1 /* 2 Copyright 2008-2015 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 <http://www.gnu.org/licenses/> 29 and <http://opensource.org/licenses/MIT/>. 30 */ 31 32 33 /*global JXG: true, define: true*/ 34 /*jslint nomen: true, plusplus: true*/ 35 36 /* depends: 37 jxg 38 base/element 39 base/constants 40 base/coords 41 parser/geonext 42 math/geometry 43 math/statistics 44 utils/type 45 elements: 46 transform 47 point 48 */ 49 50 /** 51 * @fileoverview The geometry object Circle is defined in this file. Circle stores all 52 * style and functional properties that are required to draw and move a circle on 53 * a board. 54 * @author graphjs 55 * @version 0.1 56 */ 57 58 define([ 59 'jxg', 'base/element', 'base/coords', 'base/constants', 'parser/geonext', 'math/geometry', 'math/statistics', 60 'utils/type', 'base/transformation', 'base/point' 61 ], function (JXG, GeometryElement, Coords, Const, GeonextParser, Geometry, Statistics, Type, Transform, Point) { 62 63 "use strict"; 64 65 /** 66 * A circle consists of all points with a given distance from one point. This point is called center, the distance is called radius. 67 * A circle can be constructed by providing a center and a point on the circle or a center and a radius (given as a number, function, 68 * line, or circle). 69 * @class Creates a new circle object. Do not use this constructor to create a circle. Use {@link JXG.Board#create} with 70 * type {@link Circle} instead. 71 * @constructor 72 * @augments JXG.GeometryElement 73 * @param {JXG.Board} board The board the new circle is drawn on. 74 * @param {String} method Can be 75 * <ul><li> <b>'twoPoints'</b> which means the circle is defined by its center and a point on the circle.</li> 76 * <li><b>'pointRadius'</b> which means the circle is defined by its center and its radius in user units</li> 77 * <li><b>'pointLine'</b> which means the circle is defined by its center and its radius given by the distance from the startpoint and the endpoint of the line</li> 78 * <li><b>'pointCircle'</b> which means the circle is defined by its center and its radius given by the radius of another circle</li></ul> 79 * The parameters p1, p2 and radius must be set according to this method parameter. 80 * @param {JXG.Point} par1 center of the circle. 81 * @param {JXG.Point|JXG.Line|JXG.Circle} par2 Can be 82 * <ul><li>a point on the circle if method is 'twoPoints'</li> 83 * <li>a line if the method is 'pointLine'</li> 84 * <li>a circle if the method is 'pointCircle'</li></ul> 85 * @param {Object} attributes 86 * @see JXG.Board#generateName 87 */ 88 JXG.Circle = function (board, method, par1, par2, attributes) { 89 // Call the constructor of GeometryElement 90 this.constructor(board, attributes, Const.OBJECT_TYPE_CIRCLE, Const.OBJECT_CLASS_CIRCLE); 91 92 /** 93 * Stores the given method. 94 * Can be 95 * <ul><li><b>'twoPoints'</b> which means the circle is defined by its center and a point on the circle.</li> 96 * <li><b>'pointRadius'</b> which means the circle is defined by its center and its radius given in user units or as term.</li> 97 * <li><b>'pointLine'</b> which means the circle is defined by its center and its radius given by the distance from the startpoint and the endpoint of the line.</li> 98 * <li><b>'pointCircle'</b> which means the circle is defined by its center and its radius given by the radius of another circle.</li></ul> 99 * @type string 100 * @see #center 101 * @see #point2 102 * @see #radius 103 * @see #line 104 * @see #circle 105 */ 106 this.method = method; 107 108 // this is kept so existing code won't ne broken 109 this.midpoint = this.board.select(par1); 110 111 /** 112 * The circles center. Do not set this parameter directly as it will break JSXGraph's update system. 113 * @type JXG.Point 114 */ 115 this.center = this.board.select(par1); 116 117 /** Point on the circle only set if method equals 'twoPoints'. Do not set this parameter directly as it will break JSXGraph's update system. 118 * @type JXG.Point 119 * @see #method 120 */ 121 this.point2 = null; 122 123 /** Radius of the circle 124 * only set if method equals 'pointRadius' 125 * @type Number 126 * @default null 127 * @see #method 128 */ 129 this.radius = 0; 130 131 /** Line defining the radius of the circle given by the distance from the startpoint and the endpoint of the line 132 * only set if method equals 'pointLine'. Do not set this parameter directly as it will break JSXGraph's update system. 133 * @type JXG.Line 134 * @default null 135 * @see #method 136 */ 137 this.line = null; 138 139 /** Circle defining the radius of the circle given by the radius of the other circle 140 * only set if method equals 'pointLine'. Do not set this parameter directly as it will break JSXGraph's update system. 141 * @type JXG.Circle 142 * @default null 143 * @see #method 144 */ 145 this.circle = null; 146 147 if (method === 'twoPoints') { 148 this.point2 = board.select(par2); 149 this.radius = this.Radius(); 150 } else if (method === 'pointRadius') { 151 this.gxtterm = par2; 152 // Converts GEONExT syntax into JavaScript syntax and generally ensures that the radius is a function 153 this.updateRadius = Type.createFunction(par2, this.board, null, true); 154 // First evaluation of the graph 155 this.updateRadius(); 156 } else if (method === 'pointLine') { 157 // dann ist p2 die Id eines Objekts vom Typ Line! 158 this.line = board.select(par2); 159 this.radius = this.line.point1.coords.distance(Const.COORDS_BY_USER, this.line.point2.coords); 160 } else if (method === 'pointCircle') { 161 // dann ist p2 die Id eines Objekts vom Typ Circle! 162 this.circle = board.select(par2); 163 this.radius = this.circle.Radius(); 164 } 165 166 // create Label 167 this.id = this.board.setId(this, 'C'); 168 this.board.renderer.drawEllipse(this); 169 this.board.finalizeAdding(this); 170 171 this.createGradient(); 172 this.elType = 'circle'; 173 this.createLabel(); 174 175 this.center.addChild(this); 176 177 if (method === 'pointRadius') { 178 this.notifyParents(par2); 179 } else if (method === 'pointLine') { 180 this.line.addChild(this); 181 } else if (method === 'pointCircle') { 182 this.circle.addChild(this); 183 } else if (method === 'twoPoints') { 184 this.point2.addChild(this); 185 } 186 187 this.methodMap = Type.deepCopy(this.methodMap, { 188 setRadius: 'setRadius', 189 getRadius: 'getRadius', 190 Area: 'Area', 191 area: 'Area', 192 radius: 'Radius', 193 center: 'center', 194 line: 'line', 195 point2: 'point2' 196 }); 197 }; 198 199 JXG.Circle.prototype = new GeometryElement(); 200 201 JXG.extend(JXG.Circle.prototype, /** @lends JXG.Circle.prototype */ { 202 /** 203 * Checks whether (x,y) is near the circle line or inside of the ellipse 204 * (in case JXG.Options.conic#hasInnerPoints is true). 205 * @param {Number} x Coordinate in x direction, screen coordinates. 206 * @param {Number} y Coordinate in y direction, screen coordinates. 207 * @returns {Boolean} True if (x,y) is near the circle, False otherwise. 208 * @private 209 */ 210 hasPoint: function (x, y) { 211 var prec = this.board.options.precision.hasPoint / (this.board.unitX), 212 mp = this.center.coords.usrCoords, 213 p = new Coords(Const.COORDS_BY_SCREEN, [x, y], this.board), 214 r = this.Radius(), 215 dist = Math.sqrt((mp[1] - p.usrCoords[1]) * (mp[1] - p.usrCoords[1]) + (mp[2] - p.usrCoords[2]) * (mp[2] - p.usrCoords[2])); 216 217 if (this.visProp.hasinnerpoints) { 218 return (dist < r + prec); 219 } 220 221 return (Math.abs(dist - r) < prec); 222 }, 223 224 /** 225 * Used to generate a polynomial for a point p that lies on this circle. 226 * @param {JXG.Point} p The point for which the polynomial is generated. 227 * @returns {Array} An array containing the generated polynomial. 228 * @private 229 */ 230 generatePolynomial: function (p) { 231 /* 232 * We have four methods to construct a circle: 233 * (a) Two points 234 * (b) center and radius 235 * (c) center and radius given by length of a segment 236 * (d) center and radius given by another circle 237 * 238 * In case (b) we have to distinguish two cases: 239 * (i) radius is given as a number 240 * (ii) radius is given as a function 241 * In the latter case there's no guarantee the radius depends on other geometry elements 242 * in a polynomial way so this case has to be omitted. 243 * 244 * Another tricky case is case (d): 245 * The radius depends on another circle so we have to cycle through the ancestors of each circle 246 * until we reach one that's radius does not depend on another circles radius. 247 * 248 * 249 * All cases (a) to (d) vary only in calculation of the radius. So the basic formulae for 250 * a glider G (g1,g2) on a circle with center M (m1,m2) and radius r is just: 251 * 252 * (g1-m1)^2 + (g2-m2)^2 - r^2 = 0 253 * 254 * So the easiest case is (b) with a fixed radius given as a number. The other two cases (a) 255 * and (c) are quite the same: Euclidean distance between two points A (a1,a2) and B (b1,b2), 256 * squared: 257 * 258 * r^2 = (a1-b1)^2 + (a2-b2)^2 259 * 260 * For case (d) we have to cycle recursively through all defining circles and finally return the 261 * formulae for calculating r^2. For that we use JXG.Circle.symbolic.generateRadiusSquared(). 262 */ 263 var m1 = this.center.symbolic.x, 264 m2 = this.center.symbolic.y, 265 g1 = p.symbolic.x, 266 g2 = p.symbolic.y, 267 rsq = this.generateRadiusSquared(); 268 269 /* No radius can be calculated (Case b.ii) */ 270 if (rsq === '') { 271 return []; 272 } 273 274 return ['((' + g1 + ')-(' + m1 + '))^2 + ((' + g2 + ')-(' + m2 + '))^2 - (' + rsq + ')']; 275 }, 276 277 /** 278 * Generate symbolic radius calculation for loci determination with Groebner-Basis algorithm. 279 * @returns {String} String containing symbolic calculation of the circle's radius or an empty string 280 * if the radius can't be expressed in a polynomial equation. 281 * @private 282 */ 283 generateRadiusSquared: function () { 284 /* 285 * Four cases: 286 * 287 * (a) Two points 288 * (b) center and radius 289 * (c) center and radius given by length of a segment 290 * (d) center and radius given by another circle 291 */ 292 var m1, m2, p1, p2, q1, q2, 293 rsq = ''; 294 295 if (this.method === "twoPoints") { 296 m1 = this.center.symbolic.x; 297 m2 = this.center.symbolic.y; 298 p1 = this.point2.symbolic.x; 299 p2 = this.point2.symbolic.y; 300 301 rsq = '((' + p1 + ')-(' + m1 + '))^2 + ((' + p2 + ')-(' + m2 + '))^2'; 302 } else if (this.method === "pointRadius") { 303 if (typeof this.radius === 'number') { 304 rsq = (this.radius * this.radius).toString(); 305 } 306 } else if (this.method === "pointLine") { 307 p1 = this.line.point1.symbolic.x; 308 p2 = this.line.point1.symbolic.y; 309 310 q1 = this.line.point2.symbolic.x; 311 q2 = this.line.point2.symbolic.y; 312 313 rsq = '((' + p1 + ')-(' + q1 + '))^2 + ((' + p2 + ')-(' + q2 + '))^2'; 314 } else if (this.method === "pointCircle") { 315 rsq = this.circle.Radius(); 316 } 317 318 return rsq; 319 }, 320 321 /** 322 * Uses the boards renderer to update the circle. 323 */ 324 update: function () { 325 if (this.needsUpdate) { 326 if (this.visProp.trace) { 327 this.cloneToBackground(true); 328 } 329 330 if (this.method === 'pointLine') { 331 this.radius = this.line.point1.coords.distance(Const.COORDS_BY_USER, this.line.point2.coords); 332 } else if (this.method === 'pointCircle') { 333 this.radius = this.circle.Radius(); 334 } else if (this.method === 'pointRadius') { 335 this.radius = this.updateRadius(); 336 } 337 338 this.updateStdform(); 339 this.updateQuadraticform(); 340 } 341 342 return this; 343 }, 344 345 /** 346 * Updates this circle's {@link JXG.Circle#quadraticform}. 347 * @private 348 */ 349 updateQuadraticform: function () { 350 var m = this.center, 351 mX = m.X(), 352 mY = m.Y(), 353 r = this.Radius(); 354 355 this.quadraticform = [ 356 [mX * mX + mY * mY - r * r, -mX, -mY], 357 [-mX, 1, 0], 358 [-mY, 0, 1] 359 ]; 360 }, 361 362 /** 363 * Updates the stdform derived from the position of the center and the circle's radius. 364 * @private 365 */ 366 updateStdform: function () { 367 this.stdform[3] = 0.5; 368 this.stdform[4] = this.Radius(); 369 this.stdform[1] = -this.center.coords.usrCoords[1]; 370 this.stdform[2] = -this.center.coords.usrCoords[2]; 371 if (!isFinite(this.stdform[4])) { 372 this.stdform[0] = Type.exists(this.point2) ? -( 373 this.stdform[1] * this.point2.coords.usrCoords[1] + 374 this.stdform[2] * this.point2.coords.usrCoords[2] 375 ) : 0; 376 } 377 this.normalize(); 378 }, 379 380 /** 381 * Uses the boards renderer to update the circle. 382 * @private 383 */ 384 updateRenderer: function () { 385 var wasReal; 386 387 if (this.needsUpdate && this.visProp.visible) { 388 wasReal = this.isReal; 389 this.isReal = (!isNaN(this.center.coords.usrCoords[1] + this.center.coords.usrCoords[2] + this.Radius())) && this.center.isReal; 390 391 if (this.isReal) { 392 if (wasReal !== this.isReal) { 393 this.board.renderer.show(this); 394 395 if (this.hasLabel && this.label.visProp.visible) { 396 this.board.renderer.show(this.label); 397 } 398 } 399 this.board.renderer.updateEllipse(this); 400 } else { 401 if (wasReal !== this.isReal) { 402 this.board.renderer.hide(this); 403 404 if (this.hasLabel && this.label.visProp.visible) { 405 this.board.renderer.hide(this.label); 406 } 407 } 408 } 409 this.needsUpdate = false; 410 } 411 412 // Update the label if visible. 413 if (this.hasLabel && this.label.visProp.visible && this.isReal) { 414 this.label.update(); 415 this.board.renderer.updateText(this.label); 416 } 417 }, 418 419 /** 420 * Finds dependencies in a given term and resolves them by adding the elements referenced in this 421 * string to the circle's list of ancestors. 422 * @param {String} contentStr 423 * @private 424 */ 425 notifyParents: function (contentStr) { 426 if (typeof contentStr === 'string') { 427 GeonextParser.findDependencies(this, contentStr, this.board); 428 } 429 }, 430 431 /** 432 * Set a new radius, then update the board. 433 * @param {String|Number|function} r A string, function or number describing the new radius. 434 * @returns {JXG.Circle} Reference to this circle 435 */ 436 setRadius: function (r) { 437 this.updateRadius = Type.createFunction(r, this.board, null, true); 438 this.board.update(); 439 440 return this; 441 }, 442 443 /** 444 * Calculates the radius of the circle. 445 * @param {String|Number|function} [value] Set new radius 446 * @returns {Number} The radius of the circle 447 */ 448 Radius: function (value) { 449 if (Type.exists(value)) { 450 this.setRadius(value); 451 return this.Radius(); 452 } 453 454 if (this.method === 'twoPoints') { 455 if (Type.cmpArrays(this.point2.coords.usrCoords, [0, 0, 0]) || 456 Type.cmpArrays(this.center.coords.usrCoords, [0, 0, 0])) { 457 458 return NaN; 459 } 460 461 return this.center.Dist(this.point2); 462 } 463 464 if (this.method === 'pointLine' || this.method === 'pointCircle') { 465 return this.radius; 466 } 467 468 if (this.method === 'pointRadius') { 469 return this.updateRadius(); 470 } 471 472 return NaN; 473 }, 474 475 /** 476 * Use {@link JXG.Circle#Radius}. 477 * @deprecated 478 */ 479 getRadius: function () { 480 return this.Radius(); 481 }, 482 483 // documented in geometry element 484 getTextAnchor: function () { 485 return this.center.coords; 486 }, 487 488 // documented in geometry element 489 getLabelAnchor: function () { 490 var x, y, 491 r = this.Radius(), 492 c = this.center.coords.usrCoords; 493 494 switch (this.visProp.label.position) { 495 case 'lft': 496 x = c[1] - r; 497 y = c[2]; 498 break; 499 case 'llft': 500 x = c[1] - Math.sqrt(0.5) * r; 501 y = c[2] - Math.sqrt(0.5) * r; 502 break; 503 case 'rt': 504 x = c[1] + r; 505 y = c[2]; 506 break; 507 case 'lrt': 508 x = c[1] + Math.sqrt(0.5) * r; 509 y = c[2] - Math.sqrt(0.5) * r; 510 break; 511 case 'urt': 512 x = c[1] + Math.sqrt(0.5) * r; 513 y = c[2] + Math.sqrt(0.5) * r; 514 break; 515 case 'top': 516 x = c[1]; 517 y = c[2] + r; 518 break; 519 case 'bot': 520 x = c[1]; 521 y = c[2] - r; 522 break; 523 default: 524 // includes case 'ulft' 525 x = c[1] - Math.sqrt(0.5) * r; 526 y = c[2] + Math.sqrt(0.5) * r; 527 break; 528 } 529 530 return new Coords(Const.COORDS_BY_USER, [x, y], this.board); 531 }, 532 533 534 // documented in geometry element 535 cloneToBackground: function () { 536 var er, 537 r = this.Radius(), 538 copy = { 539 id: this.id + 'T' + this.numTraces, 540 elementClass: Const.OBJECT_CLASS_CIRCLE, 541 center: { 542 coords: this.center.coords 543 }, 544 Radius: function () { 545 return r; 546 }, 547 getRadius: function () { 548 return r; 549 }, 550 board: this.board, 551 visProp: Type.deepCopy(this.visProp, this.visProp.traceattributes, true) 552 }; 553 554 copy.visProp.layer = this.board.options.layer.trace; 555 556 this.numTraces++; 557 Type.clearVisPropOld(copy); 558 559 er = this.board.renderer.enhancedRendering; 560 this.board.renderer.enhancedRendering = true; 561 this.board.renderer.drawEllipse(copy); 562 this.board.renderer.enhancedRendering = er; 563 this.traces[copy.id] = copy.rendNode; 564 565 return this; 566 }, 567 568 /** 569 * Add transformations to this circle. 570 * @param {JXG.Transformation|Array} transform Either one {@link JXG.Transformation} or an array of {@link JXG.Transformation}s. 571 * @returns {JXG.Circle} Reference to this circle object. 572 */ 573 addTransform: function (transform) { 574 var i, 575 list = Type.isArray(transform) ? transform : [transform], 576 len = list.length; 577 578 for (i = 0; i < len; i++) { 579 this.center.transformations.push(list[i]); 580 581 if (this.method === 'twoPoints') { 582 this.point2.transformations.push(list[i]); 583 } 584 } 585 586 return this; 587 }, 588 589 // see element.js 590 snapToGrid: function () { 591 var forceIt = this.visProp.snaptogrid; 592 593 this.center.snapToGrid(forceIt); 594 if (this.method === 'twoPoints') { 595 this.point2.snapToGrid(forceIt); 596 } 597 598 return this; 599 }, 600 601 // see element.js 602 snapToPoints: function () { 603 var forceIt = this.visProp.snaptopoints; 604 605 this.center.handleSnapToPoints(forceIt); 606 if (this.method === 'twoPoints') { 607 this.point2.handleSnapToPoints(forceIt); 608 } 609 610 return this; 611 }, 612 613 /** 614 * Treats the circle as parametric curve and calculates its X coordinate. 615 * @param {Number} t Number between 0 and 1. 616 * @returns {Number} <tt>X(t)= radius*cos(t)+centerX</tt>. 617 */ 618 X: function (t) { 619 return this.Radius() * Math.cos(t * 2 * Math.PI) + this.center.coords.usrCoords[1]; 620 }, 621 622 /** 623 * Treats the circle as parametric curve and calculates its Y coordinate. 624 * @param {Number} t Number between 0 and 1. 625 * @returns {Number} <tt>X(t)= radius*sin(t)+centerY</tt>. 626 */ 627 Y: function (t) { 628 return this.Radius() * Math.sin(t * 2 * Math.PI) + this.center.coords.usrCoords[2]; 629 }, 630 631 /** 632 * Treat the circle as parametric curve and calculates its Z coordinate. 633 * @param {Number} t ignored 634 * @return {Number} 1.0 635 */ 636 Z: function (t) { 637 return 1.0; 638 }, 639 640 /** 641 * Returns 0. 642 * @private 643 */ 644 minX: function () { 645 return 0.0; 646 }, 647 648 /** 649 * Returns 1. 650 * @private 651 */ 652 maxX: function () { 653 return 1.0; 654 }, 655 656 Area: function () { 657 var r = this.Radius(); 658 659 return r * r * Math.PI; 660 }, 661 662 bounds: function () { 663 var uc = this.center.coords.usrCoords, 664 r = this.Radius(); 665 666 return [uc[1] - r, uc[2] + r, uc[1] + r, uc[2] - r]; 667 } 668 }); 669 670 /** 671 * @class This element is used to provide a constructor for a circle. 672 * @pseudo 673 * @description A circle consists of all points with a given distance from one point. This point is called center, the distance is called radius. 674 * A circle can be constructed by providing a center and a point on the circle or a center and a radius (given as a number, function, 675 * line, or circle). 676 * @name Circle 677 * @augments JXG.Circle 678 * @constructor 679 * @type JXG.Circle 680 * @throws {Exception} If the element cannot be constructed with the given parent objects an exception is thrown. 681 * @param {JXG.Point_number,JXG.Point,JXG.Line,JXG.Circle} center,radius The center must be given as a {@link JXG.Point}, see {@link JXG.providePoints}, but the radius can be given 682 * as a number (which will create a circle with a fixed radius), another {@link JXG.Point}, a {@link JXG.Line} (the distance of start and end point of the 683 * line will determine the radius), or another {@link JXG.Circle}. 684 * @example 685 * // Create a circle providing two points 686 * var p1 = board.create('point', [2.0, 2.0]), 687 * p2 = board.create('point', [2.0, 0.0]), 688 * c1 = board.create('circle', [p1, p2]); 689 * 690 * // Create another circle using the above circle 691 * var p3 = board.create('point', [3.0, 2.0]), 692 * c2 = board.create('circle', [p3, c1]); 693 * </pre><div id="5f304d31-ef20-4a8e-9c0e-ea1a2b6c79e0" style="width: 400px; height: 400px;"></div> 694 * <script type="text/javascript"> 695 * (function() { 696 * var cex1_board = JXG.JSXGraph.initBoard('5f304d31-ef20-4a8e-9c0e-ea1a2b6c79e0', {boundingbox: [-1, 9, 9, -1], axis: true, showcopyright: false, shownavigation: false}); 697 * cex1_p1 = cex1_board.create('point', [2.0, 2.0]), 698 * cex1_p2 = cex1_board.create('point', [2.0, 0.0]), 699 * cex1_c1 = cex1_board.create('circle', [cex1_p1, cex1_p2]), 700 * cex1_p3 = cex1_board.create('point', [3.0, 2.0]), 701 * cex1_c2 = cex1_board.create('circle', [cex1_p3, cex1_c1]); 702 * })(); 703 * </script><pre> 704 * @example 705 * // Create a circle providing two points 706 * var p1 = board.create('point', [2.0, 2.0]), 707 * c1 = board.create('circle', [p1, 3]); 708 * 709 * // Create another circle using the above circle 710 * var c2 = board.create('circle', [function() { return [p1.X(), p1.Y() + 1];}, function() { return c1.Radius(); }]); 711 * </pre><div id="54165f60-93b9-441d-8979-ac5d0f193020" style="width: 400px; height: 400px;"></div> 712 * <script type="text/javascript"> 713 * (function() { 714 * var cex1_board = JXG.JSXGraph.initBoard('54165f60-93b9-441d-8979-ac5d0f193020', {boundingbox: [-1, 9, 9, -1], axis: true, showcopyright: false, shownavigation: false}); 715 * var p1 = board.create('point', [2.0, 2.0]); 716 * var c1 = board.create('circle', [p1, 3]); 717 * 718 * // Create another circle using the above circle 719 * var c2 = board.create('circle', [function() { return [p1.X(), p1.Y() + 1];}, function() { return c1.Radius(); }]); 720 * })(); 721 * </script><pre> 722 */ 723 JXG.createCircle = function (board, parents, attributes) { 724 var el, p, i, attr, 725 isDraggable = true; 726 727 p = []; 728 for (i = 0; i < parents.length; i++) { 729 if (Type.isPointType(parents[i], board)) { 730 p = p.concat(Type.providePoints(board, [parents[i]], attributes, 'circle', ['center'])); 731 if (p[p.length - 1] === false) { 732 throw new Error('JSXGraph: Can\'t create circle from this type. Please provide a point type.'); 733 } 734 } else { 735 p.push(parents[i]); 736 } 737 } 738 739 attr = Type.copyAttributes(attributes, board.options, 'circle'); 740 741 if (p.length === 2 && Type.isPoint(p[0]) && Type.isPoint(p[1])) { 742 // Point/Point 743 el = new JXG.Circle(board, 'twoPoints', p[0], p[1], attr); 744 } else if ((Type.isNumber(p[0]) || Type.isFunction(p[0]) || Type.isString(p[0])) && Type.isPoint(p[1])) { 745 // Number/Point 746 el = new JXG.Circle(board, 'pointRadius', p[1], p[0], attr); 747 } else if ((Type.isNumber(p[1]) || Type.isFunction(p[1]) || Type.isString(p[1])) && Type.isPoint(p[0])) { 748 // Point/Number 749 el = new JXG.Circle(board, 'pointRadius', p[0], p[1], attr); 750 } else if ((p[0].elementClass === Const.OBJECT_CLASS_CIRCLE) && Type.isPoint(p[1])) { 751 // Circle/Point 752 el = new JXG.Circle(board, 'pointCircle', p[1], p[0], attr); 753 } else if ((p[1].elementClass === Const.OBJECT_CLASS_CIRCLE) && Type.isPoint(p[0])) { 754 // Point/Circle 755 el = new JXG.Circle(board, 'pointCircle', p[0], p[1], attr); 756 } else if ((p[0].elementClass === Const.OBJECT_CLASS_LINE) && Type.isPoint(p[1])) { 757 // Line/Point 758 el = new JXG.Circle(board, 'pointLine', p[1], p[0], attr); 759 } else if ((p[1].elementClass === Const.OBJECT_CLASS_LINE) && Type.isPoint(p[0])) { 760 // Point/Line 761 el = new JXG.Circle(board, 'pointLine', p[0], p[1], attr); 762 } else if (parents.length === 3 && Type.isPoint(p[0]) && Type.isPoint(p[1]) && Type.isPoint(p[2])) { 763 // Circle through three points 764 // Check if circumcircle element is available 765 if (JXG.elements.circumcircle) { 766 el = JXG.elements.circumcircle(board, p, attr); 767 } else { 768 throw new Error('JSXGraph: Can\'t create circle with three points. Please include the circumcircle element (element/composition).'); 769 } 770 } else { 771 throw new Error("JSXGraph: Can't create circle with parent types '" + 772 (typeof parents[0]) + "' and '" + (typeof parents[1]) + "'." + 773 "\nPossible parent types: [point,point], [point,number], [point,function], [point,circle], [point,point,point]"); 774 } 775 776 el.isDraggable = isDraggable; 777 el.parents = []; 778 779 for (i = 0; i < parents.length; i++) { 780 if (parents[i].id) { 781 el.parents.push(parents[i].id); 782 } 783 } 784 785 el.elType = 'circle'; 786 return el; 787 }; 788 789 JXG.registerElement('circle', JXG.createCircle); 790 791 return { 792 Circle: JXG.Circle, 793 createCircle: JXG.createCircle 794 }; 795 }); 796