2D Slicers

Up to Core Widgets.

In a standard setup, there are three slicer widgets shown, each shows an axis-aligned cut through the loaded dataset, along a specified and changeable slice number. On the bottom you will see a scale of the distances (in the units specified in the image). On the right side there is a bar visualizing the intensity range of the image and the associated color values (as specified via the transfer function that is adaptable through the Histogram).

Several interactions are possible directly in the view:

Mouse commands

• Ctrl + Shift + Mousewheel changes the current slice up or down. Alternatively, you can use the scrollbar on the right or the spin box on the upper left to change the slice currently shown.
• Mousewheel zooms in and out of the dataset (centered on the current mouse position)
• Middle Button Drag or Shift + Left Button Drag pans the view around (i.e., moves the view on the dataset)

Several more commands are available if the magic lens is enabled.

Key commands

When the slicer is highlighted (click on it once to highlight it), these key commands are available:

• 'r' resets the view
• 'm' enables a measurement mode. The position under the mouse cursor when pressing 'm' is considered as the starting point. Any further mouse movement causes a line and a circle to be drawn to the current mouse curser, and the tooltip displays the distance from the starting point to the current location. Pressing the Escape key terminates the measurement mode.
• 'o' enables the fisheye lens. While this is enabled, the region around the mouse cursor will be enlarged, while the rest of the image will be shrinked. You can use the keys '+' and '-' to increase/decrease the fisheye lens size, and the key combination Ctrl+'+'/Ctrl+'-' to increase/decrease the magnification effect.

On the top right, a button bar is available:

The first button stores a movie of scrolling through the whole range of slices in this widget. The second button stores a screenshot of this widget, the third saves an image stack of all slicers. The rightmost button enlarges the slicer widget to take up all the space in the current window.

Settings

Via Edit-> Default Settings -> View: Slicer"" you can change the default settings for any slicer window opened in the future. You have access to a specific slicer's settings by right click inside the slicer, and clicking "Settings". These are the available settings:

• Mouse Cursor (default: "Crosshair default") - selects the color and style (thin/thick) of the mouse cursor when it's over one of the slicer views.
• Linear Interpolation (default: true) - whether rendering should use linear interploation (less block artefacts, but picture can look blurry). Also available directly via right-click menu in slicer
• Adjust Window/Level via Mouse Click+Drag - whether window and level should be adjustable by clicking and dragging the mouse left/right / up/down. See also Click+Drag options in the context menu below.
• Show Position (default: true) - whether the position in other slicers should be indicated with a green rectangle.
• Show Axes Caption (default: false) - show a textual caption for the slice axes (X / Y / Z)
• Tooltip Font Size (pt) (default: 12pt) - the font size of the tooltip in the slicer (in point unit)
• Show Tooltip - whether a tooltip should be shown in the slicers at mouse position (with the current position + data value(s) at that position)
• Magic Lens Size (default: 120) - the size of the 2D magic lens
• Magic Lens Frame Width (default: 3) - the width of the border of the 2D magic lens
• Background Color (YZ|XZ|XY) Slicer (default: empty) - enables setting custom background colors for each slicer window. If left empty, the default background colors (YZ: rgb(0.2, 0.2, 0.2), XY: rgb(0.3, 0.3, 0.3), XZ: rgb(0.6, 0.6, 0.6) will be used.

• Show Isolines (default: false) - whether a number of isolines should be generated and shown (see also Number of Isolines, Min Isovalue, Max Isovalue)
• Number of Isolines (default: 5) - how many iso lines should be shown if that feature is turned on (see Show Isolines).
• Min Isovalue (default: 20000) - minimum iso value for isolines feature (see Show Isolines)
• Max Isovalue (default: 40000) - maximum iso value for isolines feature (see Show Isolines)

Context Menu

The context menu provides quick access to some settings:

With the first two options, you can quickly enable/disable linear interpolation and tooltips (only for the current slicer widget, this individual setting will be changed back to the window's overall settings if you change the slicer settings as explained above).

The next three entries enable configuring treatment of Mouse Click+Drag operations:

• By default, this interaction is disabled (Click+Drag: disabled).
• "Click+Drag: Set Transfer Function for Region" allows to quickly adapt the transfer function for maximum contrast in a selected region.
• With "Click+Drag: Adjust Window/Level", you enable the same mode as with the "Adjust Window/Level via Mouse Click+Drag" setting in the slicer settings above.

The final two options enable the Fisheye Lens (also enabled via 'o' key, see Key Commands above) and the Magic Lens.