7 ms·

Text wrapping is actually a difficult optimization problem. That's part of the reason LaTeX has such good text wrapping -- it can spend serious CPU cycles on th

Text wrapping is actually a difficult optimization problem. That's part of the reason LaTeX has such good text wrapping -- it can spend serious CPU cycles on the problem because it doesn't do it in real time.

jkmcf 1y ago
That's true, but I think the OP is commenting on the state of FE development :)
- taeric 1y ago
  Largely, yes. I also challenge if it would be measurable for the size of most sites. Typesetting all of wikipedia? Probably measurable. Typesetting a single article of wikipedia? Probably not. And I'd wager most sites would be even easier than wikipedia.
taeric 1y ago
You aren't wrong; but I stand by my claim. For one, plenty of things are actually difficult optimization problems that people don't give any passing thought to. But, more importantly, the amount of cycles that would be needed to text-wrap most websites is effectively zero. Most websites are simply not typesetting the volumes of text that would be needed for this to be a concern. Happy to be shown I'm flat wrong on that. What sites are you envisioning this will take a lot of time for?
- cobertos 1y ago
  Any page with dynamic text. If the calculation takes a moderate amount of time, that will accumulate if the page layout reflows a lot.
  - taeric 1y ago
    Only if the entire text has to be optimized as a whole? Which, most dynamic text sites do not have to do this. Most dynamic sites will be a series of individual "card" like things that could be justified internally, but are not justified with regard to anything else on the page.
- NoMoreNicksLeft 1y ago
  Won't this end up in Apple iBooks or whatever it's called now? Most novels can be a megabyte or more of text, pretty much all of it needing to be wrapped.
  - CharlesW 1y ago
    It seems more likely that Apple would've adapted this from the proven technology that they currently use for Apple Books and everything else, TextKit (which first appeared in OpenStep). https://developer.apple.com/videos/play/wwdc2021/10061/ https://developer.apple.com/videos/play/wwdc2021/10061/
    - addaon 1y ago
      > Apple Books and everything else Can't speak to Apple Books, but at least Pages.app (and iWork in general) use a separate text engine from TextKit, focused on higher fidelity at the cost of performance -- optical kerning, etc. (Terminal.app also does not use TextKit.)
    - alwillis 1y ago
      Doubtful. OpenStep used Display Postscript and was written in Objective-C; WebKit is written in C++. Rendering text on the web is a different animal all together.
      - NoMoreNicksLeft 1y ago
        I was under the impression that when we got new css in Safari, in the next software cycle those same features ended up in Books. It wouldn't make sense to give it a different rendering engine... but then I've never been able to find much in the way of which epub readers used which rendering engines anywhere.
  - taeric 1y ago
    I mean, not wrong. But optimizing over a megabyte's worth of text is almost certainly not going to take a lot of time. Especially as there will be chapter stops. Such that we are down to, what 100k of text per chapter to layout? Again, I won't claim it is absolutely free. It is almost certainly negligible in terms of processing power involved with any of the things we are talking about.
- binaryturtle 1y ago
  With the current state of Websites and how much resources they waste any text wrapping is probably not an issue at all. :) I hardly can open any website w/o some anti-bot check burning my CPU to the ground for 1/2 minute or something (if it doesn't manage to entirely crash my Firefox in the process like cloudflare). I rather would wait for 0.2s text wrapping than that, that's for sure. :)
- contact9879 1y ago
  Quick example would be https://standardebooks.org/ebooks/mark-twain/the-innocents-abroad/text/single-page https://standardebooks.org/ebooks/mark-twain/the-innocents-a... Try zooming in and out with text-wrap: pretty vs text-wrap: wrap
  - taeric 1y ago
    I... uh, wouldn't consider a text dump of a full novel getting completely typeset as a good example to consider when talking about sites?
    - contact9879 1y ago
      sure, but html isn't only used in a browser context. I have a severely under-powered ereader that I use to read epubs (html). It already takes ten seconds to paginate on first open and font size changes. I can't imagine how long it would take to non-naively wrap lines
      - taeric 1y ago
        I don't know why you'd expect an ereader to do a full text optimization of a book, though? Pick the starting line and layout to the next screen's breaking point. If needed, consider if you left an orphan for the next page and try to adjust that into the current screen. Are there ereaders that have to typeset the entire text of what you are reading? What is the advantage of making the task harder?
        tjader 1y ago
        KOReader typesets the whole book at once. It is needed in order to get page counts right, for example.
        taeric 1y ago
        Even if that is the case, it has to redo this how often? If the page counts are to be stable, I'm assuming so are page numbers? At which point we are back to this not being something I would expect to slow things down appreciably on the vast majority of actual uses. Still, I should acknowledge you provided an example. It surprises me.
- pcwalton 1y ago
  > But, more importantly, the amount of cycles that would be needed to text-wrap most websites is effectively zero. I've measured this, and no, it's not. What you're missing is the complexities of typesetting Unicode and OpenType, where GSUB/GPOS tables, bidi, ruby text, etc. combine to make typesetting quite complex and expensive. HarfBuzz is 290,000 lines of code for a reason. Typesetting Latin-only text in Times New Roman is quick, sure, but that doesn't cut it nowadays.
  - taeric 1y ago
    Apologies, the additional cycles to do justified text is effectively zero compared to the rest of the stack for most sites. Clearly, it is work, so not actually zero. And, yes, proper text handling is huge. I would wager you can find scenarios where it is a large number. My question is if there are sites people use? Seriously taken, these would all be reasons not to do many of the things Unicode does. And yet here we are. That all said, if you have measurements, please share. Happy to be proven wrong.
    - rhdunn 1y ago
      Some complexities: - handling shy hyphens/hyphenation when splitting long words -- working out where to hyphenate so it is readable, then how that affects the available space takes time to compute to ensure that justified text doesn't result in large blocks of whitespace esp. for long words; - handing text effects like making the first letter large, or the first word(s) larger, like is done in various books; - reflow due to any changes resulting from text rendering/formatting (e.g. if applying kerning or hyphenation results in/does not result in text wrapping); - impact of things like kerning and digraphs (e.g. ffi) on text width -- including determining if a word can be split in the middle of one of these or not; - combining characters, emoji (with zero-width non-joiners), flag Unicode character pairs (including determining valid pairs to determine if/where to split on), etc.; - mixed direction text (left to right and right to left) handling and positioning; - the mentioned Ruby text (e.g. https://www.w3.org/International/articles/ruby/styling.en.html https://www.w3.org/International/articles/ruby/styling.en.ht...) -- dealing with both the main text wrapping and the above/below text wrapping, both of which could happen; - for Chinese/Japanese/Korean ensuring that characters within a word don't have extra space, as those languages don't use spacing to delimit words; - other things affecting line height such as sub/super script text (mathematical equations, chemical symbols, references, etc.).
int_19h 1y ago
Lest we forget, TeX is almost 50 years old now, so what constitutes "serious CPU cycles" has to be understood in the context of hardware available at the time.
- setopt 1y ago
  TeX is still slow to compile documents on my current device (MacBook M1), especially when compared to e.g. Typst. I can only imagine how slow it would have been on a 40yo computer.
  - xigoi 1y ago
    How much of that time is spent on text wrapping?
porphyra 1y ago
But with modern hardware, running the dynamic programming solution to this optimization problem takes a trivial amount of cycles* compared to rendering your typical React webapp. * for most webpages. Of course you can come up with giant ebooks or other lengthy content for which this will be more challenging.
- ta988 1y ago
  even on 5 pages documents LaTeX can spend a surprising amount of time
  - taeric 1y ago
    What five page documents? I've seen it zip through far larger texts on the regular. And is most of the effort from LaTeX in paragraph layout? Most slowness there, is in Mathematica typesetting, I would think.
  - lttlrck 1y ago
    Is Latex text wrapping known to be well optimized?
    - taeric 1y ago
      The main algorithm most any folks know by name for doing this was created for it, so sorta? I don't know that it is necessarily better than any closed source options. I was under the impression it is the baseline good, though.
    - __david__ 1y ago
      Its author was supposedly pretty good at algorithms. I think he may have even written a book or four about them. So I suspect it’s decently optimized.
jgalt212 1y ago
Computerphile did a nice video on this. https://www.youtube.com/watch?v=kzdugwr4Fgk https://www.youtube.com/watch?v=kzdugwr4Fgk The Kindle Text Problem - Computerphile
frereubu 1y ago
You've phrased your comment as if it's a counterpoint to OP, but it's not - both can be true (and from personal experience OP is absolutely right).
throw0101d 1y ago
> That's part of the reason LaTeX has such good text wrapping -- it can spend serious CPU cycles on the problem because it doesn't do it in real time. Is that the reason the Microsoft Word team tells themselves as well? We have multi-core, multi-gigahertz CPUs these days: there aren't cycles to spare to do this?
- jcelerier 1y ago
  to be honest as a LaTeX user on a very beefy CPU I regularly have 30s+ of build times for larger documents. I doubt Word users would want that. A simple 3 page letter without any graphics is a couple seconds already.
  - throw0101c 1y ago
    > to be honest as a LaTeX user on a very beefy CPU I regularly have 30s+ of build times for larger documents. A lot of the time folks are sitting and thinking and things are idle. Perhaps Word could 'reflow' text in the background (at least the parts that are off screen)? Also, maybe the saved .docx could perhaps have hints so that on loading things don't have be recalculated?
    - taeric 1y ago
      Oh dear lord, the last thing I ever wanted Word to do was to try and reflow things. I can't be the only person that tried to move an image only to have it somehow disappear into the ether while Word tried to flow around it. :D
  - taeric 1y ago
    I'd hazard most of that 30s+ build time is not in the line wrapping algorithm. Most slow documents are either very heavy in math typesetting, or loaded with many cross references needing multiple passes through TeX to reconcile. To be clear, just because I would hazard that, does not mean I'm right. Would love to see some benchmarks.
    - 1y ago

jkmcf 1y ago

That's true, but I think the OP is commenting on the state of FE development :)

taeric 1y ago
Largely, yes. I also challenge if it would be measurable for the size of most sites. Typesetting all of wikipedia? Probably measurable. Typesetting a single article of wikipedia? Probably not. And I'd wager most sites would be even easier than wikipedia.

taeric 1y ago

You aren't wrong; but I stand by my claim. For one, plenty of things are actually difficult optimization problems that people don't give any passing thought to. But, more importantly, the amount of cycles that would be needed to text-wrap most websites is effectively zero. Most websites are simply not typesetting the volumes of text that would be needed for this to be a concern. Happy to be shown I'm flat wrong on that. What sites are you envisioning this will take a lot of time for?

cobertos 1y ago
Any page with dynamic text. If the calculation takes a moderate amount of time, that will accumulate if the page layout reflows a lot.
- taeric 1y ago
  Only if the entire text has to be optimized as a whole? Which, most dynamic text sites do not have to do this. Most dynamic sites will be a series of individual "card" like things that could be justified internally, but are not justified with regard to anything else on the page.
NoMoreNicksLeft 1y ago
Won't this end up in Apple iBooks or whatever it's called now? Most novels can be a megabyte or more of text, pretty much all of it needing to be wrapped.
- CharlesW 1y ago
  It seems more likely that Apple would've adapted this from the proven technology that they currently use for Apple Books and everything else, TextKit (which first appeared in OpenStep). https://developer.apple.com/videos/play/wwdc2021/10061/ https://developer.apple.com/videos/play/wwdc2021/10061/
  - addaon 1y ago
    > Apple Books and everything else Can't speak to Apple Books, but at least Pages.app (and iWork in general) use a separate text engine from TextKit, focused on higher fidelity at the cost of performance -- optical kerning, etc. (Terminal.app also does not use TextKit.)
  - alwillis 1y ago
    Doubtful. OpenStep used Display Postscript and was written in Objective-C; WebKit is written in C++. Rendering text on the web is a different animal all together.
    - NoMoreNicksLeft 1y ago
      I was under the impression that when we got new css in Safari, in the next software cycle those same features ended up in Books. It wouldn't make sense to give it a different rendering engine... but then I've never been able to find much in the way of which epub readers used which rendering engines anywhere.
- taeric 1y ago
  I mean, not wrong. But optimizing over a megabyte's worth of text is almost certainly not going to take a lot of time. Especially as there will be chapter stops. Such that we are down to, what 100k of text per chapter to layout? Again, I won't claim it is absolutely free. It is almost certainly negligible in terms of processing power involved with any of the things we are talking about.
binaryturtle 1y ago
With the current state of Websites and how much resources they waste any text wrapping is probably not an issue at all. :) I hardly can open any website w/o some anti-bot check burning my CPU to the ground for 1/2 minute or something (if it doesn't manage to entirely crash my Firefox in the process like cloudflare). I rather would wait for 0.2s text wrapping than that, that's for sure. :)
contact9879 1y ago
Quick example would be https://standardebooks.org/ebooks/mark-twain/the-innocents-abroad/text/single-page https://standardebooks.org/ebooks/mark-twain/the-innocents-a... Try zooming in and out with text-wrap: pretty vs text-wrap: wrap
- taeric 1y ago
  I... uh, wouldn't consider a text dump of a full novel getting completely typeset as a good example to consider when talking about sites?
  - contact9879 1y ago
    sure, but html isn't only used in a browser context. I have a severely under-powered ereader that I use to read epubs (html). It already takes ten seconds to paginate on first open and font size changes. I can't imagine how long it would take to non-naively wrap lines
    - taeric 1y ago
      I don't know why you'd expect an ereader to do a full text optimization of a book, though? Pick the starting line and layout to the next screen's breaking point. If needed, consider if you left an orphan for the next page and try to adjust that into the current screen. Are there ereaders that have to typeset the entire text of what you are reading? What is the advantage of making the task harder?
      - tjader 1y ago
        KOReader typesets the whole book at once. It is needed in order to get page counts right, for example.
        taeric 1y ago
        Even if that is the case, it has to redo this how often? If the page counts are to be stable, I'm assuming so are page numbers? At which point we are back to this not being something I would expect to slow things down appreciably on the vast majority of actual uses. Still, I should acknowledge you provided an example. It surprises me.
pcwalton 1y ago
> But, more importantly, the amount of cycles that would be needed to text-wrap most websites is effectively zero. I've measured this, and no, it's not. What you're missing is the complexities of typesetting Unicode and OpenType, where GSUB/GPOS tables, bidi, ruby text, etc. combine to make typesetting quite complex and expensive. HarfBuzz is 290,000 lines of code for a reason. Typesetting Latin-only text in Times New Roman is quick, sure, but that doesn't cut it nowadays.
- taeric 1y ago
  Apologies, the additional cycles to do justified text is effectively zero compared to the rest of the stack for most sites. Clearly, it is work, so not actually zero. And, yes, proper text handling is huge. I would wager you can find scenarios where it is a large number. My question is if there are sites people use? Seriously taken, these would all be reasons not to do many of the things Unicode does. And yet here we are. That all said, if you have measurements, please share. Happy to be proven wrong.
  - rhdunn 1y ago
    Some complexities: - handling shy hyphens/hyphenation when splitting long words -- working out where to hyphenate so it is readable, then how that affects the available space takes time to compute to ensure that justified text doesn't result in large blocks of whitespace esp. for long words; - handing text effects like making the first letter large, or the first word(s) larger, like is done in various books; - reflow due to any changes resulting from text rendering/formatting (e.g. if applying kerning or hyphenation results in/does not result in text wrapping); - impact of things like kerning and digraphs (e.g. ffi) on text width -- including determining if a word can be split in the middle of one of these or not; - combining characters, emoji (with zero-width non-joiners), flag Unicode character pairs (including determining valid pairs to determine if/where to split on), etc.; - mixed direction text (left to right and right to left) handling and positioning; - the mentioned Ruby text (e.g. https://www.w3.org/International/articles/ruby/styling.en.html https://www.w3.org/International/articles/ruby/styling.en.ht...) -- dealing with both the main text wrapping and the above/below text wrapping, both of which could happen; - for Chinese/Japanese/Korean ensuring that characters within a word don't have extra space, as those languages don't use spacing to delimit words; - other things affecting line height such as sub/super script text (mathematical equations, chemical symbols, references, etc.).

int_19h 1y ago

Lest we forget, TeX is almost 50 years old now, so what constitutes "serious CPU cycles" has to be understood in the context of hardware available at the time.

setopt 1y ago
TeX is still slow to compile documents on my current device (MacBook M1), especially when compared to e.g. Typst. I can only imagine how slow it would have been on a 40yo computer.
- xigoi 1y ago
  How much of that time is spent on text wrapping?

porphyra 1y ago

But with modern hardware, running the dynamic programming solution to this optimization problem takes a trivial amount of cycles* compared to rendering your typical React webapp. * for most webpages. Of course you can come up with giant ebooks or other lengthy content for which this will be more challenging.

ta988 1y ago
even on 5 pages documents LaTeX can spend a surprising amount of time
- taeric 1y ago
  What five page documents? I've seen it zip through far larger texts on the regular. And is most of the effort from LaTeX in paragraph layout? Most slowness there, is in Mathematica typesetting, I would think.
- lttlrck 1y ago
  Is Latex text wrapping known to be well optimized?
  - taeric 1y ago
    The main algorithm most any folks know by name for doing this was created for it, so sorta? I don't know that it is necessarily better than any closed source options. I was under the impression it is the baseline good, though.
  - __david__ 1y ago
    Its author was supposedly pretty good at algorithms. I think he may have even written a book or four about them. So I suspect it’s decently optimized.

jgalt212 1y ago

Computerphile did a nice video on this. https://www.youtube.com/watch?v=kzdugwr4Fgk https://www.youtube.com/watch?v=kzdugwr4Fgk The Kindle Text Problem - Computerphile

frereubu 1y ago

You've phrased your comment as if it's a counterpoint to OP, but it's not - both can be true (and from personal experience OP is absolutely right).

throw0101d 1y ago

> That's part of the reason LaTeX has such good text wrapping -- it can spend serious CPU cycles on the problem because it doesn't do it in real time. Is that the reason the Microsoft Word team tells themselves as well? We have multi-core, multi-gigahertz CPUs these days: there aren't cycles to spare to do this?

jcelerier 1y ago
to be honest as a LaTeX user on a very beefy CPU I regularly have 30s+ of build times for larger documents. I doubt Word users would want that. A simple 3 page letter without any graphics is a couple seconds already.
- throw0101c 1y ago
  > to be honest as a LaTeX user on a very beefy CPU I regularly have 30s+ of build times for larger documents. A lot of the time folks are sitting and thinking and things are idle. Perhaps Word could 'reflow' text in the background (at least the parts that are off screen)? Also, maybe the saved .docx could perhaps have hints so that on loading things don't have be recalculated?
  - taeric 1y ago
    Oh dear lord, the last thing I ever wanted Word to do was to try and reflow things. I can't be the only person that tried to move an image only to have it somehow disappear into the ether while Word tried to flow around it. :D
- taeric 1y ago
  I'd hazard most of that 30s+ build time is not in the line wrapping algorithm. Most slow documents are either very heavy in math typesetting, or loaded with many cross references needing multiple passes through TeX to reconcile. To be clear, just because I would hazard that, does not mean I'm right. Would love to see some benchmarks.
  - 1y ago