I looked up the word ruler in the suggestion list and found three hits with multiple replies, but it looks like the entire subject seems to be closed as of three years ago, so I couldn't bump it to show support for this feature. I would only add that the rule shouldn't be placed in the borders of the canvas as it is in Google Chrome's Inspection tool. Instead, I should be able to place the ruler or rulers anywhere I want so that I can measure a graphic item's edge. tallest point, etc, or the distance between two items, even if the items are at a slant. The lengths of the ruler should be adjustable, too. The ruler/rulers should work with the zoom. And the ruler's color should be adjustable, to include semi-transparent, so that it can be seen against the graphics, whatever color(s) is/are in the image under the ruler(s).