We don't know that. Apple never shipped subpixel AA on top of Core Animation, so they seemed to shy away from implementing it in a GPU-accelerated way.
Same goes for Microsoft.
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The subpixel-AA debacle and font rendering
- Thread starter mathcolo
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We don't know that. Apple never shipped subpixel AA on top of Core Animation, so they seemed to shy away from implementing it in a GPU-accelerated way.
Same goes for Microsoft.
I've had subpixel AA on my Macs for years, and it's always worked beautifully in rendering text. That's what I meant when I said "they were fully capable of implementing it well."
Not sure what you're trying to say that contradicts this. But if I were to try to guess at your meaning:
I don't know what Core Animation is, but it sounds like it's for, well, animations, which aren't as demanding of sharpness as text. So it sounds like you're saying they may not have been able to implement subpixel AA in a regime in which it's not needed, but were able to implement in a regime where it is. If so, I think that qualifies as being able to implement it well.
Unfortunately, for me, after having experienced the superb crispness of subpixel antialiased and subpixel positioned text on Linux using a 1440p display, I have now made Linux my main operating system for browsing, emails, and reading pdfs. I will retain OS X with Adobe Lightroom and Photoshop as an excellent environment for photo editing.
Hopefully, once good 24 and 25 inch 4K and 5K displays become available in a few years, I may revisit OS X as a daily OS.
I’m going to purchase a 21.5” LG 22md4ka (that has been sitting in a box for most of its life) and see what it looks like compared to my 31.5” QHD display.
The extra real-estate is nice (even when I drive it at higher resolutions using RD) however I’m curious what font quality in Catalina looks like at quite a bit higher (200+) ppi.
But don't you already know what Catalina looks like at >200 ppi? I ask because you already have retina (220 ppi) displays on both your 2020 13" MBP and your mid-2012 15" retina MBP. [Even if you've not installed Catalina on either of them, you could create a separate test partition with Catalina and take a look.]
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Not on an external display (that is quite a bit larger than either of my MBP screens).
If it is a winner, I'm going to deal my larger/lower ppi display to my lovely wife.
So I just had a chance to compare a 27 inch 5k iMac against my 24 inch 2k Dell (OS X / Linux) and this is how I'd rank font rendering:
24 inch 2k OS X < 27 inch 5k OS X < 24 inch 2k Linux
I found that fonts were all very readable, smooth, and perfectly spaced on the iMac but somehow the "dilation*" that OS X performs removes and simplifies some of the character of the font. This was true even with font smoothing turned off in preferences. Also, the glass front distances the text from your vision, even though I presume Apple are using the highest quality laminating.
Obviously I was expected the subpixel AA, subpixel spaced, gamma corrected, Linux rendering to beat OS X on a 2K screen, but somewhat surprised that I prefer it to the Retina.
I guess the proportion of Apple's customer base that spend a long time reading on their computers, and care about font quality, is quite low. If you're a photographer or video editor you probably don't care as long as text is legible.
* slight emboldening to preserve glyph shape?
Also, interesting article here: https://www.puredevsoftware.com/blog/2019/01/22/sub-pixel-gamma-correct-font-rendering/
24 inch 2k OS X < 27 inch 5k OS X < 24 inch 2k Linux
I found that fonts were all very readable, smooth, and perfectly spaced on the iMac but somehow the "dilation*" that OS X performs removes and simplifies some of the character of the font. This was true even with font smoothing turned off in preferences. Also, the glass front distances the text from your vision, even though I presume Apple are using the highest quality laminating.
Obviously I was expected the subpixel AA, subpixel spaced, gamma corrected, Linux rendering to beat OS X on a 2K screen, but somewhat surprised that I prefer it to the Retina.
I guess the proportion of Apple's customer base that spend a long time reading on their computers, and care about font quality, is quite low. If you're a photographer or video editor you probably don't care as long as text is legible.
* slight emboldening to preserve glyph shape?
Also, interesting article here: https://www.puredevsoftware.com/blog/2019/01/22/sub-pixel-gamma-correct-font-rendering/
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What OS versions of Mac and Linux did you use? And what is the specific res of your 2K? 1920 x 1080?
Current release of OS X with supersampling enabled. Linux is KDE environment with Freetype 2.10 (https://www.freetype.org/), but freetype has had solid font rendering for several years now.
2K is the loose term people use to refer to 2560x1440 displays.
2K is the loose term people use to refer to 2560x1440 displays.
So that would be a 122 ppi display.
I'd be very interested to hear how the Linux KDE compares with with Mac OS High Sierra your iMac, since in that case you'd be comparing Linux with anti-aliasing and Mac with anti-aliasing. Also would be interesting to compare High Sierra vs. Catalina on the 5k. If your iMac isn't too new you should be able to install High Sierra on a separate partition.
It might also be interesting to compare Linux with High Sierra on your 2K, but in that case I don't expect the MacOS would do well, since IME High Sierra needs about 160 ppi to look good. Now Snow Leopard (which looked good at 100 ppi) vs Linux OTOH....
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All of those comparisons would be interesting, although the iMac 5K was in a shop so not so practical 
But, for me, I need to use a modern OS.
Actually I never felt that text readability was historically an Apple strong point. Their approach was always to conserve the original shape of the font, even if that meant "fattening" it on low-res displays to avoid jaggies. This suits well their core markets of photographers, designers, creatives etc. who, if they are working with text, it's mainly small chunks in graphic design. The rest of us never complained as it we got used to it.
Cleartype was originally invented to help people reading on-screen in offices all day long, and is one of the few inventions I think Microsoft deserve a lot of credit for.
But, for me, I need to use a modern OS.Actually I never felt that text readability was historically an Apple strong point. Their approach was always to conserve the original shape of the font, even if that meant "fattening" it on low-res displays to avoid jaggies. This suits well their core markets of photographers, designers, creatives etc. who, if they are working with text, it's mainly small chunks in graphic design. The rest of us never complained as it we got used to it.
Cleartype was originally invented to help people reading on-screen in offices all day long, and is one of the few inventions I think Microsoft deserve a lot of credit for.
Definitely agree with you there. Always wished Apple provided a Cleartype-equivalent option, but they're instead going in the opposite direction, making fonts progressively less readable.All of those comparisons would be interesting, although the iMac 5K was in a shop so not so practical
Actually I never felt that text readability was historically an Apple strong point. Their approach was always to conserve the original shape of the font, even if that meant "fattening" it on low-res displays to avoid jaggies. This suits well their core markets of photographers, designers, creatives etc. who, if they are working with text, it's mainly small chunks in graphic design. The rest of us never complained as it we got used to it.
Cleartype was originally invented to help people reading on-screen in offices all day long, and is one of the few inventions I think Microsoft deserve a lot of credit for.
The reason I was wondering about High Sierra vs Catalina on the 5k is that it's of practical importance for me—is the pixel density of a "retina" monitor sufficient overcome the lack of AA, and thus make Catalina as sharp as HS?
On the iMac 5K in a shop (so was latest model) I did try switching font smoothing off in the preferences. That got rid of the "dilation" semibold effect on fonts, but somehow I still wasn't that impressed. Rendering fonts is a complex topic, and I think Apple does manipulate the shape of them in certain ways even on retina displays. Readability was great, but the character of individual fonts was a bit lost.
In one article I read they do point out that the problem of how best to raster a glyph to the screen grid doesn't go away with retina, it just decreases a lot. Furthermore, when you think about it, the calculation for a subpixel grid is actually 7680 x 1440 resolution on a 2K display, whereas just using a standard pixel grid is 5120x2880 on a 5K iMac.
Horizontal resolution is more important than vertical for readability. You can also use a font with a large x-height (distance from baseline to mean of lowercase) to make up for a lower vertical resolution.
Also, I would add that getting subpixel-AA just right requires a very careful setup. The text should be filtered using a 5-tap bezel, sub-pixel positioned, and gamma corrected to the screen. Font hinting shouldn't be used in conjunction with subpixel AA. On Windows 10 it is an absolute mess as only a fraction of the user interface obeys those rules, and the rest is just a mix of various technologies and often down to the program developer to set their own rules. On Linux it is consistent, you set it once, and anything that isn't a Java app obeys.
Amazingly until around October 2019, none of the main browsers had sub-pixel positioning implemented, although they did have subpixel-AA for Windows/Linux/High Sierra. Now Firefox has it, and Chrome does but only with a flag. I guess the majority of people don't even notice things like this.
In one article I read they do point out that the problem of how best to raster a glyph to the screen grid doesn't go away with retina, it just decreases a lot. Furthermore, when you think about it, the calculation for a subpixel grid is actually 7680 x 1440 resolution on a 2K display, whereas just using a standard pixel grid is 5120x2880 on a 5K iMac.
Horizontal resolution is more important than vertical for readability. You can also use a font with a large x-height (distance from baseline to mean of lowercase) to make up for a lower vertical resolution.
Also, I would add that getting subpixel-AA just right requires a very careful setup. The text should be filtered using a 5-tap bezel, sub-pixel positioned, and gamma corrected to the screen. Font hinting shouldn't be used in conjunction with subpixel AA. On Windows 10 it is an absolute mess as only a fraction of the user interface obeys those rules, and the rest is just a mix of various technologies and often down to the program developer to set their own rules. On Linux it is consistent, you set it once, and anything that isn't a Java app obeys.
Amazingly until around October 2019, none of the main browsers had sub-pixel positioning implemented, although they did have subpixel-AA for Windows/Linux/High Sierra. Now Firefox has it, and Chrome does but only with a flag. I guess the majority of people don't even notice things like this.
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FWIW I’ve managed to track down the cause of the fuzzy text problem and the solution for poor text rendering on non-Retina and non-UHD monitors.
After much searching, encountering much nonsense (e.g. Apple renders fonts so perfectly they only look good on Retina screens etc etc) I finally found the solution - kudos to the serious Geek who figured out how to solve it (links below).
My quick summary:
Each individual monitor has a configuration file.
They are organised by manufacturer (folders) and model (plist files without plist extension) located here:
Macintosh HD ▸ System ▸ Library ▸ Displays ▸ Contents ▸ Resources ▸ Overrides
I don’t know if these are generated by Apple or the display manufacturers.
For various reasons these no longer play well from Mojave onwards.
To get clean text the display must be in Apple’s “HiDPI” mode for the selected resolution.
And there are gotchas: to get a nice 1920 x 1080 resolution, it needs to be configured as double that, 3840 x 2160.
So to fix that you need to customise the configuration file for you monitor.
Thankfully that excellent geek has made a tool so you can generate a new config file.
But as well, the display resolutions that you see listed under System Prefs | Displays do not show all the available resolutions. You can often see more by holding down <Option> while clicking <Scaled> but even then many may be missing.
So to fix that, you need a free tool called RDM which pops a button in the menu bar that shows all possible resolutions and also identifies those that are HiDPI and will and give the best possible text rendering.
The process once you’ve done it is actually straightforward. There are a few tricks to identify the file you need to modify and then to replace it you have to run commands in Recovery Mode, including disabling then re-enabling System Integrity Protection.
The guy who figured it out (very clear explanation): Force HiDPI Resolutions for Dell U2515H Monitor
Display configuration file generator tool he created: PropertyList Parser and Generator
RDM app (just save it in Applications folder): RDM
Hope that solves the mystery and helps someone ~ it's been a nightmare tracking this issue down!
I used these tricks for a Dell P2418D QHD monitor - text was appalling at all 16:9 resolutions - solved it perfectly.
After much searching, encountering much nonsense (e.g. Apple renders fonts so perfectly they only look good on Retina screens etc etc) I finally found the solution - kudos to the serious Geek who figured out how to solve it (links below).
My quick summary:
Each individual monitor has a configuration file.
They are organised by manufacturer (folders) and model (plist files without plist extension) located here:
Macintosh HD ▸ System ▸ Library ▸ Displays ▸ Contents ▸ Resources ▸ Overrides
I don’t know if these are generated by Apple or the display manufacturers.
For various reasons these no longer play well from Mojave onwards.
To get clean text the display must be in Apple’s “HiDPI” mode for the selected resolution.
And there are gotchas: to get a nice 1920 x 1080 resolution, it needs to be configured as double that, 3840 x 2160.
So to fix that you need to customise the configuration file for you monitor.
Thankfully that excellent geek has made a tool so you can generate a new config file.
But as well, the display resolutions that you see listed under System Prefs | Displays do not show all the available resolutions. You can often see more by holding down <Option> while clicking <Scaled> but even then many may be missing.
So to fix that, you need a free tool called RDM which pops a button in the menu bar that shows all possible resolutions and also identifies those that are HiDPI and will and give the best possible text rendering.
The process once you’ve done it is actually straightforward. There are a few tricks to identify the file you need to modify and then to replace it you have to run commands in Recovery Mode, including disabling then re-enabling System Integrity Protection.
The guy who figured it out (very clear explanation): Force HiDPI Resolutions for Dell U2515H Monitor
Display configuration file generator tool he created: PropertyList Parser and Generator
RDM app (just save it in Applications folder): RDM
Hope that solves the mystery and helps someone ~ it's been a nightmare tracking this issue down!
I used these tricks for a Dell P2418D QHD monitor - text was appalling at all 16:9 resolutions - solved it perfectly.
@moc99 yes this is basically supersampling in which everything is rendered to a canvas double your number of physical pixels, and then the GPU scales it down.
unfortunately it's not the "best possible" text rendering, as it's still grayscale antialiasing.
i have the successor to your monitor (P2421D) and with subpixel AA under linux text looks sharper than under OS X.
the one thing you can do is play around with the font your browser uses to display websites, as certain modern fonts have been designed to fit well to the pixel grid so look sharp even without much antialiasing. Fonts like Georgia, Verdana, the Cleartype collection, San Francisco, certain Google web fonts etc.
unfortunately it's not the "best possible" text rendering, as it's still grayscale antialiasing.
i have the successor to your monitor (P2421D) and with subpixel AA under linux text looks sharper than under OS X.
the one thing you can do is play around with the font your browser uses to display websites, as certain modern fonts have been designed to fit well to the pixel grid so look sharp even without much antialiasing. Fonts like Georgia, Verdana, the Cleartype collection, San Francisco, certain Google web fonts etc.
So, does this mean that if I have a 34'' Ultrawide (21:9 aspect ratio) whose native resolution is 3440x1440, is that I have to create a 6880x2880 resolution and use that to achieve crisp font rendering?
In case anyone is interested I recently discovered that Adobe Acrobat Reader renders text with subpixel AA on Macs!
If you load up a pdf side by side with preview you can do a comparison. Here is a line of bold text followed by a line of normal text in Acrobat on Catalina:
And here is the same in Preview on Catalina with grayscale AA:
Zoom in and notice how a) the space inside the letter 'e' is rendered a lot more cleanly with subpixel AA b) the difference between normal and bold text is more distinct with subpixel AA
A subjective impression would be that for reading short chunks of text Apple's rendering is acceptable. However the semi-boldening becomes fatiguing when reading a long document, and Apple can't beat the subpixel for crispness.
Sadly, I haven't found a web browser or word processor with it's own rendering engine but it does seem possible. One useful trick is to make the default font for your web browser something like Lato (free google font) which fits quite neatly into the pixel grid in the first place, so that Apple's rendering doesn't need to adjust it much.
If you load up a pdf side by side with preview you can do a comparison. Here is a line of bold text followed by a line of normal text in Acrobat on Catalina:
And here is the same in Preview on Catalina with grayscale AA:
Zoom in and notice how a) the space inside the letter 'e' is rendered a lot more cleanly with subpixel AA b) the difference between normal and bold text is more distinct with subpixel AA
A subjective impression would be that for reading short chunks of text Apple's rendering is acceptable. However the semi-boldening becomes fatiguing when reading a long document, and Apple can't beat the subpixel for crispness.
Sadly, I haven't found a web browser or word processor with it's own rendering engine but it does seem possible. One useful trick is to make the default font for your web browser something like Lato (free google font) which fits quite neatly into the pixel grid in the first place, so that Apple's rendering doesn't need to adjust it much.
Hello, I have a questions? In this example, subpixel antialiasing is something that is handled by Acrobat itself?
Is it possible at all to enable systemwide subpixel antialiasing on Catalina?
Currently running 720p@ 2x on 1080p monitor. Credits to this person: https://github.com/xzhih/one-key-hidpi
Now it's clear why Mac OS is meant for Retina monitors.
Everything is bigger now, but I guess I can get used to it.
Now it's clear why Mac OS is meant for Retina monitors.
Everything is bigger now, but I guess I can get used to it.
Anyone with 4K monitor running at 1080p HiDPI mode? How does it look, do you lose too much screen estate?
Depends on the monitor size. 1080p HiDPI on a 21" or 24" would ok, but too big on a 27" or 32". On my 4K 32" I run "looks like" 1440p HiDPI as a good comprise between size and quality given the ~140 PPI. Obviously a monitor with > 200 PPI is better, but the LG 5K is the only display on the market, but has serious QA issues.
How can you run 1440p HiDPI on 4K monitor. 2560 x 2 = 5120. 5K is already HiDPI so no need scaling it down to 1440p.
macOS renders it at 5120x2880 and then scales it down to 3840x2160. I run my 27" 4K at 1440p and works good enough.
There's a catch though. Combining that with a 1080p display on polaris graphics like the rx 580 will lock mem/core clocks to max and heat the GPU. It doesnt happen in windows so it's a macOS thing. The issue doesnt happen with 1080p HDPI + 1080p display and interestingly, also good with the next slider up, 3008 x 1692