svgo-browser/plugins/removeOffCanvasPaths.js

svgo tool for browser and node usage

exports.type = 'perItem';

exports.active = false;

exports.description = 'removes elements that are drawn outside of the viewbox (disabled by default)';

const SVGO = require('../lib/svgo.js');
const _path = require('./_path.js');

const { intersects } = _path;
const { path2js } = _path;
let viewBox;
let viewBoxJS;

/**
 * Remove elements that are drawn outside of the viewbox.
 *
 * @param {Object} item current iteration item
 * @return {Boolean} if false, item will be filtered out
 *
 * @author JoshyPHP
 */
exports.fn = function (item) {
  if (item.isElem('path') && item.hasAttr('d') && typeof viewBox !== 'undefined') {
    // Consider that any item with a transform attribute or a M instruction
    // within the viewBox is visible
    if (hasTransform(item) || pathMovesWithinViewBox(item.attr('d').value)) {
      return true;
    }

    let pathJS = path2js(item);
    if (pathJS.length === 2) {
      // Use a closed clone of the path if it's too short for intersects()
      pathJS = JSON.parse(JSON.stringify(pathJS));
      pathJS.push({ instruction: 'z' });
    }

    return intersects(viewBoxJS, pathJS);
  }
  if (item.isElem('svg')) {
    parseViewBox(item);
  }

  return true;
};

/**
 * Test whether given item or any of its ancestors has a transform attribute.
 *
 * @param {String} path
 * @return {Boolean}
 */
function hasTransform(item) {
  return item.hasAttr('transform') || (item.parentNode && hasTransform(item.parentNode));
}

/**
 * Parse the viewBox coordinates and compute the JS representation of its path.
 *
 * @param {Object} svg svg element item
 */
function parseViewBox(svg) {
  let viewBoxData = '';
  if (svg.hasAttr('viewBox')) {
    // Remove commas and plus signs, normalize and trim whitespace
    viewBoxData = svg.attr('viewBox').value;
  } else if (svg.hasAttr('height') && svg.hasAttr('width')) {
    viewBoxData = `0 0 ${svg.attr('width').value} ${svg.attr('height').value}`;
  }

  // Remove commas and plus signs, normalize and trim whitespace
  viewBoxData = viewBoxData
    .replace(/[,+]|px/g, ' ')
    .replace(/\s+/g, ' ')
    .replace(/^\s*|\s*$/g, '');

  // Ensure that the dimensions are 4 values separated by space
  const m = /^(-?\d*\.?\d+) (-?\d*\.?\d+) (\d*\.?\d+) (\d*\.?\d+)$/.exec(viewBoxData);
  if (!m) {
    return;
  }

  // Store the viewBox boundaries
  viewBox = {
    left: parseFloat(m[1]),
    top: parseFloat(m[2]),
    right: parseFloat(m[1]) + parseFloat(m[3]),
    bottom: parseFloat(m[2]) + parseFloat(m[4]),
  };

  const path = new SVGO().createContentItem({
    elem: 'path',
    prefix: '',
    local: 'path',
  });
  path.addAttr({
    name: 'd',
    prefix: '',
    local: 'd',
    value: `M${m[1]} ${m[2]}h${m[3]}v${m[4]}H${m[1]}z`,
  });

  viewBoxJS = path2js(path);
}

/**
 * Test whether given path has a M instruction with coordinates within the viewBox.
 *
 * @param {String} path
 * @return {Boolean}
 */
function pathMovesWithinViewBox(path) {
  const regexp = /M\s*(-?\d*\.?\d+)(?!\d)\s*(-?\d*\.?\d+)/g;
  let m;
  while ((m = regexp.exec(path)) !== null) {
    if (
      m[1] >= viewBox.left
      && m[1] <= viewBox.right
      && m[2] >= viewBox.top
      && m[2] <= viewBox.bottom
    ) {
      return true;
    }
  }

  return false;
}