maxGraph/packages/html/stories/Drop.stories.js

/*
Copyright 2021-present The maxGraph project Contributors
Copyright (c) 2006-2020, JGraph Ltd

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import {
  Graph,
  RubberBandHandler,
  styleUtils,
  eventUtils,
  InternalEvent,
  Client,
} from '@maxgraph/core';

import { globalTypes } from '../.storybook/preview';
import { getXml, parseXml } from '@maxgraph/core/util/xmlUtils';

export default {
  title: 'DnD_CopyPaste/Drop',
  argTypes: {
    ...globalTypes,
    contextMenu: {
      type: 'boolean',
      defaultValue: false,
    },
    rubberBand: {
      type: 'boolean',
      defaultValue: true,
    },
  },
};

const Template = ({ label, ...args }) => {
  const div = document.createElement('div');
  div.innerHTML = 'Drag & drop your images below:<br>';

  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';
  div.appendChild(container);

  // Checks if the browser is supported
  const fileSupport =
    window.File != null && window.FileReader != null && window.FileList != null;

  if (!fileSupport || !Client.isBrowserSupported()) {
    // Displays an error message if the browser is not supported.
    utils.error('Browser is not supported!', 200, false);
  } else {
    // Disables the built-in context menu
    if (!args.contextMenu) InternalEvent.disableContextMenu(container);

    // Creates the graph inside the given this.el
    const graph = new Graph(container);

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

    InternalEvent.addListener(container, 'dragover', function (evt) {
      if (graph.isEnabled()) {
        evt.stopPropagation();
        evt.preventDefault();
      }
    });

    InternalEvent.addListener(container, 'drop', (evt) => {
      if (graph.isEnabled()) {
        evt.stopPropagation();
        evt.preventDefault();

        // Gets drop location point for vertex
        const pt = styleUtils.convertPoint(
          graph.container,
          eventUtils.getClientX(evt),
          eventUtils.getClientY(evt)
        );
        const tr = graph.view.translate;
        const { scale } = graph.view;
        const x = pt.x / scale - tr.x;
        const y = pt.y / scale - tr.y;

        // Converts local images to data urls
        const filesArray = evt.dataTransfer.files;

        for (let i = 0; i < filesArray.length; i++) {
          handleDrop(graph, filesArray[i], x + i * 10, y + i * 10);
        }
      }
    });
  }

  return div;
};

function handleDrop(graph, file, x, y) {
  // Handles each file as a separate insert for simplicity.
  // Use barrier to handle multiple files as a single insert.

  if (file.type.substring(0, 5) === 'image') {
    const reader = new FileReader();

    reader.onload = function (e) {
      // Gets size of image for vertex
      let data = e.target.result;

      // SVG needs special handling to add viewbox if missing and
      // find initial size from SVG attributes (only for IE11)
      if (file.type.substring(0, 9) === 'image/svg') {
        const comma = data.indexOf(',');
        const svgText = atob(data.substring(comma + 1));
        const root = parseXml(svgText);

        // Parses SVG to find width and height
        if (root != null) {
          const svgs = root.getElementsByTagName('svg');

          if (svgs.length > 0) {
            const svgRoot = svgs[0];
            let w = parseFloat(svgRoot.getAttribute('width'));
            let h = parseFloat(svgRoot.getAttribute('height'));

            // Check if viewBox attribute already exists
            const vb = svgRoot.getAttribute('viewBox');

            if (vb == null || vb.length === 0) {
              svgRoot.setAttribute('viewBox', `0 0 ${w} ${h}`);
            }
            // Uses width and height from viewbox for
            // missing width and height attributes
            else if (Number.isNaN(w) || Number.isNaN(h)) {
              const tokens = vb.split(' ');

              if (tokens.length > 3) {
                w = parseFloat(tokens[2]);
                h = parseFloat(tokens[3]);
              }
            }

            w = Math.max(1, Math.round(w));
            h = Math.max(1, Math.round(h));

            data = `data:image/svg+xml,${btoa(getXml(svgs[0], '\n'))}`;
            graph.insertVertex({
              position: [x, y],
              size: [w, h],
              style: {
                shape: 'image',
                image: data,
              },
            });
          }
        }
      } else {
        const img = new Image();

        img.onload = () => {
          const w = Math.max(1, img.width);
          const h = Math.max(1, img.height);

          // Converts format of data url to cell style value for use in vertex
          const semi = data.indexOf(';');

          if (semi > 0) {
            data = data.substring(0, semi) + data.substring(data.indexOf(',', semi + 1));
          }

          graph.insertVertex({
            position: [x, y],
            size: [w, h],
            style: { shape: 'image', image: data },
          });
        };

        img.src = data;
      }
    };

    reader.readAsDataURL(file);
  }
}

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