How to make color the wick portion of a candlestic

Question

I'm looking to make the wick portion of a candlestick stick black using matplotlib? I couldn't find any mention of it in the documentation, but I've seen pictoral examples showing that it can be done.

here's what I currently have:

here's an example of the wicks being colored black:

Update:

I used the solution provided below but changed the code slightly to remove the vertical line over the body area of the candlestick:

from matplotlib.lines import Line2D
from matplotlib.patches import Rectangle


def blackwickcandlestick(ax, quotes, width=0.2, colorup='#00FF00', colordown='#FF0000',
                         alpha=1.0, shadowCol='k', ochl=True):

    OFFSET = width / 2.0

    lines = []
    patches = []
    for q in quotes:
        if ochl:
            t, open, close, high, low = q[:5]
        else:
            t, open, high, low, close = q[:5]

        if close >= open:
            color = colorup
            lower = open
            height = close - open
            vline = Line2D(
                xdata=(t, t), ydata=(low, high),
                color=colorup,      # This changed from the default implementation
                linewidth=0.5,
                antialiased=True,
                )
        else:
            color = colordown
            lower = close
            height = open - close
            vline = Line2D(
                xdata=(t, t), ydata=(low, high),
                color=colordown,      # This changed from the default implementation
                linewidth=0.5,
                antialiased=True,
                )


        rect = Rectangle(
            xy=(t - OFFSET, lower),
            width=width,
            height=height,
            facecolor=color,
            edgecolor=color,
        )
        rect.set_alpha(alpha)

        lines.append(vline)
        patches.append(rect)
        ax.add_line(vline)
        ax.add_patch(rect)
    ax.autoscale_view()

    return lines, patches


import matplotlib.finance as mpl_finance

mpl_finance._candlestick = blackwickcandlestick

Answer 1

As Paul says, A MCVE would assist people in helping you greatly.

However - just having a quick glance at the source code for the candlestick plotting in matplotlib shows that it uses the colorup/colordown parameter for both the candle and the wick.

So in order to get them to be different colours you will most likely need to reimplement the method and/or monkey patch the base implementation.

So in your plotting module, use something along the lines of:

from matplotlib.lines import Line2D
from matplotlib.patches import Rectangle


def blackwickcandlestick(ax, quotes, width=0.2, colorup='k', colordown='r',
                         alpha=1.0, ochl=True):

    OFFSET = width / 2.0

    lines = []
    patches = []
    for q in quotes:
        if ochl:
            t, open, close, high, low = q[:5]
        else:
            t, open, high, low, close = q[:5]

        if close >= open:
            color = colorup
            lower = open
            height = close - open
        else:
            color = colordown
            lower = close
            height = open - close

        vline = Line2D(
            xdata=(t, t), ydata=(low, high),
            color='k',      # This is the only line changed from the default implmentation
            linewidth=0.5,
            antialiased=True,
        )

        rect = Rectangle(
            xy=(t - OFFSET, lower),
            width=width,
            height=height,
            facecolor=color,
            edgecolor=color,
        )
        rect.set_alpha(alpha)

        lines.append(vline)
        patches.append(rect)
        ax.add_line(vline)
        ax.add_patch(rect)
    ax.autoscale_view()

    return lines, patches


import matplotlib.finance as mpl_finance

mpl_finance._candlestick = blackwickcandlestick

Then elsewhere in this module you can use the mpl_finance.candlestick_ohlc(...) plotting functions.

Answer 2

Rewriting the complete candlestick_ohlc seems overly complicated. You can just iterate over the lines returned by the function and set their color to black. You may also set the zorder to have the wicks appear below the boxes.

lines, patches = candlestick_ohlc(ax, quotes, width=0.5)
for line, patch in zip(lines, patches):
    patch.set_edgecolor("k")
    patch.set_linewidth(0.72)
    patch.set_antialiased(False)
    line.set_color("k")
    line.set_zorder(0)

If this is to be used often in a script, you can of course put it in a function.

def candlestick_ohlc_black(*args,**kwargs):
    lines, patches = candlestick_ohlc(*args,**kwargs)
    for line, patch in zip(lines, patches):
        patch.set_edgecolor("k")
        patch.set_linewidth(0.72)
        patch.set_antialiased(False)
        line.set_color("k")
        line.set_zorder(0)

candlestick_ohlc_black(ax, quotes, width=0.5)