easy measurement tool

This tool is used to improve the accuracy of measurements for our customizable keyguard device. In particular it is used to measure the size of the opening in the tablet case but it can also be used to measure the sizes and locations of screen elements without requiring that the tablet be taken out of its case. It's very hard to replicate these measurements with a ruler because most cases are smaller than the ruler which then has to be propped up on one side of the case and the extent of the o