Plot with filled area

ab_trader

I was trying to create filled area plot for the broker value observer. I've sub-classed existing value observer, add zero line, and filled area between value and zero lines, same approach as you used for ichimoku indicator. Finally ended with the following code:

class ValueFilled(bt.Observer):

    lines = ('pnl', 'zero',)

    params = (('initial_cash', None),)

    plotinfo = dict(plot=True, subplot=True, plotname='Cumulative P/L')

    plotlines = dict(pnl=dict(ls='-', linewidth=1.0, color='black',
                              _fill_gt=('zero', 'green'), _fill_lt=('zero', 'red'),),
                     zero=dict(_plotskip=True,),
    )

    def next(self):

        self.lines.pnl[0] = self._owner.broker.getvalue() - self.p.initial_cash
        self.lines.zero[0] = 0.0

Is there any easier way to draw filled area under/below the line? In the plot.py I've fond only ax.fill_between method, so created second line above to use it.

Here is the link to the picture picture
Somehow pictures inserted into the post usually don't show up.

backtrader

Not now. But it would seem sensible to support not only a line name as the reference to fill (above/below) but also a numeric value.

backtrader

You may try this commit: https://github.com/mementum/backtrader/commit/8ef8555d4fd5685b4811c848009bcd19e553e4a4

ab_trader

Thank you!

Since this is re-written, could you please get hard-coded alpha (line 471 of the plot.py) for the fill to 'plotlines' parameter level?

backtrader

The latest commit to development allows that

The Docs - Plotting has been updated to reflect the possibilities (you may need to use Shift + F5 to bypass the browser cache)

ab_trader

@backtrader Thank you!

It seems that you have a typo in the docs: _fill_gt / _less_gt should be _fill_gt / _fill_lt.
At least latter works.

backtrader

Better in the docs as in the code. Updated