On ne peut pas régler la taille des fléches des instructions DRAWARROW, donc on utilise du texte dans lequel on place un caractère ASCII, ici les plus grosses flèches que j’ai pu trouver, et j’ai augmenté la taille au max:

//
defparam calculateonlastbars = 1000
if Close>( max(max(high,high[1]),max(high[1],high[1]) ))[1] then
D=Min(Min(low,low[1]),Min(low[1],low[1]))
elsif close<(Min(Min(low,low[1]),Min(low[1],low[1])))[1] then
D=Max(Max(high,high[1]),Max(high[1],high[1]))
else
D=D[1]
endif
//plot1 = 0
//plot2 = 0

rge = averagetruerange[10](close)

if (close crosses over D) then
//plot1 = 1
//DRAWARROWUP(barindex,low[1]-0.1*rge) coloured(0,250,0,250)
//DRAWTEXT("⬆",barindex,low[1]-0.1*rge,dialog,bold,40) coloured(0,250,0,250)
DRAWTEXT("▲",barindex,low[1]-0.1*rge,dialog,bold,40) coloured(0,250,0,250)
//DRAWTEXT(".",BarIndex,low[1]-0.1*rge,dialog,bold,25) coloured(0,0,250,255) //(H1/H4 = +7) (1 min = -1)

levelDwn=low[0]
hh=high

//else
//plot1 = 0
endif
if (close crosses under D) then
//DRAWARROWDOWN(barindex,high[1]+0.1*rge) coloured(250,0,0,250)
//DRAWTEXT("⬇",barindex,high[1]+0.1*rge,dialog,bold,40) coloured(250,0,0,250)
DRAWTEXT("▼",barindex,high[1]+0.1*rge,dialog,bold,40) coloured(250,0,0,250)
//DRAWTEXT(".",BarIndex,high[1]+0.6*rge,serif,bold,1) coloured(250,250,0,255) //(H1/H4 = +7) (1 min //= -1)
//plot2=-1
//else
//plot2=0
levelUP=high[0]
ll=low
endif

return D,levelUp coloured(0,250,0) STYLE(DOTTEDLINE),levelDwn coloured(250,0,0) STYLE(DOTTEDLINE),hh coloured(0,250,0) STYLE(LINE),ll coloured(250,0,0) STYLE(LINE)