maxGraph/packages/html/stories/Grid.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,
  InternalEvent,
  RubberBandHandler,
  MaxLog,
  GraphView,
  Point,
  DomHelpers,
  eventUtils,
} from '@maxgraph/core';

import { globalTypes } from '../.storybook/preview';

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

const Template = ({ label, ...args }) => {
  const div = document.createElement('div');

  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.cursor = 'default';
  div.appendChild(container);

  if (!args.contextMenu) InternalEvent.disableContextMenu(container);

  // Creates the graph inside the given container
  var graph = new Graph(container);
  const graphHandler = graph.getPlugin('SelectionHandler');
  graphHandler.scaleGrid = true;
  graph.setPanning(true);

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

  let repaintGrid;

  // Create grid dynamically (requires canvas)
  (function () {
    try {
      var canvas = document.createElement('canvas');
      canvas.style.position = 'absolute';
      canvas.style.top = '0px';
      canvas.style.left = '0px';
      canvas.style.zIndex = -1;
      graph.container.appendChild(canvas);

      var ctx = canvas.getContext('2d');

      // Modify event filtering to accept canvas as container
      var mxGraphViewIsContainerEvent = GraphView.prototype.isContainerEvent;
      GraphView.prototype.isContainerEvent = function (evt) {
        return (
          mxGraphViewIsContainerEvent.apply(this, arguments) ||
          eventUtils.getSource(evt) == canvas
        );
      };

      var s = 0;
      var gs = 0;
      var tr = new Point();
      var w = 0;
      var h = 0;

      repaintGrid = function () {
        if (ctx != null) {
          var bounds = graph.getGraphBounds();
          var width = Math.max(bounds.x + bounds.width, graph.container.clientWidth);
          var height = Math.max(bounds.y + bounds.height, graph.container.clientHeight);
          var sizeChanged = width != w || height != h;

          if (
            graph.view.scale != s ||
            graph.view.translate.x != tr.x ||
            graph.view.translate.y != tr.y ||
            gs != graph.gridSize ||
            sizeChanged
          ) {
            tr = graph.view.translate.clone();
            s = graph.view.scale;
            gs = graph.gridSize;
            w = width;
            h = height;

            // Clears the background if required
            if (!sizeChanged) {
              ctx.clearRect(0, 0, w, h);
            } else {
              canvas.setAttribute('width', w);
              canvas.setAttribute('height', h);
            }

            var tx = tr.x * s;
            var ty = tr.y * s;

            // Sets the distance of the grid lines in pixels
            var minStepping = graph.gridSize;
            var stepping = minStepping * s;

            if (stepping < minStepping) {
              var count = Math.round(Math.ceil(minStepping / stepping) / 2) * 2;
              stepping = count * stepping;
            }

            var xs = Math.floor((0 - tx) / stepping) * stepping + tx;
            var xe = Math.ceil(w / stepping) * stepping;
            var ys = Math.floor((0 - ty) / stepping) * stepping + ty;
            var ye = Math.ceil(h / stepping) * stepping;

            xe += Math.ceil(stepping);
            ye += Math.ceil(stepping);

            var ixs = Math.round(xs);
            var ixe = Math.round(xe);
            var iys = Math.round(ys);
            var iye = Math.round(ye);

            // Draws the actual grid
            ctx.strokeStyle = '#f6f6f6';
            ctx.beginPath();

            for (var x = xs; x <= xe; x += stepping) {
              x = Math.round((x - tx) / stepping) * stepping + tx;
              var ix = Math.round(x);

              ctx.moveTo(ix + 0.5, iys + 0.5);
              ctx.lineTo(ix + 0.5, iye + 0.5);
            }

            for (var y = ys; y <= ye; y += stepping) {
              y = Math.round((y - ty) / stepping) * stepping + ty;
              var iy = Math.round(y);

              ctx.moveTo(ixs + 0.5, iy + 0.5);
              ctx.lineTo(ixe + 0.5, iy + 0.5);
            }

            ctx.closePath();
            ctx.stroke();
          }
        }
      };
    } catch (e) {
      MaxLog.show();
      MaxLog.debug('Using background image');

      container.style.backgroundImage = "url('editors/images/grid.gif')";
    }

    var mxGraphViewValidateBackground = GraphView.prototype.validateBackground;
    GraphView.prototype.validateBackground = function () {
      mxGraphViewValidateBackground.apply(this, arguments);
      repaintGrid();
    };
  })();

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

  // Adds cells to the model in a single step
  graph.batchUpdate(() => {
    var v1 = graph.insertVertex(parent, null, 'Hello,', 20, 20, 80, 30);
    var v2 = graph.insertVertex(parent, null, 'World!', 200, 150, 80, 30);
    var e1 = graph.insertEdge(parent, null, '', v1, v2);
  });

  graph.centerZoom = false;

  const controller = document.createElement('div');
  div.appendChild(controller);

  controller.appendChild(
    DomHelpers.button('+', function () {
      graph.zoomIn();
    })
  );

  controller.appendChild(
    DomHelpers.button('-', function () {
      graph.zoomOut();
    })
  );

  return div;
};

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