Below is basic information about how to use the three-, two-, and one-button mouse (or trackpad) on Windows, Mac, and Linux platforms to perform basic interaction operations in Slicer:

Adjusting Window & Level on All Platforms: Left-clicking and dragging the mouse in any Slice viewer is a quick way to adjust Window and Level. Adjust the middle value (level) of the greyscale window by moving the mouse up (increase level) or down (decrease level), and adjust the greyscale window size by moving the mouse to the left (decrease window size) or right (increase window size). Slicer's Volumes Module provides a "Display" interface for more precise adjustments.

Selecting & Manipulating on All Platforms: Mousing over any "pickable" object in any of Slicer's viewers will cause the cursor to change from a "pointer" into a "picking hand". When the cursor shows a picking hand, left-clicking and dragging the mouse will pick and manipulate the object. Releasing the mouse button will de-select the object.

Viewer Cross reference on All Platforms: Holding down the Shift-Key while moving the mouse in any Slice Viewer will cause other Slice Viewers to interactively scroll to the same RAS position indexed by the mouse. This feature is useful when inspecting

Zoom In & Out in Slice & 3D Viewers: Windows with 3-Button Mouse: Right-Click & drag down & up. Windows with 2-Button Mouse: Right-Click & drag down & up Windows with 1-Button Mouse: Ctrl+Left-Click & drag down & up Mac with 3-Button Mouse: Right-Click & drag down & up Mac with 2-Button Mouse: Right-Click & drag down & up Mac with 1-Button Mouse: Ctrl+Left-Click & drag down & up (or two-finger click & drag in the trackpad) Linux with 3-Button Mouse: Right-Click & drag down & up. Linux with 2-Button Mouse: Right-Click & drag down & up Linux with 1-Button Mouse: Ctrl+Left-Click & drag down & up
Pan (Translate) in Slice & 3D Viewers: Windows with 3-Button Mouse: Middle-Click & drag Windows with 2-Button Mouse: Shift+Left-Click & drag Windows with 1-Button Mouse: Shift+Left-Click & drag Mac with 3-Button Mouse: Middle-Click & drag Mac with 2-Button Mouse: Shift+Left-Click & drag Mac with 1-Button Mouse: Shift+Left-Click & drag Linux with 3-Button Mouse: Middle-Click & drag Linux with 2-Button Mouse: Shift+Left-Click & drag Linux with 1-Button Mouse: Shift+Left-Click & drag
Rotate in 3D Viewers: Windows with 3-Button Mouse: Left-click & drag Windows with 2-Button Mouse: Left-click & drag Windows with 1-Button Mouse: Left-click & drag Mac with 3-Button Mouse: Left-click & drag Mac with 2-Button Mouse: Left-click & drag Mac with 1-Button Mouse: Left-click & drag Linux with 3-Button Mouse: Left-click & drag Linux with 2-Button Mouse: Left-click & drag Linux with 1-Button Mouse: Left-click & drag

Mouse Modes: Slicer has two mouse modes: Transform (which allows interactive rotate, translate and zoom operations), and Place (which permits objects to be interactively placed). The toolbar icons that switch between these mouse modes are shown from left to right above, respectively. "Place Fiducial" is the default place option as shown above; options to place both Ruler and Region Of Interest (ROI) Widgets are available in the Place Mode menu as well.

Hint: Transform mode is the default interaction mode. By default, Place mode persists for one "place" operation after the Place Mode icon is selected, and then the mode switches modes back to Transform. Place mode can be made persistent (useful for creating multiple fiducial points, rulers, etc.) by checking the Persistent checkbox.