Some users who utilize the hinting method 'hintfull' may have noticed that when transitioning from Pango version 1.43 to 1.44 some font families or .
The problem is caused by the library switching from using to obtain kerning information (the spacing between glyphs) of fonts to , and the developers of the latter decided font smoothing using the 'hintfull' method. It is noted that on high pixel density (Hi-DPI) screens, there are no font rendering issues when using hinting methods other than 'hintfull'.
HarfBuzz developer (Behdad Esfahbod) from the relevant problem discussion:
I tried to use hinting styles other than hintfull, but only it gives a font display close to ClearType v2 in Windows 7, which, in my opinion, has the best rendering of all existing solutions.
That's right. So we decided not to support it anymore. You can try to get used to the 'blurry' rendering or try to find something else. You're using Open Source, you understand?
An addition following further discussion:
In subsequent comments, the developer , stated that Open Source provides choice, and those who are not satisfied with the current state can create a fork of Pango. The developers of HarfBuzz cannot influence its maintenance and the decisions made in it. Behdad Esfahbod, the current maintainer of HarfBuzz, who is ranked first in the number of commits in
, mentioned that he has not been associated with Red Hat for over 10 years and is not a maintainer of Pango. Since 2010, he has moved to Google and now only works on HarfBuzz, which was previously his personal project. HarfBuzz the rendering process and Pango can override the requested hinting modes on its side.
Another HarfBuzz developer , noted that the problem lies on Pango’s side, as HarfBuzz is not a font rendering system and does not support hinting by its architecture. If Pango needs to maintain hinting, transitioning to HarfBuzz is not a choice to expect support. In The reasons for refusing to implement hinting in HarfBuzz include the fact that some hinting modes lead to changes in the original glyph width, and this change depends on the pixel size. Previously, Pango performed such operations via FreeType, which supports hinting, but then switched to HarfBuzz, which processes glyphs without being tied to their size. Therefore, solving the issues that arose when using Pango falls under the responsibility of Pango, not HarfBuzz.
Ultimately, Behdad Esfahbod provides a comprehensive retrospective of the development of the Linux font stack. After his departure to Google, the Pango and Cairo libraries became almost abandoned and fell into stagnation. In HarfBuzz, the focus shifted to supporting variable fonts, while Red Hat concentrated on GTK and Glib. Over time, advancements in variable fonts were transferred to FreeType, fontconfig, and Cairo but remained unfinished in Pango due to a lack of developers. Access to new APIs in Pango was provided via FontMap abstraction and was only supported for FreeType-based backends. Meanwhile, backends for Windows and macOS have been unsupported for over 10 years.
After the expansion of mobile devices and browsers, Microsoft discontinued support for subpixel font rendering and GDI-style drawing in Windows 8. macOS has always supported rendering that is referred to as 'blurred' in this discussion. Since 2018, several HarfBuzz developers have attempted to port the features added to HarfBuzz over the past years to Pango. Concurrently, during the development of GTK4, a transition to OpenGL-based rendering was made, which entails linear text scaling, intensifying the conflict between pixel rendering and scalable layout.
LibreOffice, Chrome, and Firefox have transitioned to using HarfBuzz as a unified shaping engine, at the cost of discontinuing support for bitmap fonts and the Type1 format. For those who need bitmap fonts, an offer was made to convert them into an OpenType container. A request was sent to Adobe to implement Type1 for HarfBuzz, but they responded that it makes no sense since they themselves are discontinuing support for Type1 this year.
To catch up with advancing technologies, a similar decision to switch to HarfBuzz was made for the Pango library. The cost was the discontinuation of support for some outdated technologies from 20 years ago. It was noted that considering the limited resources, developers struggle to handle everything, and those interested in maintaining old technologies may need to find someone willing to provide the missing functionality. As a comparison, GNOME3 is mentioned; after its release, dissatisfied users continued to develop the outdated GNOME2 technologies through the Mate and Cinnamon projects. The same applies to Pango, but so far, no takers have been found.
Source: opennet.ru
