[isabelle-dev] Isabelle DejaVu against old Isabelle Text font

Makarius makarius at sketis.net
Wed Feb 13 22:20:35 CET 2019

On 10/02/2019 19:47, Makarius wrote:

> I have fine-tuned the Isabelle DejaVu fonts in
> Isabelle/4791988fcbc4 to impose the FreeType auto-hinting beforehand to
> the TrueType file: this leads to isabelle_fonts-20190210 in
> Isabelle/7e5a7a11d5d1.
> In summary:
>   * Isabelle font rendering should be once again slightly better on Linux.
>   * There is a small risk that it has slightly degraded on Windows and
> macOS.
> In other words: early adopters should look closely if it is all fine. We
> are (very slowly) moving towards the Isabelle2019 release (presumably
> June 2019), and everything needs to be beyond doubt when released.

I have invested 96 EUR into an old-style HD display from iiyama
(1920x1080 21.5") and made some tests with Linux, Windows, macOS.

* All platforms use the custom font-renderer of Java 11, not the native
one (of Windows or macOS) as I first thought.

* Using the defaults of Isabelle/f610115ca3d0, font shapes come out much
better than in Java 8, 7, 6, and our "Isabelle DejaVu" fonts work nicely
at 14, 16, 18, 24 pixels etc. -- in the past only 18 was OK, and most
other sizes a bit too thin.

* Some degree of blurriness appears to be normal for the FreeType font
rendering of OpenJDK 11, but after a short time the Java 8 (Oracle)
rendering already looks quite ugly to me.

* Blurriness is absent on my up-to-date UHD display (330 EUR), even for
tiny font sizes 14, 16, 18 -- normally I use 30 or 36.

I cannot imagine anybody still using low resolution displays on a desk,
after 5 years of fairly cheap UHD displays. Equipment that is used every
day should be of good quality.


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