Skip Navigation
How to obtain the density (DPI / PPI) of a PGM file -- anyone know? ImageMagick does not cut it.
  • That was my intuition but then consider this bug in unpaper:

    https://github.com/unpaper/unpaper/issues/230

    I have a script that runs unpaper on PGM files. When the DPI is 600, that bug in unpaper is triggered, but no problem if the source is 300dpi. So it means there is a difference. Although I suppose it’s possible that it’s not really DPI that causes unpaper to produce a truncated image; it could come down to sheer number of pixels. Guess I could work that out by testing further with smaller source scans.

    The reason for my question is that I’d like to write my script to work around that bug. If a source file has more than 300 dpi, I would use ImageMagick instead of unpaper to do the bileveling.

    (update)
    I cropped a 600dpi image in half using GIMP. Then fed that into unpaper. The bug was not triggered and the full canvas was processed correctly. So I think you are right.. DPI is not a concept on PGM files. Which implies unpaper’s bug is simply a limitation on the number of pixels it can handle. It’s apparently incidental that scanning a full size page at 600 dpi results in more pixels than unpaper can handle.

  • Paperless office; document/image processing @sopuli.xyz plantteacher @mander.xyz
    How to obtain the density (DPI / PPI) of a PGM file -- anyone know? ImageMagick does not cut it.

    Running this gives the geometry but not the density: $ identify -verbose myfile.pgm | grep -iE 'geometry|pixel|dens|size|dimen|inch|unit' There is also a “Pixels per second” attribute which means nothing to me. No density and not even a canvas/page dimension (which would make it possible to compute the density). The “Units” attribute on my source images are “undefined”.

    Suggestions?

    4
    Saffron: The Story of the World’s Most Expensive Spice - JSTOR Daily
  • For centuries, saffron has been a prized dye

    Bizarre that such a costly substance would be used as a dye for clothing. Why pay what’s likely the equivalent of HP ink when you can just get a box of Rit yellow dye at the supermarket?

    Surely the price will drop when someone figures out that drones can fly around and harvest the saffron.

  • What kind of liquor is in Borgetti Di Vero Caffe Espresso?

    The website of the producer of this coffee liquor is useless for getting info about this product. Some digging around on 3rd party sites reveals that it’s made of 70% Arabica from South America and 30% Robusto from Africa, and that 3 different coffees are made in a giant moka machine (thus unfiltered) and blended. One source says it’s “steeped in grain alcohol, blended and sweetened with sugar. No coffee aromas, chocolate, extracts or distilled additives are added.”

    I cannot find any direct info as to what spirit is used. Coffee liquors are all over the map (rum, jenever, tequila, brandy, vodka, whisky, etc). If the source claiming use of grain alcohol is correct, I suppose that rules out rum, tequila, & brandy. Whiskey and jenever have a clear character. So I’m tempted to assume vodka is in play. Can anyone confirm or deny?

    1
    Water Science and Technologies @mander.xyz plantteacher @mander.xyz
    is it safe to let a water heater to be unplugged for ~3—6 months at a time?

    My house has a tankless water for most of the house. Exceptionally, one floor gets hot water from a tank. I rarely need hot water on that floor so I keep the tank unplugged. But when I need a backup shower (e.g. the tankless gets clogged with limescale) I plugin the tank, let it reach a quite high temp, then shower.

    Is this risky? I just heard from someone saying they only unpower their water heater for 1 day at a time because of some specific kind of bacteria. I was assuming whatever bacteria colonizes in 6 months or whatever would be killed off when I fire it up. But I know that some bacteria (which goes after spoiling meat) produces toxins, so even when the bacteria is dead there are dangerous chemicals remaining. Is this the same risk with water heaters?

    If it’s unsafe, what do I need to do? Do I have to fill the tank with air between uses? Or can I just run the water for as long as needed to get all new water in the tank before powering it?

    4
    posts blackholed on the onion instance
  • As a test, I enabled js on the onion site and tried again to post from the onion connection. Again my message was simply blackholed. So noscript’s default disabling of JS is not the issue.

    (edit) then I posted from the clearnet site mader.xyz.. no issue. This problem is onion-specific.

  • posts blackholed on the onion instance

    I just got burnt. Wrote up a relatively high-effort post in:

    http://mandermybrewn3sll4kptj2ubeyuiujz6felbaanzj3ympcrlykfs2id.onion/c/water

    clicked sumbit, and it simply ate my msg. Redrew a blank form.. no way to recover the info loss. This is my 1st use of the onion, so I did not think to enable 1st party j/s (which is strangely off be default in noScript on Tor Browser despite clearnet sites having 1st party js enabled by default). It’s unclear if it’s a JS problem or if it’s because the onion version uses a quite old/classic reddit-like theme. In any case, it sucks.. it’s a defect for sure.

    1
    African elephants call each other by unique names, new study shows
  • I would assume the extent of the uniqueness is probably unknown at this point. The researchers probably meant uniqueness within a group. Though I suppose the population is small enough that the names could be unique globally.

  • Animal behavior @mander.xyz plantteacher @mander.xyz
    African elephants call each other by unique names, new study shows
    www.ctvnews.ca African elephants call each other by unique names, new study shows

    African elephants call each other and respond to individual names — something that few wild animals do, according to new research published Monday.

    African elephants call each other by unique names, new study shows
    2
    (US) the unnecessary-IV (swindle?) [update: price corrected to $600]
  • That would make sense. In Europe I got an IV just for blood samples. They could have been anticipating the possibility that I would need pain killers later, but seemed like it would have made more sense to use a normal needle and only do the IV if it came to the point of needing meds.

  • Loss of cooking skills has hurt our ability to adapt to rising food prices, experts say
  • .. or farmers trying to sell obscure things like celery root!

    seriously though, the article seems reasonable and balanced to me. E.g:

    • “Of course no amount of cooking prowess will help if you can't afford a basket of groceries”
    • “It's important to note, however, that cooking skills alone cannot solve the affordability problem”.
  • Loss of cooking skills has hurt our ability to adapt to rising food prices, experts say
  • Right but what if the cheapest food is idk, something like celery root? I think the idea w/the thesis of the article is that a skilled cook can adapt to whatever ingredients are cheapest at any moment.

    I think I’m a decent cook but I also think I need to improve because when I’m in the produce area and have no idea how to use like 15—20% of the options there. E.g. celery root, cactus, and ½ dozen things I don’t even recognize.

  • (US) the unnecessary-IV (swindle?) [update: price corrected to $600]

    Hospitals will often give patients an IV as an automatic procedure and then use it for just one blood draw or injection, or even not use it at all. Then charge ≥$60 600¹ for it (in the US)!

    I went to the ER in Europe and got an automatic IV. They only used it to take blood and nothing else. So I took notes and prepared for a dispute. When the invoice finally came, I found no charge for the IV. But had to probe because I’m the type that will fight over a nickel on principle. I asked for details on some of the doctor’s fees, since it was not itemized separately. After my investigation, it turns out the IV was bundled in but only €6. LOL. So insignificant indeed.

    Not sure if it’s fair to call it a swindle in the US. Is it typically a deliberate money-grab when the IV is not really needed? Staff are (generally rightfully) unaware of pricing and just focused on giving the best care for the patient independent of cost. And for insured people that’s ideal. But I often steer the staff, saying I’m an uninsured cash payer and need price quotes and to asses the degree of need on various things. It’s a burden on them but it’s important to me. I have gotten discharged a day early on a couple occasions (which generally saves me ~$/€ 1k each day I avoid).

    Funny side story: a doc who I steered well toward budget treatment pulls out his smartphone with a gadget that does an echo. He said this is free but unofficial… maybe we can get out of the pricey proper echo imaging. And indeed the pics were good enough.

    Anyway - to the question:

    Whether to give an IV involves guesswork on whether more things will need to be injected. Do docs have any criteria to follow when ordering an IV, or is it their full discretion and they just order it for convenience without much thought?

    1. $60 was the price ~15-20 years ago.. probably even more today. CORRECTION: the ER nurse in my family apparently tells patients who possibly don’t need an IV that the cost on the bill will be $600 (as a good samaritan warning). I don’t have direct contact with this family member.. heard it through someone else. Can any other ER nurses in the US confirm whether that’s accurate? I am really struggling to believe this price and wonder if someone’s memory failed. I think if I were quoted that price I would surely say for that price I do not need it.. feel free to stick me 10-20 times if needed. (update 2: seems realistic)
    3
    Dishwasher guide: salt will harm the stainless steel lining. What about salt water in stainless steel pots?

    The manual for my dishwasher says to refill salt just before running a wash cycle, because if any grains of salt spill onto the stainless steel interior it will corrode. If it runs right away, no issue because the salt is quickly dissolved, diluted, and flushed.

    So then I realized when I cook pasta I heavily salt the water (following the advice that pasta water should taste as salty as the ocean). But what happens when I leave that highly salty brine in a pot, sometimes for a couple days to reuse it? Does that risk corroding the pots?

    0
    What You Don’t Know About Sperm
  • When the hard-working little swimmers encounter the thicker vaginal mucus, their path is slowed. So the sperm often join together at their heads, which gives them greater swimming speed (up to 50 percent faster) than if they were to carry on individually.

    I wonder why that is. If a group of people were to join together and run, the speed of the group would be capped by the slowest runner. And aerodynamics would be worse.

  • InitialsDiceBearhttps://github.com/dicebear/dicebearhttps://creativecommons.org/publicdomain/zero/1.0/„Initials” (https://github.com/dicebear/dicebear) by „DiceBear”, licensed under „CC0 1.0” (https://creativecommons.org/publicdomain/zero/1.0/)PL
    plantteacher @mander.xyz
    Posts 7
    Comments 13