4 ms·

But nobody knows what baseline PPD is (47) and you can't actually specify a laptop screen in PPD, you can only specify it in PPI. So I think it's reasonable an

But nobody knows what baseline PPD is (47) and you can't actually specify a laptop screen in PPD, you can only specify it in PPI. So I think it's reasonable and maybe even preferable to use PPI here.

perching_aix 1y ago
I can understanding finding it reasonable, it's just not getting at the heart of the problem. It also introduces an element of uncertainty: as you say, you can't specify a laptop screen's PPD since that's dependent on viewing distance. But that's exactly the problem: it's dependent on viewing distance. Some people hunch over and look at their laptops up close and personal, others have it on a stand at a reasonable height and distance. To use PPI is to intentionally mask over this uncertainty, and start using ballpark measures people may or may not agree with without knowing. To put it in context, for this display, "Retina resolution" (60 PPD), i.e. the 20/20 visual acuity threshold, is passed when viewed from 47.09 cm (18.54 inches, so basically a feet and a half). I don't know about you, but I think this is a very reasonable distance to view your laptop from, even if it's just 12.2" in diagonal. It corresponds to a horizontal field of view of 32°.
- Dylan16807 1y ago
  You could say it masks over the uncertainty in some ways, but it doesn't introduce that uncertainty. Asking for a laptop with 100PPD doesn't even make sense. > the 20/20 visual acuity threshold The acuity threshold for random blobs of light. The threshold for sharp edges is much finer, and the things we put on computer displays have a lot of sharp edges. https://en.wikipedia.org/wiki/Hyperacuity https://en.wikipedia.org/wiki/Hyperacuity
  - deleted 1y ago
    [deleted]
  - perching_aix 1y ago
    > Asking for a laptop with 100PPD doesn't even make sense. Won't deny, since again, PPD depends on your field of view. Yes, if you shop for "resolution and diagonal size", you may as well shop for PPI directly. This just doesn't generalize to displays overall (see my other comment with a TV example), as it's not actually the right variable. Wrong method, "right" result. > The threshold for sharp edges is much finer, and the things we put on computer displays have a lot of sharp edges. And the cell density is even finer. It was merely an example using a known reference value that lots of people would find excellent; I didn't mean to argue that it's the be-all end-all of vision. It's just 20/20.
    - Dylan16807 1y ago
      PPI doesn't generalize across different types of display but it works pretty well within a category of monitor, laptop, tablet, phone. For TV you probably just assume it's 4K and figure out the size you like. It's wrong but it's wrong in a way that causes minimal trouble and there's no better option. And if you add viewing distance explicitly, PPI+distance isn't meaningfully worse than PPD+distance, and people will understand PPI+distance better.
      - perching_aix 1y ago
        Eh, I suppose. Just the criteria of "is it hidpi? yes/no" readily mislead GP for example (i.e. it definitely is, just still "not hidpi enough"), so I felt it would be helpful if the mechanism at play was clarified. Maybe I came off too strong though. Felt it would be clearer to use the correct variable at least, than to try and relativize PPI.
        Dylan16807 1y ago
        I guess, but even without measuring pixel inches/degrees it feels clearly wrong to me to say that proper 1x on a 12 inch laptop screen is only 960x600. 1280x720 or 1280x800 makes more sense to me, and then there's no confusion because 1920 is a clear 1.5x resolution.

But nobody knows what baseline PPD is (47) and you can't actually specify a laptop screen in PPD, you can only specify it in PPI. So I think it's reasonable and maybe even preferable to use PPI here.

perching_aix 1y ago

I can understanding finding it reasonable, it's just not getting at the heart of the problem. It also introduces an element of uncertainty: as you say, you can't specify a laptop screen's PPD since that's dependent on viewing distance. But that's exactly the problem: it's dependent on viewing distance. Some people hunch over and look at their laptops up close and personal, others have it on a stand at a reasonable height and distance. To use PPI is to intentionally mask over this uncertainty, and start using ballpark measures people may or may not agree with without knowing. To put it in context, for this display, "Retina resolution" (60 PPD), i.e. the 20/20 visual acuity threshold, is passed when viewed from 47.09 cm (18.54 inches, so basically a feet and a half). I don't know about you, but I think this is a very reasonable distance to view your laptop from, even if it's just 12.2" in diagonal. It corresponds to a horizontal field of view of 32°.

Dylan16807 1y ago
You could say it masks over the uncertainty in some ways, but it doesn't introduce that uncertainty. Asking for a laptop with 100PPD doesn't even make sense. > the 20/20 visual acuity threshold The acuity threshold for random blobs of light. The threshold for sharp edges is much finer, and the things we put on computer displays have a lot of sharp edges. https://en.wikipedia.org/wiki/Hyperacuity https://en.wikipedia.org/wiki/Hyperacuity
- deleted 1y ago
  [deleted]
- perching_aix 1y ago
  > Asking for a laptop with 100PPD doesn't even make sense. Won't deny, since again, PPD depends on your field of view. Yes, if you shop for "resolution and diagonal size", you may as well shop for PPI directly. This just doesn't generalize to displays overall (see my other comment with a TV example), as it's not actually the right variable. Wrong method, "right" result. > The threshold for sharp edges is much finer, and the things we put on computer displays have a lot of sharp edges. And the cell density is even finer. It was merely an example using a known reference value that lots of people would find excellent; I didn't mean to argue that it's the be-all end-all of vision. It's just 20/20.
  - Dylan16807 1y ago
    PPI doesn't generalize across different types of display but it works pretty well within a category of monitor, laptop, tablet, phone. For TV you probably just assume it's 4K and figure out the size you like. It's wrong but it's wrong in a way that causes minimal trouble and there's no better option. And if you add viewing distance explicitly, PPI+distance isn't meaningfully worse than PPD+distance, and people will understand PPI+distance better.
    - perching_aix 1y ago
      Eh, I suppose. Just the criteria of "is it hidpi? yes/no" readily mislead GP for example (i.e. it definitely is, just still "not hidpi enough"), so I felt it would be helpful if the mechanism at play was clarified. Maybe I came off too strong though. Felt it would be clearer to use the correct variable at least, than to try and relativize PPI.
      - Dylan16807 1y ago
        I guess, but even without measuring pixel inches/degrees it feels clearly wrong to me to say that proper 1x on a 12 inch laptop screen is only 960x600. 1280x720 or 1280x800 makes more sense to me, and then there's no confusion because 1920 is a clear 1.5x resolution.