Flickering on Live Plotting with Rich

I tried to modify the example code that was raised in this issue that managed to get plotext working with Rich. This is a fairly minimal script that tries to plot a moving sine curve.

The problem is that it shows a lot of flickering.

I am very new to coding with Python so I’m sure there are things that I’m doing that are not right. Possible issues might be around the def make_plot section, or the section when I initialise the plots, or the final Live section.

from rich.layout import Layout
from rich.live import Live
from rich.ansi import AnsiDecoder
from rich.console import RenderGroup
from rich.jupyter import JupyterMixin
from rich.panel import Panel

from datetime import datetime
from rich.table import Table

from time import sleep
import plotext as plt

import numpy as np

def make_plot(width, height):
    # plt.clf()
    plt.clear_data()
    plt.scatter(yy, marker="x")
    plt.plotsize(width, height)
    plt.title(str(count))
    plt.colorless()
    return plt.build()

class plotextMixin(JupyterMixin):
    def __init__(self):
        self.decoder = AnsiDecoder()
        self.count = count
        
    def __rich_console__(self, console, options):
        self.width = options.max_width or console.width
        self.height = options.height or console.height
        canvas = make_plot(self.width, self.height)
        self.rich_canvas = RenderGroup(*self.decoder.decode(canvas))
        yield self.rich_canvas

def make_layout():
    layout = Layout(name="root")
    layout.split(
        Layout(name="header", size=3),
        Layout(name="main", ratio=1),
    )
    layout["main"].split_row(
        Layout(name="plotext", size=100),
        Layout(name="main_right", size=30),
    )
    return layout

# Clear the plot
plt.clf()

# Initialise he count
count = 0

# Initialise the plots
xx = np.arange(0, 6*np.pi, 0.1)
yy = np.sin(xx)
uu = np.stack((xx,yy), axis=1)

layout = make_layout()
plotext_layout = layout["plotext"]
mix = plotextMixin()
mix = Panel(mix, style="white on black")
plotext_layout.update(mix)

header_layout = layout["header"]

with Live(layout, refresh_per_second=0.1) as live:
    while True:
        xx = xx + 0.1*count
        yy = np.sin(xx)
        uu = np.stack((xx,yy),axis=1)
        count = count + 1

        plotext_layout.update(mix)

        plt.sleep(0.01)
        plt.show()

[piccolomo]

Hi @ThSGM,

thanks a lot for dropping your feedback! 😃

I have modified your code and it seem to work fine on my machine. I changed colouring, marker and layout but you could tweek it to suite your preferences. Here it is:

from rich.layout import Layout
from rich.live import Live
from rich.ansi import AnsiDecoder
from rich.console import RenderGroup
from rich.jupyter import JupyterMixin
from rich.panel import Panel
from rich.text import Text
import plotext as plt

def make_plot(width, height, phase = 0, title = None):
    plt.clf()
    l, frames = 1000, 30
    x = range(1, l + 1)
    y = plt.sin(1, periods = 2, length = l, phase = 2 * phase  / frames)
    plt.scatter(x, y, marker = "fhd")
    plt.plotsize(width, height)
    plt.xaxis(0, "upper")
    plt.yaxis(0, "right")
    plt.title(title)
    #color = 255
    #plt.canvas_color(color)
    #plt.axes_color(color)
    #plt.cls()
    return plt.build()

class plotextMixin(JupyterMixin):
    def __init__(self, phase = 0, title = None):
        self.decoder = AnsiDecoder()
        self.phase = phase
        self.title = title
        
    def __rich_console__(self, console, options):
        self.width = options.max_width or console.width
        self.height = options.height or console.height
        canvas = make_plot(self.width, self.height, self.phase, self.title)
        self.rich_canvas = RenderGroup(*self.decoder.decode(canvas))
        yield self.rich_canvas

def make_layout():
    layout = Layout(name = "root")
    layout.split(Layout(name = "header", size = 3), Layout(name="main", ratio = 1))
    layout["main"].split_column(
        Layout(name = "static", ratio = 1),
        Layout(name = "dynamic"))
    return layout

layout = make_layout()

header = layout['header']
title = plt.colorize("Pl✺ ", "cyan bold") + plt.colorize("text ", "dim bold") + "integration with " + plt.colorize("rich_", "bold dim")
spaces = (plt.terminal_size()[0] - len(plt.uncolorize(title))) // 2
header.update(Text("\n" + " " * spaces + title))

static = layout["static"]
dynamic = layout["dynamic"]

mixin_static = plotextMixin(title = "Static Plot")
mixin_static_panel = Panel(mixin_static)
static.update(mixin_static_panel)

mixin_dynamic = plotextMixin(title = "Dynamic Plot")
mixin_dynamic_panel = Panel(mixin_dynamic)

with Live(layout, refresh_per_second = 0.0001) as live:
    while True:
        mixin_dynamic.phase += 1
        dynamic.update(mixin_dynamic_panel)
        live.refresh()

which outputs a static and dynamic plot:

What do you think? Does it work for you as well? Feel free to drop your version if you find a better one 😃

All the best, Savino

P.S. Apologies I edited your post by mistake: I have restored later.

[ThSGM]

Hello @ThSGM, any update?

(Re-sending on the appropriate account; this response predates this one)

Hello! Thank you for all your help. I’ll do a quick reply for now as I’ve been busy with work.

Basically, your alternative code did not seem to help. I tested it on both macOS iTerm2 and Alacritty and it showed significant flickering. The delay is due to the fact that I wanted to test on a Raspberry Pi/Debian system to see if it was due to the terminal.

I have uploaded a video to show here: https://streamable.com/tl3ktr

But then, even if it does work on Linux/Debian, I think the flickering that persists on iTerm2/Alacritty is still a problem.