function RectFromCenterSizeBJ takes location center, real width, real height returns rect
    local real x = GetLocationX(center)
    local real y = GetLocationY(center)
    return Rect(x - width*0.5, y - height*0.5, x + width*0.5, y + height*0.5)
endfunction

native RegionAddRect            takes region whichRegion, rect r returns nothing
native RegionClearRect          takes region whichRegion, rect r returns nothing

function DistanceBetweenCord takes real AX, real AY, real BX, real BY returns real
    local real dx = BX - AX
    local real dy = BY - AY
    return SquareRoot(dx * dx + dy * dy)
endfunction

function AngleBetweenCord takes real AX, real AY, real BX, real BY returns real
    return bj_RADTODEG * Atan2(BY - AY, BX - AX)
endfunction

function UnitAddGroupOnLine takes group gr2, real X1, real Y1, real X2, real Y2, real Size returns group
    local integer Count = R2I(DistanceBetweenCord(X1, Y1, X2, Y2)/10+0.9)
    local real Angle = AngleBetweenCord   (X1, Y1, X2, Y2)*bj_DEGTORAD
    local group gr = CreateGroup()
    local unit u
    loop
        exitwhen Count < 0
        set X1 = X1 + 10*Cos(Angle)
        set Y1 = Y1 + 10*Sin(Angle)
        call GroupEnumUnitsInRange (gr, X1, Y1, Size, null)
        loop
            set u = FirstOfGroup(gr)
            exitwhen u == null
            call GroupAddUnit   (gr2, u)
            call GroupRemoveUnit(gr , u)
        endloop
        call GroupClear(gr)
        set Count = Count - 1
    endloop
    call DestroyGroup(gr)
    set gr = null
    return gr2
endfunction