Attach horizontal line (ruler) to cursor

I am currently reading a lot of texts on my computer, some which have wide rows, and shifting focus to write summaries. When I read on paper i sometimes use a ruler to keep track of my location, I find this helps when I get tired. Therefore, I would like something similar on linux. Is there any way to code some transparent ruler that follows the mouse pointer? Most of the ruler applications like "kruler" are not attached to the mouse. I also tried the cross-hairs in the accessibility but it's not quite what I want as i find the vertical lines distracting. And want something where I can set the opacity. Does anyone have any suggestions on where to start with this problem? Best, Michael