Segmentation Tools {#segmentation-tool}

"Segmentation Tools" are derivatives of BaseTool that interact with the labelmap layer in some way other than by manually brushing, for which you would choose to derive from BaseBrushTool.

Anatomy

Segmentation Tools are more of a modular design pattern rather than a tool type, and so are constructed via composition rather than inheritance.

SegmentationTools are comprised of a few components:

• A Segmentation Mixin - The role of a segmentation mixin is to provide a delineation mechanism, which generates an operationData object which is passed to the active strategy alongside the cornerstone event.
• One or more strategies to be called when the segmentation mixin calls this.applyActiveStrategy(evt, operationData).
• An (optional) set of cursors for strategies.

Example

Below is an example of a Segementation Tool:

/**
 * @public
 * @class CircleScissorsTool
 * @memberof Tools
 * @classdesc Tool for manipulating labelmap data using a circle.
 * @extends Tools.Base.BaseTool
 */
export default class CircleScissorsTool extends BaseTool {
  /** @inheritdoc */
  constructor(props = {}) {
    const defaultProps = {
      name: 'CircleScissors',
      strategies: {
        FILL_INSIDE: fillInsideCircle,
        FILL_OUTSIDE: fillOutsideCircle,
        ERASE_OUTSIDE: eraseOutsideCircle,
        ERASE_INSIDE: eraseInsideCircle,
      },
      cursors: {
        FILL_INSIDE: segCircleFillInsideCursor,
        FILL_OUTSIDE: segCircleFillOutsideCursor,
        ERASE_OUTSIDE: segCircleEraseOutsideCursor,
        ERASE_INSIDE: segCircleEraseInsideCursor,
      },
      defaultStrategy: 'FILL_INSIDE',
      supportedInteractionTypes: ['Mouse', 'Touch'],
      svgCursor: segCircleFillInsideCursor,
      mixins: ['circleSegmentationMixin'],
    };

    super(props, defaultProps);
  }
}

Lets analyse the components unique to segmentation tools:

Segmentation Mixins

// ...
mixins: ['circleSegmentationMixin'];
// ...

The mixins prop can be used as with BaseTool, but at least one segmentation mixin must be used. The job the segmentation mixin is to take user input through some means, implement _applyStrategy, and call the strategy with appropriate input.

Mixin-aware Strategies

// ...
strategies: {
  FILL_INSIDE: fillInsideCircle,
  FILL_OUTSIDE: fillOutsideCircle,
  ERASE_OUTSIDE: eraseOutsideCircle,
  ERASE_INSIDE: eraseInsideCircle,
},
// ...
defaultStrategy: 'FILL_INSIDE',
// ...

The strategies prop defines a set of operations that can be executed at the end of delineation. The strategies implemented should expect operationData of the form provided by the segmentation mixin implemented by the Tool.