feat: support font variants (bold/italic) from ~/.termux

[sghoshm]

Summary

This PR adds support for loading font variants (font-bold.ttf, font-italic.ttf, font-bold-italic.ttf) from ~/.termux/.

When present, these files are used for rendering bold and italic text instead of synthesized styles.

Motivation

Currently, Termux renders bold and italic using:

• setFakeBoldText
• setTextSkewX

This causes:

• italic text to appear as a geometric slant
• loss of intended font design for fonts like VictorMono or MapleMono

Changes Made

• Added support for optional font variant files:

  • ~/.termux/font-bold.ttf
  • ~/.termux/font-italic.ttf
  • ~/.termux/font-bold-italic.ttf

• Updated TerminalRenderer to select the appropriate typeface based on style flags

• Preserved fallback behavior:

  • If a variant file is not present, existing synthesized styling is used

Implementation Notes

• Changes are limited to TerminalRenderer
• Font paths are resolved locally within the renderer to avoid additional dependencies
• No changes to existing configuration or settings

How to Use

1. Place font files in:

   ~/.termux/
   

2. Example:

   font.ttf
   font-bold.ttf
   font-italic.ttf
   

3. Reload settings:

   termux-reload-settings
   

Testing

• Verified fallback behavior when variant files are absent
• Verified correct rendering when variant files are present
• Tested using VictorMono font

Compatibility

• Fully backward compatible
• No behavior change for users without custom font variants

Challenges Faced

• terminal-view module does not have access to shared constants, so paths are resolved locally
• Ensured minimal and localized changes to avoid regressions in rendering

Related Issue

Addresses the issue raised by @MapleMocha

---

Thanks to @MapleMocha for the original idea 🙏

[MapleMocha]

Thank you for your contribution! I really like this❤️❤️❤️

[synthyst]

The PR for this feature already exists here.