This add-on helps to measure a length in an image.

The add-on tries to read the pixel size from the image meta data. If it is not found in the meta data, the user can configure it in the options.

The add-on automatically adds the marker type "ruler" which displays the length of the line next to it. It also adds a scale bar at the bottom right corner of the image, which is also exported when the picture is exported by the video exporter.