Using the Ruler Tool
You can use the Ruler tool to measure the distance between any two points on an image.
Measurements are shown with the annotation, while settings for customizing the annotation are available in the lower section of the Data Properties and Settings panel (see Ruler Properties). Additional options available for the Ruler tool include profiling the intensity values along its length (see Profiling Intensity) and plotting the intensity distribution on any dataset available in the Data Properties and Settings panel (see Plotting Histograms from Annotations).
Rulers can be drawn in any direction or you can constrain measurements vertically or horizontally.
If you need to constrain the ruler, hold down Left Ctrl (or your configured key) to switch to Horizontal Ruler mode or hold down 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.
- Maximize the required view, recommended.
- Click the Ruler
tool in the Annotate panel.
- 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.
-
Do the following to resize a ruler:
- Select the required ruler, either directly in a view or in the top section of the Data Properties and Settings panel.
- Click inside either the start or end control point and then drag.
The current measurement is updated automatically.
- Do the following to move a ruler:
- Select the required ruler, either directly in a view or in the top section of the Data Properties and Settings panel.
Select the line connecting the two end points and then drag to reposition the ruler.
Ruler Properties
You can customize the appearance of rulers and their captions in the Properties box, shown below.
Ruler properties
| Description | |
|---|---|
| Thickness | Indicates the thickness (in screen percentage) of the contour that defines the shape of the annotation, including its control points.
|
| Align text horizontally | Lets you set the horizontal alignment of the caption to the Start, Center, or End of the annotation.
Note Not available if Projected or Floating caption is selected. |
| Align text vertically | Lets you set the vertical alignment of the caption to the Top or Bottom of the annotation.
Note Not available if Floating caption is selected. |
| Line style | Lets you choose a line style for the annotation — Solid or Dashed. |
| Arrow head style | Lets you choose an arrow head style for the annotation — None , Flat, or Barbed. |
| Show ticks | If selected, tick marks will appear at the end points of the annotation. |
| Drop shadow | If selected, a drop shadow will appear below the annotation. |
| Projected | If selected, the annotation will appear 'projected'. A projected ruler includes two dashed lines that extend from the start and end points of the annotation with a solid connecting line with or without arrow heads.
Additional settings for projected rulers include: Alignment drop-down menu… Lets you choose to align the projection to the left/right or top/bottom of the annotation. Position slider… Lets you position the projection closer or further from the annotation, as shown below.
|
| Show background | If selected, a background will be added to the annotation and its caption. Additional settings for background include:
Background color box… Lets you select a background color. Background opacity slider… Lets you set the opacity of the background. Background padding slider… Lets you increase or decrease the size of the background. |
| Show border | If selected, a border will appear around the annotation and its caption.
Border color box… Lets you select a border color. |
| Show captions | If selected, a caption will appear with the annotation. Options include:
Length… If selected, the length of the ruler will be shown as the caption. Custom… If selected, the caption entered in the Caption edit box will be shown. Custom and Length… If selected, the caption entered in the Caption edit box, along with the length of the ruler, will be shown. |
| Floating caption | If selected, the caption will appear in a floating box that can be repositioned manually anywhere within the view to avoid overlapping, as shown below.
|
| Font size and style | Lets you increase or decrease the font size of the caption with the Increase font size and Decease font size buttons, as well as choose a font style. |
| Control point size | Lets you set the size (in screen percentage) of the annotation's control points.
|
| Control point appearance | Let you choose a shape — circle, square, triangle, cross, or "X" — for the annotation's control points. |
| Ruler |
Indicates the length of the selected ruler.
|
Ruler Tools
The following tools are available for plotting and profiling intensity values along the length of rulers.
| Description | ||
|---|---|---|
| Histogram |
|
Lets you plot intensity values along the length of the ruler (see Plotting Histograms from Annotations). |
| Profile |
|
Lets you profile intensity values along the length of the ruler (see Profiling Intensity). |
Configured Actions for Rulers
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.
| Action | Key | Mouse |
|---|---|---|
| Create a ruler in Ruler mode | Left mouse | |
| Edit a ruler in Ruler mode | Left mouse | |
| Create a horizontal constrained ruler | Left Ctrl | Left mouse |
| Edit a horizontal ruler | Left mouse | |
| Create a vertical constrained ruler | Left Shift | Left mouse |
| Edit a vertical ruler | Left mouse | |
| Constrain a ruler to be horizontal | Left Ctrl | |
| Constrain a ruler to be vertical | Left Shift | |
| Switch to Ruler mode | R |
