1 /* 2 Copyright 2008-2025 3 Matthias Ehmann, 4 Michael Gerhaeuser, 5 Carsten Miller, 6 Bianca Valentin, 7 Alfred Wassermann, 8 Peter Wilfahrt 9 10 This file is part of JSXGraph. 11 12 JSXGraph is free software dual licensed under the GNU LGPL or MIT License. 13 14 You can redistribute it and/or modify it under the terms of the 15 16 * GNU Lesser General Public License as published by 17 the Free Software Foundation, either version 3 of the License, or 18 (at your option) any later version 19 OR 20 * MIT License: https://github.com/jsxgraph/jsxgraph/blob/master/LICENSE.MIT 21 22 JSXGraph is distributed in the hope that it will be useful, 23 but WITHOUT ANY WARRANTY; without even the implied warranty of 24 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 25 GNU Lesser General Public License for more details. 26 27 You should have received a copy of the GNU Lesser General Public License and 28 the MIT License along with JSXGraph. If not, see <https://www.gnu.org/licenses/> 29 and <https://opensource.org/licenses/MIT/>. 30 */ 31 32 /*global JXG: true, define: true*/ 33 /*jslint nomen: true, plusplus: true*/ 34 35 /** 36 * @fileoverview In this file the geometry object Arc is defined. Arc stores all 37 * style and functional properties that are required to draw an arc on a board. 38 */ 39 40 import JXG from "../jxg.js"; 41 import Geometry from "../math/geometry.js"; 42 import Mat from "../math/math.js"; 43 import Coords from "../base/coords.js"; 44 import Circle from "../base/circle.js"; 45 import Type from "../utils/type.js"; 46 import Const from "../base/constants.js"; 47 48 /** 49 * @class An arc is a partial circumference line of a circle. 50 * It is defined by a center, one point that 51 * defines the radius, and a third point that defines the angle of the arc. 52 * <p> 53 * As a curve the arc has curve length 6. 54 * @pseudo 55 * @name Arc 56 * @augments Curve 57 * @constructor 58 * @type JXG.Curve 59 * @throws {Error} If the element cannot be constructed with the given parent objects an exception is thrown. 60 * @param {JXG.Point_JXG.Point_JXG.Point} p1,p2,p3 The result will be an arc of a circle around p1 through p2. The arc is drawn 61 * counter-clockwise from p2 to p3. 62 * @example 63 * // Create an arc out of three free points 64 * var p1 = board.create('point', [2.0, 2.0]); 65 * var p2 = board.create('point', [1.0, 0.5]); 66 * var p3 = board.create('point', [3.5, 1.0]); 67 * 68 * var a = board.create('arc', [p1, p2, p3]); 69 * board.create('text',[1,6,function(){return 'arclength: '+Math.round(a.Value()*100)/100}]) 70 * </pre><div class="jxgbox" id="JXG114ef584-4a5e-4686-8392-c97501befb5b" style="width: 300px; height: 300px;"></div> 71 * <script type="text/javascript"> 72 * (function () { 73 * var board = JXG.JSXGraph.initBoard('JXG114ef584-4a5e-4686-8392-c97501befb5b', {boundingbox: [-1, 7, 7, -1], axis: true, showcopyright: false, shownavigation: false}), 74 * p1 = board.create('point', [2.0, 2.0]), 75 * p2 = board.create('point', [1.0, 0.5]), 76 * p3 = board.create('point', [3.5, 1.0]), 77 * 78 * a = board.create('arc', [p1, p2, p3]); 79 * board.create('text',[1,6,function(){return 'arclength: '+Math.round(a.Value()*100)/100}]) 80 * })(); 81 * </script><pre> 82 * 83 * @example 84 * var t = board.create('transform', [2, 1.5], {type: 'scale'}); 85 * var a1 = board.create('arc', [[1, 1], [0, 1], [1, 0]], {strokeColor: 'red'}); 86 * var a2 = board.create('curve', [a1, t], {strokeColor: 'red'}); 87 * 88 * </pre><div id="JXG1949da46-6339-11e8-9fb9-901b0e1b8723" class="jxgbox" style="width: 300px; height: 300px;"></div> 89 * <script type="text/javascript"> 90 * (function() { 91 * var board = JXG.JSXGraph.initBoard('JXG1949da46-6339-11e8-9fb9-901b0e1b8723', 92 * {boundingbox: [-8, 8, 8,-8], axis: true, showcopyright: false, shownavigation: false}); 93 * var t = board.create('transform', [2, 1.5], {type: 'scale'}); 94 * var a1 = board.create('arc', [[1, 1], [0, 1], [1, 0]], {strokeColor: 'red'}); 95 * var a2 = board.create('curve', [a1, t], {strokeColor: 'red'}); 96 * 97 * })(); 98 * 99 * </script><pre> 100 * 101 */ 102 JXG.createArc = function (board, parents, attributes) { 103 var el, attr, points; 104 105 // attributes.radiusPoint = {visible: false}; 106 points = Type.providePoints(board, parents, attributes, "arc", [ 107 "center", 108 "radiuspoint", 109 "anglepoint" 110 ]); 111 if (points === false || points.length < 3) { 112 throw new Error( 113 "JSXGraph: Can't create Arc with parent types '" + 114 typeof parents[0] + 115 "' and '" + 116 typeof parents[1] + 117 "' and '" + 118 typeof parents[2] + 119 "'." + 120 "\nPossible parent types: [point,point,point], [arc, transformation]" 121 ); 122 } 123 124 attr = Type.copyAttributes(attributes, board.options, "arc"); 125 el = board.create("curve", [[0], [0], 0, 4], attr); 126 127 el.elType = "arc"; 128 el.setParents(points); 129 130 /** 131 * documented in JXG.GeometryElement 132 * @ignore 133 */ 134 el.type = Const.OBJECT_TYPE_ARC; 135 136 /** 137 * Center of the arc. 138 * @memberOf Arc.prototype 139 * @name center 140 * @type JXG.Point 141 */ 142 el.center = points[0]; 143 144 /** 145 * Point defining the arc's radius. 146 * @memberOf Arc.prototype 147 * @name radiuspoint 148 * @type JXG.Point 149 */ 150 el.radiuspoint = points[1]; 151 el.point2 = el.radiuspoint; 152 153 /** 154 * The point defining the arc's angle. 155 * @memberOf Arc.prototype 156 * @name anglepoint 157 * @type JXG.Point 158 */ 159 el.anglepoint = points[2]; 160 el.point3 = el.anglepoint; 161 162 // Add arc as child to defining points 163 // or vice versa if the points are provided as coordinates 164 if (Type.exists(el.center._is_new)) { 165 el.addChild(el.center); 166 delete el.center._is_new; 167 } else { 168 el.center.addChild(el); 169 } 170 if (Type.exists(el.radiuspoint._is_new)) { 171 el.addChild(el.radiuspoint); 172 delete el.radiuspoint._is_new; 173 } else { 174 el.radiuspoint.addChild(el); 175 } 176 if (Type.exists(el.anglepoint._is_new)) { 177 el.addChild(el.anglepoint); 178 delete el.anglepoint._is_new; 179 } else { 180 el.anglepoint.addChild(el); 181 } 182 183 // This attribute is necessary for circumCircleArcs 184 el.useDirection = attr.usedirection; // This makes the attribute immutable 185 186 // documented in JXG.Curve 187 /** 188 * @class 189 * @ignore 190 */ 191 el.updateDataArray = function () { 192 var ar, phi, det, 193 p0c, p1c, p2c, 194 sgn = 1, 195 A = this.radiuspoint, 196 B = this.center, 197 C = this.anglepoint, 198 ev_s = this.evalVisProp('selection'); 199 200 phi = Geometry.rad(A, B, C); 201 if ((ev_s === "minor" && phi > Math.PI) || (ev_s === "major" && phi < Math.PI)) { 202 sgn = -1; 203 } 204 205 // This is true for circumCircleArcs. In that case there is 206 // a fourth parent element: [center, point1, point3, point2] 207 if (this.useDirection) { 208 p0c = points[1].coords.usrCoords; 209 p1c = points[3].coords.usrCoords; 210 p2c = points[2].coords.usrCoords; 211 det = (p0c[1] - p2c[1]) * (p0c[2] - p1c[2]) - (p0c[2] - p2c[2]) * (p0c[1] - p1c[1]); 212 213 if (det < 0) { 214 this.radiuspoint = points[1]; 215 this.anglepoint = points[2]; 216 } else { 217 this.radiuspoint = points[2]; 218 this.anglepoint = points[1]; 219 } 220 } 221 222 A = A.coords.usrCoords; 223 B = B.coords.usrCoords; 224 C = C.coords.usrCoords; 225 226 ar = Geometry.bezierArc(A, B, C, false, sgn); 227 228 this.dataX = ar[0]; 229 this.dataY = ar[1]; 230 231 this.bezierDegree = 3; 232 233 this.updateStdform(); 234 this.updateQuadraticform(); 235 }; 236 237 /** 238 * Determines the arc's current radius. I.e. the distance between {@link Arc#center} and {@link Arc#radiuspoint}. 239 * @memberOf Arc.prototype 240 * @name Radius 241 * @function 242 * @returns {Number} The arc's radius 243 */ 244 el.Radius = function () { 245 return this.radiuspoint.Dist(this.center); 246 }; 247 248 /** 249 * @deprecated Use {@link Arc#Radius} 250 * @memberOf Arc.prototype 251 * @name getRadius 252 * @function 253 * @returns {Number} 254 */ 255 el.getRadius = function () { 256 JXG.deprecated("Arc.getRadius()", "Arc.Radius()"); 257 return this.Radius(); 258 }; 259 260 /** 261 * Returns the length of the arc or the value of the angle spanned by the arc. 262 * @memberOf Arc.prototype 263 * @name Value 264 * @function 265 * @param {String} [unit='length'] Unit of the returned values. Possible units are 266 * <ul> 267 * <li> 'length' (default): length of the arc line 268 * <li> 'radians': angle spanned by the arc in radians 269 * <li> 'degrees': angle spanned by the arc in degrees 270 * <li> 'semicircle': angle spanned by the arc in radians as a multiple of π, e.g. if the angle is 1.5π, 1.5 will be returned. 271 * <li> 'circle': angle spanned by the arc in radians as a multiple of 2π 272 * </ul> 273 * It is sufficient to supply the first three characters of the unit, e.g. 'len'. 274 * @param {Number} [rad=undefined] Value of angle which can be used instead of the generic one. 275 * @returns {Number} The arc length or the angle value in various units. 276 */ 277 el.Value = function (unit, rad) { 278 var val; 279 280 rad = rad || Geometry.rad(this.radiuspoint, this.center, this.anglepoint); 281 282 unit = unit || 'length'; 283 unit = unit.toLocaleLowerCase(); 284 if (unit === '' || unit.indexOf('len') === 0) { 285 val = rad * this.Radius(); 286 } else if (unit.indexOf('rad') === 0) { 287 val = rad; 288 } else if (unit.indexOf('deg') === 0) { 289 val = rad * 180 / Math.PI; 290 } else if (unit.indexOf('sem') === 0) { 291 val = rad / Math.PI; 292 } else if (unit.indexOf('cir') === 0) { 293 val = rad * 0.5 / Math.PI; 294 } 295 296 return val; 297 }; 298 299 /** 300 * Arc length. 301 * @memberOf Arc.prototype 302 * @name L 303 * @returns {Number} Length of the arc. 304 * @see Arc#Value 305 */ 306 el.L = function() { 307 return this.Value('length'); 308 }; 309 310 // documented in geometry element 311 el.hasPoint = function (x, y) { 312 var dist, 313 checkPoint, 314 has, 315 invMat, 316 c, 317 prec, 318 type, 319 r = this.Radius(); 320 321 if (this.evalVisProp('hasinnerpoints')) { 322 return this.hasPointSector(x, y); 323 } 324 325 if (Type.isObject(this.evalVisProp('precision'))) { 326 type = this.board._inputDevice; 327 prec = this.evalVisProp('precision.' + type); 328 } else { 329 // 'inherit' 330 prec = this.board.options.precision.hasPoint; 331 } 332 prec /= Math.min(Math.abs(this.board.unitX), Math.abs(this.board.unitY)); 333 checkPoint = new Coords(Const.COORDS_BY_SCREEN, [x, y], this.board); 334 335 if (this.transformations.length > 0) { 336 // Transform the mouse/touch coordinates 337 // back to the original position of the curve. 338 this.updateTransformMatrix(); 339 invMat = Mat.inverse(this.transformMat); 340 c = Mat.matVecMult(invMat, checkPoint.usrCoords); 341 checkPoint = new Coords(Const.COORDS_BY_USER, c, this.board); 342 } 343 344 dist = this.center.coords.distance(Const.COORDS_BY_USER, checkPoint); 345 has = Math.abs(dist - r) < prec; 346 347 /** 348 * At that point we know that the user has touched the circle line. 349 * Now, we have to check, if the user has hit the arc path. 350 */ 351 if (has) { 352 has = Geometry.coordsOnArc(this, checkPoint); 353 } 354 return has; 355 }; 356 357 /** 358 * Checks whether (x,y) is within the sector defined by the arc. 359 * @memberOf Arc.prototype 360 * @name hasPointSector 361 * @function 362 * @param {Number} x Coordinate in x direction, screen coordinates. 363 * @param {Number} y Coordinate in y direction, screen coordinates. 364 * @returns {Boolean} True if (x,y) is within the sector defined by the arc, False otherwise. 365 */ 366 el.hasPointSector = function (x, y) { 367 var checkPoint = new Coords(Const.COORDS_BY_SCREEN, [x, y], this.board), 368 r = this.Radius(), 369 dist = this.center.coords.distance(Const.COORDS_BY_USER, checkPoint), 370 has = dist < r; 371 372 if (has) { 373 has = Geometry.coordsOnArc(this, checkPoint); 374 } 375 return has; 376 }; 377 378 // documented in geometry element 379 el.getTextAnchor = function () { 380 return this.center.coords; 381 }; 382 383 // documented in geometry element 384 /** 385 * @class 386 * @ignore 387 */ 388 el.getLabelAnchor = function () { 389 var coords, 390 vec, vecx, vecy, 391 len, 392 pos = this.label.evalVisProp('position'), 393 angle = Geometry.rad(this.radiuspoint, this.center, this.anglepoint), 394 dx = 10 / this.board.unitX, 395 dy = 10 / this.board.unitY, 396 p2c = this.point2.coords.usrCoords, 397 pmc = this.center.coords.usrCoords, 398 bxminusax = p2c[1] - pmc[1], 399 byminusay = p2c[2] - pmc[2], 400 ev_s = this.evalVisProp('selection'), 401 l_vp = this.label ? this.label.visProp : this.visProp.label; 402 403 // If this is uncommented, the angle label can not be dragged 404 //if (Type.exists(this.label)) { 405 // this.label.relativeCoords = new Coords(Const.COORDS_BY_SCREEN, [0, 0], this.board); 406 //} 407 408 if ( 409 !Type.isString(pos) || 410 (pos.indexOf('right') < 0 && pos.indexOf('left') < 0) 411 ) { 412 413 if ((ev_s === "minor" && angle > Math.PI) || (ev_s === "major" && angle < Math.PI)) { 414 angle = -(2 * Math.PI - angle); 415 } 416 417 coords = new Coords( 418 Const.COORDS_BY_USER, 419 [ 420 pmc[1] + Math.cos(angle * 0.5) * bxminusax - Math.sin(angle * 0.5) * byminusay, 421 pmc[2] + Math.sin(angle * 0.5) * bxminusax + Math.cos(angle * 0.5) * byminusay 422 ], 423 this.board 424 ); 425 426 vecx = coords.usrCoords[1] - pmc[1]; 427 vecy = coords.usrCoords[2] - pmc[2]; 428 429 len = Mat.hypot(vecx, vecy); 430 vecx = (vecx * (len + dx)) / len; 431 vecy = (vecy * (len + dy)) / len; 432 vec = [pmc[1] + vecx, pmc[2] + vecy]; 433 434 l_vp.position = Geometry.calcLabelQuadrant(Geometry.rad([1, 0], [0, 0], vec)); 435 436 return new Coords(Const.COORDS_BY_USER, vec, this.board); 437 } else { 438 return this.getLabelPosition(pos, this.label.evalVisProp('distance')); 439 } 440 441 }; 442 443 // documentation in jxg.circle 444 el.updateQuadraticform = Circle.prototype.updateQuadraticform; 445 446 // documentation in jxg.circle 447 el.updateStdform = Circle.prototype.updateStdform; 448 449 el.methodMap = JXG.deepCopy(el.methodMap, { 450 getRadius: "getRadius", 451 radius: "Radius", 452 Radius: "Radius", 453 center: "center", 454 radiuspoint: "radiuspoint", 455 anglepoint: "anglepoint", 456 Value: "Value", 457 L: "L" 458 }); 459 460 el.prepareUpdate().update(); 461 return el; 462 }; 463 464 JXG.registerElement("arc", JXG.createArc); 465 466 /** 467 * @class A semicircle is a special arc defined by two points. The arc hits both points. 468 * @pseudo 469 * @name Semicircle 470 * @augments Arc 471 * @constructor 472 * @type Arc 473 * @throws {Error} If the element cannot be constructed with the given parent objects an exception is thrown. 474 * @param {JXG.Point_JXG.Point} p1,p2 The result will be a composition of an arc drawn clockwise from <tt>p1</tt> and 475 * <tt>p2</tt> and the midpoint of <tt>p1</tt> and <tt>p2</tt>. 476 * @example 477 * // Create an arc out of three free points 478 * var p1 = board.create('point', [4.5, 2.0]); 479 * var p2 = board.create('point', [1.0, 0.5]); 480 * 481 * var a = board.create('semicircle', [p1, p2]); 482 * </pre><div class="jxgbox" id="JXG5385d349-75d7-4078-b732-9ae808db1b0e" style="width: 300px; height: 300px;"></div> 483 * <script type="text/javascript"> 484 * (function () { 485 * var board = JXG.JSXGraph.initBoard('JXG5385d349-75d7-4078-b732-9ae808db1b0e', {boundingbox: [-1, 7, 7, -1], axis: true, showcopyright: false, shownavigation: false}), 486 * p1 = board.create('point', [4.5, 2.0]), 487 * p2 = board.create('point', [1.0, 0.5]), 488 * 489 * sc = board.create('semicircle', [p1, p2]); 490 * })(); 491 * </script><pre> 492 */ 493 JXG.createSemicircle = function (board, parents, attributes) { 494 var el, mp, attr, points; 495 496 // we need 2 points 497 points = Type.providePoints(board, parents, attributes, "point"); 498 if (points === false || points.length !== 2) { 499 throw new Error( 500 "JSXGraph: Can't create Semicircle with parent types '" + 501 typeof parents[0] + 502 "' and '" + 503 typeof parents[1] + 504 "'." + 505 "\nPossible parent types: [point,point]" 506 ); 507 } 508 509 attr = Type.copyAttributes(attributes, board.options, "semicircle", "center"); 510 mp = board.create("midpoint", points, attr); 511 mp.dump = false; 512 513 attr = Type.copyAttributes(attributes, board.options, "semicircle"); 514 el = board.create("arc", [mp, points[1], points[0]], attr); 515 el.elType = "semicircle"; 516 el.setParents([points[0].id, points[1].id]); 517 el.subs = { 518 midpoint: mp 519 }; 520 el.inherits.push(mp); 521 522 /** 523 * The midpoint of the two defining points. 524 * @memberOf Semicircle.prototype 525 * @name midpoint 526 * @type Midpoint 527 */ 528 el.midpoint = el.center = mp; 529 530 return el; 531 }; 532 533 JXG.registerElement("semicircle", JXG.createSemicircle); 534 535 /** 536 * @class A partial circum circle through three points. 537 * @pseudo 538 * @name CircumcircleArc 539 * @augments Arc 540 * @constructor 541 * @type Arc 542 * @throws {Error} If the element cannot be constructed with the given parent objects an exception is thrown. 543 * @param {JXG.Point_JXG.Point_JXG.Point} p1,p2,p3 The result will be a composition of an arc of the circumcircle of 544 * <tt>p1</tt>, <tt>p2</tt>, and <tt>p3</tt> and the midpoint of the circumcircle of the three points. The arc is drawn 545 * counter-clockwise from <tt>p1</tt> over <tt>p2</tt> to <tt>p3</tt>. 546 * @example 547 * // Create a circum circle arc out of three free points 548 * var p1 = board.create('point', [2.0, 2.0]); 549 * var p2 = board.create('point', [1.0, 0.5]); 550 * var p3 = board.create('point', [3.5, 1.0]); 551 * 552 * var a = board.create('circumcirclearc', [p1, p2, p3]); 553 * </pre><div class="jxgbox" id="JXG87125fd4-823a-41c1-88ef-d1a1369504e3" style="width: 300px; height: 300px;"></div> 554 * <script type="text/javascript"> 555 * (function () { 556 * var board = JXG.JSXGraph.initBoard('JXG87125fd4-823a-41c1-88ef-d1a1369504e3', {boundingbox: [-1, 7, 7, -1], axis: true, showcopyright: false, shownavigation: false}), 557 * p1 = board.create('point', [2.0, 2.0]), 558 * p2 = board.create('point', [1.0, 0.5]), 559 * p3 = board.create('point', [3.5, 1.0]), 560 * 561 * cca = board.create('circumcirclearc', [p1, p2, p3]); 562 * })(); 563 * </script><pre> 564 */ 565 JXG.createCircumcircleArc = function (board, parents, attributes) { 566 var el, mp, attr, points; 567 568 // We need three points 569 points = Type.providePoints(board, parents, attributes, "point"); 570 if (points === false || points.length !== 3) { 571 throw new Error( 572 "JSXGraph: create Circumcircle Arc with parent types '" + 573 typeof parents[0] + 574 "' and '" + 575 typeof parents[1] + 576 "' and '" + 577 typeof parents[2] + 578 "'." + 579 "\nPossible parent types: [point,point,point]" 580 ); 581 } 582 583 attr = Type.copyAttributes(attributes, board.options, "circumcirclearc", "center"); 584 mp = board.create("circumcenter", points, attr); 585 mp.dump = false; 586 587 attr = Type.copyAttributes(attributes, board.options, "circumcirclearc"); 588 attr.usedirection = true; 589 el = board.create("arc", [mp, points[0], points[2], points[1]], attr); 590 591 el.elType = "circumcirclearc"; 592 el.setParents([points[0].id, points[1].id, points[2].id]); 593 el.subs = { 594 center: mp 595 }; 596 el.inherits.push(mp); 597 598 /** 599 * The midpoint of the circumcircle of the three points defining the circumcircle arc. 600 * @memberOf CircumcircleArc.prototype 601 * @name center 602 * @type Circumcenter 603 */ 604 el.center = mp; 605 606 return el; 607 }; 608 609 JXG.registerElement("circumcirclearc", JXG.createCircumcircleArc); 610 611 /** 612 * @class A minor arc given by three points is that part of the circumference of a circle having 613 * measure at most 180 degrees (pi radians). It is defined by a center, one point that 614 * defines the radius, and a third point that defines the angle of the arc. 615 * @pseudo 616 * @name MinorArc 617 * @augments Curve 618 * @constructor 619 * @type JXG.Curve 620 * @throws {Error} If the element cannot be constructed with the given parent objects an exception is thrown. 621 * @param {JXG.Point_JXG.Point_JXG.Point} p1,p2,p3 . Minor arc is an arc of a circle around p1 having measure less than or equal to 622 * 180 degrees (pi radians) and starts at p2. The radius is determined by p2, the angle by p3. 623 * @example 624 * // Create an arc out of three free points 625 * var p1 = board.create('point', [2.0, 2.0]); 626 * var p2 = board.create('point', [1.0, 0.5]); 627 * var p3 = board.create('point', [3.5, 1.0]); 628 * 629 * var a = board.create('arc', [p1, p2, p3]); 630 * </pre><div class="jxgbox" id="JXG64ba7ca2-8728-45f3-96e5-3c7a4414de2f" style="width: 300px; height: 300px;"></div> 631 * <script type="text/javascript"> 632 * (function () { 633 * var board = JXG.JSXGraph.initBoard('JXG64ba7ca2-8728-45f3-96e5-3c7a4414de2f', {boundingbox: [-1, 7, 7, -1], axis: true, showcopyright: false, shownavigation: false}), 634 * p1 = board.create('point', [2.0, 2.0]), 635 * p2 = board.create('point', [1.0, 0.5]), 636 * p3 = board.create('point', [3.5, 1.0]), 637 * 638 * a = board.create('minorarc', [p1, p2, p3]); 639 * })(); 640 * </script><pre> 641 */ 642 643 JXG.createMinorArc = function (board, parents, attributes) { 644 attributes.selection = "minor"; 645 return JXG.createArc(board, parents, attributes); 646 }; 647 648 JXG.registerElement("minorarc", JXG.createMinorArc); 649 650 /** 651 * @class A major arc given by three points is that part of the circumference of a circle having 652 * measure at least 180 degrees (pi radians). It is defined by a center, one point that 653 * defines the radius, and a third point that defines the angle of the arc. 654 * @pseudo 655 * @name MajorArc 656 * @augments Curve 657 * @constructor 658 * @type JXG.Curve 659 * @throws {Error} If the element cannot be constructed with the given parent objects an exception is thrown. 660 * @param {JXG.Point_JXG.Point_JXG.Point} p1,p2,p3 . Major arc is an arc of a circle around p1 having measure greater than or equal to 661 * 180 degrees (pi radians) and starts at p2. The radius is determined by p2, the angle by p3. 662 * @example 663 * // Create an arc out of three free points 664 * var p1 = board.create('point', [2.0, 2.0]); 665 * var p2 = board.create('point', [1.0, 0.5]); 666 * var p3 = board.create('point', [3.5, 1.0]); 667 * 668 * var a = board.create('majorarc', [p1, p2, p3]); 669 * </pre><div class="jxgbox" id="JXG17a10d38-5629-40a4-b150-f41806edee9f" style="width: 300px; height: 300px;"></div> 670 * <script type="text/javascript"> 671 * (function () { 672 * var board = JXG.JSXGraph.initBoard('JXG17a10d38-5629-40a4-b150-f41806edee9f', {boundingbox: [-1, 7, 7, -1], axis: true, showcopyright: false, shownavigation: false}), 673 * p1 = board.create('point', [2.0, 2.0]), 674 * p2 = board.create('point', [1.0, 0.5]), 675 * p3 = board.create('point', [3.5, 1.0]), 676 * 677 * a = board.create('majorarc', [p1, p2, p3]); 678 * })(); 679 * </script><pre> 680 */ 681 JXG.createMajorArc = function (board, parents, attributes) { 682 attributes.selection = "major"; 683 return JXG.createArc(board, parents, attributes); 684 }; 685 686 JXG.registerElement("majorarc", JXG.createMajorArc); 687