ImageScale

1. Upload an image. 2. Click Calibrate, drag the amber line onto a known distance (or use Detect scale bar and click on an existing bar), enter its length → the scale is set and the calibration line disappears.

3. Turn on Ruler, Coord. system, circles or polygon as needed — everything is hidden by default to keep the canvas clean.

Drag a circle or polygon by its center handle to reposition it after measuring; value labels can be dragged too. Set line color and width under Display.