Fix RichProgressBar visibility

[ashikshafi08]

What does this PR do?

Implemented RichProgressBarTheme with a new feature to detect the terminal background color and adjust the styles based on it. The terminal background color is detected using the Console class from the rich library. If the terminal supports truecolor, the TERMINAL_BG_COLOR environment variable is checked, otherwise, it is assumed to be a dark theme.

This implementation allows the RichProgressBar to be visible by default in both light and dark themes without requiring users to modify the theme.

Changes Made

• Use the first 16 standard colors combined with ANSI styles in RichProgressBarTheme to ensure that the RichProgressBar is visible by default in both light and dark themes.
• Modify the RichProgressBarTheme class to include a method detect_terminal_bg() that detects the background color of the terminal and sets the default theme colors accordingly.

Note: This is my first pull request in a big code base, if I did something wrong please do let me know thats why I made a draft pull request instead of the actual one. Thanks for your time!.

Fixes #17118

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[tshu-w]

I want to know if this environment variable is set by the Terminal. My color system is 256 and I don't have this environment variable.

My idea is whether it's possible to have one solution that can adapt to two backgrounds, for example, not setting the colors of default_description and default_batch_progress, will they be consistent with the default font color in different backgrounds, i.e., black in light theme and white in dark theme?

[ashikshafi08]

But it may not be perfect in all cases, right? Especially if the user has a custom terminal theme with non-standard colors.

Also, what if we create a dictionary to store the default colors for each supported color system, so it makes it easy to add or modify the color settings accordingly?

Something like this,

from dataclasses import dataclass
from typing import Union
from rich.console import Console
from rich.style import Style


@dataclass
class RichProgressBarTheme:

    @staticmethod
    def detect_color_system() -> str:
        console = Console()
        return console.color_system

    color_system = detect_color_system.__func__()

    # Default colors for each color system
    default_colors = {
        "truecolor": {
            "progress_bar": "bright_blue",
            "time": "bright_cyan",
            "processing_speed": "bright_yellow",
        },
        "256": {
            "progress_bar": "color51",
            "time": "color45",
            "processing_speed": "color227",
        },
        "default": {
            "progress_bar": "blue",
            "time": "cyan",
            "processing_speed": "yellow",
        },
    }

    # Apply specific colors based on the detected color system
    colors = default_colors.get(color_system, default_colors["default"])

    description: Union[str, Style] = "default"
    progress_bar: Union[str, Style] = colors["progress_bar"]
    progress_bar_finished: Union[str, Style] = colors["progress_bar"]
    progress_bar_pulse: Union[str, Style] = colors["progress_bar"]
    batch_progress: Union[str, Style] = "default"
    time: Union[str, Style] = colors["time"]
    processing_speed: Union[str, Style] = colors["processing_speed"]
    metrics: Union[str, Style] = "default"

[tshu-w]

Yes, what I mean is to use the default style for description and batch_progress, which can avoid the problem of being invisible in light themes as mentioned in issue #17532.

But it may not be perfect in all cases, right? Especially if the user has a custom terminal theme with non-standard colors.

As I mentioned in #17532, from my perspective, the first 16 standard colors of most themes are carefully selected and suitable for the theme. So my idea is to only use them.

Try to use the first 16 standard colors combined with ansi styles in RichProgressBarTheme, which are usually defined by the terminal theme.

[ashikshafi08]

So the above code works?

[tshu-w]

I think so :), although I haven't tested it.

[ashikshafi08]

Thanks!
I will update the code and run some test cases, then make a PR again.

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