Configuration JSON File

By loading a JSON file, you can set VolView's configuration:

• View layouts (grid size, view types, or hierarchical layouts)
• Disabled view types
• Labels for tools
• Visibility of Sample Data section
• Keyboard shortcuts

Loading Configuration Files

Use the config URL parameter to load configuration before data files:

https://volview.kitware.com/?config=https://example.com/config.json&urls=https://example.com/data.nrrd

View Layouts

Define one or more named layouts using the layouts key. VolView will use the first layout as the default. Each named layout will be in the layout selector menu. Layout are specified in three formats:

1. Grid with View Types (2D String Array)

Use a 2D array of view type strings to specify both the grid layout and which views appear in each position:

{
  "layouts": {
    "Four Up": [
      ["axial", "coronal"],
      ["sagittal", "volume"]
    ]
  }
}

Available view type strings: "axial", "coronal", "sagittal", "volume", "oblique"

2. Simple Grid (gridSize)

Use gridSize to set the layout grid as [width, height]. For example, [2, 2] creates a 2x2 grid of views:

{
  "layouts": {
    "Four by Four": {
      "gridSize": [2, 2]
    }
  }
}

3. Nested Hierarchical Layout

For complex layouts, use a nested structure with full control over view placement and properties:

{
  "layouts": {
    "Volume Primary": {
      "direction": "row",
      "items": [
        "volume",
        {
          "direction": "column",
          "items": ["axial", "coronal", "sagittal"]
        }
      ]
    }
  }
}

Direction values:

• "row" - items arranged horizontally
• "column" - items stacked vertically

You can also specify full view objects with custom options:

{
  "layouts": {
    "Custom 3D Orientation": {
      "direction": "column",
      "items": [
        {
          "type": "3D",
          "name": "Top View",
          "viewDirection": "Superior",
          "viewUp": "Anterior"
        },
        {
          "direction": "row",
          "items": [
            { "type": "2D", "orientation": "Axial" },
            { "type": "2D", "orientation": "Coronal" }
          ]
        }
      ]
    }
  }
}

View object properties:

• 2D views: type: "2D", orientation: "Axial" | "Coronal" | "Sagittal", name (optional)
• 3D views: type: "3D", viewDirection (optional), viewUp (optional), name (optional)
• Oblique views: type: "Oblique", name (optional)

Multiple Layouts Example

You can define multiple named layouts that users can switch between:

{
  "layouts": {
    "Four up": [
      ["axial", "coronal"],
      ["sagittal", "volume"]
    ],
    "Volume focus": {
      "direction": "row",
      "items": [
        "volume",
        {
          "direction": "column",
          "items": ["axial", "coronal", "sagittal"]
        }
      ]
    }
  }
}

Disabled View Types

Use disabledViewTypes to prevent certain view types from being available in the view type switcher:

{
  "disabledViewTypes": ["3D", "Oblique"]
}

This removes the specified view types from the dropdown menu and replaces them in the default layout with allowed types. Valid values: "2D", "3D", "Oblique"

Labels for tools

Each tool type (Rectangle, Polygon, etc.) can have tool specific labels. To share labels across tools, define the defaultLabels key and don't provide labels for a tool that should use the default labels.

{
  "labels": {
    "defaultLabels": {
      "lesion": { "color": "#ff0000" },
      "tumor": { "color": "green", "strokeWidth": 3 }
    }
  }
}

Segment Group File Format

The segmentGroupSaveFormat key specifies the file extension of the segment group images VolView will include in the volview.zip file.

{
  "io": {
    "segmentGroupSaveFormat": "nii"
  }
}

Working segment group file formats:

hdf5, iwi.cbor, mha, nii, nii.gz, nrrd, vtk

Automatic Layers and Segment Groups by File Name

When loading multiple files, VolView can automatically associate related images based on file naming patterns. Example: base.[extension].nrrd will match base.nii.

The extension must appear anywhere in the filename after splitting by dots, and the filename must start with the same prefix as the base image (everything before the first dot). Files matching base.[extension]... will be associated with a base image named base.*.

Ordering: When multiple layers/segment groups match a base image, they are sorted alphabetically by filename and added to the stack in that order. To control the stacking order explicitly, you could use numeric prefixes in your filenames.

For example, with a base image patient001.nrrd:

• Layers (sorted alphabetically): patient001.layer.1.pet.nii, patient001.layer.2.ct.mha, patient001.layer.3.overlay.vtk
• Segment groups: patient001.seg.1.tumor.nii.gz, patient001.seg.2.lesion.mha

Both features default to '' which disables them.

Segment Groups

Use segmentGroupExtension to automatically convert matching non-DICOM images to segment groups. For example, myFile.seg.nrrd becomes a segment group for myFile.nii. Defaults to '' which disables matching.

{
  "io": {
    "segmentGroupExtension": "seg"
  }
}

Layering

Use layerExtension to automatically layer matching non-DICOM images on top of the base image. For example, myImage.layer.nii is layered on top of myImage.nii. Defaults to '' which disables matching.

{
  "io": {
    "layerExtension": "layer"
  }
}

Keyboard Shortcuts

Configure the keys to activate tools, change selected labels, and more. All shortcut actions are under the ACTIONS variable.

To configure a key for an action, add its action name and the key(s) under the shortcuts section. For key combinations, use + like Ctrl+f.

{
  "shortcuts": {
    "polygon": "Ctrl+p",
    "showKeyboardShortcuts": "t"
  }
}

Example JSON:

{
  "labels": {
    "defaultLabels": {
      "lesion": { "color": "#ff0000" },
      "tumor": { "color": "green", "strokeWidth": 3 }
    }
  },
  "layouts": {
    "single-view": {
      "gridSize": [1, 1]
    }
  }
}

All options:

{
  "labels": {
    "defaultLabels": {
      "lesion": { "color": "#ff0000" },
      "tumor": { "color": "green", "strokeWidth": 3 },
      "innocuous": { "color": "white" }
    },
    "rulerLabels": {
      "big": { "color": "#ff0000" },
      "small": { "color": "white" }
    },
    "rectangleLabels": {
      "red": { "color": "#ff0000", "fillColor": "transparent" },
      "green": { "color": "green", "fillColor": "transparent" },
      "white-yellow-fill": {
        "color": "white",
        "fillColor": "#00ff0030"
      }
    },
    "polygonLabels": {
      "poly1": { "color": "#ff0000" },
      "poly2Label": { "color": "green" }
    }
  },
  "layouts": {
    "Volume primary": {
      "direction": "row",
      "items": [
        "volume",
        {
          "direction": "column",
          "items": ["axial", "coronal", "sagittal"]
        }
      ]
    },
    "Four up": [
      ["axial", "coronal"],
      ["sagittal", "volume"]
    ]
  },
  "disabledViewTypes": ["Oblique"],
  "dataBrowser": {
    "hideSampleData": false
  },
  "shortcuts": {
    "polygon": "Ctrl+p",
    "showKeyboardShortcuts": "t"
  },
  "io": {
    "segmentGroupSaveFormat": "nrrd",
    "segmentGroupExtension": "seg",
    "layerExtension": "layer"
  }
}