Description
Hello! I'm developing a Textual application that needs to run on hardened Rocky Linux 9 systems, directly on the Linux virtual console (TTY) without a graphical desktop.
I've had success getting the console into a high-resolution framebuffer mode with 32-bit color depth (video=1280x1024-32 kernel parameter), though there's basically nothing that actually can make the vt
linux terminal go above 16 color support.
The bug
When running textual colors
or my own app, the console correctly renders the base 8 ANSI colors. However, it fails to render the high-intensity "bright" colors.
ansi_bright_red
renders asansi_red
.ansi_bright_green
renders asansi_green
.- ...and so on for all 8 bright colors.
A test script confirms the console is capable of displaying at least 16 distinct colors (the 8 base colors + their bolded versions).
for i in {0..255}; do printf "\x1b[38;5;${i}mcolour${i} "; done; echo
But in textual colors... well... things aren't so great.
Hypothesis:
This suggests that Textual/Rich is emitting the modern ANSI escape codes for bright colors (e.g., \x1b[91m
for bright red), but the underlying Linux kernel virtual terminal (vt
) console driver does not interpret these codes correctly, falling back to the base colors.
The vt
console typically uses the "bold" or "intensity" attribute (\x1b[1m
) to produce bright colors (e.g., \x1b[1;31m
).
Feature Request / The Question:
Would it be possible for Textual's color rendering system to have a fallback mechanism? When it detects a terminal that supports 16 colors but might not support the 90-series codes (like TERM=linux
or linux-16color
), could it attempt to render bright colors by emitting the bold attribute (\x1b[1m
) instead of the base color code?
This, in conjunction with the textual-ansi theme should help improve compatibility and appearance on the linux virtual terminal. The conversation still, of course, continues in many discussions like #5011 on how to make the glyphs work better, but having functional colors is a pretty important first step.
Textual Diagnostics
Versions
Name | Value |
---|---|
Textual | 3.5.0 |
Rich | 14.0.0 |
Python
Name | Value |
---|---|
Version | 3.9.21 |
Implementation | CPython |
Compiler | GCC 11.5.0 20240719 (Red Hat 11.5.0-5) |
Executable | /redacted/.venv/bin/python |
Operating System
Name | Value |
---|---|
System | Linux |
Release | 5.14.0-570.21.1.el9_6.x86_64 |
Version | #1 SMP PREEMPT_DYNAMIC Tue Jun 10 18:07:35 UTC 2025 |
Terminal
Name | Value |
---|---|
Terminal Application | Unknown |
TERM | linux |
COLORTERM | Not set |
FORCE_COLOR | Not set |
NO_COLOR | Not set |
Rich Console options
Name | Value |
---|---|
size | width=160, height=64 |
legacy_windows | False |
min_width | 1 |
max_width | 160 |
is_terminal | False |
encoding | utf-8 |
max_height | 64 |
justify | None |
overflow | None |
no_wrap | False |
highlight | None |
markup | None |
height | None |