[NTG-context] How to improve appearance of bars in frac, sqrt, etc. on screens?

[NTG-context] How to improve appearance of bars in frac, sqrt, etc. on screens?

[Ralph]

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Hello,


I’m relatively new to ConTeXt (version 2024.05.31, LMTX, standalone) and 
really enjoy learning it so far, but I have one little problem with the 
appearance of horizontal bars in math mode.

It seems the way ConTeXt displayed horizontal extensible bars in math 
mode some time ago (as used in \frac, \sqrt, \overbar, ...) was similar 
to the way LaTeX (PDFLaTeX and LuaLaTeX) and Plain TeX handled this, but 
it has changed since then. Instead of one bar there are now multiple 
characters attached to each other.

This makes it look more consistent with the font, but unfortunately it 
doesn’t display well in any PDF viewer I’ve tried (on Linux, so I’ve not 
tried Adobe Acrobat Reader). The bars look dotted, I guess it’s due to 
anti-aliasing (the dots disappear when anti-aliasing is disabled, but 
then of course everything looks pixelated). Two screenshots are attached 
(different zoom levels in PDF viewer) so that you know what I’m talking 
about.

Source:
\setuppapersize[S3]
\starttext
\startformula \sqrt{a^2 + b^2} = \frac{1000 \cdot c}{1000} \stopformula
\stoptext

Is there a way to switch to the old bars for documents viewed mainly on 
screens, or is there any other way to improve their appearance? I 
couldn’t find any documentation on this, so I would be very thankful if 
somebody here could help out.


Best,
Ralph

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[NTG-context] Re: How to improve appearance of bars in frac, sqrt, etc. on screens?

[Otared Kavian]

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Hi Ralph,

I don’t see any pixels in the PDF file when I typeset your code snipet (on MacOS 11.7.10). Here is what I get.

Best regards: Otared



> On 13 Jun 2024, at 13:10, Ralph <ralph.2718@email-postfach.info> wrote:
> 
> Hello,
> 
> 
> I’m relatively new to ConTeXt (version 2024.05.31, LMTX, standalone) and really enjoy learning it so far, but I have one little problem with the appearance of horizontal bars in math mode.
> 
> It seems the way ConTeXt displayed horizontal extensible bars in math mode some time ago (as used in \frac, \sqrt, \overbar, ...) was similar to the way LaTeX (PDFLaTeX and LuaLaTeX) and Plain TeX handled this, but it has changed since then. Instead of one bar there are now multiple characters attached to each other.
> 
> This makes it look more consistent with the font, but unfortunately it doesn’t display well in any PDF viewer I’ve tried (on Linux, so I’ve not tried Adobe Acrobat Reader). The bars look dotted, I guess it’s due to anti-aliasing (the dots disappear when anti-aliasing is disabled, but then of course everything looks pixelated). Two screenshots are attached (different zoom levels in PDF viewer) so that you know what I’m talking about.
> 
> Source:
> \setuppapersize[S3]
> \starttext
> \startformula \sqrt{a^2 + b^2} = \frac{1000 \cdot c}{1000} \stopformula
> \stoptext
> 
> Is there a way to switch to the old bars for documents viewed mainly on screens, or is there any other way to improve their appearance? I couldn’t find any documentation on this, so I would be very thankful if somebody here could help out.
> 
> 
> Best,
> Ralph
> 
> <small.png><zoomed.png>___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
> 
> maillist : ntg-context@ntg.nl / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl
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> ___________________________________________________________________________________

Otared Kavian
e-mail: otared@gmail.com
Phone: +33 6 88 26 70 95





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[NTG-context] Re: How to improve appearance of bars in frac, sqrt, etc. on screens?

[Bruce Horrocks]

> On 13 Jun 2024, at 21:04, Otared Kavian <otared@gmail.com> wrote:
> 
> Hi Ralph,
> 
> I don’t see any pixels in the PDF file when I typeset your code snipet (on MacOS 11.7.10). Here is what I get.
> 
> Best regards: Otared
> 
> <fraction-bar-pixels.pdf>

I see it on both - the original and Otared's.

Otared: If open yours (on MacOS 14.5) by double-clicking the image in the email and clicking zoom+ twice then the 'wobble' in the line is visible if you squint. 

Bound to be monitor and resolution dependent as well though - not sure how to provide settings that would be repeatable by others. Just go up and down zoom sizes looking carefully.

—
Bruce Horrocks
Hampshire, UK

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[NTG-context] Re: How to improve appearance of bars in frac, sqrt, etc. on screens?

[Hans Hagen via ntg-context]

On 6/13/2024 10:04 PM, Otared Kavian wrote:
> Hi Ralph,
> 
> I don’t see any pixels in the PDF file when I typeset your code snipet 
> (on MacOS 11.7.10). Here is what I get.
No problems on windows on chrome-os either. Mikael S and I checked it on 
his linux box and one can indeed see anti aliasing when taking a screen 
dump (depends on resolution).

So it's a linux rendering issue when taking dumps. That said: we can't 
do anything about it. Using rules (traditional approach) is pretty bad 
in screen dumps and even regular rendering, depending on zoom; there one 
has interaction between the font rendering and other graphic elements 
(rules).

Btw, vertical extensibles are not different (take the bracket which has 
similar constructs). Interesting is that it is straight blob connections 
that can show these occasional gray pixels and it only seems to happen 
with a little overlap. Kind of a bug we think.

Hans

ps. One reason when I always use (x)ubuntu when i have to use a linux 
desktop is that it always was set up right wrt rendering fonts and anti 
aliasing. I might need to check that.

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------

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[NTG-context] Re: How to improve appearance of bars in frac, sqrt, etc. on screens?

[Henning Hraban Ramm]

Am 13.06.24 um 23:13 schrieb Hans Hagen via ntg-context:
> On 6/13/2024 10:04 PM, Otared Kavian wrote:
>> Hi Ralph,
>>
>> I don’t see any pixels in the PDF file when I typeset your code snipet 
>> (on MacOS 11.7.10). Here is what I get.
> No problems on windows on chrome-os either. Mikael S and I checked it on 
> his linux box and one can indeed see anti aliasing when taking a screen 
> dump (depends on resolution).
> 
> So it's a linux rendering issue when taking dumps. 

Not only. It also happens with all(?) PDF viewers on MacOS – at least 
10.14 and 10.15, can anyone confirm with current versions?

So it’s dependend on the screen rendering, anti aliasing settings (that 
you usually can’t influence).

It doesn’t affect printing – or does it for anyone? I can imagine 
printing from Firefox, i.e. pdf.js, is affected, since it prints only in 
screen resolution.

Hraban

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[NTG-context] Re: How to improve appearance of bars in frac, sqrt, etc. on screens?

[Hans Hagen via ntg-context]

On 6/14/2024 9:35 AM, Henning Hraban Ramm wrote:
> Am 13.06.24 um 23:13 schrieb Hans Hagen via ntg-context:
>> On 6/13/2024 10:04 PM, Otared Kavian wrote:
>>> Hi Ralph,
>>>
>>> I don’t see any pixels in the PDF file when I typeset your code 
>>> snipet (on MacOS 11.7.10). Here is what I get.
>> No problems on windows on chrome-os either. Mikael S and I checked it 
>> on his linux box and one can indeed see anti aliasing when taking a 
>> screen dump (depends on resolution).
>>
>> So it's a linux rendering issue when taking dumps. 
> 
> Not only. It also happens with all(?) PDF viewers on MacOS – at least 
> 10.14 and 10.15, can anyone confirm with current versions?
> 
> So it’s dependend on the screen rendering, anti aliasing settings (that 
> you usually can’t influence).

hm, so i have to stick to windows for viewing (and an ancient hardware 
laptop in order to avoid copilot and recall) but i'll check ubuntu anyway

> It doesn’t affect printing – or does it for anyone? I can imagine 
> printing from Firefox, i.e. pdf.js, is affected, since it prints only in 
> screen resolution.
it's not related to math then, as there are also ligatures built this 
way, although often they often are less sensitive to thsi due to 
generous overlaps (unless they use a sequence of connecting strokes in 
the same direction)

also keep in mind that looking at a blown up character is not that 
realistic (for instance a traditional bitmap font might look great at 
600 or 1200 dpi at intended size so zooming in showing raggedness is not 
the normal way to see it)

btw, if one wants to observe inaccuracy, just zoom in in graphics made 
by drawing programs (even of famous companies)

Hans


-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------

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[NTG-context] Re: How to improve appearance of bars in frac, sqrt, etc. on screens?

[Taco Hoekwater]

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> On 14 Jun 2024, at 11:44, Hans Hagen via ntg-context <ntg-context@ntg.nl> wrote:
> 
> On 6/14/2024 9:35 AM, Henning Hraban Ramm wrote:
>> Am 13.06.24 um 23:13 schrieb Hans Hagen via ntg-context:
>>> On 6/13/2024 10:04 PM, Otared Kavian wrote:
>>>> Hi Ralph,
>>>> 
>>>> I don’t see any pixels in the PDF file when I typeset your code snipet (on MacOS 11.7.10). Here is what I get.
>>> No problems on windows on chrome-os either. Mikael S and I checked it on his linux box and one can indeed see anti aliasing when taking a screen dump (depends on resolution).
>>> 
>>> So it's a linux rendering issue when taking dumps.
>> Not only. It also happens with all(?) PDF viewers on MacOS – at least 10.14 and 10.15, can anyone confirm with current versions?

Artifacts like mentioned were visible in Preview on my Mac (14.5) as well.

The PDF view in chrome on this Mac shows a slightly different artifact effect, see image below.

Neither bothers me, though. 

Best wishes,
Taco


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— 
Taco Hoekwater              E: taco@bittext.nl
genderfluid (all pronouns)



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[NTG-context] Re: How to improve appearance of bars in frac, sqrt, etc. on screens?

[ralph.2718]

Hi,

thank you all for your replies so far. I guess I’ll have to live with that for now (of course this isn’t really a problem, but a bit unpleasant to look at when you’re used to the straight lines in LaTeX). Just wanted to add that I can see this artifacts quite clearly on a 13 inch 1080p screen in the PDF viewer (depends on zoom level, on some zoom levels I see nothing) and not only when enlarging a screenshot. After all, it’s visible in my attached screenshots even if displayed in their original resolution. (Naming of my screenshots wasn’t very clear, zoomed.png is zoomed-in in the pdf viewer, not a zoomed-in screenshot.)

Best,
Ralph
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[NTG-context] Re: How to improve appearance of bars in frac, sqrt, etc. on screens?

[Hans Hagen via ntg-context]

On 6/15/2024 10:59 AM, ralph.2718@email-postfach.info wrote:
> Hi,
> 
> thank you all for your replies so far. I guess I’ll have to live with that for now (of course this isn’t really a problem, but a bit unpleasant to look at when you’re used to the straight lines in LaTeX). Just wanted to add that I can see this artifacts quite clearly on a 13 inch 1080p screen in the PDF viewer (depends on zoom level, on some zoom levels I see nothing) and not only when enlarging a screenshot. After all, it’s visible in my attached screenshots even if displayed in their original resolution. (Naming of my screenshots wasn’t very clear, zoomed.png is zoomed-in in the pdf viewer, not a zoomed-in screenshot.)
The "left radical + rule" isn't perfect either, because it depends on 
overlap. Depending on the font you can see issues at the connection 
(actually these might be obscured by aliasing at low res). You can try 
that outside lmtx with different fonts.

Also, because rules are often rendered differently from glyphs (and 
rules can use either a line or rectangle fill) it's always been an issue 
(which is also why engines have some heuristics for choosing one or the 
other method).

And, as mentioned, vertical extenders also use the same etechnology as 
we now use for radicals, it's just that there was never a concept like 
that in engines for radicals. Arrows sit in the same category and also 
use the same glyphs so there one can observe the same. Actually, even in 
traditional tex arrows are made from minusus and an arrowhead 
overlapping piecewise.

Maybe viewers will catch up.

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------

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