1 /*
  2     Copyright 2008-2022
  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 /*global JXG: true, define: true, window: true*/
 33 /*jslint nomen: true, plusplus: true*/
 34 
 35 /* depends:
 36  jxg
 37  base/constants
 38  base/coords
 39  base/element
 40  parser/geonext
 41  math/statistics
 42  utils/env
 43  utils/type
 44  */
 45 
 46 /**
 47  * @fileoverview In this file the Text element is defined.
 48  */
 49 
 50 define([
 51     'jxg', 'base/constants', 'base/element', 'parser/geonext',
 52     'utils/env', 'utils/type', 'math/math', 'base/coordselement'
 53 ], function (JXG, Const, GeometryElement, GeonextParser, Env, Type, Mat, CoordsElement) {
 54 
 55     "use strict";
 56 
 57     var priv = {
 58         HTMLSliderInputEventHandler: function () {
 59             this._val = parseFloat(this.rendNodeRange.value);
 60             this.rendNodeOut.value = this.rendNodeRange.value;
 61             this.board.update();
 62         }
 63     };
 64 
 65     /**
 66      * Construct and handle texts.
 67      *
 68      * The coordinates can be relative to the coordinates of an element
 69      * given in {@link JXG.Options#text.anchor}.
 70      *
 71      * MathJax, HTML and GEONExT syntax can be handled.
 72      * @class Creates a new text object. Do not use this constructor to create a text. Use {@link JXG.Board#create} with
 73      * type {@link Text} instead.
 74      * @augments JXG.GeometryElement
 75      * @augments JXG.CoordsElement
 76      * @param {string|JXG.Board} board The board the new text is drawn on.
 77      * @param {Array} coordinates An array with the user coordinates of the text.
 78      * @param {Object} attributes An object containing visual properties and optional a name and a id.
 79      * @param {string|function} content A string or a function returning a string.
 80      *
 81      */
 82     JXG.Text = function (board, coords, attributes, content) {
 83         this.constructor(board, attributes, Const.OBJECT_TYPE_TEXT, Const.OBJECT_CLASS_TEXT);
 84 
 85         this.element = this.board.select(attributes.anchor);
 86         this.coordsConstructor(coords, Type.evaluate(this.visProp.islabel));
 87 
 88         this.content = '';
 89         this.plaintext = '';
 90         this.plaintextOld = null;
 91         this.orgText = '';
 92 
 93         this.needsSizeUpdate = false;
 94         // Only used by infobox anymore
 95         this.hiddenByParent = false;
 96 
 97         /**
 98          * Width and height of the the text element in pixel.
 99          *
100          * @private
101          * @type Array
102          */
103         this.size = [1.0, 1.0];
104         this.id = this.board.setId(this, 'T');
105 
106         this.board.renderer.drawText(this);
107         this.board.finalizeAdding(this);
108 
109         // Set text before drawing
110         // this._createFctUpdateText(content);
111         // this.updateText();
112 
113         this.setText(content);
114 
115         if (Type.isString(this.content)) {
116             this.notifyParents(this.content);
117         }
118         this.elType = 'text';
119 
120         this.methodMap = Type.deepCopy(this.methodMap, {
121             setText: 'setTextJessieCode',
122             // free: 'free',
123             move: 'setCoords'
124         });
125     };
126 
127     JXG.Text.prototype = new GeometryElement();
128     Type.copyPrototypeMethods(JXG.Text, CoordsElement, 'coordsConstructor');
129 
130     JXG.extend(JXG.Text.prototype, /** @lends JXG.Text.prototype */ {
131         /**
132          * @private
133          * Test if the the screen coordinates (x,y) are in a small stripe
134          * at the left side or at the right side of the text.
135          * Sensitivity is set in this.board.options.precision.hasPoint.
136          * If dragarea is set to 'all' (default), tests if the the screen
137          * coordinates (x,y) are in within the text boundary.
138          * @param {Number} x
139          * @param {Number} y
140          * @returns {Boolean}
141          */
142         hasPoint: function (x, y) {
143             var lft, rt, top, bot, ax, ay, type, r;
144 
145             if (Type.isObject(Type.evaluate(this.visProp.precision))) {
146                 type = this.board._inputDevice;
147                 r = Type.evaluate(this.visProp.precision[type]);
148             } else {
149                 // 'inherit'
150                 r = this.board.options.precision.hasPoint;
151             }
152             if (this.transformations.length > 0) {
153                 //Transform the mouse/touch coordinates
154                 // back to the original position of the text.
155                 lft = Mat.matVecMult(Mat.inverse(this.board.renderer.joinTransforms(this, this.transformations)), [1, x, y]);
156                 x = lft[1];
157                 y = lft[2];
158             }
159 
160             ax = this.getAnchorX();
161             if (ax === 'right') {
162                 lft = this.coords.scrCoords[1] - this.size[0];
163             } else if (ax === 'middle') {
164                 lft = this.coords.scrCoords[1] - 0.5 * this.size[0];
165             } else {
166                 lft = this.coords.scrCoords[1];
167             }
168             rt = lft + this.size[0];
169 
170             ay = this.getAnchorY();
171             if (ay === 'top') {
172                 bot = this.coords.scrCoords[2] + this.size[1];
173             } else if (ay === 'middle') {
174                 bot = this.coords.scrCoords[2] + 0.5 * this.size[1];
175             } else {
176                 bot = this.coords.scrCoords[2];
177             }
178             top = bot - this.size[1];
179 
180             if (Type.evaluate(this.visProp.dragarea) === 'all') {
181                 return x >= lft - r && x < rt + r && y >= top - r && y <= bot + r;
182             }
183             // e.g. 'small'
184             return (y >= top - r && y <= bot + r) &&
185                 ((x >= lft - r && x <= lft + 2 * r) ||
186                     (x >= rt - 2 * r && x <= rt + r));
187         },
188 
189         /**
190          * This sets the updateText function of this element depending on the type of text content passed.
191          * Used by {@link JXG.Text#_setText} and {@link JXG.Text} constructor.
192          * @param {String|Function|Number} text
193          * @private
194          */
195         _createFctUpdateText: function (text) {
196             var updateText, resolvedText,
197                 ev_p = Type.evaluate(this.visProp.parse),
198                 ev_um = Type.evaluate(this.visProp.usemathjax),
199                 ev_uk = Type.evaluate(this.visProp.usekatex);
200 
201             this.orgText = text;
202             if (Type.isFunction(text)) {
203                 this.updateText = function () {
204                     resolvedText = text().toString();
205                     if (ev_p && !ev_um && !ev_uk) {
206                         this.plaintext = this.replaceSub(this.replaceSup(this.convertGeonextAndSketchometry2CSS(resolvedText)));
207                     } else {
208                         this.plaintext = resolvedText;
209                     }
210                 };
211             } else if (Type.isString(text) && !ev_p) {   // Do not parse
212                 this.updateText = function () {
213                     this.plaintext = text;
214                 };
215             } else {                                     // Parse
216                 if (Type.isNumber(text)) {
217                     this.content = Type.toFixed(text, Type.evaluate(this.visProp.digits));
218                 } else {
219                     if (Type.evaluate(this.visProp.useasciimathml)) {
220                         // Convert via ASCIIMathML
221                         this.content = "'`" + text + "`'";
222                     } else if (ev_um || ev_uk) {
223                         this.content = "'" + text + "'";
224                     } else {
225                         // Converts GEONExT syntax into JavaScript string
226                         // Short math is allowed
227                         // Avoid geonext2JS calls
228                         this.content = this.generateTerm(text, true, true);
229                     }
230                 }
231                 updateText = this.board.jc.snippet(this.content, true, '', false);
232                 this.updateText = function () {
233                     this.plaintext = updateText();
234                 };
235             }
236         },
237 
238         /**
239          * Defines new content. This is used by {@link JXG.Text#setTextJessieCode} and {@link JXG.Text#setText}. This is required because
240          * JessieCode needs to filter all Texts inserted into the DOM and thus has to replace setText by setTextJessieCode.
241          * @param {String|Function|Number} text
242          * @returns {JXG.Text}
243          * @private
244          */
245         _setText: function (text) {
246             this._createFctUpdateText(text);
247 
248             // First evaluation of the string.
249             // We need this for display='internal' and Canvas
250             this.updateText();
251             this.fullUpdate();
252 
253             // We do not call updateSize for the infobox to speed up rendering
254             if (!this.board.infobox || this.id !== this.board.infobox.id) {
255                 this.updateSize();    // updateSize() is called at least once.
256             }
257 
258             // This may slow down canvas renderer
259             // if (this.board.renderer.type === 'canvas') {
260             //     this.board.fullUpdate();
261             // }
262 
263             return this;
264         },
265 
266         /**
267          * Defines new content but converts < and > to HTML entities before updating the DOM.
268          * @param {String|function} text
269          */
270         setTextJessieCode: function (text) {
271             var s;
272 
273             this.visProp.castext = text;
274             if (Type.isFunction(text)) {
275                 s = function () {
276                     return Type.sanitizeHTML(text());
277                 };
278             } else {
279                 if (Type.isNumber(text)) {
280                     s = text;
281                 } else {
282                     s = Type.sanitizeHTML(text);
283                 }
284             }
285 
286             return this._setText(s);
287         },
288 
289         /**
290          * Defines new content.
291          * @param {String|function} text
292          * @returns {JXG.Text} Reference to the text object.
293          */
294         setText: function (text) {
295             return this._setText(text);
296         },
297 
298         /**
299          * Recompute the width and the height of the text box.
300          * Updates the array {@link JXG.Text#size} with pixel values.
301          * The result may differ from browser to browser
302          * by some pixels.
303          * In canvas an old IEs we use a very crude estimation of the dimensions of
304          * the textbox.
305          * JSXGraph needs {@link JXG.Text#size} for applying rotations in IE and
306          * for aligning text.
307          *
308          * @return {[type]} [description]
309          */
310         updateSize: function () {
311             var tmp, that, node,
312                 ev_d = Type.evaluate(this.visProp.display);
313 
314             if (!Env.isBrowser || this.board.renderer.type === 'no') {
315                 return this;
316             }
317             node = this.rendNode;
318 
319             /**
320              * offsetWidth and offsetHeight seem to be supported for internal vml elements by IE10+ in IE8 mode.
321              */
322             if (ev_d === 'html' || this.board.renderer.type === 'vml') {
323                 if (Type.exists(node.offsetWidth)) {
324                     that = this;
325                     window.setTimeout(function () {
326                         that.size = [node.offsetWidth, node.offsetHeight];
327                         that.needsUpdate = true;
328                         that.updateRenderer();
329                     }, 0);
330                     // In case, there is non-zero padding or borders
331                     // the following approach does not longer work.
332                     // s = [node.offsetWidth, node.offsetHeight];
333                     // if (s[0] === 0 && s[1] === 0) { // Some browsers need some time to set offsetWidth and offsetHeight
334                     //     that = this;
335                     //     window.setTimeout(function () {
336                     //         that.size = [node.offsetWidth, node.offsetHeight];
337                     //         that.needsUpdate = true;
338                     //         that.updateRenderer();
339                     //     }, 0);
340                     // } else {
341                     //     this.size = s;
342                     // }
343                 } else {
344                     this.size = this.crudeSizeEstimate();
345                 }
346             } else if (ev_d === 'internal') {
347                 if (this.board.renderer.type === 'svg') {
348                     that = this;
349                     window.setTimeout(function () {
350                         try {
351                             tmp = node.getBBox();
352                             that.size = [tmp.width, tmp.height];
353                             that.needsUpdate = true;
354                             that.updateRenderer();
355                         } catch (e) {
356                         }
357                     }, 0);
358                 } else if (this.board.renderer.type === 'canvas') {
359                     this.size = this.crudeSizeEstimate();
360                 }
361             }
362 
363             return this;
364         },
365 
366         /**
367          * A very crude estimation of the dimensions of the textbox in case nothing else is available.
368          * @returns {Array}
369          */
370         crudeSizeEstimate: function () {
371             var ev_fs = parseFloat(Type.evaluate(this.visProp.fontsize));
372             return [ev_fs * this.plaintext.length * 0.45, ev_fs * 0.9];
373         },
374 
375         /**
376          * Decode unicode entities into characters.
377          * @param {String} string
378          * @returns {String}
379          */
380         utf8_decode: function (string) {
381             return string.replace(/&#x(\w+);/g, function (m, p1) {
382                 return String.fromCharCode(parseInt(p1, 16));
383             });
384         },
385 
386         /**
387          * Replace _{} by <sub>
388          * @param {String} te String containing _{}.
389          * @returns {String} Given string with _{} replaced by <sub>.
390          */
391         replaceSub: function (te) {
392             if (!te.indexOf) {
393                 return te;
394             }
395 
396             var j,
397                 i = te.indexOf('_{');
398 
399             // the regexp in here are not used for filtering but to provide some kind of sugar for label creation,
400             // i.e. replacing _{...} with <sub>...</sub>. What is passed would get out anyway.
401             /*jslint regexp: true*/
402 
403             while (i >= 0) {
404                 te = te.substr(0, i) + te.substr(i).replace(/_\{/, '<sub>');
405                 j = te.substr(i).indexOf('}');
406                 if (j >= 0) {
407                     te = te.substr(0, j) + te.substr(j).replace(/\}/, '</sub>');
408                 }
409                 i = te.indexOf('_{');
410             }
411 
412             i = te.indexOf('_');
413             while (i >= 0) {
414                 te = te.substr(0, i) + te.substr(i).replace(/_(.?)/, '<sub>$1</sub>');
415                 i = te.indexOf('_');
416             }
417 
418             return te;
419         },
420 
421         /**
422          * Replace ^{} by <sup>
423          * @param {String} te String containing ^{}.
424          * @returns {String} Given string with ^{} replaced by <sup>.
425          */
426         replaceSup: function (te) {
427             if (!te.indexOf) {
428                 return te;
429             }
430 
431             var j,
432                 i = te.indexOf('^{');
433 
434             // the regexp in here are not used for filtering but to provide some kind of sugar for label creation,
435             // i.e. replacing ^{...} with <sup>...</sup>. What is passed would get out anyway.
436             /*jslint regexp: true*/
437 
438             while (i >= 0) {
439                 te = te.substr(0, i) + te.substr(i).replace(/\^\{/, '<sup>');
440                 j = te.substr(i).indexOf('}');
441                 if (j >= 0) {
442                     te = te.substr(0, j) + te.substr(j).replace(/\}/, '</sup>');
443                 }
444                 i = te.indexOf('^{');
445             }
446 
447             i = te.indexOf('^');
448             while (i >= 0) {
449                 te = te.substr(0, i) + te.substr(i).replace(/\^(.?)/, '<sup>$1</sup>');
450                 i = te.indexOf('^');
451             }
452 
453             return te;
454         },
455 
456         /**
457          * Return the width of the text element.
458          * @returns {Array} [width, height] in pixel
459          */
460         getSize: function () {
461             return this.size;
462         },
463 
464         /**
465          * Move the text to new coordinates.
466          * @param {number} x
467          * @param {number} y
468          * @returns {object} reference to the text object.
469          */
470         setCoords: function (x, y) {
471             var coordsAnchor, dx, dy;
472             if (Type.isArray(x) && x.length > 1) {
473                 y = x[1];
474                 x = x[0];
475             }
476 
477             if (Type.evaluate(this.visProp.islabel) && Type.exists(this.element)) {
478                 coordsAnchor = this.element.getLabelAnchor();
479                 dx = (x - coordsAnchor.usrCoords[1]) * this.board.unitX;
480                 dy = -(y - coordsAnchor.usrCoords[2]) * this.board.unitY;
481 
482                 this.relativeCoords.setCoordinates(Const.COORDS_BY_SCREEN, [dx, dy]);
483             } else {
484                 /*
485                 this.X = function () {
486                     return x;
487                 };
488 
489                 this.Y = function () {
490                     return y;
491                 };
492                 */
493                 this.coords.setCoordinates(Const.COORDS_BY_USER, [x, y]);
494             }
495 
496             // this should be a local update, otherwise there might be problems
497             // with the tick update routine resulting in orphaned tick labels
498             this.fullUpdate();
499 
500             return this;
501         },
502 
503         /**
504          * Evaluates the text.
505          * Then, the update function of the renderer
506          * is called.
507          */
508         update: function (fromParent) {
509             if (!this.needsUpdate) {
510                 return this;
511             }
512 
513             this.updateCoords(fromParent);
514             this.updateText();
515 
516             if (Type.evaluate(this.visProp.display) === 'internal') {
517                 if (Type.isString(this.plaintext)) {
518                     this.plaintext = this.utf8_decode(this.plaintext);
519                 }
520             }
521 
522             this.checkForSizeUpdate();
523             if (this.needsSizeUpdate) {
524                 this.updateSize();
525             }
526 
527             return this;
528         },
529 
530         /**
531          * Used to save updateSize() calls.
532          * Called in JXG.Text.update
533          * That means this.update() has been called.
534          * More tests are in JXG.Renderer.updateTextStyle. The latter tests
535          * are one update off. But this should pose not too many problems, since
536          * it affects fontSize and cssClass changes.
537          *
538          * @private
539          */
540         checkForSizeUpdate: function () {
541             if (this.board.infobox && this.id === this.board.infobox.id) {
542                 this.needsSizeUpdate = false;
543             } else {
544                 // For some magic reason it is more efficient on the iPad to
545                 // call updateSize() for EVERY text element EVERY time.
546                 this.needsSizeUpdate = (this.plaintextOld !== this.plaintext);
547 
548                 if (this.needsSizeUpdate) {
549                     this.plaintextOld = this.plaintext;
550                 }
551             }
552 
553         },
554 
555         /**
556          * The update function of the renderert
557          * is called.
558          * @private
559          */
560         updateRenderer: function () {
561             if (//this.board.updateQuality === this.board.BOARD_QUALITY_HIGH &&
562                 Type.evaluate(this.visProp.autoposition)) {
563 
564                 this.setAutoPosition()
565                     .updateConstraint();
566             }
567             return this.updateRendererGeneric('updateText');
568         },
569 
570         /**
571          * Converts shortened math syntax into correct syntax:  3x instead of 3*x or
572          * (a+b)(3+1) instead of (a+b)*(3+1).
573          *
574          * @private
575          * @param{String} expr Math term
576          * @returns {string} expanded String
577          */
578         expandShortMath: function (expr) {
579             var re = /([)0-9.])\s*([(a-zA-Z_])/g;
580             return expr.replace(re, '$1*$2');
581         },
582 
583         /**
584          * Converts the GEONExT syntax of the <value> terms into JavaScript.
585          * Also, all Objects whose name appears in the term are searched and
586          * the text is added as child to these objects.
587          *
588          * @param{String} contentStr String to be parsed
589          * @param{Boolean} [expand] Optional flag if shortened math syntax is allowed (e.g. 3x instead of 3*x).
590          * @param{Boolean} [avoidGeonext2JS] Optional flag if geonext2JS should be called. For backwards compatibility
591          * this has to be set explicitely to true.
592          * @private
593          * @see JXG.GeonextParser.geonext2JS
594          */
595         generateTerm: function (contentStr, expand, avoidGeonext2JS) {
596             var res, term, i, j,
597                 plaintext = '""';
598 
599             // revert possible jc replacement
600             contentStr = contentStr || '';
601             contentStr = contentStr.replace(/\r/g, '');
602             contentStr = contentStr.replace(/\n/g, '');
603             contentStr = contentStr.replace(/"/g, '\'');
604             contentStr = contentStr.replace(/'/g, "\\'");
605 
606             contentStr = contentStr.replace(/&arc;/g, '∠');
607             contentStr = contentStr.replace(/<arc\s*\/>/g, '∠');
608             contentStr = contentStr.replace(/<arc\s*\/>/g, '∠');
609             contentStr = contentStr.replace(/<sqrt\s*\/>/g, '√');
610 
611             contentStr = contentStr.replace(/<value>/g, '<value>');
612             contentStr = contentStr.replace(/<\/value>/g, '</value>');
613 
614             // Convert GEONExT syntax into  JavaScript syntax
615             i = contentStr.indexOf('<value>');
616             j = contentStr.indexOf('</value>');
617             if (i >= 0) {
618                 while (i >= 0) {
619                     plaintext += ' + "' + this.replaceSub(this.replaceSup(contentStr.slice(0, i))) + '"';
620                     term = contentStr.slice(i + 7, j);
621                     term = term.replace(/\s+/g, ''); // Remove all whitespace
622                     if (expand === true) {
623                         term = this.expandShortMath(term);
624                     }
625                     if (avoidGeonext2JS) {
626                         res = term;
627                     } else {
628                         res = GeonextParser.geonext2JS(term, this.board);
629                     }
630                     res = res.replace(/\\"/g, "'");
631                     res = res.replace(/\\'/g, "'");
632 
633                     // GEONExT-Hack: apply rounding once only.
634                     if (res.indexOf('toFixed') < 0) {
635                         // output of a value tag
636                         if (Type.isNumber((Type.bind(this.board.jc.snippet(res, true, '', false), this))())) {
637                             // may also be a string
638                             plaintext += '+(' + res + ').toFixed(' + (Type.evaluate(this.visProp.digits)) + ')';
639                         } else {
640                             plaintext += '+(' + res + ')';
641                         }
642                     } else {
643                         plaintext += '+(' + res + ')';
644                     }
645 
646                     contentStr = contentStr.slice(j + 8);
647                     i = contentStr.indexOf('<value>');
648                     j = contentStr.indexOf('</value>');
649                 }
650             }
651 
652             plaintext += ' + "' + this.replaceSub(this.replaceSup(contentStr)) + '"';
653             plaintext = this.convertGeonextAndSketchometry2CSS(plaintext);
654 
655             // This should replace &pi; by π
656             plaintext = plaintext.replace(/&/g, '&');
657             plaintext = plaintext.replace(/"/g, "'");
658 
659             return plaintext;
660         },
661 
662         /**
663          * Converts the GEONExT tags <overline> and <arrow> to
664          * HTML span tags with proper CSS formatting.
665          * @private
666          * @see JXG.Text.generateTerm
667          * @see JXG.Text._setText
668          */
669         convertGeonext2CSS: function (s) {
670             if (Type.isString(s)) {
671                 s = s.replace(
672                     /(<|<)overline(>|>)/g,
673                     '<span style=text-decoration:overline;>'
674                 );
675                 s = s.replace(
676                     /(<|<)\/overline(>|>)/g,
677                     '</span>'
678                 );
679                 s = s.replace(
680                     /(<|<)arrow(>|>)/g,
681                     '<span style=text-decoration:overline;>'
682                 );
683                 s = s.replace(
684                     /(<|<)\/arrow(>|>)/g,
685                     '</span>'
686                 );
687             }
688 
689             return s;
690         },
691 
692         /**
693          * Converts the sketchometry tag <sketchofont> to
694          * HTML span tags with proper CSS formatting.
695          * @private
696          * @see JXG.Text.generateTerm
697          * @see JXG.Text._setText
698          */
699         convertSketchometry2CSS: function (s) {
700             if (Type.isString(s)) {
701                 s = s.replace(
702                     /(<|<)sketchofont(>|>)/g,
703                     '<span style=font-family:sketchometry-light;font-weight:500;>'
704                 );
705                 s = s.replace(
706                     /(<|<)\/sketchofont(>|>)/g,
707                     '</span>'
708                 );
709                 s = s.replace(
710                     /(<|<)sketchometry-light(>|>)/g,
711                     '<span style=font-family:sketchometry-light;font-weight:500;>'
712                 );
713                 s = s.replace(
714                     /(<|<)\/sketchometry-light(>|>)/g,
715                     '</span>'
716                 );
717             }
718 
719             return s;
720         },
721 
722         /**
723          * Alias for convertGeonext2CSS and convertSketchometry2CSS
724          * @private
725          * @see JXG.Text.convertGeonext2CSS
726          * @see JXG.Text.convertSketchometry2CSS
727          */
728         convertGeonextAndSketchometry2CSS: function (s){
729             s = this.convertGeonext2CSS(s);
730             s = this.convertSketchometry2CSS(s);
731             return s;
732         },
733 
734         /**
735          * Finds dependencies in a given term and notifies the parents by adding the
736          * dependent object to the found objects child elements.
737          * @param {String} content String containing dependencies for the given object.
738          * @private
739          */
740         notifyParents: function (content) {
741             var search,
742                 res = null;
743 
744             // revert possible jc replacement
745             content = content.replace(/<value>/g, '<value>');
746             content = content.replace(/<\/value>/g, '</value>');
747 
748             do {
749                 search = /<value>([\w\s*/^\-+()[\],<>=!]+)<\/value>/;
750                 res = search.exec(content);
751 
752                 if (res !== null) {
753                     GeonextParser.findDependencies(this, res[1], this.board);
754                     content = content.substr(res.index);
755                     content = content.replace(search, '');
756                 }
757             } while (res !== null);
758 
759             return this;
760         },
761 
762         // documented in element.js
763         getParents: function () {
764             var p;
765             if (this.relativeCoords !== undefined) { // Texts with anchor elements, excluding labels
766                 p = [this.relativeCoords.usrCoords[1], this.relativeCoords.usrCoords[2], this.orgText];
767             } else {                                 // Other texts
768                 p = [this.Z(), this.X(), this.Y(), this.orgText];
769             }
770 
771             if (this.parents.length !== 0) {
772                 p = this.parents;
773             }
774 
775             return p;
776         },
777 
778         bounds: function () {
779             var c = this.coords.usrCoords;
780 
781             if (Type.evaluate(this.visProp.islabel) || this.board.unitY === 0 || this.board.unitX === 0) {
782                 return [0, 0, 0, 0];
783             }
784             return [c[1], c[2] + this.size[1] / this.board.unitY, c[1] + this.size[0] / this.board.unitX, c[2]];
785         },
786 
787         getAnchorX: function () {
788             var a = Type.evaluate(this.visProp.anchorx);
789             if (a === 'auto') {
790                 switch (this.visProp.position) {
791                     case 'top':
792                     case 'bot':
793                         return 'middle';
794                     case 'rt':
795                     case 'lrt':
796                     case 'urt':
797                         return 'left';
798                     case 'lft':
799                     case 'llft':
800                     case 'ulft':
801                     default:
802                         return 'right';
803                 }
804             }
805             return a;
806         },
807 
808         getAnchorY: function () {
809             var a = Type.evaluate(this.visProp.anchory);
810             if (a === 'auto') {
811                 switch (this.visProp.position) {
812                     case 'top':
813                     case 'ulft':
814                     case 'urt':
815                         return 'bottom';
816                     case 'bot':
817                     case 'lrt':
818                     case 'llft':
819                         return 'top';
820                     case 'rt':
821                     case 'lft':
822                     default:
823                         return 'middle';
824                 }
825             }
826             return a;
827         },
828 
829         /**
830          * Computes the number of overlaps of a box of w pixels width, h pixels height
831          * and center (x, y)
832          *
833          * @private
834          * @param  {Number} x x-coordinate of the center (screen coordinates)
835          * @param  {Number} y y-coordinate of the center (screen coordinates)
836          * @param  {Number} w width of the box in pixel
837          * @param  {Number} h width of the box in pixel
838          * @return {Number}   Number of overlapping elements
839          */
840         getNumberofConflicts: function (x, y, w, h) {
841             var count = 0,
842                 i, obj, le,
843                 savePointPrecision;
844 
845             // Set the precision of hasPoint to half the max if label isn't too long
846             savePointPrecision = this.board.options.precision.hasPoint;
847             // this.board.options.precision.hasPoint = Math.max(w, h) * 0.5;
848             this.board.options.precision.hasPoint = (w + h) * 0.25;
849             // TODO:
850             // Make it compatible with the objects' visProp.precision attribute
851             for (i = 0, le = this.board.objectsList.length; i < le; i++) {
852                 obj = this.board.objectsList[i];
853                 if (obj.visPropCalc.visible &&
854                     obj.elType !== 'axis' &&
855                     obj.elType !== 'ticks' &&
856                     obj !== this.board.infobox &&
857                     obj !== this &&
858                     obj.hasPoint(x, y)) {
859 
860                     count++;
861                 }
862             }
863             this.board.options.precision.hasPoint = savePointPrecision;
864 
865             return count;
866         },
867 
868         /**
869          * Sets the offset of a label element to the position with the least number
870          * of overlaps with other elements, while retaining the distance to its
871          * anchor element. Twelve different angles are possible.
872          *
873          * @returns {JXG.Text} Reference to the text object.
874          */
875         setAutoPosition: function () {
876             var x, y, cx, cy,
877                 anchorCoords,
878                 // anchorX, anchorY,
879                 w = this.size[0],
880                 h = this.size[1],
881                 start_angle, angle,
882                 optimum = {
883                     conflicts: Infinity,
884                     angle: 0,
885                     r: 0
886                 },
887                 max_r, delta_r,
888                 conflicts, offset, r,
889                 num_positions = 12,
890                 step = 2 * Math.PI / num_positions,
891                 j, dx, dy, co, si;
892 
893             if (this === this.board.infobox ||
894                 !this.visPropCalc.visible ||
895                 !Type.evaluate(this.visProp.islabel) ||
896                 !this.element) {
897                 return this;
898             }
899 
900             // anchorX = Type.evaluate(this.visProp.anchorx);
901             // anchorY = Type.evaluate(this.visProp.anchory);
902             offset = Type.evaluate(this.visProp.offset);
903             anchorCoords = this.element.getLabelAnchor();
904             cx = anchorCoords.scrCoords[1];
905             cy = anchorCoords.scrCoords[2];
906 
907             // Set dx, dy as the relative position of the center of the label
908             // to its anchor element ignoring anchorx and anchory.
909             dx = offset[0];
910             dy = offset[1];
911 
912             conflicts = this.getNumberofConflicts(cx + dx, cy - dy, w, h);
913             if (conflicts === 0) {
914                 return this;
915             }
916             // console.log(this.id, conflicts, w, h);
917             // r = Geometry.distance([0, 0], offset, 2);
918 
919             r = 12;
920             max_r = 28;
921             delta_r = 0.2 * r;
922 
923             start_angle = Math.atan2(dy, dx);
924 
925             optimum.conflicts = conflicts;
926             optimum.angle = start_angle;
927             optimum.r = r;
928 
929             while (optimum.conflicts > 0 && r < max_r) {
930                 for (j = 1, angle = start_angle + step; j < num_positions && optimum.conflicts > 0; j++) {
931                     co = Math.cos(angle);
932                     si = Math.sin(angle);
933 
934                     x = cx + r * co;
935                     y = cy - r * si;
936 
937                     conflicts = this.getNumberofConflicts(x, y, w, h);
938                     if (conflicts < optimum.conflicts) {
939                         optimum.conflicts = conflicts;
940                         optimum.angle = angle;
941                         optimum.r = r;
942                     }
943                     if (optimum.conflicts === 0) {
944                         break;
945                     }
946                     angle += step;
947                 }
948                 r += delta_r;
949             }
950             // console.log(this.id, "after", optimum)
951             r = optimum.r;
952             co = Math.cos(optimum.angle);
953             si = Math.sin(optimum.angle);
954             this.visProp.offset = [r * co, r * si];
955 
956             if (co < -0.2) {
957                 this.visProp.anchorx = 'right';
958             } else if (co > 0.2) {
959                 this.visProp.anchorx = 'left';
960             } else {
961                 this.visProp.anchorx = 'middle';
962             }
963 
964             return this;
965         }
966     });
967 
968     /**
969      * @class Construct and handle texts.
970      *
971      * The coordinates can be relative to the coordinates of an element
972      * given in {@link JXG.Options#text.anchor}.
973      *
974      * MathJaX, HTML and GEONExT syntax can be handled.
975      * @pseudo
976      * @description
977      * @name Text
978      * @augments JXG.Text
979      * @constructor
980      * @type JXG.Text
981      *
982      * @param {number,function_number,function_number,function_String,function} z_,x,y,str Parent elements for text elements.
983      *                     <p>
984      *   Parent elements can be two or three elements of type number, a string containing a GEONE<sub>x</sub>T
985      *   constraint, or a function which takes no parameter and returns a number. Every parent element determines one coordinate. If a coordinate is
986      *   given by a number, the number determines the initial position of a free text. If given by a string or a function that coordinate will be constrained
987      *   that means the user won't be able to change the texts's position directly by mouse because it will be calculated automatically depending on the string
988      *   or the function's return value. If two parent elements are given the coordinates will be interpreted as 2D affine Euclidean coordinates, if three such
989      *   parent elements are given they will be interpreted as homogeneous coordinates.
990      *                     <p>
991      *                     The text to display may be given as string or as function returning a string.
992      *
993      * There is the attribute 'display' which takes the values 'html' or 'internal'. In case of 'html' a HTML division tag is created to display
994      * the text. In this case it is also possible to use ASCIIMathML. Incase of 'internal', a SVG or VML text element is used to display the text.
995      * @see JXG.Text
996      * @example
997      * // Create a fixed text at position [0,1].
998      *   var t1 = board.create('text',[0,1,"Hello World"]);
999      * </pre><div class="jxgbox" id="JXG896013aa-f24e-4e83-ad50-7bc7df23f6b7" style="width: 300px; height: 300px;"></div>
1000      * <script type="text/javascript">
1001      *   var t1_board = JXG.JSXGraph.initBoard('JXG896013aa-f24e-4e83-ad50-7bc7df23f6b7', {boundingbox: [-3, 6, 5, -3], axis: true, showcopyright: false, shownavigation: false});
1002      *   var t1 = t1_board.create('text',[0,1,"Hello World"]);
1003      * </script><pre>
1004      * @example
1005      * // Create a variable text at a variable position.
1006      *   var s = board.create('slider',[[0,4],[3,4],[-2,0,2]]);
1007      *   var graph = board.create('text',
1008      *                        [function(x){ return s.Value();}, 1,
1009      *                         function(){return "The value of s is"+JXG.toFixed(s.Value(), 2);}
1010      *                        ]
1011      *                     );
1012      * </pre><div class="jxgbox" id="JXG5441da79-a48d-48e8-9e53-75594c384a1c" style="width: 300px; height: 300px;"></div>
1013      * <script type="text/javascript">
1014      *   var t2_board = JXG.JSXGraph.initBoard('JXG5441da79-a48d-48e8-9e53-75594c384a1c', {boundingbox: [-3, 6, 5, -3], axis: true, showcopyright: false, shownavigation: false});
1015      *   var s = t2_board.create('slider',[[0,4],[3,4],[-2,0,2]]);
1016      *   var t2 = t2_board.create('text',[function(x){ return s.Value();}, 1, function(){return "The value of s is "+JXG.toFixed(s.Value(), 2);}]);
1017      * </script><pre>
1018      * @example
1019      * // Create a text bound to the point A
1020      * var p = board.create('point',[0, 1]),
1021      *     t = board.create('text',[0, -1,"Hello World"], {anchor: p});
1022      *
1023      * </pre><div class="jxgbox" id="JXGff5a64b2-2b9a-11e5-8dd9-901b0e1b8723" style="width: 300px; height: 300px;"></div>
1024      * <script type="text/javascript">
1025      *     (function() {
1026      *         var board = JXG.JSXGraph.initBoard('JXGff5a64b2-2b9a-11e5-8dd9-901b0e1b8723',
1027      *             {boundingbox: [-8, 8, 8,-8], axis: true, showcopyright: false, shownavigation: false});
1028      *     var p = board.create('point',[0, 1]),
1029      *         t = board.create('text',[0, -1,"Hello World"], {anchor: p});
1030      *
1031      *     })();
1032      *
1033      * </script><pre>
1034      *
1035      */
1036     JXG.createText = function (board, parents, attributes) {
1037         var t,
1038             attr = Type.copyAttributes(attributes, board.options, 'text'),
1039             coords = parents.slice(0, -1),
1040             content = parents[parents.length - 1];
1041 
1042         // downwards compatibility
1043         attr.anchor = attr.parent || attr.anchor;
1044         t = CoordsElement.create(JXG.Text, board, coords, attr, content);
1045 
1046         if (!t) {
1047             throw new Error("JSXGraph: Can't create text with parent types '" +
1048                 (typeof parents[0]) + "' and '" + (typeof parents[1]) + "'." +
1049                 "\nPossible parent types: [x,y], [z,x,y], [element,transformation]");
1050         }
1051 
1052         if (attr.rotate !== 0 && attr.display === 'internal') { // This is the default value, i.e. no rotation
1053             t.addRotation(attr.rotate);
1054         }
1055 
1056         return t;
1057     };
1058 
1059     JXG.registerElement('text', JXG.createText);
1060 
1061     /**
1062      * @class Labels are text objects tied to other elements like points, lines and curves.
1063      * Labels are handled internally by JSXGraph, only. There is NO constructor "board.create('label', ...)".
1064      *
1065      * @pseudo
1066      * @description
1067      * @name Label
1068      * @augments JXG.Text
1069      * @constructor
1070      * @type JXG.Text
1071      */
1072     //  See element.js#createLabel
1073 
1074     /**
1075      * [[x,y], [w px, h px], [range]
1076      */
1077     JXG.createHTMLSlider = function (board, parents, attributes) {
1078         var t, par,
1079             attr = Type.copyAttributes(attributes, board.options, 'htmlslider');
1080 
1081         if (parents.length !== 2 || parents[0].length !== 2 || parents[1].length !== 3) {
1082             throw new Error("JSXGraph: Can't create htmlslider with parent types '" +
1083                 (typeof parents[0]) + "' and '" + (typeof parents[1]) + "'." +
1084                 "\nPossible parents are: [[x,y], [min, start, max]]");
1085         }
1086 
1087         // backwards compatibility
1088         attr.anchor = attr.parent || attr.anchor;
1089         attr.fixed = attr.fixed || true;
1090 
1091         par = [parents[0][0], parents[0][1],
1092             '<form style="display:inline">' +
1093             '<input type="range" /><span></span><input type="text" />' +
1094             '</form>'];
1095 
1096         t = JXG.createText(board, par, attr);
1097         t.type = Type.OBJECT_TYPE_HTMLSLIDER;
1098 
1099         t.rendNodeForm = t.rendNode.childNodes[0];
1100 
1101         t.rendNodeRange = t.rendNodeForm.childNodes[0];
1102         t.rendNodeRange.min = parents[1][0];
1103         t.rendNodeRange.max = parents[1][2];
1104         t.rendNodeRange.step = attr.step;
1105         t.rendNodeRange.value = parents[1][1];
1106 
1107         t.rendNodeLabel = t.rendNodeForm.childNodes[1];
1108         t.rendNodeLabel.id = t.rendNode.id + '_label';
1109 
1110         if (attr.withlabel) {
1111             t.rendNodeLabel.innerHTML = t.name + '=';
1112         }
1113 
1114         t.rendNodeOut = t.rendNodeForm.childNodes[2];
1115         t.rendNodeOut.value = parents[1][1];
1116 
1117         try {
1118             t.rendNodeForm.id = t.rendNode.id + '_form';
1119             t.rendNodeRange.id = t.rendNode.id + '_range';
1120             t.rendNodeOut.id = t.rendNode.id + '_out';
1121         } catch (e) {
1122             JXG.debug(e);
1123         }
1124 
1125         t.rendNodeRange.style.width = attr.widthrange + 'px';
1126         t.rendNodeRange.style.verticalAlign = 'middle';
1127         t.rendNodeOut.style.width = attr.widthout + 'px';
1128 
1129         t._val = parents[1][1];
1130 
1131         if (JXG.supportsVML()) {
1132             /*
1133             * OnChange event is used for IE browsers
1134             * The range element is supported since IE10
1135             */
1136             Env.addEvent(t.rendNodeForm, 'change', priv.HTMLSliderInputEventHandler, t);
1137         } else {
1138             /*
1139             * OnInput event is used for non-IE browsers
1140             */
1141             Env.addEvent(t.rendNodeForm, 'input', priv.HTMLSliderInputEventHandler, t);
1142         }
1143 
1144         t.Value = function () {
1145             return this._val;
1146         };
1147 
1148         return t;
1149     };
1150 
1151     JXG.registerElement('htmlslider', JXG.createHTMLSlider);
1152 
1153     return {
1154         Text: JXG.Text,
1155         createText: JXG.createText,
1156         createHTMLSlider: JXG.createHTMLSlider
1157     };
1158 });
1159