webgme-dss/src/client/gme/BaseComponents/BasicConnectingComponent.jsx

Design Studio for Dynamic Systems with Modelica as backend

import React, {Component} from 'react';
import PropTypes from 'prop-types';
import ZLEVELS from '../utils/zLevels';

export default class BasicConnectingComponent extends Component {
    static propTypes = {
        connectionManager: PropTypes.object.isRequired,
    };

    constructor(props) {
        super(props);

        const {connectionManager} = this.props;

        connectionManager.setListener(this.onChange);
    }

    state = {
        startPos: null,
        currentPos: null,
        isConnecting: false,
    };

    onChange = (event) => {
        this.setState(event);
    };

    render() {
        const {isConnecting, startPos, currentPos} = this.state;
        let top;
        let left;
        let width;
        let height;

        if (isConnecting) {
            top = Math.min(startPos.y, currentPos.y);
            left = Math.min(startPos.x, currentPos.x);
            height = Math.abs(currentPos.y - startPos.y) + 5;
            width = Math.abs(currentPos.x - startPos.x) + 5;
            if (height > 0 && width > 0) {
                return (
                    <svg
                        width={width}
                        height={height}
                        viewBox={`${0} ${0} ${width} ${height}`}
                        style={{
                            position: 'absolute',
                            top: `${top - 5}px`,
                            left: `${left - 5}px`,
                            zIndex: ZLEVELS.connection,
                        }}
                    >
                        <line
                            strokeWidth="3"
                            stroke="orange"
                            strokeDasharray="5 5"
                            x1={startPos.x - (left - 5)}
                            y1={startPos.y - (top - 5)}
                            x2={currentPos.x - (left - 5)}
                            y2={currentPos.y - (top - 5)}
                        />
                    </svg>
                );
            }
        }
        return null;
    }
}