FaithType

Modify fonts to remove bitmap and disable gridfit for Windows font rendering.

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Description

Since Windows 10 version 1703 (Creators Update), its built-in TrueType renderer now supports vertical anti-aliasing. Despite there are only 30 levels of grayscale shade, it dramatically improves text rendering, especially for CJK languages. Sadly, it is only enabled for selected fonts at selected sizes.

By using this tool, you can enable vertical anti-aliasing for almost any TrueType outline font, also removing the embedded bitmap, to make the text look much better on Hi-DPI displays.

How to use this tool?

1. Download the Rust compiler.

2. Download the source code of FaithType.

3. Open a terminal (either Command Prompt or PowerShell):

   cd path_to_FaithType
   cargo build --release
   cd .\target\release

4. Read how to use the tool:

   .\faithtype.exe --help

5. Optional: If you want to completely remove hinting, download ttfautohint and use ttfautohint --dehint at this step.

6. Process the font:

   mkdir "C:\Patched Fonts"
   .\faithtype.exe "C:\Windows\Fonts\simsun.ttc" -o "C:\Patched Fonts\simsun.ttc" --remove-bitmap --remove-hinting --modify-gasp

   Depending on whether you want to remove or regenerate hinting, use one of --remove-hinting or --keep-hinting.

7. Optional: If you want to regenerate hinting instructions, use ttfautohint at this step instead of Step 5.

8. Make sure Windows can open and preview the modified font file.

9. Change the registry:

   Windows Registry Editor Version 5.00
   
   [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts]
   "SimSun & NSimSun (TrueType)"="C:\Patched Fonts\simsun.ttc"
   "宋体 & 新宋体 (TrueType)"="C:\Patched Fonts\simsun.ttc"

10. Restart the system.

FAQs

• Why remove bitmap?

  Although OpenType supports grayscale bitmap, all Windows built-in bitmap fonts only contain black-and-white version. This happens even on Hi-DPI displays, where the number of pixels are already enough to produce legible anti-aliased text.

  Also, some bitmap fonts only load when ClearType is off. Normally we don't care about them. But since current ClearType is broken (see below), we now need to remove these bitmaps.

• Why disable gridfit?

  Windows built-in fonts tend to use TrueType hinting to heavily gridfit the outlines, rendering the text blocky and pixelated even on Hi-DPI screens. Some people, who may be using an old VGA connector or an uncalibrated display, claims this style maintains color contrast and sharpness. But to me, heavily gridfitted text gives me headache after reading for a few minutes.

• Why patch the gasp table?

  Because ClearType is now broken somewhere between Windows 10 version 1703 and 21H1. The LCD filter can no longer be turned off through the “ClearType Text Tuner”.

  LCD filter is originally designed for LCD screens with 1:1 viewing scale. Meaning you should not use LCD filter on projectors, televisions, PenTile displays, rotatable displays, video recordings, screenshots, remote meetings, slideshows, DPI-scaled applications, etc. But now, even the Text Tool in “Microsoft Paint” can only draw LCD-filtered text.

  If you turn ClearType off altogether, you also get bugs and lose legibility with certain built-in fonts. One solution is to process those fonts with FaithType, which patches the gasp table to request bidirectional anti-aliasing while you can keep ClearType turned off.

Strokes look too thin!

On older versions of (Mac) OS X, the TrueType renderer widens the strokes to maintain a stable contrast on Low-DPI displays. Windows can't do stroke widening. My personal experience with graphics indicates 1.3px is the minimum width for legible font rendering, but most built-in fonts in Windows are way too thin.

1. Changing the gamma level from 0x00000898 to 0x00000708 may help:

   Windows Registry Editor Version 5.00
   
   [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Avalon.Graphics\DISPLAY1]
   "GammaLevel"=dword:00000708

2. Another way is to use ttfautohint to generate TrueType hinting to widen the strokes.

3. The ultimate solution is to buy a Hi-DPI display.

Common issues

• Microsoft Yahei (微软雅黑), Microsoft Jhenghei (微軟正黑體), and Meiryo (メイリオ):

  Their hinting instructions have issues with vertical anti-aliasing. You need to remove hinting.

• Monotype Courier New:

  The Monotype Courier New is designed according to the metal letter used in IBM typewriters, instead of the real appearance on a paper, where the ink spreads and emboldens the strokes. Therefore, this Monotype font is garbage, replace it with “Bitstream Courier 10 Pitch”.

• DynaLab MingLiU (華康細明體) before version 4.55:

  The font rendering requires TrueType hinting. Don't remove hinting.

License and warranty

This software is released under the GPL license, version 3 or later.

This software may cause instability to your operating system due to bugs on my side, or on Microsoft's side, or on any third-paty application's side. This software is released free-of-charge only under the hope that it may be helpful, thus comes with no warranty in case anything happens during your usage of this software.

Acknowledgement

• RemoveBitmapFont
• ttfautohint