Bad font rendering affects numerous applications

[Mariusz W]

Originally Posted by Ard Righ

Adam I think the issue is that hinting appears disabled altogether in Fedora 15, by default. Installed on my laptop today, and the first thing I noticed when reading was how thin and jagged the fonts appeared.

Your description matches exactly what I observed fater preupgrading from Fedora 14 to 15. I am not sure what is the exact source of the problem, however.

As reported above, I later observed that if one increases font size just one step up, the fonts undergo a drastic leap in width. This may be providing some pointers: it is possible that a similar contrast in rendering was also occurring in Fedora 14, but was affecting sizes a step or two smaller than the default size, rather than the default size itself. Thus, it was much less noticeable. Now, excessively thin and jagged rendering of glyphs occurs at the default font size which is the reason why it is so conspicuous and eye straining.

This wouldn't normally be a problem, in previous releases, as we could alter the hinting under the Appearance font dialogue. But that dialogue has now been removed.

For all LCD users, especially laptops, lack of hinting for LCDs is a killer on the eyes

Since this problem affects equally all desktop environements it is not GNOME specific. How would you propose to handle it say in fluxbox or Openbox?

[AdamW]

in my testing hinting was not disabled by default, it was set to medium.

[AdamW]

Originally Posted by Mariusz W

As reported above, I later observed that if one increases font size just one step up, the fonts undergo a drastic leap in width. This may be providing some pointers: it is possible that a similar contrast in rendering was also occurring in Fedora 14, but was affecting sizes a step or two smaller than the default size, rather than the default size itself. Thus, it was much less noticeable. Now, excessively thin and jagged rendering of glyphs occurs at the default font size which is the reason why it is so conspicuous and eye straining.

So, a couple of things to remember here. This is certainly true in general: if you think about it, it becomes fairly clear. The straight lines in a glyph have to be (integer) pixels in width, obviously. At very small font sizes, that integer is going to be 1. At some point, it's going to flip over to 2.

Now that means that the width of the lines in the font doubles, which is a huge change; and there's no way to make that gradual. You can't draw the lines as 1.5pixels wide. =) So at some point on the font size continuum, you're going to get a point where a very small change in font size results in a doubling of the width of the straight lines in the fonts, which will be a very obvious change.

This has always been the case and there's really no way to change it. It would be mitigated if we all had super-high resolution screens so that even at quite small apparent character sizes, the lines in fonts were five pixels wide; then the next jump would be to six pixels, which is a much smaller change. Sadly, we don't.

Second thing to remember is that the 'default font size' is not an entirely un-problematic concept; it depends - or _should_ depend - on the screen resolution (as in pixels per inch). In theory, a 12pt character should be the same physical size on every screen; so on a very high resolution screen it might be, say, about 30x30 pixels, and on a lower resolution screen it'd be say 10x10 pixels.

So if you think about it, on our two example screens, the stem-width-pixel-count shifts are going to happen at different sizes. If you ask the question 'at what font size does the stem width go from 1 to 2 pixels?', the answer will be different depending on the density of the screen. On our super high density screen, maybe it happens at 3pt/4pt - a font size so tiny no-one would ever notice it. But on our boring old screen, maybe it happens at 10pt/11pt - a size that _is_ going to be noticed.

So the font point size at which the stem width changes happen on _your_ system is not necessarily the font point size at which the stem width changes happen on someone else's system.

This all goes up the spout if the system doesn't properly consider the screen density and just always renders a given font point size using a given number of pixels, of course. In that case, our 12pt character will be 10x10 pixels on both the super-high density display and the boring old one; so it'll look three times smaller, physically, on the super-high density screen. Windows does this - it assumes the screen density is 96dpi, always. This is why, if you buy a laptop with a super high-density screen - say 1920x1080 at 13" - all the fonts look tiny. (There's a rather hidden option somewhere in Windows' preferences where you can choose a couple of different presets, I think 120dpi and 150dpi or something like that).

A good counter-example is the iPhone; the iPhone 4's display is the same physical size as, but four times higher resolution than, the iPhone 3's screen - twice the pixels in both axes - so the iPhone OS renders all the interface elements four times 'bigger', in pixel terms, on the iPhone 4...which means that on the screen, they look exactly the same size on both iPhones, just much sharper on the iPhone 4.

Linux systems tend to flip-flop around between resolution independence (detecting the density of the screen in use, and adjusting the pixel size of fonts accordingly) and just assuming everything's 96dpi, like Windows does. I'm not 100% sure where F15 is on this. There's two elements to it: the X server can try and detect the correct density, or just ignore that and use an arbitrary default, and the desktop can then override what the X server does, or respect it. So it's a bit tricky to figure out.

whew, I'm essay-ing again...

[Mariusz W]

I appreciate, Adam, the effort that went into writing an in depth explanation of various issues related to font rendering on the computer screen. I understand technical limitations involved. Font rendering techniques have been developed over the years to cope with such limitations.

The reports about ugly, jagged, and very thin glyphs in Fedora 15 come however from people who have been exposed to on-screen text in several previous releases of Fedora and other operating systems. So we have much to compare. If on the same screen the same text looks conspicuously worse in the next release of an OS, this is not due to technical limitations of the medium but to some oversight, or outright mistake, in how fonts should be rendered.

[AdamW]

mariusz: I agree, but I'm pointing out that there are lots of complexities involved which make it quite difficult to be entirely sure of what the problem is, and where it lies. Screenshots would definitely help, so we could compare rendering between different systems at least, and be sure if we're all seeing the same thing and some of us like it more than others, or if those who have problems actually have *different* rendering to those who are happy.

[RupertPupkin]

Here is a screenshot of the thin fonts in 64-bit F15 on my 23" LCD: http://i.imgur.com/aY2IT.png

Mariusz is right, this is a noticeable change from earlier versions of Fedora. Those same fonts in the screenshot were much thicker by default in both F14 and F13. And this is running in WindowMaker as a standalone window manager, so it isn't about GNOME or KDE. And it's like this in every app that uses freetype. Something changed in the Fedora freetype packages from F14 to F15, and I would assume that in the Fedora team's version control repos and even in regression testing there would be a record of such changes.

For me it's not a showstopper. The fonts are harder to read when they're that thin; it makes it hard to focus. And I agree that it looks ugly. I can live with it for now, but it should definitely be fixed, and as soon as possible. This is going to give Fedora a bad name as "the ugly font distro" if it continues much longer.

By the way, I tried the infinality packages from the rawhide repo for F15 to see if that would help, and they definitely improved the thickness of the fonts. However, the fonts became too blurry and multi-colored, making it even worse than before overall. So I removed those and am back with the thin ugly fonts.

[jtfolden]

Originally Posted by RupertPupkin

By the way, I tried the infinality packages from the rawhide repo for F15 to see if that would help, and they definitely improved the thickness of the fonts. However, the fonts became too blurry and multi-colored, making it even worse than before overall. So I removed those and am back with the thin ugly fonts.

Perhaps changing the antialiasing to grayscale instead of RGBa would have helped the multi-color issue in your case?

[AdamW]

the major thing that changed between f14 and f15 in freetype is that the bytecode interpreter was enabled because the patents covering that function expired; *not* having the bytecode interpreter used to be the trendy thing to moan about when it came to Fedora fonts, and people would install packages from third-party repos which had the bytecode interpreter enabled...

if you follow the procedure at https://kevinkofler.wordpress.com/20...-on-fedora-15/ to force autohinting instead of the bytecode interpreter, does that give you what you're looking for?

[Mariusz W]

Originally Posted by AdamW

the major thing that changed between f14 and f15 in freetype is that the bytecode interpreter was enabled because the patents covering that function expired; *not* having the bytecode interpreter used to be the trendy thing to moan about when it came to Fedora fonts, and people would install packages from third-party repos which had the bytecode interpreter enabled...

if you follow the procedure at https://kevinkofler.wordpress.com/20...-on-fedora-15/ to force autohinting instead of the bytecode interpreter, does that give you what you're looking for?

The reference you provide contains an essential information. I feel, we are closing on the source of this "font drama".

Kevin Kofler's remark (is he by the way involved in the freetype Fedora package?) to the effect:

In most cases, the BCI is what you want

sounds almost grotesque when you see it next to comments like:

Wow, thanks for this post! I had exactly this problem – the nice fonts in firefox suddenly became ugly – and I couldn’t figure out why. Your advice did the trick in fixing it.

if it is precisely BCI (Byte Code Interpreter) that is responsible for these "ugly" fonts.

I urge people responsible for the freetype package to re-evaluate all aspects of their decision and how seriously it does affect activities involving text on the screen (terminal windows, text editors, web browsers, etc).

[RupertPupkin]

Originally Posted by AdamW

if you follow the procedure at https://kevinkofler.wordpress.com/20...-on-fedora-15/ to force autohinting instead of the bytecode interpreter, does that give you what you're looking for?

Yes. Much, much better. Thank you, Adam!
This is why I stick with Fedora; stuff gets solved. I am now a thoroughly happy F15 user.

[AdamW]

well, there's *one* comment on the post. If you go through the archives in this forum, you'll find hundreds and hundreds of posts recommending freetype-freeworld, which was the package you used to have to install to enable the BCI, when it was patent-encumbered. Seriously, the threads about how horrible autohinting is, pleading for instructions on how to enable the BCI, are not hard to find.

It sort of goes to prove the point about how subjective an issue font rendering is. =)

[Ard Righ]

I installed the freetype-infinality package and the font-config package along with it, and noticed an improvement with the default fonts looking slightly thicker.

I also used gnome-tweak-tool to change the fonts and the hinting that was enabled there, to full, with RGBa antialiasing.

Removing the freetype-infinality package, and the fonts definitely do appear more jagged. Maybe it's the extra sub-pixel hinting that freetype-infinality is meant to enable that makes the difference?

Also, for the people reading this, try coping font config files form the /etc/fonts/conf.avail/ directory into /etc/fonts/conf.d/ directory before creating new files like the one below.

Just having a quick look through /etc/fonts/conf.avail/ shows a number of autohint, subpixel and other options in config files just waiting to be copied

[Mariusz W]

Originally Posted by AdamW

well, there's *one* comment on the post. If you go through the archives in this forum, you'll find hundreds and hundreds of posts recommending freetype-freeworld, which was the package you used to have to install to enable the BCI, when it was patent-encumbered. Seriously, the threads about how horrible autohinting is, pleading for instructions on how to enable the BCI, are not hard to find.

It sort of goes to prove the point about how subjective an issue font rendering is. =)

I cannot go with this logic, I am afraid, Adam. I have seen this line too often used in defence of mediocrity. With this logic it would not be possible to tell apart ugly fonts from well proportioned ones. Difference would be always possible to explain as subjective. Font experts know very well that this is not the case. There are rules and guidelines governing design of a high quality font, whether it is designed for a printed page or a computer screen. It takes time and effort to study and learn those rules, it takes a lot of skill, expertise, time and effort to design fonts that satisfy those criteria.

I would like to ask people responsible for the introduction of new defaults that they return to the drawing board and carefully examine the effect of their decision in a variety of situations where a Fedora user comes face to face with text. It is not at all credible that they consider what I, and several others, recently saw as a conspicuous regression caused by freetype, to be an improvement.

[jff]

On my laptop I have set Hinting to Full and Antialiasing to Rgba .
Using Liberation fonts.
Then installed
yum install freetype-freeworld fonts-config
and rebooted Fedora 15.
The result is that the fonts are now slightly ticker and clearer i.e. slightly better.

[dd_wizard]

Originally Posted by AdamW

well, there's *one* comment on the post. If you go through the archives in this forum, you'll find hundreds and hundreds of posts recommending freetype-freeworld, which was the package you used to have to install to enable the BCI, when it was patent-encumbered. Seriously, the threads about how horrible autohinting is, pleading for instructions on how to enable the BCI, are not hard to find.

It sort of goes to prove the point about how subjective an issue font rendering is. =)

I wonder if some of the variation is due to differences between LCDs and CRTs. I used gnome-tweak-tool to improve rendering as much as possible, earlier. I used Kevin's info to switch from BCI to hinting, and now I'd say my fonts look even better. This is on a Toshiba laptop with a 1440 x 900 LCD.

dd_wizard