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I have a half of a card and want to animate that card half reflection about purple line. The problem is that I can't position image so that the image's (card half) 3rd corner is fixed and that's why that corner is moving while changing the value of the slider as well as the 4th corner...
4th image's corner is defined as: C''=Enlarge(C', a, C) where var a is a slider (0 to 1), C' = Reflect(C, f), f is a mirror line (purple line).
Any suggestions would be much appreciated. Thanks.
Files:
osmica-osna-3.ggb
The same question 
This is what I've created so far... I'm creating reflection gifs for my students...
Sample
How's this? Uses the Stretch() command on the image itself which might be easier.
Might also be useful: https://stage.geogebra.org/...
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