Pine script 如何从指定时间段的开始到结束绘制线

我正在写一个代码来绘制每周的高点和低点，并以此为基础试图得到范围。问题是，在绘制线时，应参考x1和x2，以便从时间范围的开始到结束绘制线，例如从一周的开始到一周的结束

这是我的密码。我已经输入了一些barindex，但它会向后绘制线条。非常感谢您的帮助。谢谢

// This source code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © alphatrader09

//@version=4
study("Range" , overlay = true)

_1              = input(title = "═════ TimeFrame Settings ═════",    type = input.bool,          defval = true)
i_resolution    = input(title = "Select Timeframe",       type = input.resolution,    defval ="W")

tfHighLow() =>
    float   _highestHigh    =   na
    float   _lowestLow      =   na
    
    _highestHigh    :=  highest(high,2)
    _lowestLow      :=  lowest(low,2)
    [_highestHigh, _lowestLow]
    
[_hH,_lL]   =   security(syminfo.tickerid, expression = tfHighLow(), resolution = i_resolution, gaps = barmerge.gaps_off, lookahead = barmerge.lookahead_on )

// Values to plot
_h  =   _hH[1]
_l  =   _lL[1]
_r  =   (_h  - _l)
_t1 =   _lL +   _r*1.382
_t2 =   _lL +   _r*1.618
_m  =   (_h +   _l)/2
_s1 =   _hH -   _r*1.382
_s2 =   _hH -   _r*1.618

// lines to plot

var line    _Lh     =   na
var line    _Ll     =   na
var line    _Lt1    =   na
var line    _Lt2    =   na
var line    _Lm     =   na
var line    _Ls1    =   na
var line    _Ls2    =   na

bool    newSess     =   change(time(i_resolution)) > 0

if  newSess and bar_index > 1
    _Lh     :=  line.new(x1=bar_index[20], y1=_h, x2=bar_index[0], y2 = _h, xloc = xloc.bar_index, color= color.teal)

---

做了一些研发，改进了代码中的一些问题，下面是脚本

// This source code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © alphatrader09

//@version=4
study("Range" , overlay = true)

_1              = input(title = "═════ TimeFrame Settings ═════",    type = input.bool,          defval = true)
i_resolution    = input(title = "Select Timeframe",       type = input.resolution,    defval ="W")

tfHighLow() =>
    float   _highestHigh    =   na
    float   _lowestLow      =   na
    
    _highestHigh    :=  high[1]
    _lowestLow      :=  low[1]
    [_highestHigh, _lowestLow]
    
[_hH,_lL]   =   security(syminfo.tickerid, expression = tfHighLow(), resolution = i_resolution, gaps = barmerge.gaps_off, lookahead = barmerge.lookahead_on )

// Values to plot
_h  =   _hH
_l  =   _lL
_r  =   (_h  - _l)
_t1 =   _lL +   _r*1.382
_t2 =   _lL +   _r*1.618
_m  =   (_h +   _l)/2
_s1 =   _hH -   _r*1.382
_s2 =   _hH -   _r*1.618

// lines to plot

var line    _Lh     =   na
var line    _Ll     =   na
var line    _Lt1    =   na
var line    _Lt2    =   na
var line    _Lm     =   na
var line    _Ls1    =   na
var line    _Ls2    =   na



if  _m[1]   !=  _m
    line.set_x2(_Lh, bar_index)
    line.set_x2(_Ll, bar_index)
    line.set_x2(_Lt1, bar_index)
    line.set_x2(_Lt2, bar_index)
    line.set_x2(_Lm, bar_index)
    line.set_x2(_Ls1, bar_index)
    line.set_x2(_Ls2, bar_index)
    _Lm     :=  line.new(bar_index, _m, bar_index,  _m, xloc = xloc.bar_index, extend= extend.none,color= color.black, width=2)
    _Lh     :=  line.new(bar_index, _h, bar_index,  _h, xloc = xloc.bar_index, extend= extend.none,color= color.teal)
    _Ll     :=  line.new(bar_index, _l, bar_index,  _l, xloc = xloc.bar_index, extend= extend.none,color= color.red)
    _Lt1    :=  line.new(bar_index, _t1, bar_index,  _t1, xloc = xloc.bar_index, extend= extend.none,color= color.teal, style =line.style_dashed)
    _Lt2    :=  line.new(bar_index, _t2, bar_index,  _t2, xloc = xloc.bar_index, extend= extend.none,color= color.teal, style = line.style_dashed)
    _Ls1    :=  line.new(bar_index, _s1, bar_index,  _s1, xloc = xloc.bar_index, extend= extend.none,color= color.red, style = line.style_dashed)
    _Ls2    :=  line.new(bar_index, _s2, bar_index,  _s2, xloc = xloc.bar_index, extend= extend.none,color= color.red, style = line.style_dashed)
    
    
     
     
if  not na(_Lm) and line.get_x2(_Lm)    !=  bar_index
    line.set_x2(_Lh, bar_index)
    line.set_x2(_Ll, bar_index)
    line.set_x2(_Lt1, bar_index)
    line.set_x2(_Lt2, bar_index)
    line.set_x2(_Lm, bar_index)
    line.set_x2(_Ls1, bar_index)
    line.set_x2(_Ls2, bar_index)