this post was submitted on 24 Aug 2024
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2d trulesformations (lemmy.blahaj.zone)
submitted 2 months ago* (last edited 2 months ago) by nicknonya@lemmy.blahaj.zone to c/196@lemmy.blahaj.zone
 
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[–] Ashelyn@lemmy.blahaj.zone 101 points 2 months ago (8 children)

The scaled down rectangle should be narrower; it's not scaled in this diagram, it's squished.

(Yes I know you can 'scale' objects on one axis but that's usually not how it's taught on an introductory level. Standard scaling assumes object similarity, which is not present in the diagram's 'scaled' rectangle.)

[–] woodgen@lemm.ee 10 points 2 months ago* (last edited 2 months ago) (2 children)

Scaling in 2D has 2 parameters, X and Y, in the example X was at 1 while Y was below 1. You are referring to a subset of scaling transformation where X = Y and the aspect ratio is kept.

[–] Ashelyn@lemmy.blahaj.zone 12 points 2 months ago

Yes, and introductory geometry courses teach students how to do uniform scaling far before they teach them axis-based because it's better illustrative of the concepts of similarity and congruence

[–] shundi82@sh.itjust.works 4 points 2 months ago* (last edited 2 months ago)

And what about the arrow?

It's pointing down diagonally, which - at least to me (and for pretty much any GUI I can think of) - indicates, that it should be affecting both axes.

Then again, that whole illustration isn't all that great to begin with. So who knows, what that arrow is supposed to signify...

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