How can I transform XY coordinates and height/width on a scaled image to an original sized image?

Question

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I am trying to do the same thing as in the linked question, but with C#. I am showing a scaled image and am allowing a user to select an area to cro

Answer 1

You can get the percent locations for the scaled images and turn them back into coords for the unscaled image:

pX1 = scaledX1/scaled_width
pY1 = scaledY1/scaled_height

unscaledX1 = ceiling(unscaled_width * pX1)
unscaledY1 = ceiling(unscaled_height * pY1)