
end try
end tell

property h_offset : 2
property window_gutter : 4
property win_h : 450

set menubarHeight to 44
-- otteniamo la dimensione del dock, in realtà non funziona
tell application "System Events" to set dockSize to value of property list item "tilesize" of property list file "~/Library/Preferences/com.apple.dock.plist"
tell application "Finder"
-- otteniamo la dimensione dello schermo
set screenBounds to bounds of window of desktop
-- calcoliamo l'area usabile in verticale
set usableHeight to (item 4 of screenBounds) - menubarHeight - dockSize
-- calcoliamo l'area usabile in orizzontale
set usableWidth to (item 3 of screenBounds) - 2 * h_offset

-- contiamo le finestre
set window_count to count of window
try
if the window_count is less than 2 then error number -128

-- calcoliamo la nuova larghezza delle finestre
set winWidth to (usableWidth - ((window_count - 1) * window_gutter)) / window_count

set nextTop to menubarHeight
set nextLeft to h_offset
set wins to every window
-- per ogni finestra…
repeat with win in wins
-- impostiamo i nuovi estremi della finestra
set bounds of win to {nextLeft, nextTop, nextLeft + winWidth, nextTop + win_h}
-- aggiorniamo il contatore della posizione orizzontale
set nextLeft to nextLeft + window_gutter + winWidth
end repeat

on error error_message number error_number
if the error_number is not -128 then
beep
display dialog error_message buttons {"Cancel"} default button 1
end if
end try
end tell

tell application "System Events" to set dockSize to value of property list item "tilesize" of property list file "~/Library/Preferences/com.apple.dock.plist"

tell application "System Events" to tell dock preferences to get dock size