I'm a programmer working in Java and I'm not sure if this is the right place to ask this kind of question, here it goes:
In my program, I need to show an image (.jpeg .png etc.) based on the screen size, this image is used to compare to real size (physical) of an actual label which is later printed on a specific machine.
The issue is, for example on my machine I have the laptop screen and a '27 monitor they are both using the same resolution 1920x1080 but as you imagine if you resize any window/program/image it looks smaller on the laptop as the physical screen size is different although it has the same resolution (I imagine is because the physical size of the pixel is smaller than the ones on my monitor)
Now what I would need to do is somehow always show the image on it's corect physical size (as it were printed), on any type of screen.
Regarding to programming I could easily get the screens size and resize the image but, this is because the OS gives the size (it's set up size) back to the program, yet even if I have the correct size the physical screen could display the image smaller for example, as the screen's pixels are smaller.
Any ideas where to start with this? How can I know the real physical screen size? This seems to be more a hardware issue than graphics..