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Is my vision that bad? No, it's just a bug in Apple's Calculator

(martin.wojtczyk.de)
631 points wojtczyk | 8 comments | 31 Aug 24 04:29 UTC | HN request time: 0.001s | source | bottom
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dylan-m ◴[31 Aug 24 05:51 UTC] No.41406819[source]▶
One of my favourite unreported MacOS issues comes from how, at some point, they changed the appearance of the window close button to be a particular shade of red with a tiny little X in the center. And if you happen to be using a particular kind of screen and possibly wearing glasses, that little X kind of wanders around in the button, appearing just slightly off center in a maddening way. Made only more maddening by the glasses component: https://www.robbert.org/2014/10/the-off-center-close-button/.

That post points out it’s probably just subpixel stuff causing the issue, but I think my thick, cheap glasses at the time were adding a layer of chromatic aberration to something that was already visually confusing.

I assume it’s kind of gone away at this point with all the high DPI screens these days. But I remember thinking at the time, if there was a public bug tracker, that issue would be a fun one.

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trilbyglens ◴[31 Aug 24 06:01 UTC] No.41406849[source]▶
This is not a software bug, but rather an optical phenomenon called "chromatic aberration". What's happening is that your glasses are bending light at different angles depending on the wavelength, to the red and blue and green are landing at slightly different places on your retina.

It's a hard problem to solve optically and requires specially shaped lens. It's a common issue in telescopes, with higher end expensive scopes having these specially shaped lenses to reduce this effect.

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1. dustincoates ◴[31 Aug 24 06:26 UTC] No.41406914[source]▶
Is this why, when I'm reading text on a dark background, red will appear on a different plane than white? I was just wondering the reason last night.
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2. leereeves ◴[31 Aug 24 07:24 UTC] No.41407113[source]▶
A different plane?
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3. amiga ◴[31 Aug 24 07:43 UTC] No.41407179[source]▶
The red text seems to be closer than the other text. As if it were floating above the other text.
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4. ◴[31 Aug 24 08:02 UTC] No.41407252{3}[source]▶
5. zimpenfish ◴[31 Aug 24 08:14 UTC] No.41407296[source]▶
Sounds a bit like https://en.wikipedia.org/wiki/Chromostereopsis

> Another interesting reversal effect was observed in 1928 by Verhoeff in which the red bars were perceived as farther away and the blue bars as protruding when the bars are paired on a white background instead of a black background.

6. zerocrates ◴[31 Aug 24 08:16 UTC] No.41407305[source]▶
I have pretty strong high-index lenses, and definitely can get a kind of 3D effect.

The classic terminal blue and green text colors on a black background is the situation where I first noticed it: moving my head makes them shift in different directions giving a parallax or depth effect.

7. krispyfi ◴[31 Aug 24 08:19 UTC] No.41407321[source]▶
https://en.m.wikipedia.org/wiki/Chromostereopsis
8. TeMPOraL ◴[31 Aug 24 09:12 UTC] No.41407503{3}[source]▶
I get that a lot with default terminal colors - on black background, dark blue and dark red look shifted in opposite directions relative to baseline (white/light colors); when both colors are used in close proximity, it gives me a strong and quite distracting 3D effect.

I always thought this is specific to that color combination (red and blue on black) and LCDs, thus is perceivable by anyone, and could be used to create intentional 3D effects; I never considered glasses may be a factor too.