maxGraph/packages/html/stories/FixedPoints.stories.js

import {
  Graph,
  RubberBandHandler,
  ConnectionHandler,
  ConnectionConstraint,
  ConstraintHandler,
  Point,
  CellState,
  EdgeHandler,
} from '@maxgraph/core';

import { globalTypes } from '../.storybook/preview';
import { intersects } from '@maxgraph/core/util/mathUtils';

export default {
  title: 'Connections/FixedPoints',
  argTypes: {
    ...globalTypes,
    rubberBand: {
      type: 'boolean',
      defaultValue: true,
    },
  },
};

const Template = ({ label, ...args }) => {
  const container = document.createElement('div');
  container.style.position = 'relative';
  container.style.overflow = 'hidden';
  container.style.width = `${args.width}px`;
  container.style.height = `${args.height}px`;
  container.style.background = 'url(/images/grid.gif)';
  container.style.cursor = 'default';

  class MyCustomConstraintHandler extends ConstraintHandler {
    // Snaps to fixed points
    intersects(icon, point, source, existingEdge) {
      return !source || existingEdge || intersects(icon.bounds, point);
    }
  }

  class MyCustomConnectionHandler extends ConnectionHandler {
    // connectImage = new ImageBox('images/connector.gif', 16, 16);

    isConnectableCell(cell) {
      return false;
    }

    /*
     * Special case: Snaps source of new connections to fixed points
     * Without a connect preview in connectionHandler.createEdgeState mouseMove
     * and getSourcePerimeterPoint should be overriden by setting sourceConstraint
     * sourceConstraint to null in mouseMove and updating it and returning the
     * nearest point (cp) in getSourcePerimeterPoint (see below)
     */
    updateEdgeState(pt, constraint) {
      if (pt != null && this.previous != null) {
        const constraints = this.graph.getAllConnectionConstraints(this.previous);
        let nearestConstraint = null;
        let dist = null;

        for (let i = 0; i < constraints.length; i++) {
          const cp = this.graph.getConnectionPoint(this.previous, constraints[i]);

          if (cp != null) {
            const tmp = (cp.x - pt.x) * (cp.x - pt.x) + (cp.y - pt.y) * (cp.y - pt.y);

            if (dist == null || tmp < dist) {
              nearestConstraint = constraints[i];
              dist = tmp;
            }
          }
        }

        if (nearestConstraint != null) {
          this.sourceConstraint = nearestConstraint;
        }

        // In case the edge style must be changed during the preview:
        // this.edgeState.style.edgeStyle = 'orthogonalEdgeStyle';
        // And to use the new edge style in the new edge inserted into the graph,
        // update the cell style as follows:
        // this.edgeState.cell.style = utils.setStyle(this.edgeState.cell.style, 'edgeStyle', this.edgeState.style.edgeStyle);
      }
      return super.updateEdgeState(pt, constraint);
    }

    createEdgeState(me) {
      // Connect preview
      const edge = this.graph.createEdge(
        null,
        null,
        null,
        null,
        null,
        'edgeStyle=orthogonalEdgeStyle'
      );

      return new CellState(this.graph.view, edge, this.graph.getCellStyle(edge));
    }
  }

  class MyCustomEdgeHandler extends EdgeHandler {
    // Disables floating connections (only use with no connect image)
    isConnectableCell(cell) {
      return graph.getPlugin('ConnectionHandler').isConnectableCell(cell);
    }
  }

  class MyCustomGraph extends Graph {
    createConnectionHandler() {
      const r = new MyCustomConnectionHandler();
      r.constraintHandler = new MyCustomConstraintHandler(this);
      return r;
    }

    createEdgeHandler(state, edgeStyle) {
      const r = new MyCustomEdgeHandler(state, edgeStyle);
      r.constraintHandler = new MyCustomConstraintHandler(this);
      return r;
    }

    getAllConnectionConstraints(terminal) {
      if (terminal != null && terminal.cell.isVertex()) {
        return [
          new ConnectionConstraint(new Point(0, 0), true),
          new ConnectionConstraint(new Point(0.5, 0), true),
          new ConnectionConstraint(new Point(1, 0), true),
          new ConnectionConstraint(new Point(0, 0.5), true),
          new ConnectionConstraint(new Point(1, 0.5), true),
          new ConnectionConstraint(new Point(0, 1), true),
          new ConnectionConstraint(new Point(0.5, 1), true),
          new ConnectionConstraint(new Point(1, 1), true),
        ];
      }
      return null;
    }
  }

  // Creates the graph inside the given container
  const graph = new MyCustomGraph(container);
  graph.setConnectable(true);

  // Enables rubberband selection
  if (args.rubberBand) new RubberBandHandler(graph);

  // Gets the default parent for inserting new cells. This
  // is normally the first child of the root (ie. layer 0).
  const parent = graph.getDefaultParent();

  // Adds cells to the model in a single step
  graph.batchUpdate(() => {
    const v1 = graph.insertVertex({
      parent,
      value: 'Hello,',
      position: [20, 20],
      size: [80, 60],
      style: 'shape=triangle;perimeter=trianglePerimeter',
    });
    const v2 = graph.insertVertex({
      parent,
      value: 'World!',
      position: [200, 150],
      size: [80, 60],
      style: 'shape=ellipse;perimeter=ellipsePerimeter',
    });
    const v3 = graph.insertVertex({
      parent,
      value: 'Hello,',
      position: [200, 20],
      size: [80, 30],
    });
    const e1 = graph.insertEdge({
      parent,
      value: '',
      source: v1,
      target: v2,
      style:
        'edgeStyle=elbowEdgeStyle;elbow=horizontal;' +
        'exitX=0.5;exitY=1;exitPerimeter=1;entryX=0;entryY=0;entryPerimeter=1;',
    });
    const e2 = graph.insertEdge({
      parent,
      value: '',
      source: v3,
      target: v2,
      style:
        'edgeStyle=elbowEdgeStyle;elbow=horizontal;orthogonal=0;' +
        'entryX=0;entryY=0;entryPerimeter=1;',
    });
  });

  // Use this code to snap the source point for new connections without a connect preview,
  // ie. without an overridden graph.getPlugin('ConnectionHandler').createEdgeState
  /*
    let mxConnectionHandlerMouseMove = ConnectionHandler.prototype.mouseMove;
    ConnectionHandler.prototype.mouseMove = function(sender, me)
    {
        this.sourceConstraint = null;

        mxConnectionHandlerMouseMove.apply(this, arguments);
    };

    let mxConnectionHandlerGetSourcePerimeterPoint = ConnectionHandler.prototype.getSourcePerimeterPoint;
    ConnectionHandler.prototype.getSourcePerimeterPoint = function(state, pt, me)
    {
        let result = null;

        if (this.previous != null && pt != null)
        {
            let constraints = this.graph.getAllConnectionConstraints(this.previous);
            let nearestConstraint = null;
            let nearest = null;
            let dist = null;

            for (let i = 0; i < constraints.length; i++)
            {
                let cp = this.graph.getConnectionPoint(this.previous, constraints[i]);

                if (cp != null)
                {
                    let tmp = (cp.x - pt.x) * (cp.x - pt.x) + (cp.y - pt.y) * (cp.y - pt.y);

                    if (dist == null || tmp < dist)
                    {
                        nearestConstraint = constraints[i];
                        nearest = cp;
                        dist = tmp;
                    }
                }
            }

            if (nearestConstraint != null)
            {
                this.sourceConstraint = nearestConstraint;
                result = nearest;
            }
        }

        if (result == null)
        {
            result = mxConnectionHandlerGetSourcePerimeterPoint.apply(this, arguments);
        }

        return result;
    };
    */

  return container;
};

export const Default = Template.bind({});