How could I plot Crossover Signal on master window(plotinfo.plotmaster == self.datas[0]) as triangle indicating where it happens??

xyshell

Hi everyone.
Currently I want to plot some Crossover Signal (bt.ind.CrossOver) on the price to gain some insight.
I want to plot it as triangle (just like the buy and sell point) with probably different colors and directions (up-triangle indicating it's crossing up, down-triangle indicating it's crossing down), just like selling gives a red downside triangle and buying gives a green upside triangle.
Is there anyone know how to do that?

xyshell

I think I found some part of solution in this article.

https://www.backtrader.com/blog/posts/2016-12-10-buysellarrows/buysellarrows/

But this only re-defines buy-sell signal pattern, not exactly what I want.

ab_trader

You may want to create custom indicator with two lines up and down which has a CrossOver indicator inside. Something like this (not tested):

class CrossOverWithArrows(bt.Indicator):

    lines = ('up', 'down')

    plotlines = dict(
        up=dict(marker='$\u21E7$', markersize=12.0),
        down=dict(marker='$\u21E9$', markersize=12.0)

    def __init__(self):
        up = bt.ind.CrossUp(smthng, smthng)
        down = bt.ind.CrossDown(smthng, smthng)