maxGraph/packages/html/stories/ExtendCanvas.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,
  Rectangle,
  Point,
  styleUtils,
} from '@maxgraph/core';

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

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

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

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

  /**
   * Specifies the size of the size for "tiles" to be used for a graph with
   * scrollbars but no visible background page. A good value is large
   * enough to reduce the number of repaints that is caused for auto-
   * translation, which depends on this value, and small enough to give
   * a small empty buffer around the graph. Default is 400x400.
   */
  const scrollTileSize = new Rectangle(0, 0, 400, 400);

  class MyCustomGraph extends Graph {
    /**
     * Returns the padding for pages in page view with scrollbars.
     */
    getPagePadding() {
      return new Point(
        Math.max(0, Math.round(this.container.offsetWidth - 34)),
        Math.max(0, Math.round(this.container.offsetHeight - 34))
      );
    }

    /**
     * Returns the size of the page format scaled with the page size.
     */
    getPageSize() {
      return this.pageVisible
        ? new Rectangle(
            0,
            0,
            this.pageFormat.width * this.pageScale,
            this.pageFormat.height * this.pageScale
          )
        : scrollTileSize;
    }

    /**
     * Returns a rectangle describing the position and count of the
     * background pages, where x and y are the position of the top,
     * left page and width and height are the vertical and horizontal
     * page count.
     */
    getPageLayout() {
      const size = this.pageVisible ? this.getPageSize() : scrollTileSize;
      const bounds = this.getGraphBounds();

      if (bounds.width === 0 || bounds.height === 0) {
        return new Rectangle(0, 0, 1, 1);
      }

      // Computes untransformed graph bounds
      const x = Math.ceil(bounds.x / this.view.scale - this.view.translate.x);
      const y = Math.ceil(bounds.y / this.view.scale - this.view.translate.y);
      const w = Math.floor(bounds.width / this.view.scale);
      const h = Math.floor(bounds.height / this.view.scale);

      const x0 = Math.floor(x / size.width);
      const y0 = Math.floor(y / size.height);
      const w0 = Math.ceil((x + w) / size.width) - x0;
      const h0 = Math.ceil((y + h) / size.height) - y0;

      return new Rectangle(x0, y0, w0, h0);
    }

    getPreferredPageSize(bounds, width, height) {
      const pages = this.getPageLayout();
      const size = this.getPageSize();

      return new Rectangle(0, 0, pages.width * size.width, pages.height * size.height);
    }

    sizeDidChange() {
      if (this.container != null && styleUtils.hasScrollbars(this.container)) {
        const pages = this.getPageLayout();
        const pad = this.getPagePadding();
        const size = this.getPageSize();

        // Updates the minimum graph size
        const minw = Math.ceil((2 * pad.x) / this.view.scale + pages.width * size.width);
        const minh = Math.ceil(
          (2 * pad.y) / this.view.scale + pages.height * size.height
        );

        const min = this.minimumGraphSize;

        // LATER: Fix flicker of scrollbar size in IE quirks mode
        // after delayed call in window.resize event handler
        if (min == null || min.width !== minw || min.height !== minh) {
          this.minimumGraphSize = new Rectangle(0, 0, minw, minh);
        }

        // Updates auto-translate to include padding and graph size
        const dx = pad.x / this.view.scale - pages.x * size.width;
        const dy = pad.y / this.view.scale - pages.y * size.height;

        if (
          !this.autoTranslate &&
          (this.view.translate.x !== dx || this.view.translate.y !== dy)
        ) {
          this.autoTranslate = true;
          this.view.x0 = pages.x;
          this.view.y0 = pages.y;

          // NOTE: THIS INVOKES THIS METHOD AGAIN. UNFORTUNATELY THERE IS NO WAY AROUND THIS SINCE THE
          // BOUNDS ARE KNOWN AFTER THE VALIDATION AND SETTING THE TRANSLATE TRIGGERS A REVALIDATION.
          // SHOULD MOVE TRANSLATE/SCALE TO VIEW.
          const tx = this.view.translate.x;
          const ty = this.view.translate.y;

          this.view.setTranslate(dx, dy);
          this.container.scrollLeft += (dx - tx) * this.view.scale;
          this.container.scrollTop += (dy - ty) * this.view.scale;

          this.autoTranslate = false;
          return;
        }
        super.sizeDidChange();
      }
    }
  }

  // Creates the graph inside the given container
  const graph = new MyCustomGraph(container);
  const panningHandler = graph.getPlugin('PanningHandler');
  panningHandler.ignoreCell = true;
  graph.setPanning(true);

  // Fits the number of background pages to the graph
  graph.view.getBackgroundPageBounds = function () {
    const layout = this.graph.getPageLayout();
    const page = this.graph.getPageSize();

    return new Rectangle(
      this.scale * (this.translate.x + layout.x * page.width),
      this.scale * (this.translate.y + layout.y * page.height),
      this.scale * layout.width * page.width,
      this.scale * layout.height * page.height
    );
  };

  /**
   * Guesses autoTranslate to avoid another repaint (see below).
   * Works if only the scale of the graph changes or if pages
   * are visible and the visible pages do not change.
   */
  const graphViewValidate = graph.view.validate;
  graph.view.validate = function () {
    if (this.graph.container != null && styleUtils.hasScrollbars(this.graph.container)) {
      const pad = this.graph.getPagePadding();
      const size = this.graph.getPageSize();

      // Updating scrollbars here causes flickering in quirks and is not needed
      // if zoom method is always used to set the current scale on the graph.
      const tx = this.translate.x;
      const ty = this.translate.y;
      this.translate.x = pad.x / this.scale - (this.x0 || 0) * size.width;
      this.translate.y = pad.y / this.scale - (this.y0 || 0) * size.height;
    }

    graphViewValidate.apply(this, arguments);
  };

  // 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, 30],
    });
    const v2 = graph.insertVertex({
      parent,
      value: 'World!',
      position: [200, 150],
      size: [80, 30],
    });
    const e1 = graph.insertEdge({
      parent,
      source: v1,
      target: v2,
    });
  });

  // Sets initial scrollbar positions
  window.setTimeout(() => {
    const bounds = graph.getGraphBounds();
    const width = Math.max(bounds.width, scrollTileSize.width * graph.view.scale);
    const height = Math.max(bounds.height, scrollTileSize.height * graph.view.scale);
    graph.container.scrollTop = Math.floor(
      Math.max(0, bounds.y - Math.max(20, (graph.container.clientHeight - height) / 4))
    );
    graph.container.scrollLeft = Math.floor(
      Math.max(0, bounds.x - Math.max(0, (graph.container.clientWidth - width) / 2))
    );
  }, 0);

  return container;
};

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