ChaoticNeutralCzech
@ChaoticNeutralCzech@feddit.org
- Comment on Velma can't math. 10 hours ago:
Nope, it looks like a basic vector graphics editor, think Inkscape, PowerPoint or whatever is built into their animation/effects software. They just used straight horizontal lines for the fraction and the bar of the square root.
- Comment on Velma can't math. 1 day ago:
Unicode isn’t meant to replace all typesetting like LaTeX. For example, I can’t make proper horizontal fractions (unlike ⅝, perhaps) that are normal in my part of the world because that would be too much scope creep.
An imperfect solution is adding
̅ U+0305 COMBINING OVERLINEabove everything. For example, it does not sit at consistent height (√4̅a̅c̅) and Windows renders it incorrectly (centered to the right edge of the character, not its center).This is how I’d render the numerator using Unicode only: 𝑏² ± √4̅𝑎̅𝑐̅
- Comment on Velma can't math. 1 day ago:
I’m guessing a typesetter was too lazy to add a different-size font and although they knew how to type “√”, didn’t realize “²” is in Unicode too. They added a horizontal line as separate graphics to extend the square root symbol but only realized too late the whole thing is in a fraction: maybe someone reminded them and they misinterpreted the advice, or just decided not to split the text box to put the nominator higher.
- Comment on Velma can't math. 1 day ago:
Do you have a truly universal method for quadratic expansion that is easier to remember and compute than the formula? Don’t get me wrong, I enjoy quadratic expansion and always give it a few shots before resorting to the formula.
- Comment on Illustration from ‘Zen and the Art of the Macintosh - Discoveries on the Path to Computer Enlightenment’, Michael Green, 1988 2 days ago:
Nah, it’s a Mac-themed temple. Questionable cult things used to happen there but it’s laid abandoned for centuries…
- Comment on Banana 2 days ago:
Wow, we have Banana Man here
(I skimmed your profile and I’m 90% sure you’re male)
- Comment on Banana 2 days ago:
After all the chemical treatment? Sorry, no.
- Comment on Banana 2 days ago:
It’s weight-based.
- Comment on Manic Stew 5 days ago:
- Comment on Fucking math... 5 days ago:
Asian Superman knows this
- Comment on Time is of the essence! 5 days ago:
American money and continental-European decimal comma. Might be fake but I upvoted just in case.
- Comment on Nintendon't 1 week ago:
This one is for media, as an HDMI alternative. It goes up to 8K (192 Gb/s) and 480 W of power delivery. I hope there is no DRM on those.
- Comment on Internet email for dummies 1 week ago:
Not anymore
- Comment on Internet email for dummies 1 week ago:
WinRAR’s password and archive-splitting feature, I assume. 7-Zip was around since 1999 but not as popular.
- Comment on Leak From the Sky: It Turns Out a Lot of Satellite Data Is Unencrypted 1 week ago:
Wikipedia only mentions analog/digital terrestrial, IPTV and cable as of 2020.
- Comment on Leak From the Sky: It Turns Out a Lot of Satellite Data Is Unencrypted 1 week ago:
Does DPRK really have a TV satellite or is that guy just capturing analog (yes, analog) PAL or DVB-T2 terrestrial signals that make it to South Korea?
- Comment on Oppa oppa 1 week ago:
The statue is, unsurprisingly, in Gangnam. Personal judgement of the song aside, it made the district world-famous. That’s enough reason to erect a monument.
- Comment on What time is it? 2 weeks ago:
NFC implants are expensive but wristbands are not. Maybe that could work… I wonder if they make some that don’t look like mini watches, maybe a strap with a fashionably integrated chip and antenna?
- Comment on What time is it? 2 weeks ago:
Lemmy automatically adds trailing slashes to links, apparently. However, you can cheat that by creating a hyperlink whose display text is “time.<zwsp>gov” where “<zwsp>” is a zero-width space.
- Comment on What time is it? 2 weeks ago:
You don’t have to print on temporary tattoo paper. Use regular paper and scissors to create a wristband. That is enough to test if the geometry is good enough for the scanner.
- Comment on What time is it? 2 weeks ago:
Yeah, at 1 mm per pixel, this will not last long.
How about an NFC implant? They can point to URLs too…
- Comment on What time is it? 2 weeks ago:
Nah, it’s 30%, and very much depends on how the damage is laid out.
- The corner squares (finder patterns) must keep a ⬜⬛⬜⬛⬛⬛⬜⬛⬜ cross-section at most angles. Most readers will accept even round ones. This applies to the smaller squares (alignment patterns) on larger QR codes too.
- The zebra strips ⬛⬜⬛⬜⬛ (“timing patterns” if you’re a nerd) connecting the finder patterns must remain intact. Very few readers can correct for errors in that.
- At this point, a good reader will be able to detect the QR code’s position in the image and its resolution (“version” if you consume ISO propaganda), and thus calculate the location of every pixel (“element”, ditto). Each of those will usually be sampled at a radius of around ⅓ of the distance between them. This allows for slightly wavy codes but also codes with rounded pixels or even unrelated content in the edges. (For the record, this is lazy and I prefer this version of the concept that uses almost up-to-spec QR codes.) Google Lens is more sophisticated than just using a 3D perspective transform, as I already mentioned.
- One line of pixels around finder patterns is necessary for decoding (mask and ECC level info) and has basically no error correction so it should be also clear except the ⅓²=⅑ trick described above.
- The data is stored with robust Reed-Solomon correction, which is byte-wise. You can safely cover about half of the advertised recoverable area with contiguous damage anywhere except the sections mentioned above. Still, you can damage more area by taking several things into account:
- Know how the data is laid out in the specific QR resolution, and keep in mind that Reed-Solomon is bytewise. Thus, you want to damage as few bytes as possible, and for most total area, the strategy is to ruin all 8 bits in each. Without deeper analysis (looking up the byte layout), a good rule of thumb is that vertical damage aligned to an even number of columns from the right (skipping Column 7 with the vertical zebra stripe and thus no data) is likely to ruin the least amount of bytes partially.
- Looking up the byte layout will also reveal that there are probably 1-7 unused pixels in the leftmost two columns, probably arranged like ⡿ in the very top of the data portion (Row 10 and below). These can be damaged without consequence!
- Damage whose very dark spots line up with original black pixels (and vice versa) does not really count. Keep in mind that while using this strict definition of damage results in way fewer damaged bits, those are most likely not contiguous, so only a few 8-bit bytes will remain intact through this.
- Know how the data is laid out in the specific QR resolution, and keep in mind that Reed-Solomon is bytewise. Thus, you want to damage as few bytes as possible, and for most total area, the strategy is to ruin all 8 bits in each. Without deeper analysis (looking up the byte layout), a good rule of thumb is that vertical damage aligned to an even number of columns from the right (skipping Column 7 with the vertical zebra stripe and thus no data) is likely to ruin the least amount of bytes partially.
- Comment on I will be taking no followup questions. Thank you for your time 2 weeks ago:
"We have ἤλεκτρον (elektron), can you show us?
- Comment on What time is it? 2 weeks ago:
Print one out at 1:1 scale and wrap it around your wrist, then test it. Curved surfaces are challenging for QR code readers. AFAIK Google Lens is one of the best ones (it will follow edges of pixels in wavy codes) but you’ll want any old open source one to work.
- Comment on What time is it? 2 weeks ago:
Yes it’s already scannable…
Why wouldn’t it be? I’ve drawn 2 QR codes on graph paper already and of course they work.
- Comment on It would have been really funny if a video game ejected the disk if you lost too many times 2 weeks ago:
Well I knew about that, but how does it mess with people any better than the default audio sink?
- Comment on It would have been really funny if a video game ejected the disk if you lost too many times 2 weeks ago:
What do you mean?
- Comment on Can someone fact check this 2 weeks ago:
PLEASE DON’T starve the owl! There is another way: metabolism rate is proportional to the number of O₂ + hydrocarbons → CO₂ + H₂O reactions in the body, which can be measured as the amount of CO₂ created during respiration. For humans, the CO₂ concentration in exhaled air is close to constant, so by inhaling through the nose and exhaling through the mouth into a bag (and not consciously hyper- or hypoventilating), one can get a very good measurement of one’s metabolism rate in different scenarios (and the lag is seconds, not hours for nutrition!). This is obviously way more difficult to do with a flying owl (even in a wind tunnel) but perhaps a surgically inserted airflow meter could work.
- Comment on Fell off the horizon into a black hole 3 weeks ago:
Haha, and insert chest joke
- Comment on These mugs are getting out of hand 3 weeks ago:
Wordpress makes kitchen sink taps now?
