path-intersection.js 9.7 KB

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  1. var isArray = require('../type/is-array');
  2. var rectPath = require('./rect-path');
  3. var pathTocurve = require('./path2curve');
  4. var base3 = function base3(t, p1, p2, p3, p4) {
  5. var t1 = -3 * p1 + 9 * p2 - 9 * p3 + 3 * p4;
  6. var t2 = t * t1 + 6 * p1 - 12 * p2 + 6 * p3;
  7. return t * t2 - 3 * p1 + 3 * p2;
  8. };
  9. var bezlen = function bezlen(x1, y1, x2, y2, x3, y3, x4, y4, z) {
  10. if (z === null) {
  11. z = 1;
  12. }
  13. z = z > 1 ? 1 : z < 0 ? 0 : z;
  14. var z2 = z / 2;
  15. var n = 12;
  16. var Tvalues = [-0.1252, 0.1252, -0.3678, 0.3678, -0.5873, 0.5873, -0.7699, 0.7699, -0.9041, 0.9041, -0.9816, 0.9816];
  17. var Cvalues = [0.2491, 0.2491, 0.2335, 0.2335, 0.2032, 0.2032, 0.1601, 0.1601, 0.1069, 0.1069, 0.0472, 0.0472];
  18. var sum = 0;
  19. for (var i = 0; i < n; i++) {
  20. var ct = z2 * Tvalues[i] + z2;
  21. var xbase = base3(ct, x1, x2, x3, x4);
  22. var ybase = base3(ct, y1, y2, y3, y4);
  23. var comb = xbase * xbase + ybase * ybase;
  24. sum += Cvalues[i] * Math.sqrt(comb);
  25. }
  26. return z2 * sum;
  27. };
  28. var curveDim = function curveDim(x0, y0, x1, y1, x2, y2, x3, y3) {
  29. var tvalues = [];
  30. var bounds = [[], []];
  31. var a = void 0;
  32. var b = void 0;
  33. var c = void 0;
  34. var t = void 0;
  35. for (var i = 0; i < 2; ++i) {
  36. if (i === 0) {
  37. b = 6 * x0 - 12 * x1 + 6 * x2;
  38. a = -3 * x0 + 9 * x1 - 9 * x2 + 3 * x3;
  39. c = 3 * x1 - 3 * x0;
  40. } else {
  41. b = 6 * y0 - 12 * y1 + 6 * y2;
  42. a = -3 * y0 + 9 * y1 - 9 * y2 + 3 * y3;
  43. c = 3 * y1 - 3 * y0;
  44. }
  45. if (Math.abs(a) < 1e-12) {
  46. if (Math.abs(b) < 1e-12) {
  47. continue;
  48. }
  49. t = -c / b;
  50. if (t > 0 && t < 1) {
  51. tvalues.push(t);
  52. }
  53. continue;
  54. }
  55. var b2ac = b * b - 4 * c * a;
  56. var sqrtb2ac = Math.sqrt(b2ac);
  57. if (b2ac < 0) {
  58. continue;
  59. }
  60. var t1 = (-b + sqrtb2ac) / (2 * a);
  61. if (t1 > 0 && t1 < 1) {
  62. tvalues.push(t1);
  63. }
  64. var t2 = (-b - sqrtb2ac) / (2 * a);
  65. if (t2 > 0 && t2 < 1) {
  66. tvalues.push(t2);
  67. }
  68. }
  69. var j = tvalues.length;
  70. var jlen = j;
  71. var mt = void 0;
  72. while (j--) {
  73. t = tvalues[j];
  74. mt = 1 - t;
  75. bounds[0][j] = mt * mt * mt * x0 + 3 * mt * mt * t * x1 + 3 * mt * t * t * x2 + t * t * t * x3;
  76. bounds[1][j] = mt * mt * mt * y0 + 3 * mt * mt * t * y1 + 3 * mt * t * t * y2 + t * t * t * y3;
  77. }
  78. bounds[0][jlen] = x0;
  79. bounds[1][jlen] = y0;
  80. bounds[0][jlen + 1] = x3;
  81. bounds[1][jlen + 1] = y3;
  82. bounds[0].length = bounds[1].length = jlen + 2;
  83. return {
  84. min: {
  85. x: Math.min.apply(0, bounds[0]),
  86. y: Math.min.apply(0, bounds[1])
  87. },
  88. max: {
  89. x: Math.max.apply(0, bounds[0]),
  90. y: Math.max.apply(0, bounds[1])
  91. }
  92. };
  93. };
  94. var intersect = function intersect(x1, y1, x2, y2, x3, y3, x4, y4) {
  95. if (Math.max(x1, x2) < Math.min(x3, x4) || Math.min(x1, x2) > Math.max(x3, x4) || Math.max(y1, y2) < Math.min(y3, y4) || Math.min(y1, y2) > Math.max(y3, y4)) {
  96. return;
  97. }
  98. var nx = (x1 * y2 - y1 * x2) * (x3 - x4) - (x1 - x2) * (x3 * y4 - y3 * x4);
  99. var ny = (x1 * y2 - y1 * x2) * (y3 - y4) - (y1 - y2) * (x3 * y4 - y3 * x4);
  100. var denominator = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
  101. if (!denominator) {
  102. return;
  103. }
  104. var px = nx / denominator;
  105. var py = ny / denominator;
  106. var px2 = +px.toFixed(2);
  107. var py2 = +py.toFixed(2);
  108. if (px2 < +Math.min(x1, x2).toFixed(2) || px2 > +Math.max(x1, x2).toFixed(2) || px2 < +Math.min(x3, x4).toFixed(2) || px2 > +Math.max(x3, x4).toFixed(2) || py2 < +Math.min(y1, y2).toFixed(2) || py2 > +Math.max(y1, y2).toFixed(2) || py2 < +Math.min(y3, y4).toFixed(2) || py2 > +Math.max(y3, y4).toFixed(2)) {
  109. return;
  110. }
  111. return {
  112. x: px,
  113. y: py
  114. };
  115. };
  116. var isPointInsideBBox = function isPointInsideBBox(bbox, x, y) {
  117. return x >= bbox.x && x <= bbox.x + bbox.width && y >= bbox.y && y <= bbox.y + bbox.height;
  118. };
  119. var box = function box(x, y, width, height) {
  120. if (x === null) {
  121. x = y = width = height = 0;
  122. }
  123. if (y === null) {
  124. y = x.y;
  125. width = x.width;
  126. height = x.height;
  127. x = x.x;
  128. }
  129. return {
  130. x: x,
  131. y: y,
  132. width: width,
  133. w: width,
  134. height: height,
  135. h: height,
  136. x2: x + width,
  137. y2: y + height,
  138. cx: x + width / 2,
  139. cy: y + height / 2,
  140. r1: Math.min(width, height) / 2,
  141. r2: Math.max(width, height) / 2,
  142. r0: Math.sqrt(width * width + height * height) / 2,
  143. path: rectPath(x, y, width, height),
  144. vb: [x, y, width, height].join(' ')
  145. };
  146. };
  147. var isBBoxIntersect = function isBBoxIntersect(bbox1, bbox2) {
  148. bbox1 = box(bbox1);
  149. bbox2 = box(bbox2);
  150. return isPointInsideBBox(bbox2, bbox1.x, bbox1.y) || isPointInsideBBox(bbox2, bbox1.x2, bbox1.y) || isPointInsideBBox(bbox2, bbox1.x, bbox1.y2) || isPointInsideBBox(bbox2, bbox1.x2, bbox1.y2) || isPointInsideBBox(bbox1, bbox2.x, bbox2.y) || isPointInsideBBox(bbox1, bbox2.x2, bbox2.y) || isPointInsideBBox(bbox1, bbox2.x, bbox2.y2) || isPointInsideBBox(bbox1, bbox2.x2, bbox2.y2) || (bbox1.x < bbox2.x2 && bbox1.x > bbox2.x || bbox2.x < bbox1.x2 && bbox2.x > bbox1.x) && (bbox1.y < bbox2.y2 && bbox1.y > bbox2.y || bbox2.y < bbox1.y2 && bbox2.y > bbox1.y);
  151. };
  152. var bezierBBox = function bezierBBox(p1x, p1y, c1x, c1y, c2x, c2y, p2x, p2y) {
  153. if (!isArray(p1x)) {
  154. p1x = [p1x, p1y, c1x, c1y, c2x, c2y, p2x, p2y];
  155. }
  156. var bbox = curveDim.apply(null, p1x);
  157. return box(bbox.min.x, bbox.min.y, bbox.max.x - bbox.min.x, bbox.max.y - bbox.min.y);
  158. };
  159. var findDotsAtSegment = function findDotsAtSegment(p1x, p1y, c1x, c1y, c2x, c2y, p2x, p2y, t) {
  160. var t1 = 1 - t;
  161. var t13 = Math.pow(t1, 3);
  162. var t12 = Math.pow(t1, 2);
  163. var t2 = t * t;
  164. var t3 = t2 * t;
  165. var x = t13 * p1x + t12 * 3 * t * c1x + t1 * 3 * t * t * c2x + t3 * p2x;
  166. var y = t13 * p1y + t12 * 3 * t * c1y + t1 * 3 * t * t * c2y + t3 * p2y;
  167. var mx = p1x + 2 * t * (c1x - p1x) + t2 * (c2x - 2 * c1x + p1x);
  168. var my = p1y + 2 * t * (c1y - p1y) + t2 * (c2y - 2 * c1y + p1y);
  169. var nx = c1x + 2 * t * (c2x - c1x) + t2 * (p2x - 2 * c2x + c1x);
  170. var ny = c1y + 2 * t * (c2y - c1y) + t2 * (p2y - 2 * c2y + c1y);
  171. var ax = t1 * p1x + t * c1x;
  172. var ay = t1 * p1y + t * c1y;
  173. var cx = t1 * c2x + t * p2x;
  174. var cy = t1 * c2y + t * p2y;
  175. var alpha = 90 - Math.atan2(mx - nx, my - ny) * 180 / Math.PI;
  176. // (mx > nx || my < ny) && (alpha += 180);
  177. return {
  178. x: x,
  179. y: y,
  180. m: {
  181. x: mx,
  182. y: my
  183. },
  184. n: {
  185. x: nx,
  186. y: ny
  187. },
  188. start: {
  189. x: ax,
  190. y: ay
  191. },
  192. end: {
  193. x: cx,
  194. y: cy
  195. },
  196. alpha: alpha
  197. };
  198. };
  199. var interHelper = function interHelper(bez1, bez2, justCount) {
  200. var bbox1 = bezierBBox(bez1);
  201. var bbox2 = bezierBBox(bez2);
  202. if (!isBBoxIntersect(bbox1, bbox2)) {
  203. return justCount ? 0 : [];
  204. }
  205. var l1 = bezlen.apply(0, bez1);
  206. var l2 = bezlen.apply(0, bez2);
  207. var n1 = ~~(l1 / 8);
  208. var n2 = ~~(l2 / 8);
  209. var dots1 = [];
  210. var dots2 = [];
  211. var xy = {};
  212. var res = justCount ? 0 : [];
  213. for (var i = 0; i < n1 + 1; i++) {
  214. var d = findDotsAtSegment.apply(0, bez1.concat(i / n1));
  215. dots1.push({
  216. x: d.x,
  217. y: d.y,
  218. t: i / n1
  219. });
  220. }
  221. for (var _i = 0; _i < n2 + 1; _i++) {
  222. var _d = findDotsAtSegment.apply(0, bez2.concat(_i / n2));
  223. dots2.push({
  224. x: _d.x,
  225. y: _d.y,
  226. t: _i / n2
  227. });
  228. }
  229. for (var _i2 = 0; _i2 < n1; _i2++) {
  230. for (var j = 0; j < n2; j++) {
  231. var di = dots1[_i2];
  232. var di1 = dots1[_i2 + 1];
  233. var dj = dots2[j];
  234. var dj1 = dots2[j + 1];
  235. var ci = Math.abs(di1.x - di.x) < 0.001 ? 'y' : 'x';
  236. var cj = Math.abs(dj1.x - dj.x) < 0.001 ? 'y' : 'x';
  237. var is = intersect(di.x, di.y, di1.x, di1.y, dj.x, dj.y, dj1.x, dj1.y);
  238. if (is) {
  239. if (xy[is.x.toFixed(4)] === is.y.toFixed(4)) {
  240. continue;
  241. }
  242. xy[is.x.toFixed(4)] = is.y.toFixed(4);
  243. var t1 = di.t + Math.abs((is[ci] - di[ci]) / (di1[ci] - di[ci])) * (di1.t - di.t);
  244. var t2 = dj.t + Math.abs((is[cj] - dj[cj]) / (dj1[cj] - dj[cj])) * (dj1.t - dj.t);
  245. if (t1 >= 0 && t1 <= 1 && t2 >= 0 && t2 <= 1) {
  246. if (justCount) {
  247. res++;
  248. } else {
  249. res.push({
  250. x: is.x,
  251. y: is.y,
  252. t1: t1,
  253. t2: t2
  254. });
  255. }
  256. }
  257. }
  258. }
  259. }
  260. return res;
  261. };
  262. var interPathHelper = function interPathHelper(path1, path2, justCount) {
  263. path1 = pathTocurve(path1);
  264. path2 = pathTocurve(path2);
  265. var x1 = void 0;
  266. var y1 = void 0;
  267. var x2 = void 0;
  268. var y2 = void 0;
  269. var x1m = void 0;
  270. var y1m = void 0;
  271. var x2m = void 0;
  272. var y2m = void 0;
  273. var bez1 = void 0;
  274. var bez2 = void 0;
  275. var res = justCount ? 0 : [];
  276. for (var i = 0, ii = path1.length; i < ii; i++) {
  277. var pi = path1[i];
  278. if (pi[0] === 'M') {
  279. x1 = x1m = pi[1];
  280. y1 = y1m = pi[2];
  281. } else {
  282. if (pi[0] === 'C') {
  283. bez1 = [x1, y1].concat(pi.slice(1));
  284. x1 = bez1[6];
  285. y1 = bez1[7];
  286. } else {
  287. bez1 = [x1, y1, x1, y1, x1m, y1m, x1m, y1m];
  288. x1 = x1m;
  289. y1 = y1m;
  290. }
  291. for (var j = 0, jj = path2.length; j < jj; j++) {
  292. var pj = path2[j];
  293. if (pj[0] === 'M') {
  294. x2 = x2m = pj[1];
  295. y2 = y2m = pj[2];
  296. } else {
  297. if (pj[0] === 'C') {
  298. bez2 = [x2, y2].concat(pj.slice(1));
  299. x2 = bez2[6];
  300. y2 = bez2[7];
  301. } else {
  302. bez2 = [x2, y2, x2, y2, x2m, y2m, x2m, y2m];
  303. x2 = x2m;
  304. y2 = y2m;
  305. }
  306. var intr = interHelper(bez1, bez2, justCount);
  307. if (justCount) {
  308. res += intr;
  309. } else {
  310. for (var k = 0, kk = intr.length; k < kk; k++) {
  311. intr[k].segment1 = i;
  312. intr[k].segment2 = j;
  313. intr[k].bez1 = bez1;
  314. intr[k].bez2 = bez2;
  315. }
  316. res = res.concat(intr);
  317. }
  318. }
  319. }
  320. }
  321. }
  322. return res;
  323. };
  324. module.exports = function pathIntersection(path1, path2) {
  325. return interPathHelper(path1, path2);
  326. };