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#26 2020-01-10 12:35:48

Potomac
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Registered: 2011-12-25
Posts: 498

Re: Konsole font rendering regression.

Difference with QT_AUTO_SCREEN_SCALE_FACTOR enabled/disabled in konsole on my system :

https://bugsfiles.kde.org/attachment.cgi?id=125013

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#27 2020-01-10 12:36:48

Trilby
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Re: Konsole font rendering regression.

Earth to wall.  I'm talking to you.

I don't know if it's the only problem, but your DPI is definitely wrong.  If you don't fix that first, it's silly to try to point fingers elsewhere.  Fix your DPI, then check if there are still problems.

Last edited by Trilby (2020-01-10 12:38:08)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#28 2020-01-10 12:41:58

Potomac
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Registered: 2011-12-25
Posts: 498

Re: Konsole font rendering regression.

You assume that 96 DPI value is wrong on 24 inch LCD monitor,  and triggers this bug, I am not convinced (96 is the default value in Xorg), as a new value may solve the bug in plasma, but can trigger others bugs for other softwares (gtk, chromium) for font rendering.


But I will try to set manually other value.

Last edited by Potomac (2020-01-10 12:43:42)

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#29 2020-01-10 12:49:25

Trilby
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Re: Konsole font rendering regression.

I don't assume it is wrong.  I calculated that it is wrong.  You provided your actual screen dimensions above.  Do the math.  Your screen is not 96x96 DPI.

I do suspect that this is the cause of your problems.  This part could be wrong.  But there is no guessing or assuming about whether your DPI is wrong.  It is.  And don't just set an "other" value.  Set the correct value by putting in your physical screen measurements into an Xorg.conf excerpt as described in the wiki pages I linked several posts ago.  This will result in xdpyinfo reporting 92x92 DPI for your screen.

Last edited by Trilby (2020-01-10 12:51:47)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#30 2020-01-10 12:57:19

Potomac
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Registered: 2011-12-25
Posts: 498

Re: Konsole font rendering regression.

Trilby wrote:

The solution isn't to force Konsole to ignore false DPI values fed to it, but rather to correctly set up your DPI values.

You forgot a thing : Xorg by default sets the DPI to 96 (according to archlinux wiki pages), for all type of monitors, meaning that the bug should be present on every PC configuration (where optimal DPI for the monitor is not 96), but it's not clear if all archlinux user have the bug.

Setting a new DPI may solve the bug in plasma (I will test it), but it may trigger new bugs on other softwares for font rendering.

Last edited by Potomac (2020-01-10 13:00:16)

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#31 2020-01-10 13:02:41

V1del
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Registered: 2012-10-16
Posts: 8,382

Re: Konsole font rendering regression.

It doesn't do that. My DPI is 109 and I've never manually changed that. It does if your EDID data is wrong or inconclusive.

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#32 2020-01-10 13:02:51

gee
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Registered: 2006-11-29
Posts: 300

Re: Konsole font rendering regression.

@Trilby: I've tried setting my DPI as you suggested, by measuring my display and putting the value in monitor.conf.
Now I see DPI set to (44, 44) in Xorg.0.log, whereas before it was (96, 96), but xdpyinfo still returns 96x96.
Which is wrong?

As for the current issue, well I don't see a difference either way I think, but I'm happy to set things correctly.

Thank you!

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#33 2020-01-10 13:04:18

Trilby
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Re: Konsole font rendering regression.

Potomac wrote:

You forgot a thing : Xorg by default sets the DPI to 96 (according to archlinux wiki pages), for all type of monitors, meaning that the bug should be present on every PC configuration (where optimal DPI for the monitor is not 96), but it's not clear if all archlinux user have the bug.

I didn't forget anything.

It is astronomically easier for you to fix your clearly incorrect configuration than it is to take a survey of all arch linux users.  Or at least it should be.  The available evidence is proving otherwise.

I do know that not all arch users keep the 96x96 default.  Case in point: there's a wiki page explaining exactly how to set up DPI values correctly.

The only thing I'm forgetting is why I should five a damn about helping people with their problems when they just will not accept the help.  So I'll refrain from commenting here further unless /until the OP actually becomes active again as that's who I intended to help and request information from when I commented on this thread.


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#34 2020-01-10 13:04:55

Potomac
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Registered: 2011-12-25
Posts: 498

Re: Konsole font rendering regression.

V1del : Did you connect your monitor with a DVI cable ?
Or a display port, hdmi ?

I use a DVI cable, I don't know if it allow EDID communication between monitor and graphic card.

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#35 2020-01-10 13:07:23

Trilby
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Re: Konsole font rendering regression.

Gee, If xdpyinfo still reports 96x96 then you've not successfully set it.  Have you restarted Xorg?  If so, and xdpyinfo still reports 96x96, could you post the content of the monitor conf and the output from xrandr?


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#36 2020-01-10 13:07:26

Potomac
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Registered: 2011-12-25
Posts: 498

Re: Konsole font rendering regression.

Trilby wrote:

The only thing I'm forgetting is why I should five a damn about helping people with their problems when they just will not accept the help.  So I'll refrain from commenting here further unless /until the OP actually becomes active again as that's who I intended to help and request information from when I commented on this thread.

I said at several times that I will change the DPI, so no need to get angry.

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#37 2020-01-10 13:09:15

V1del
Forum Moderator
Registered: 2012-10-16
Posts: 8,382

Re: Konsole font rendering regression.

It's display port and the nvidia blob. Maybe it indeed does happen for the free drivers implicitly.

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#38 2020-01-10 13:19:52

gee
Member
Registered: 2006-11-29
Posts: 300

Re: Konsole font rendering regression.

Trilby wrote:

Gee, If xdpyinfo still reports 96x96 then you've not successfully set it.  Have you restarted Xorg?  If so, and xdpyinfo still reports 96x96, could you post the content of the monitor conf and the output from xrandr?

Yup, I restarted the whole computer.
I don't really remember how xorg.conf.d works anymore (thankfully) but I had to create a Screen section, for this to work.
Anyway, conf files:
10-monitor.conf https://gist.github.com/John-Gee/679c4f … 285fd626a7
40-screen.conf: https://gist.github.com/John-Gee/9e4b70 … a9616e503f
xrandr: https://gist.github.com/John-Gee/71793a … 493ca360c5

Maybe wrong DPI is actually why I've always needed to zoom fonts in KDE/Plasma all this time...

I appreciate your help, thank you!

Last edited by gee (2020-01-10 13:20:22)

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#39 2020-01-10 13:29:05

Trilby
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Re: Konsole font rendering regression.

I'm no master of xorg.confs, but that seems far too complex and lacks one bit of information that it should: the identifier.  As described in the wiki page I linked, this should be sufficient for you:

Section "Monitor"
        Identifier             "HDMI-A-1"
        DisplaySize            1105 616
EndSection

That is assuming those measurements are correct - that's quite a big screen.  You will not have HiDPI issues, but Low DPI issues!

Last edited by Trilby (2020-01-10 13:31:03)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#40 2020-01-10 13:35:32

gee
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Registered: 2006-11-29
Posts: 300

Re: Konsole font rendering regression.

Trilby wrote:

I'm no master of xorg.confs, but that seems far too complex and lacks one bit of information that it should: the identifier.  As described in the wiki page I linked, this should be sufficient for you:

Section "Monitor"
        Identifier             "HDMI-A-1"
        DisplaySize            1105 616
EndSection

That is assuming those measurements are correct - that's quite a big screen.  You will not have HiDPI issues, but Low DPI issues!

There already is an identifier in the monitor section, isn't there? Or are you saying that it should match the one in xrandr?
The rest is unrelated to this topic, just stuff that I needed for other reasons.
When I tried just adding the display size to my monitor.conf, without a ScreenSection nothing seemed to change, that's what I added that too.
Well it is 50", so not that small yeah.

Thank you!

edit: Yup renaming it to what was in xrandr works, but now I cannot read anything, it's so tiny everywhere hmm
edit: Well, I doubled all fonts sizes and I'm back to normal, not sure what I gained though, but if it's the right setup, all the better I guess.

Last edited by gee (2020-01-10 14:14:21)

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#41 2020-01-10 14:23:59

Trilby
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Re: Konsole font rendering regression.

That screen size is large for the resolution.  Setting the right DPI will mean that 11pt fonts are actually 11pt (not pixels, but an actual physical size).  Given the size of the screen, you probably sit further away than one often would sit from a computer monitor, in which case it makes sense to need significantly larger fonts.

That said, there's also nothing wrong with intentially misrepresenting your DPI if it makes things more convenient for you - the important thing is to make an informed decision on the settings.

Last edited by Trilby (2020-01-10 14:25:05)


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#42 2020-01-10 15:29:01

gee
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Registered: 2006-11-29
Posts: 300

Re: Konsole font rendering regression.

Yup, I'm probably 10ft away or so.
Though when my eyes get tired, I do lean in quite a bit. smile

Actually I just decided to set it to 120, it looks a lot better for me, so I lied about the screen size in xorg conf...
I think this will help me not have to change font sizes as I've had all along.
Putting it to 44 made things weird, like some fonts looked fine at size 12 but some looked really tiny and I needed size 20 in the same Plasma setting to be able to read, not sure why it was different but eh, it works now, so no more playing with it.

Thank you!

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#43 2020-01-10 17:00:37

ss2
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Registered: 2007-10-05
Posts: 75

Re: Konsole font rendering regression.

I'm surprised how often this problem always returns after a certain time has passed.  Just recently I spent almost two days figuring out how to get this old crisp font rendering in Debian working again.  It took me to long to get a hint how to enable it.  It annoys me how anyone would expect that as time moves on all people would magically start using modern hardware with displays at a higher resolution.

Now KDE pushes an upgrade (Plasma version 5.17.5, Konsole version 19.12.1) where font rendering is broken again.  I noticed that `Fonts' in systemsettings5 doesn't know how to obay system settings regarding sub-pixel rendering and hinting anymore.

Exporting QT_AUTO_SCREEN_SCALE_FACTOR to 0 solves this. I wonder how long it will take again until rendering is broken again.

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#44 2020-01-10 17:06:27

Trilby
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Re: Konsole font rendering regression.

ss2 wrote:

It annoys me how anyone would expect that as time moves on all people would magically start using modern hardware with displays at a higher resolution.

No one expects that all people are using hi res hardware.  They just changed the old assumption that nobody was using hi res hardware.  All the change does is allows for the portion of people who do have higher (or lower even) resolution to have sizes adjusted appropriately.  This will of course fail if Xorg has incorrect information about your monitor!


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#45 2020-01-10 18:56:09

ss2
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Registered: 2007-10-05
Posts: 75

Re: Konsole font rendering regression.

I was just about to rethink what I had written earlier on.  It is not that I generally oppose hi res displays.  I just happen not to use any so far.

Trilby wrote:

They just changed the old assumption that nobody was using hi res hardware.  All the change does is allows for the portion of people who do have higher (or lower even) resolution to have sizes adjusted appropriately.

It occured to me recently that there is a push to support higher resolutions such that fresh installs in new systems default to v40 in fontconfig and leaving full-hinting disabled (Correct me if I'm wrong on this regard).  This is fine for big screens.  But it is a regress for those with low res displays that want to have their old rendering working again.  It might be my gut feeling, but it feels hard to stiffle through documentation trying to figure out why font rendering is just so different today than it was before.  Even reading at freetype [1], they fail to explain that there are different implementations to use and just mean that the `modern approach' is how it is.  This leaves us with old and rusty low res displays alone.

Trilby wrote:

This will of course fail if Xorg has incorrect information about your monitor!

Yeah, that's a thing too.  I've never figured to use actual DPI resolutions properly anyway.  I just leave it at 96x96 and see that the fonts align properly to the pixels of the screen without taking care about the actual physical size of the fonts or the screen I put them into.  By the way, I do have another laptop with a full HD screen, that I also keep it at this rendering style, because it is handy to have a screen that can display a lot of text when I need it.

Anyway, don't mean to derail this thread.  Hope all involved get their font rendering sorted again.  Mine is.

[1] https://www.freetype.org/freetype2/docs … neral.html

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#46 2020-01-10 21:42:05

selendym
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Registered: 2019-09-09
Posts: 10

Re: Konsole font rendering regression.

Trilby wrote:

Is your monitor actually 708mm x 398mm (measured with a ruler in meat-space)?

Even if it is, the 96x96 "default" is wrong, you DPI settings should be 92x92.  Konsole now sets the scaling for HiDPI to true which should do nothing if your screen is not HiDPI ... of course it will do something (undesirable) if your screen's actually DPI is different from what the application is told.

It is.

I tried setting the DPI to a proper value with 'xrandr --dpi DVI-D-0'.
After this, 'xdpyinfo' gives "resolution:    92x92 dots per inch", so this should have had some effect.
Unfortunately, I see absolutely no difference: Konsole has its fonts fucked up and other applications look exactly the same as before after restarting them.
It may be that the setting simply is not being respected by, e.g., Cinnamon (my desktop environment), but that's another can of worms altogether.

I also tried launching X with 'startx -- -dpi 92' but this seems to have no effect at all and the value is reset to 96 for some reason, although command-line options should have the highest priority (to my knowledge).

I'm not going to start debating who's right or wrong here, but the sane thing to do would be to provide a setting to toggle this kind of 'feature' off if required without needing to play with arcane env vars or to patch the source.

Last edited by selendym (2020-01-10 21:42:33)

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#47 2020-01-10 21:54:21

Trilby
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Registered: 2011-11-29
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Re: Konsole font rendering regression.

selendym wrote:

I tried setting the DPI to a proper value with 'xrandr --dpi DVI-D-0'.
After this, 'xdpyinfo' gives "resolution:    92x92 dots per inch", so this should have had some effect.
Unfortunately, I see absolutely no difference...

Thank you.  That was a good test demonstrating that, in your case, the DPI setting is not the cause of this problem.

selendym wrote:

I'm not going to start debating who's right or wrong here.

No need.  The DPI settings were wrong, and I wanted to ensure we could rule this out as a cause of your problem.  You have ruled it out.


"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

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#48 2020-01-10 22:55:56

digitalone
Member
Registered: 2011-08-19
Posts: 241

Re: Konsole font rendering regression.

Thanks Trilby, setting the right DPI and disabling the global environment variable (that I suggested before) fixed the issue for me.

Restarting the system, my fonts were very big, then I set a new size and they are correct now and even sharper than before.

There's always something to learn.

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#49 2020-01-11 15:39:21

Potomac
Member
Registered: 2011-12-25
Posts: 498

Re: Konsole font rendering regression.

ss2 wrote:

Exporting QT_AUTO_SCREEN_SCALE_FACTOR to 0 solves this. I wonder how long it will take again until rendering is broken again.

Note that QT_AUTO_SCREEN_SCALE_FACTOR is a deprecated environment variable,

It's better to replace it by a new environment variable : QT_ENABLE_HIGHDPI_SCALING

export QT_ENABLE_HIGHDPI_SCALING=0
Deprecate QT_AUTO_SCREEN_SCALE_FACTOR
 

Replace by QT_ENABLE_HIGHDPI_SCALING.

QT_AUTO_SCREEN_SCALE_FACTOR has the usability problem that it mixes
enabling the high-DPI scaling mode with the method of getting screen
scale factors (“auto”). Due to this, it ends up with a slightly
strange name.
 

QT_ENABLE_HIGHDPI_SCALING matches the C++ option
(Qt::AA_EnableHighDPiScaling), and leaves the scale factor acquisition
method unspecified, possibly to be set by some other means (like
QT_SCREEN_SCALE_FACTORS).

https://codereview.qt-project.org/c/qt/qtbase/+/176381

There are a lot of changes in Qt 5.14.0 related to HighDPI, this can add bugs or break plasma if the code has not been adapted to the new API :
https://lists.qt-project.org/pipermail/ … 37434.html
https://lists.qt-project.org/pipermail/ … 37450.html

Last edited by Potomac (2020-01-11 15:41:27)

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#50 2020-01-12 15:15:05

kero
Member
Registered: 2012-08-26
Posts: 32

Re: Konsole font rendering regression.

Hi,

I have the exactly same rendering problem since my weekly's "pacman -Syu" done yesterday.

I've read this entire thread seeking for some solution and here is what i've observed:
1) The problem happens (for me) in a lot of programs: konsole, dolphin, kate, okular, vlc... It seems to be some Qt issue, but it doesn"t happen in systemsettings5 (which, I assume also uses Qt ?)

2) I tried to adjust my configuration's DPI according to Trilby indications (Thank you). My original DPI was indeed wrong. After configuring Xorg, the DPI looks now correct: "xdpyinfo | grep -b2 resolution" gives the right monitor size and the DPI switched from the standard 96 to 92. But this doesn't solve the problem: fonts are still weird (=blurry).

3) I also tried using "export QT_AUTO_SCREEN_SCALE_FACTOR=0", which indeed makes the fonts look correctly. BUT I also noticed that with that "solution", white caracters look slightly green (I think you can notice that on the image posted by Potomac at 2020-01-10 13:35:48).

4) The feeling that I have is that the problem is not about scaling bout about hinting. That feeling comes from the fact that :  if, in systemsettings, I set "hinting" to none, systemsettings's font rendering becomes as blurry as those in Konsole or Dolphin (though systemsettings5's font rendering is basically OK). So my feeling is that the new implementation of HiDPI scaling by Qt prevents programs from considering properly the hinting setting.

Or something like that.

And, btw, sorry for my poor english.

Last edited by kero (2020-01-12 15:20:21)

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