Helix effect for Cylinder

-- Psychospiral animation by Cylgom; modified to Helix by KnifeOfPi

return function(page, offset, screen_width, screen_height)

        local percent = math.abs(offset/page.width)

        side = -1

        if(offset>0) then side=1 end



        local rollup = percent*5

        if(rollup>1) then rollup=1 end

        local runaway = (percent-0.20)/0.6

        if(runaway<0) then runaway=0 end

        if(runaway>1) then runaway=1 end



        local middleX =page.width/2

        local middleY =page.height/2+7

        local radiusparts = (middleY)/#page.subviews

        local theta = (3.5*math.pi)/#page.subviews

local size = 1

        for i, icon in subviews(page) do

          local initangle =(i-1)*theta

          local initradius =(i-1)*radiusparts

          local angle = initangle+runaway*(3.5*math.pi-initangle)

          local radius = initradius+runaway*(middleY-initradius)+45

          local iconX = icon.x+icon.width/2

          local iconY = icon.y+icon.height/2

          local pathX = (middleX+(radius*math.sin(angle))*side)

          local pathY = (middleY+(radius*math.tan(angle))*side)

          local iconAngle = angle

          icon:translate(rollup*(pathX-iconX), rollup*(pathY-iconY), 0)

          icon:rotate(rollup*iconAngle)



          icon:scale(size*size)

        end

        page:translate(offset,0,0)

end