Using the Ruler Tool

You can use the Ruler tool to measure the distance between any two points on an image. Rulers can be drawn in any direction or you can constrain measurements vertically or horizontally. Measurements are shown with the annotation in 2D and 3D views and are also available in the lower section of the Data Properties and Settings panel, as shown below. Additional options available for the Ruler tool include profiling the intensity values along its length (see Profiling Intensity).

Ruler properties and settings

Properties panel

See Annotation Properties and Settings for information about changing the visibility of rulers and their assigned color, as well as other options available for annotations.

The measurements and tools available for rulers are described in the following table.

Ruler measurements and tools
  Description

Thickness

Indicates the thickness (in screen percentage) of the contour that defines the shape of the annotation, including its control points.

  • Enter a new number in the edit box to change the thickness of the contour lines.

Control point size

Indicates the size (in screen percentage) of the annotation's control points.

  • Enter a new number in the edit box to change the size of the control points.

Control point appearance

Let you choose a shape — circle, square, triangle, cross, or "X" — for the annotation's control points.

  • Choose a shape in the drop-down menu to change the representation of the control points.

Ruler

Indicates the length of the selected ruler.

  • Enter a new value in the Ruler edit box to change the length of the annotation. You can also resize rulers by dragging a control point.

Click the Profile tool to profile intensity values along the length of the ruler (see Profiling Intensity).
  1. Maximize the required image, recommended.
  2. Click the Ruler tool in the Annotate panel.

    If you need to constrain the ruler, press Left Ctrl (or your configured key) to switch to Horizontal Ruler mode or Left Shift (or your configured key) to switch to Vertical Ruler mode. See Configured Actions for Rulers for more information about the actions related to the Ruler tool.

  3. Click at the starting point of the measurement, drag, and then release the mouse to create the end point.

    The length of the ruler is indicated at the starting point and in the bottom section of the Data Properties and Settings panel.

If required, you can resize rulers by simply dragging either the start or end control points that define the annotation. See Editing Annotations for more information about control points and how to modify annotations.

  1. Select the required ruler, either directly in the 2D view or in the top section of the Data Properties and Settings panel.

    The ruler control points appear.

  2. Click inside either the start or end control point and then drag.

    The current measurement is updated automatically.

  3. Click inside the selected control point to de-select it.
  1. Select the required ruler, either directly in the 2D view or in the top section of the Data Properties and Settings panel.
  2. Select the line connecting the two end points and then drag to reposition the ruler.

A number of configured actions and keyboard shortcuts are available for creating and editing rulers. The default settings for these actions are listed in the following table.

Default configured actions for rulers
Action State Key Mouse

Create a ruler in Ruler mode

OrsStateRuler

 

Left mouse

Edit a ruler in Ruler mode

OrsStateRulerEdit

 

Left mouse

Create a horizontal constrained ruler

OrsStateRulerHorizontal

Left Ctrl

Left mouse

Edit a horizontal ruler

OrsStateRulerHorizontalEdit

 

Left mouse

Create a vertical constrained ruler

OrsStateRulerVertical

Left Shift

Left mouse

Edit a vertical ruler

OrsStateRulerVerticalEdit

 

Left mouse

Constrain a ruler to be horizontal

OrsStateRuler

Left Ctrl

 

Constrain a ruler to be vertical

OrsStateRuler

Left Shift

 

Switch to Ruler mode

 

R

 
See Configurable Actions for information about modifying default actions.