The zoom tool can be associated with one of three mouse buttons or with the mouse scroll (top left toolbar). In the image below the zoom tool is associated with the left mouse button.
The zoom factor can be modified from different locations:
The zoom function always zooms in/out to the center of the screen regardless of where the cursor is.
For selecting directly the zoom action of the mouse left button, enter “z” as a shortcut.
The real-world zoom allows displaying the content of the image at the same size of the real objects.
The feature requires calibrating the screen where the image is displayed. From the main menu, open File > Preferences (Alt + P) > Monitors and click on “Spatial calibration”. Then enter a value that matches to the line length or the diagonal length of the screen.
Several screens can be calibrated. Each one has its own spatial calibration factor.
The magnifying lens can be activated from the toggle button of the zoom toolbar (see the image below). It has several parameters accessible from the context menu.
This lens can be used in many situations, for instance:
Freeze parameters- see image below)
Using the mouse wheel on the lens changes the zoom factor. Double-clicking on the lens adjusts the zoom factor of the lens to the one of the main image.
Parameters of the context menu:
Freeze parametersallows to keep the current image processing (c.f. Window/level, LUT or filter) and
Freeze imageallows to keep the current image and its parameters.