[PanZoom] add utility to get what scale would fit the content (related #20)

import { useEffect, useState } from "react";

import { useEffect } from "react";

import { Debug, FlagCategory } from "@sc07-canvas/lib/src/debug";

import {

  Button,

    this.emit("initialize");

  }

  /**

   * Get scale that would fit the zoom element in the viewport

   * @returns

   */

  getZoomToFit() {

    // https://github.com/BetterTyped/react-zoom-pan-pinch/blob/8dacc2746ca84db22f30275e0745c04aefde5aea/src/core/handlers/handlers.utils.ts#L141

    // const wrapperRect = this.$wrapper.getBoundingClientRect();

    const nodeRect = this.$zoom.getBoundingClientRect();

    // const nodeOffset = this._getOffset();

    // const nodeLeft = nodeOffset.x;

    // const nodeTop = nodeOffset.y;

    const nodeWidth = nodeRect.width / this.transform.scale;

    const nodeHeight = nodeRect.height / this.transform.scale;

    const scaleX = this.$wrapper.offsetWidth / nodeWidth;

    const scaleY = this.$wrapper.offsetHeight / nodeHeight;

    const newScale = Math.min(scaleX, scaleY);

    return newScale;

    // the following is from the zoomToElement from react-zoom-pan-pinch

    // const offsetX = (wrapperRect.width - nodeWidth * newScale) / 2;

    // const offsetY = (wrapperRect.height - nodeHeight * newScale) / 2;

    // const newPositionX = (wrapperRect.left - nodeLeft) * newScale + offsetX;

    // const newPositionY = (wrapperRect.top - nodeTop) * newScale + offsetY;

  }

  // https://github.com/BetterTyped/react-zoom-pan-pinch/blob/8dacc2746ca84db22f30275e0745c04aefde5aea/src/core/handlers/handlers.utils.ts#L122

  _getOffset() {

    const wrapperOffset = this.$wrapper.getBoundingClientRect();

    const contentOffset = this.$zoom.getBoundingClientRect();

    const xOff = wrapperOffset.x * this.transform.scale;

    const yOff = wrapperOffset.y * this.transform.scale;

    return {

      x: (contentOffset.x + xOff) / this.transform.scale,

      y: (contentOffset.y + yOff) / this.transform.scale,

    };

  }

  /**

   * Sets transform data

   *