
Is there a reason Hillary Clinton's logo has hidden notches? - Torgo
https://graphicdesign.stackexchange.com/questions/73601/is-there-a-reason-hillary-clintons-logo-has-hidden-notches
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criddell
They don't want the bottom color peeking out, so the notches ensure there are
no coincident edges.

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eumoria
what's a scenario that this would happen?

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spb
Any scenario where the SVG's shapes are rendered with anti-aliasing, and the
edges of both overlapping shapes are mid-pixel: the edge of the top shape
would be rendered with partial alpha, and then beneath that, the edge of the
differently-colored lower shape would bleed through as it is _also_ rendered,
at that contiguous line, with partial alpha.

EDIT: You can actually see this very effect in action if you zoom in on the
diagonal edges of the yellow and blue faces of the logo on the BBC's page for
the EU referendum happening right now:
[http://www.bbc.com/news/politics/eu_referendum/results](http://www.bbc.com/news/politics/eu_referendum/results)
\- on these anti-aliased diagonal edges (enlarged:
[http://i.imgur.com/GmxUD60.png](http://i.imgur.com/GmxUD60.png)), since
there's no indentation like the one this SE question highlights, the red shape
underneath both of the shapes bleeds through.

Compare the outlines of the shapes with the red shape conterminous beneath
them ([http://i.imgur.com/Nwyl8YE.png](http://i.imgur.com/Nwyl8YE.png)) to the
outlines they have when that shape is removed
([http://i.imgur.com/iOQmyJx.png](http://i.imgur.com/iOQmyJx.png)).

~~~
teraflop
You can see similar problems even without anti-aliasing. If you have three
collinear points A B C, drawing a line from A to B and then B to C may hit
slightly different pixels compared to just drawing a single line from A to C.
If you try to draw a polygonal mesh which has T-junctions (overlapping edges
whose endpoints are not identical) you can end up with slight gaps between
adjacent polygons.

In 3 dimensions, a similar phenomenon causes "Z-fighting".
[https://en.wikipedia.org/wiki/Z-fighting](https://en.wikipedia.org/wiki/Z-fighting)

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iconjack
I am @iconjack, poser of the question, ask me anything! Kidding aside, as an
avid user of the whole stackexchange suite, it is kind of interesting to me
how popular this question became. It was only my second question on graphics
design and it's become the all-time 3rd ranked question. Keep it going, folks!

If you're curious, the reason I was looking at the logo svg was that I
thinking about making a bumper sticker. When I saw the notches, I was
perplexed, and threw the question up on a whim.

You noticed I put the disclaimer at the top about the question not being about
politics. I honestly thought there was a chance things would get ugly because
of the __loose __tie-in to the whole election grotesquery. One time I asked a
question on english.stackexchange.com, Is "Sent from my iPhone" correctly
punctuated and capitalized?" and I practically got hate mail. Not only did I
get snarky comments and answers, I believe the question was down to −8 at one
point. It's since been upvoted into positive territory and some of the nasty
remarks have been deleted, but I never really got what all the hate was about.
One friend suggested that Apple fans would think I was dissing the iPhone or
something. That's the only theory I've got.

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dllthomas
Avoiding graphic artifacts makes sense, but I'm going to bet on conspiracy,
probably involving the Masons.

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comex
I'm getting an infinite redirect from this link.

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evanpw
Me too, but this link works:
[https://graphicdesign.stackexchange.com/questions/73601/is-t...](https://graphicdesign.stackexchange.com/questions/73601/is-
there-a-reason-hillary-clintons-logo-has-hidden-notches/73665)

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rjbwork
Weird, this link is giving me infinite redirects. I went and found it on the
stackexchange site myself under hot for graphicdesign and it did the same
thing. The other answers on that subdomain work just fine. Strange.

~~~
JeremyBanks
Do you use HTTPS Everywhere? (I don't know why that would apply in this case,
but I recall various people having similar issues with it and Stack Exchange's
partial HTTPS support.)

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smegel
"It's not a bug, it's just how the algorithm works!"

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wongarsu
Not a bug, just a bad algorithm.

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panic
Are there any solutions to this that don't involve rendering into a higher-
resolution buffer and downsampling (or the MSAA moral equivalent)?

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jcl
I guess it depends on your definition of "solution" and "MSAA moral
equivalent". What you're essentially asking is, "Is there a way to approximate
the combined contributions of overlapping polygons to a set of pixels without
sampling the exact color at multiple points per pixel?"

One approach would be to avoid sampling at all, by using boolean geometric
operations to find the exact shapes of visible polygons within a pixel, then
using their color and areas to calculate their combined contributions. I
expect the calculation involved will be impractical relative to multisampling,
though.

Another approach would be sample exactly once per pixel or, equivalently,
render the polygons without antialiasing. Naturally, that would eliminate the
show-through of hidden geometry at the expense of the accuracy of pixels
around polygon edges. You might then be able to approximate the antialiased
values by a post-processing filter, maybe guided by the presence of edges,
although doing so will introduce its own set of artifacts.

And if you consider "one sample per pixel" to be a budget over the entire
image, you could sample the polygons more densely near polygon edges and more
sparsely elsewhere, using nearby samples to approximate the values of pixels
with no samples.

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gnu8
Countdown until this guy is arrested for violating the Computer Fraud and
Abuse Act of 1986 for deconstructing that SVG image.

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tlrobinson
I was hoping for something a little more sinister.

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sevenless
It's hiding its crooked nature just like Hillary, WAKE UP SHEEPLE

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wesleytodd
hahaha, this comments wins for use of the word "sheeple"

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capote
Mmm, this answer is much better than mine because it uses the word _alpha_.

~~~
dang
We detached this subthread from
[https://news.ycombinator.com/item?id=11965054](https://news.ycombinator.com/item?id=11965054)
and marked it off-topic.

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duncan_bayne
It's a dent made by Kennedy's car.

~~~
wcummings
I can tell there aren't many New Englanders on HN from how buried this comment
is...

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DevX101
Seems crooked, Trump was right all along!

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MichaelApproved
I'm seeing a ton of (rightfully) down voted comments here with no clear reason
from the down voters. Anyone who gets a down vote for their joke might just
think it's because the joke is bad, instead if the more accurate reason that
HN comments are more serious.

One of the nicer things I've seen on Reddit was when a mod leaves a reason for
removing a comment. It serves to inform the commenter and also remind the
community of the rules.

In a thread such as this one with potential for interesting discussion, it'd
be a shame if the mods ended up killing it because the comments got out of
hand.

A top stickied comment reminding people of the rules and replying to people
who had their comments down voted into oblivion with a reminder might go a
long way to having a civil discussion about something like this.

