A label is a type of a node that is stored in the document and depicts some text in the Viewport. A label can contain a node's name, a text describing a group of nodes, or some measurement.
In this section, you will learn how to add labels and modify them (change their visibility, font, color, and positions).
Note: If you save your document in one of the SAMSON file formats (.sam or .samx), labels will be saved as well.
Prerequisites:
- Please refer to the Selecting section to learn how to select nodes in SAMSON.
- Please refer to the Inspecting section to learn how to inspect nodes in SAMSON.
Adding labels
You can add labels to selected nodes via their context toolbar.
Note: Labels cannot be added to all types of nodes but mainly to structural nodes (molecules, residues, atoms, etc).
Adding labels to selection
To add labels to selected nodes, in the context toolbar, choose 
:
- "Add label" - this will add a single label for the currently selected group of nodes (this does not add labels to descendants of the selected nodes but only to the directly selected group of node).
- "Add label to..." - you can choose to what type of nodes to add labels, including descendants of the currently selected nodes, for example to all the residues in the current selection.
Adding labels in Viewport
To add labels in the Viewport, first, you need to activate the Label editor (
) in the left-side menu of the viewport or via shortcut Ctrl / Cmd⌘ + L .
Please note, that the type of node to which a label will be added depends on the current Selection filter. For example, if it is set to "Atoms and bonds" then labels will be added to atoms or bonds, if it is set to "Residues" then labels will be added to residues.
Visibility of labels
You can switch on/off the visibility of labels in the Document view by ticking/unticking them.
The visibility of labels changes progressively when zooming in and out on the system. When zooming out, the labels for smaller nodes (e.g., atoms) will start to disappear and the labels for larger nodes (e.g., molecules) will start to appear, and vice versa when zooming in.
You can modify when labels appear and disappear. For that, select a label and, in the Inspector, change maximum and minimum display radii - these parameters govern when the label is visible.
Changing font of labels
You can modify the font for all the labels or just for a group of labels.
To modify the font for all the labels for which the font has not been specified directly, open the Preferences > Rendering > Labels and change it there. You can also modify there the number of decimal places for angles and distances shown in labels which is useful for labels created using the Measure editor.
To modify the font for a label or a group of labels, select them and open the Inspector. In the Inspector, click on "Choose font..." to modify the font for the last selected label or for all selected labels at once if you choose to Edit all selected nodes.
To reset the font for labels to the one specified in Preferences, select these labels and, in the Inspector, double-click on the "Font" as shown in the image below.
Colorizing labels
Labels can be colorized as many other nodes.
You can change the color of a label as follows:
- click on a label in the Document view, then, in the context toolbar, go to
Material > Constant and choose a color from the pop-up dialog. - select a label and in the Visualization menu > Material () click on Constant.
- select a label and in the Inspector click on Material > Constant:
You can reset the label's color to the default one in the same way.
- click on a label in the Document view, then, in the context toolbar, go to Material > None and choose a color from the pop-up dialog.
- select a label and in the Visualization menu > Material () click on None.
- select a label and in the Inspector click on X (
) button next to the Text color:
You can also modify the transparency of labels in the Inspector.
Selecting labels in Viewport
Apart from selecting labels in the document, you can select them in the Viewport as well.
The level of selection in the Viewport is governed by the Selection filter, so first you need to set it to "Labels" and only then you can select labels in the Viewport.
Note: Only the visible labels will be chosen.
Do not forget to switch the Selection filter if you want to select other types of nodes in the Viewport later.
Moving labels
Prerequisites: Please refer to the Moving objects section to learn how to move objects in the viewport.
When labels are created they are placed at the geometric center of the nodes and they are always situated in the Viewport plane.
You can move labels using one of the following ways.
- Set the Selection filter to "Labels" and use one of the Move editors, e.g. the Move displace editor (
, shortcut: D ). Do not forget to switch the Selection filter if you want to select other types of nodes in the Viewport later.
- Select a label in the Document view and use one of the Move editors.
