Measuring distance
Use the Distance Tool to measure the distance between two or more points in an image.
To measure distance:
1 Click the Distance Tool.
2 Press and hold the left mouse button on the starting point.
Note: To insert a vertex (corner), press and release the V key. To drag a freeform line, hold down the ALT key and drag the mouse pointer along the path you want to measure. (You will be able to drag the mouse in any direction.)
3 Drag to an ending point and release the mouse button. A line appears on the image as you drag.
The measurement appears on the Status Bar.