Scale a photo by an element in the photo with a known measurement

[Brad S]

Is there a way to resize an entire photo by scaling an element in the photo of which the dimension is known (i.e. you have an image of a floor plan and you know the width of a door opening is 3 foot: How to use that to resize whole image)..?

[GarryP]

As far as I know there isn’t any automatic functionality to do this in the Affinity suite.
You can probably do this manually – draw a line across the door, calculate the ratio between the length of the line and the actual door, and then resize the image as appropriate – but it’s unlikely to give an accurate result.
You may also find that the resultant photo could be very large and pixelated depending on the difference between the original size and actual size.
(If there is any perspective involved – if the image isn’t directly ‘top-down’ – then this could get a lot more tricky.)

[Wosven]

I'm not sure that I understand what you want to do. Size are relative.

If for example, you've got a perspective drawing or another image with known dimensions, you can search or calculate a 3 foot size area, and resize your other entire photo to get the 3 foots element to the same size.

If you've just got a photo and know some part is 3 foots, you can just add a ruler like on map, or most usually add people to give a feeling of the real size by comparison.

[telemax]

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