Headless and PNG exports to BytesIO

[k1mbl3]

What is best approach to run finplot in a headless environment (docker, for instance)? Since it will be a HTTP server, how could i dump the entire plot to a BytesIO object to serve it later in a request? Thanks.

[highfestiva]

I just added support for saving a screenshot to file (https://github.com/highfestiva/finplot/blob/master/finplot/example-line.py#L16).

Do this to save screen shot to memory:

...
def save():
    import io
    f = io.BytesIO()
    fplt.screenshot(f)
    do_something(f)
fplt.timer_callback(save, 0.5, single_shot=True) # wait some until we're rendered
fplt.show()

[k1mbl3]

Sorry the late reply. Thank you so much!

[engineertree5]

Hello HighFestiva,

I'm trying to save the file as a png. and i'm not sure I follow the above example or the one that you linked to saving as a file. I'm following along through the screenshot example and the one you linked to on Sep the 5th. i'm getting a blank image with zero bytes. Any thoughts here? I'm thinking the save function is not passing the right data back to the timer_callback or something.

I have this running as a class.

class stock_list(object):

def __init__(self, stock_pick, time_length ):
        self.stock_pick = stock_pick #creates an attribute called stock and is assigned to value of stock
        self.time_length = time_length

def get_stocks(self):
    #pull list of stocks from user and begin to perform TA and FA
        stock_pick = self.stock_pick
        for stock in stock_pick:
            company = yf.Ticker(stock)
            self.get_ta(company,time_length)

def get_ta(self, company, time_length):
        """
        Method for performing technical analysis on given companies.
        Values needed are the company & time length of market data.
        """
        self.company = company
        self.time_length = time_length
        today = stock_list.today
        end = dt.datetime(today.year, today.month,today.day)
        start = dt.datetime(today.year -1, today.month,today.day)

        short_name = company.get_info()['shortName']
        company_symbol = company.get_info()['symbol']

       dates = pd.date_range('01:00', '01:00:01.200', freq='1ms')
       prices = pd.Series(np.random.random(len(dates))).rolling(30).mean() + 4
       fplt.plot(dates, prices, width=3)
       line = fplt.add_line((dates[100], 4.4), (dates[1100], 4.6), color='#9900ff', interactive=True)
       text = fplt.add_text((dates[500], 4.6), "I'm here alright!", color='#bb7700')
        fplt.timer_callback(self.save, 0.5, single_shot=True) # wait some until we're rendered

    def save(self):
        # import io
        # f = io.BytesIO()
        # fplt.screenshot(f)
        fplt.screenshot(open('screenshot.png', 'wb'))

Everything works that I was able to test and i'm loving this module! but the screenshot save is giving me a hard time. Its more than likely something i'm overlooking within the magic behind the code that takes the screenshot.

link to code here if you are having trouble reading: https://github.com/engineertree5/tree5_treehouse/blob/master/tree_types/100/pyetf.py#L104-L153

Thanks for your time

[highfestiva]

You're not calling show()?

[engineertree5]

🙃 that is embarassing....I made the assumption that it would save the image without needing to show the graph, like a plt.savefig() function. Ok so this is taking an ACTUAL screenshot of what is on the screen. I need to go the headless route to get this fully automated.

I need to do more testing on my raspberry pi before coming back. I commented a bit prematurely, my bad on that and thanks for responding.

The end goal is to loop through a list of stocks, apply technical indicators, and post to the web for the commuinty to analyze. I'm currently doing this headless via cronjob and my pi (my bot).

[somguyth]

Any update, @engineertree5, on whether we can run fplt.screenshot() in a headless way (i.e., without needing to call fplt.show()?) I got a similar use-case where I want to save the screenshot to disk using code, without having it pop up on my desktop first @highfestiva

[highfestiva]

@somguyth I don't know much about these things, if you run it on your desktop, I'd probably try some virtualization thingie and have it render there. If you generate screenshots, it sounds more like a server thing though.

[nek06]

I have a telegram bot for the channel, and there I implemented the function of displaying a graph in the bot via your fin plot. Everything is fine, the graph is drawn according to the user parameters, but there is no sending until I close the Fin Plot graph window. how can I solve it? fplt. close () does not work

[highfestiva]

What happens when you try fplt.close()? Did you put it right after the screenshot save call?

[nek06]

Yes, absolutely right, I did it as you have in the examples. But closing the window for some reason does not happen with the graf
def save():

 fplt.screenshot(open('screenshot.png',` 'wb'))

fplt.timer_callback(save, 0.5, single_shot=True)

fplt.show()
time.sleep(5)
fplt.close()

[nek06]

I found a solution, added a closing function:
def save():

  fplt.screenshot(open('screenshot.png',` 'wb'))

fplt.timer_callback(save, 0.5, single_shot=True)
def close(): !!!!!
fplt.close()
fplt.timer_callback(close, 1, single_shot=True)
fplt.show()

Thank you!!!! But i have another questions, how can i change colour for cnadlestik?

[highfestiva]

See snp500 example, as well as others.