fonteditor-core/lib/graphics/pathUtil.js

fonts (ttf, woff, woff2, eot, svg, otf) parse, write, transform, glyph adjust.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.clone = clone;
exports.deInterpolate = deInterpolate;
exports.getPathHash = getPathHash;
exports.interpolate = interpolate;
exports.isClockWise = isClockWise;
exports.makeLink = makeLink;
exports.removeOverlapPoints = removeOverlapPoints;
exports.scale = scale;
var _util = require("./util");
/**
 * @file 路径相关的函数集合
 * @author mengke01(kekee000@gmail.com)
 */

/**
 * 对路径进行插值，补全省略的点
 *
 * @param {Array} path 路径
 * @return {Array} 路径
 */
function interpolate(path) {
  var newPath = [];
  for (var i = 0, l = path.length; i < l; i++) {
    var next = i === l - 1 ? 0 : i + 1;
    newPath.push(path[i]);
    // 插值
    if (!path[i].onCurve && !path[next].onCurve) {
      newPath.push({
        x: (path[i].x + path[next].x) / 2,
        y: (path[i].y + path[next].y) / 2,
        onCurve: true
      });
    }
  }
  return newPath;
}

/**
 * 去除路径中的插值点
 *
 * @param {Array} path 路径
 * @return {Array} 路径
 */
function deInterpolate(path) {
  var newPath = [];
  for (var i = 0, l = path.length; i < l; i++) {
    var next = i === l - 1 ? 0 : i + 1;
    var prev = i === 0 ? l - 1 : i - 1;
    // 插值
    if (!path[prev].onCurve && path[i].onCurve && !path[next].onCurve && Math.abs(2 * path[i].x - path[prev].x - path[next].x) < 0.001 && Math.abs(2 * path[i].y - path[prev].y - path[next].y) < 0.001) {
      continue;
    }
    newPath.push(path[i]);
  }
  return newPath;
}

/**
 * 判断路径的方向是否顺时针
 *
 * see:
 * http://debian.fmi.uni-sofia.bg/~sergei/cgsr/docs/clockwise.htm
 *
 * @param {Array} path 路径
 * @return {number} 0 无方向 1 clockwise, -1 counter clockwise
 */
function isClockWise(path) {
  if (path.length < 3) {
    return 0;
  }
  var zCount = 0;
  for (var i = 0, l = path.length; i < l; i++) {
    var cur = path[i];
    var prev = i === 0 ? path[l - 1] : path[i - 1];
    var next = i === l - 1 ? path[0] : path[i + 1];
    var z = (cur.x - prev.x) * (next.y - cur.y) - (cur.y - prev.y) * (next.x - cur.x);
    if (z < 0) {
      zCount--;
    } else if (z > 0) {
      zCount++;
    }
  }
  return zCount === 0 ? 0 : zCount < 0 ? 1 : -1;
}

/**
 * 获取路径哈希
 *
 * @param {Array} path 路径数组
 * @return {number} 哈希值
 */
function getPathHash(path) {
  var hash = 0;
  var seed = 131;
  path.forEach(function (p) {
    hash = 0x7FFFFFFF & hash * seed + (0, _util.getPointHash)(p) + (p.onCurve ? 1 : 0);
  });
  return hash;
}

/**
 * 移除重复点
 *
 * @param {Array} points 点集合
 * @return {Array} 移除后点集合
 */
function removeOverlapPoints(points) {
  var hash = {};
  var ret = [];
  for (var i = 0, l = points.length; i < l; i++) {
    var hashcode = points[i].x * 31 + points[i].y;
    if (!hash[hashcode]) {
      ret.push(points[i]);
      hash[hashcode] = 1;
    }
  }
  return ret;
}

/**
 * 对path进行双向链表连接
 *
 * @param  {Array} path 轮廓数组
 * @return {Array}         path
 */
function makeLink(path) {
  for (var i = 0, l = path.length; i < l; i++) {
    var cur = path[i];
    var prev = i === 0 ? path[l - 1] : path[i - 1];
    var next = i === l - 1 ? path[0] : path[i + 1];
    cur.index = i;
    cur.next = next;
    cur.prev = prev;
  }
  return path;
}

/**
 * 对path进行缩放
 *
 * @param  {Array} path 轮廓数组
 * @param  {number} ratio 缩放大小
 *
 * @return {Array}         path
 */
function scale(path, ratio) {
  for (var i = 0, l = path.length; i < l; i++) {
    var cur = path[i];
    cur.x *= ratio;
    cur.y *= ratio;
  }
  return path;
}
function clone(path) {
  return path ? path.map(function (p) {
    var newP = {
      x: p.x,
      y: p.y
    };
    if (p.onCurve) {
      newP.onCurve = true;
    }
    return newP;
  }) : path;
}