Plot with filled area

[ab_trader]

@backtrader

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