I'm looking for a way to display something at its actual size on a browser. For instance, if something appears to be 20cm on the screen, I want it to truly measure up to 20cm.
Some methods involve considering the diagonal resolution of the screen, like 21.5 inches, and the screen resolution to determine the actual size of a pixel.
Another approach suggests having the user hold a standard-sized card, such as a bank card, up to the screen and measuring the edges to determine size.
Is there a way to achieve this without a physical object on the screen or without the user needing to know their diagonal screen size?
If you have any alternative solutions to offer, please share them as well.