How to make the cursors independent of each other in embedded plots?

xyberian-sg commented 4 years ago

Hi, I have modified the code from example-embed.py as the following:

#!/usr/bin/env python3

import finplot as fplt
from functools import lru_cache
from PyQt5.QtWidgets import QGraphicsView, QComboBox, QLabel
from PyQt5.QtGui import QApplication, QGridLayout
from threading import Thread
import yfinance as yf

app = QApplication([])
win = QGraphicsView()
win.setWindowTitle('TradingView wannabe #2')
layout = QGridLayout()
win.setLayout(layout)
win.resize(900, 600)

combo1 = QComboBox()
combo1.setEditable(True)
[combo1.addItem(i) for i in 'AMRK FB GFN REVG TSLA TWTR WMT CT=F GC=F ^FTSE ^N225 EURUSD=X ETH-USD'.split()]
layout.addWidget(combo1, 0, 0, 1, 1)
info1 = QLabel()
layout.addWidget(info1, 0, 1, 1, 1)

combo2 = QComboBox()
combo2.setEditable(True)
[combo2.addItem(i) for i in 'AMRK FB GFN REVG TSLA TWTR WMT CT=F GC=F ^FTSE ^N225 EURUSD=X ETH-USD'.split()]
layout.addWidget(combo2, 0, 2, 1, 1)
info2 = QLabel()
layout.addWidget(info2, 0, 3, 1, 1)

ax1, ax2 = fplt.create_plot_widget(win, init_zoom_periods=100, rows=2)
win.axs = [ax1, ax2] # finplot requres this property
layout.addWidget(ax1.ax_widget, 1, 0, 1, 2)
layout.addWidget(ax2.ax_widget, 1, 2, 1, 2)

@lru_cache(maxsize=15)
def download1(symbol):
    return yf.download(symbol, '2020-01-01')

@lru_cache(maxsize=15)
def download2(symbol):
    return yf.download(symbol, '2020-06-01')

@lru_cache(maxsize=100)
def get_name(symbol):
    return yf.Ticker(symbol).info['shortName']

plots1 = []
def update1(txt):
    df = download1(txt)
    if len(df) < 20: # symbol does not exist
        return
    info1.setText('Loading symbol name...')
    price = df['Open Close High Low'.split()]
    ma20 = df.Close.rolling(20).mean()
    ma50 = df.Close.rolling(50).mean()
    volume = df['Open Close Volume'.split()]
    if not plots1:
        plots1.append(fplt.candlestick_ochl(price, ax=ax1))
        plots1.append(fplt.plot(ma20, legend='MA-20', ax=ax1))
        plots1.append(fplt.plot(ma50, legend='MA-50', ax=ax1))
        plots1.append(fplt.volume_ocv(volume, ax=ax1.overlay()))
    else:
        plots1[0].update_data(price)
        plots1[1].update_data(ma20)
        plots1[2].update_data(ma50)
        plots1[3].update_data(volume)
    Thread(target=lambda: info1.setText(get_name(txt))).start() # slow, so use thread

plots2 = []
def update2(txt):
    df = download2(txt)
    if len(df) < 20: # symbol does not exist
        return
    info2.setText('Loading symbol name...')
    price = df['Open Close High Low'.split()]
    ma20 = df.Close.rolling(20).mean()
    ma50 = df.Close.rolling(50).mean()
    volume = df['Open Close Volume'.split()]
    if not plots2:
        plots2.append(fplt.candlestick_ochl(price, ax=ax2))
        plots2.append(fplt.plot(ma20, legend='MA-20', ax=ax2))
        plots2.append(fplt.plot(ma50, legend='MA-50', ax=ax2))
        plots2.append(fplt.volume_ocv(volume, ax=ax2.overlay()))
    else:
        plots2[0].update_data(price)
        plots2[1].update_data(ma20)
        plots2[2].update_data(ma50)
        plots2[3].update_data(volume)
    Thread(target=lambda: info2.setText(get_name(txt))).start() # slow, so use thread

combo1.currentTextChanged.connect(update1)
update1(combo1.currentText())

combo2.currentTextChanged.connect(update2)
update2(combo2.currentText())

fplt.show(qt_exec=False) # prepares plots when they're all setup
win.show()
app.exec_()

The idea is to see if possible to have 2 independent plots embedded in a single QApplication. It works mostly, but I've noticed a few things:

The cursors are in sync across the 2 plots, and it would be great if only the "active" one moves while the "inactive" does not
The cursors have the same date value (x-axis). It seems that is the common denominator driving the behavior
The 2nd plot (right-hand side) has the volume missing, although the code snippets are exactly the same for both plots
The 2nd plot has different background color, and it doesn't seem to change even if I specify a different color upfront
Zooming is also in sync across the 2 plots. I purposely have different date ranges for the 2 plots to show the effect of the same scale being applied. Would be great if zooming can be made independent too.

Thanks in advance for your advice!