Add a setting to control vertical antialiasing

[ygohko]

Description of the new feature/enhancement

Adding a setting to control DirectWrite's rendering mode is wanted to improve font rendering quality when using a font that does not have hinting information.

I prefer NasuM font (https://osdn.net/users/itouhiro/pf/font/files/) because it has high readability. But it does not have hinting information and it causes decrasing rendering quality in Windows Terminal.

Below is a screenshot that taken from Windows Terminal with using NasuM font:

Below is a screenshot that taken from WSL window with using NasuM font:

Please focus on horizontal lines in the Kanji character "見".

Windows's legacy command window uses GDI and now it supports vertical antialiasing (I believe), but Windows Terminal does not support that.

If Windows Terminal has a setting to enable vertical antialiasing, it can improve font rendering quality at this situation.

Proposed technical implementation details (optional)

Firefox has a hidden setting to control DirectWrite's rendering mode (https://support.mozilla.org/en-US/questions/1115938). When gfx.font_rendering.cleartype_params.rendering_mode is 5 (Natural Symmetric), Firefox enables vertical antialiasing.

If Windows Terminal has similar one, it would solve this problem.

[DHowett-MSFT]

I'm repurposing this one for vertical antialiasing specifically, because we have an epic for all rendering flags at #1790. I've linked them and put this one on the backlog.

Thanks!

[zadjii-msft]

A bunch of relevant links:

• https://github.com/dotnet/wpf/issues/2025 - this is at least a neat thread that says the Terminal is rendering text better than Visual Studio 😆
• DWRITE_RENDERING_MODE which has DWRITE_RENDERING_MODE_NATURAL_SYMMETRIC

  Similar to natural mode except that antialiasing is performed in both the horizontal and vertical directions. This is typically used at larger sizes to make curves and diagonal lines look smoother. The antialiasing may be either ClearType or grayscale depending on the text antialiasing mode.

[ygohko]

I found information (https://qiita.com/AumyF/items/4f625ebd47603efaac7a Japanese, please read with mechanical translation) that may relates this issue. This issue may not be caused by font that does not have hinting information, but may be caused by font that have low quality hinting information.

I had made a dehinted font and set it for Windows Terminal, then rendering quality was improved as below:

Now my problem was solved, but I think this issue (vertical antialiasing setting) may be still useful for other people who can not modify fonts.

Thanks!