tornado

--[[ ******************************************************************
Tornado by KOP

******************************************************************* ]]

return function(pg, of, sw, sh)

        pg:translate(of,0,0)

    local pc, cx, cy = math.abs(of/pg.width), pg.width/2, pg.height/2
        -- target distance
local midx =pg.width/2

        local midy =pg.height/2+7
        local tg = pg.width
        local fx = pc*5
        if fx>1 then fx=1 end
local side = -1

        -- if(of>0) then side=1 end
    for i, ic in subviews(pg) do
                -- get icon center
                local icx, icy = (ic.x+ic.width/2), (ic.y+ic.height/2)
                -- get icon offset from page center
                local ox, oy = math.abs(cx-icx), math.abs(cy-icy)
                -- get angle of icon position
                local ang = math.atan(oy/ox)
                -- get hypotenuse
                local h = math.sqrt( ox^2+oy^2)
local iconX = ic.x+ic.width/2
                local fall = (1-pc)*h
          local iconY = ic.y+ic.height/2
                -- get hypotenuse extension
                local oh = fx*h+fx*tg
                -- directions
                local dx, dy = 1,1
                if icx<cx then dx=-dx end
                if icy<cy then dy=-dy end
                if icy==cy then dy=0 end
                local nx = 0
local ny = 0
                -- calc new x & y
                -- local nx = math.sqrt(h^2-oy^2)
                -- local ny = math.sqrt(h^2-ox^2)
                nx =midx+dx*fall*math.cos(pc*6*math.pi*ang)
                ny =2*midy-3*fall+math.sin(pc*4*math.pi*ang)
                local size=(3-fx)*(fall/h)
                if size>1 then size=1 end
                -- move!!
                ic:translate(fx*(nx-iconX),fx*(ny-iconY),0)
-- ic:scale(size*size)
-- ic:translate(-0.5*nx,-0.5*ny,0)

                -- if pc>0.6 then
                        ic.alpha = 1-pc
                -- end

    end
end