Some monospaced fonts cannot be loaded and used by Spyder

[zysNLP]

Problem Description

I installed fonts such as Monaco.TTF on ubuntu and found that I could not find this font in the "plain text font" font collection in spyder. All the fonts installed in the system can be found in "rich text font", but the edit text is only work with "plain text font". Could you make "plain text font" as rich as "rich text font"? Why give it so few options？

Versions

• Spyder version: 4.1.2
• Python version: 3.6.8
• Qt version: 5.9.7
• PyQt version: 5.9.2
• Operating System name/version: ubuntu16.04

Dependencies

PASTE DEPENDENCIES HERE

[ccordoba12]

Plain text fonts mean monospaced fonts, i.e. fonts whose characters take the same space in pixels. These are the right fonts for programming, so we don't plan to change that, sorry.

[ccordoba12]

There are many monospaced fonts out there. You need to find and install them instead.

[sepremento]

There are many monospaced fonts out there. You need to find and install them instead.

I have installed Fira Code and it is not available in plain text fonts section. Last time I checked Fira Code was a monospaced font. Can you please comment on why it is not available?

[feliperiosg]

I installed Fira Code in Windows OS and it was recognized by Spyder... but when I installed Fira Code in Ubuntu, it was NOT recognized by Spyder only in the "plain text font" menu.
Hence... there is indeed something going on in there.

[sohnishi]

This is due to the mismatch of the monospaced criteria of QFontComboBox and QFontMetrics. QFontComboBox judges whether the pitch of characters is fixed. On the other hand, QFontMetrics determines based on the actual character width (and this criterion matches our senses).
Fira Code is actually monospaced, but it is treated as a non-monospaced font in QFontComboBox on Linux.
So QFontComboBox rejects many good fonts for programming on Spyder-ide.

I am also suffering from this because half-width spaces (U+0020) and full-width spaces (U+3000) cannot be distinguished in all the monospaced fonts that can be used on Spyder-ide.
Qt won't change this behavior, so I'd like to implement an option (which can be enabled with a checkbox or something) to use non-monospaced fonts in plaintext.

[ccordoba12]

@sohnishi, thanks for letting us know about this limitation in Qt. The idea you proposed to fix this problem needs more work, so we'll take a look at it for Spyder 6.