Hey connormurry-
I’m investigating your issue and want to make sure I understand correctly. You have a slider value (lets say 89.7453) and take the floor (89). Then that gets multiplied by 1920 and 1080 but the results are inaccurate? Please let me know if my understanding of the problem is wrong.
For taking a screenshot, if you hold Alt and press the Print Screen button on your keyboard it will take a picture of just the window that currently has focus. You can then open a program like MS Paint or Photoshop to past the image and save.