Can Preview keep the area of a rectangle constant when adjusting the size? Say that you draw a rectangle that is 6 x 4 (width x length) (unit doesn't matter) = the area is 24. I want Preview to, if I adjust the width to 8, the length should shrink to 3 and if I make it 10 wide, the length should be 2.4 and so on. Holding down the shift key you can make Preview scale the sides proportionally (increase 6 to 9, 4 is increased to 6) but I want to keep the area fixed while changing the length of the sides.
If Preview can't do this, can you recommend some other tool?
The use case is measuring areas on blueprints. That is, I have imported old bitmapped blueprints and wants to see if I can fit a rectangle that is 12 m² in a certain spot of the blueprint by adjusting the proportions of its sides.