identify cursor location within a userform and translate into scaled coordinates

Hello, all,

I have a picture inserted into a userform and I would like to save the location on that picture where a user clicks relative to an initial click. So, for example, a user would click on a red dot on a certain image, then would click somewhere else on that same image. What would be saved is the relative x and y coordinates between those two clicks.

Maybe this is already impossible, but to take it further, I would love to have the user also able to click on two sides of a scale, and use the relative difference in x to help translate those x and y coordinates from the picture into a scaled size. So, for instance, if |--------| appeared on the image and represented 1", despite the screen resolution, by clicking on the left and right of the scale we would know how to translate pixel coordinates into inches.

Attached is a picture with an explanation.

Is this at all possible? Does any one have the time to flush this out, or help get me started (I can make userforms, but this feels well beyond my ability)?


Location explanation.png

Thanks! This looks like a great starting point! I'll report back when I've figured everything out