Bug Report: Inconsistent Volume Bar Border Colors Between v0.12.9b7 and v0.12.10b0 When Using make_marketcolors

[yorkjong]

Description When changing the volume colors using make_marketcolors, the results differ between versions v0.12.9b7 and v0.12.10b0. The older version looks fine, but in the newer version, the border color of the volume bars appears inconsistent.

Minimal Test Code

import mplfinance as mpf
import pandas as pd

# Sample data
dates = pd.date_range('2023-01-01', periods=10)
data = {
    'Open': [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
    'High': [2, 3, 4, 5, 6, 7, 8, 9, 10, 11],
    'Low': [0.5, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5, 9.5],
    'Close': [2, 1, 4, 3, 6, 5, 8, 7, 10, 9],
    'Volume': [100, 200, 300, 400, 500, 600, 700, 800, 900, 1000]
}
df = pd.DataFrame(data, index=dates)

# Get the 'yahoo' style
yahoo_style = mpf.make_mpf_style(base_mpf_style='yahoo')

# Access the 'yahoo' style market colors
yahoo_market_colors = yahoo_style['marketcolors']

# Reverse the colors
reversed_market_colors = mpf.make_marketcolors(
    up=yahoo_market_colors['candle']['down'],
    down=yahoo_market_colors['candle']['up'],
    edge={'up': yahoo_market_colors['edge']['down'], 'down': yahoo_market_colors['edge']['up']},
    wick={'up': yahoo_market_colors['wick']['down'], 'down': yahoo_market_colors['wick']['up']},
    ohlc={'up': yahoo_market_colors['ohlc']['down'], 'down': yahoo_market_colors['ohlc']['up']},
    volume={'up': yahoo_market_colors['volume']['down'], 'down': yahoo_market_colors['volume']['up']}
)

# Define a new style with reversed colors
reversed_style = mpf.make_mpf_style(base_mpf_style='yahoo', marketcolors=reversed_market_colors)

# Plot the candlestick chart
mpf.plot(df, type='candle', volume=True, style=reversed_style)

Screenshots v0.12.9b7 (looks fine):

v0.12.10b0 (the border color of the volume bars appears inconsistent):