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Show HN: The text disappears when you screenshot it

unscreenshottable.vercel.app

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Re: Show HN: The text disappears when you screenshot it

#161

Ultimately people will just take photos of the screen. Seems like you’re just annoying people. I feel like there’s an ethical issue. If something is on my screen I own it. I know the law doesn’t agree but it feels right to me.

The point is that it's noise and you can't "capture" a still image of the text / information (relies on motion to be viewable).

We figured out how to capture video though. And ChatGPT can already decipher this.

Re: Show HN: The text disappears when you screenshot it

#163

Earlier quoted context omitted.

> You can take TWO screenshots, moments apart, open in GIMP, paste one over the other and choose any one of these laying modes: You actually don't need any image editing skill. Here is a browser-only solution: 1. Take two screenshots. 2. Open these screenshots in two separate tabs on your browser. 3. Switch between tabs very, very quickly (use CTRL-Tab) Source: tested on Firefox

reminds me of this: https://www.reddit.com/r/LifeProTips/comments/5jdzsx/lpt_use...

This was used in some early-20th-century astronomical setting, I think to detect supernovae. I can't find any documentation now, but my memory is that it was called "blink testing" or something similar, where one switched rapidly between two images of a star field so that changes due to a supernova would stand out.

Re: Show HN: The text disappears when you screenshot it

#164
post #51

Earlier quoted context omitted.

Because the context is about screenshots and context matters "ffs".

You mean like all of the context I used describing something not a screenshot. Being able to pick up on context clues from the reading is a crucial skill one should have in life. It also makes one look less clueless in conversation when the topics shift quickly and one can keep up.

None of this warrants the type of response they got, nor your attitude.

Re: Show HN: The text disappears when you screenshot it

#166

Has anyone tried a long exposure to see if the motion smears into something discernible? Obviously harder to expose a bright screen without some ND since the shutter speed is the phone's main exposure control

How do you take a “long exposure” screenshot? Isn’t every screenshot a perfect digital copy of a single frame or a full on video?

[deleted]

Re: Show HN: The text disappears when you screenshot it

#167
post #17

This game disappears if you pause it: https://youtube.com/watch?v=Bg3RAI8uyVw

Not really a game, but neat all the same. It reminds me of the mid-1990s video game Magic Carpet . https://en.wikipedia.org/wiki/Magic_Carpet_(video_game) This was a pseudo-3D game and on an ordinary display it used perspective to simulate 3D like most games. If you had 3D goggles it could use them, but I didn't. However, it could do a true 3D display on a 2D monitor using a random-dot stereogram. https://en.wikipedi…

I played the game, but had no idea about that feature.

Also playable in the browser: https://playclassic.games/games/action-dos-games-online/play...

Re: Show HN: The text disappears when you screenshot it

#168

Earlier quoted context omitted.

This one is actually more sophisticated because it doesn't rely on scrolling pixels like the OP. So the object doesn't just disappear in screenshots, but also when the animation stops moving! So you can't actually display text that stands still, like the "hello" in the OP.

I'm not sure I follow. Couldn't you display text that stands still by (re)drawing the outline of the text repeatedly? It would essentially be a two frame animation

I think the algorithm in the video is doing a very specific thing where there's a zero-width pixel-grid-clamped stroke (picture an etch-a-sketch-like seam carving "between" the bounds of pixels on the grid) moving about the grid, altering (with XOR?) anything it advances across.

So, sure, you could try to implement this by having a seam that is made to "reverberate" back and forth "across" the outlining pixels of a static shape on each frame. But that's not exactly the same thing as selecting the outline of the shape itself and having those pixels update each frame. Given the way this algorithm looks to work, pushing the seam "inwards" vs "outwards" across the same set of pixels forming the outline might gather an entirely different subset of pixels, creating a lot of holes or perhaps double-counting pixels.

And if you fix those problems, then you're not really using this algorithm any more; you're just doing the much-more-boring thing of taking a list of pixel positions forming the outline and updating them each frame. :)

Re: Show HN: The text disappears when you screenshot it

#169

You can take TWO screenshots, moments apart, open in GIMP, paste one over the other and choose any one of these laying modes: Lighten, Screen, Addition, Darken, Multiply, Linear burn, Hard Mix, Difference, Exclusion, Subtract, Grain Extract, Grain Merge, or Luminance. https://ibb.co/DDQBJDKR

Neat idea. A friend of mine made a similar animated GIF type captcha a few years ago but based on multiple scrolling horizontal bars that would each reveal their portion of the underlying image including letters, and made a (friendly) bet that it should be pretty hard to solve. Grabbing the entire set of frames and greyscaling them, doing an average over all of them and then applying a few minor fixups like threshold…

That's reminiscent of a (possibly apocryphal?) method I once read about to get "clean" images of normally crowded public places - take multiple photos over time, then median each pixel. Never had the opportunity to try it myself, but I thought it sounded plausible as a way to get rid of transient "noise" from an otherwise static image.

Re: Show HN: The text disappears when you screenshot it

#170
post #163

Earlier quoted context omitted.

reminds me of this: https://www.reddit.com/r/LifeProTips/comments/5jdzsx/lpt_use...

This was used in some early-20th-century astronomical setting, I think to detect supernovae. I can't find any documentation now, but my memory is that it was called "blink testing" or something similar, where one switched rapidly between two images of a star field so that changes due to a supernova would stand out.

https://en.m.wikipedia.org/wiki/Blink_comparator
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