1 /*
  2     Copyright 2008-2013
  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, AMprocessNode: true, MathJax: true, document: true */
 33 /*jslint nomen: true, plusplus: true, newcap:true*/
 34 
 35 /* depends:
 36  jxg
 37  options
 38  renderer/abstract
 39  base/constants
 40  utils/type
 41  utils/env
 42  utils/color
 43  math/numerics
 44 */
 45 
 46 define([
 47     'jxg', 'options', 'renderer/abstract', 'base/constants', 'utils/type', 'utils/env', 'utils/color', 'math/numerics'
 48 ], function (JXG, Options, AbstractRenderer, Const, Type, Env, Color, Numerics) {
 49 
 50     "use strict";
 51 
 52     /**
 53      * Uses SVG to implement the rendering methods defined in {@link JXG.AbstractRenderer}.
 54      * @class JXG.AbstractRenderer
 55      * @augments JXG.AbstractRenderer
 56      * @param {Node} container Reference to a DOM node containing the board.
 57      * @param {Object} dim The dimensions of the board
 58      * @param {Number} dim.width
 59      * @param {Number} dim.height
 60      * @see JXG.AbstractRenderer
 61      */
 62     JXG.SVGRenderer = function (container, dim) {
 63         var i;
 64 
 65         // docstring in AbstractRenderer
 66         this.type = 'svg';
 67 
 68         /**
 69          * SVG root node
 70          * @type Node
 71          */
 72         this.svgRoot = null;
 73 
 74         /**
 75          * The SVG Namespace used in JSXGraph.
 76          * @see http://www.w3.org/TR/SVG/
 77          * @type String
 78          * @default http://www.w3.org/2000/svg
 79          */
 80         this.svgNamespace = 'http://www.w3.org/2000/svg';
 81 
 82         /**
 83          * The xlink namespace. This is used for images.
 84          * @see http://www.w3.org/TR/xlink/
 85          * @type String
 86          * @default http://www.w3.org/1999/xlink
 87          */
 88         this.xlinkNamespace = 'http://www.w3.org/1999/xlink';
 89 
 90         // container is documented in AbstractRenderer
 91         this.container = container;
 92 
 93         // prepare the div container and the svg root node for use with JSXGraph
 94         this.container.style.MozUserSelect = 'none';
 95 
 96         this.container.style.overflow = 'hidden';
 97         if (this.container.style.position === '') {
 98             this.container.style.position = 'relative';
 99         }
100 
101         this.svgRoot = this.container.ownerDocument.createElementNS(this.svgNamespace, "svg");
102         this.svgRoot.style.overflow = 'hidden';
103 
104         this.svgRoot.style.width = dim.width + 'px';
105         this.svgRoot.style.height = dim.height + 'px';
106 
107         this.container.appendChild(this.svgRoot);
108 
109         /**
110          * The <tt>defs</tt> element is a container element to reference reusable SVG elements.
111          * @type Node
112          * @see http://www.w3.org/TR/SVG/struct.html#DefsElement
113          */
114         this.defs = this.container.ownerDocument.createElementNS(this.svgNamespace, 'defs');
115         this.svgRoot.appendChild(this.defs);
116 
117         /**
118          * Filters are used to apply shadows.
119          * @type Node
120          * @see http://www.w3.org/TR/SVG/filters.html#FilterElement
121          */
122         this.filter = this.container.ownerDocument.createElementNS(this.svgNamespace, 'filter');
123         this.filter.setAttributeNS(null, 'id', this.container.id + '_' + 'f1');
124         this.filter.setAttributeNS(null, 'width', '300%');
125         this.filter.setAttributeNS(null, 'height', '300%');
126         this.filter.setAttributeNS(null, 'filterUnits', 'userSpaceOnUse');
127 
128         this.feOffset = this.container.ownerDocument.createElementNS(this.svgNamespace, 'feOffset');
129         this.feOffset.setAttributeNS(null, 'result', 'offOut');
130         this.feOffset.setAttributeNS(null, 'in', 'SourceAlpha');
131         this.feOffset.setAttributeNS(null, 'dx', '5');
132         this.feOffset.setAttributeNS(null, 'dy', '5');
133         this.filter.appendChild(this.feOffset);
134 
135         this.feGaussianBlur = this.container.ownerDocument.createElementNS(this.svgNamespace, 'feGaussianBlur');
136         this.feGaussianBlur.setAttributeNS(null, 'result', 'blurOut');
137         this.feGaussianBlur.setAttributeNS(null, 'in', 'offOut');
138         this.feGaussianBlur.setAttributeNS(null, 'stdDeviation', '3');
139         this.filter.appendChild(this.feGaussianBlur);
140 
141         this.feBlend = this.container.ownerDocument.createElementNS(this.svgNamespace, 'feBlend');
142         this.feBlend.setAttributeNS(null, 'in', 'SourceGraphic');
143         this.feBlend.setAttributeNS(null, 'in2', 'blurOut');
144         this.feBlend.setAttributeNS(null, 'mode', 'normal');
145         this.filter.appendChild(this.feBlend);
146 
147         this.defs.appendChild(this.filter);
148 
149         /**
150          * JSXGraph uses a layer system to sort the elements on the board. This puts certain types of elements in front
151          * of other types of elements. For the order used see {@link JXG.Options.layer}. The number of layers is documented
152          * there, too. The higher the number, the "more on top" are the elements on this layer.
153          * @type Array
154          */
155         this.layer = [];
156         for (i = 0; i < Options.layer.numlayers; i++) {
157             this.layer[i] = this.container.ownerDocument.createElementNS(this.svgNamespace, 'g');
158             this.svgRoot.appendChild(this.layer[i]);
159         }
160 
161         /**
162          * Defines dash patterns. Defined styles are: <ol>
163          * <li value="-1"> 2px dash, 2px space</li>
164          * <li> 5px dash, 5px space</li>
165          * <li> 10px dash, 10px space</li>
166          * <li> 20px dash, 20px space</li>
167          * <li> 20px dash, 10px space, 10px dash, 10px dash</li>
168          * <li> 20px dash, 5px space, 10px dash, 5px space</li></ol>
169          * @type Array
170          * @default ['2, 2', '5, 5', '10, 10', '20, 20', '20, 10, 10, 10', '20, 5, 10, 5']
171          * @see http://www.w3.org/TR/SVG/painting.html#StrokeProperties
172          */
173         this.dashArray = ['2, 2', '5, 5', '10, 10', '20, 20', '20, 10, 10, 10', '20, 5, 10, 5'];
174     };
175 
176     JXG.SVGRenderer.prototype = new AbstractRenderer();
177 
178     JXG.extend(JXG.SVGRenderer.prototype, /** @lends JXG.SVGRenderer.prototype */ {
179 
180         /**
181          * Creates an arrow DOM node. Arrows are displayed in SVG with a <em>marker</em> tag.
182          * @private
183          * @param {JXG.GeometryElement} element A JSXGraph element, preferably one that can have an arrow attached.
184          * @param {String} [idAppendix=''] A string that is added to the node's id.
185          * @returns {Node} Reference to the node added to the DOM.
186          */
187         _createArrowHead: function (element, idAppendix) {
188             var node2, node3,
189                 id = element.id + 'Triangle',
190                 s, d;
191 
192             if (Type.exists(idAppendix)) {
193                 id += idAppendix;
194             }
195             node2 = this.createPrim('marker', id);
196 
197             node2.setAttributeNS(null, 'stroke', Type.evaluate(element.visProp.strokecolor));
198             node2.setAttributeNS(null, 'stroke-opacity', Type.evaluate(element.visProp.strokeopacity));
199             node2.setAttributeNS(null, 'fill', Type.evaluate(element.visProp.strokecolor));
200             node2.setAttributeNS(null, 'fill-opacity', Type.evaluate(element.visProp.strokeopacity));
201             node2.setAttributeNS(null, 'stroke-width', 0);  // this is the stroke-width of the arrow head.
202                                                             // Should be zero to make the positioning easy
203 
204             node2.setAttributeNS(null, 'orient', 'auto');
205             node2.setAttributeNS(null, 'markerUnits', 'strokeWidth'); // 'strokeWidth' 'userSpaceOnUse');
206 
207             s = parseInt(element.visProp.strokewidth, 10);
208             //node2.setAttributeNS(null, 'viewBox', (-s) + ' ' + (-s) + ' ' + s * 12 + ' ' + s * 12);
209             node2.setAttributeNS(null, 'viewBox', (-s) + ' ' + (-s) + ' ' + s * 10 + ' ' + s * 10);
210 
211             /*
212                The arrow head is an equilateral triangle with base length 10 and height 10.
213                This 10 units are scaled to strokeWidth*3 pixels or minimum 10 pixels.
214                See also abstractRenderer.updateLine() where the line path is shortened accordingly.
215             */
216             d = Math.max(s * 3, 10);
217 
218             node2.setAttributeNS(null, 'markerHeight', d);
219             node2.setAttributeNS(null, 'markerWidth', d);
220 
221             node3 = this.container.ownerDocument.createElementNS(this.svgNamespace, 'path');
222 
223             if (idAppendix === 'End') {     // First arrow
224                 node2.setAttributeNS(null, 'refY', 5);
225                 node2.setAttributeNS(null, 'refX', 10);
226                 node3.setAttributeNS(null, 'd', 'M 10 0 L 0 5 L 10 10 z');
227             } else {                        // Last arrow
228                 node2.setAttributeNS(null, 'refY', 5);
229                 node2.setAttributeNS(null, 'refX', 0);
230                 node3.setAttributeNS(null, 'd', 'M 0 0 L 10 5 L 0 10 z');
231             }
232 
233             node2.appendChild(node3);
234             return node2;
235         },
236 
237         /**
238          * Updates an arrow DOM node.
239          * @param {Node} node The arrow node.
240          * @param {String} color Color value in a HTML compatible format, e.g. <tt>#00ff00</tt> or <tt>green</tt> for green.
241          * @param {Number} opacity
242          * @param {Number} width
243          */
244         _setArrowAtts: function (node, color, opacity, width) {
245             if (node) {
246                 node.setAttributeNS(null, 'stroke', color);
247                 node.setAttributeNS(null, 'stroke-opacity', opacity);
248                 node.setAttributeNS(null, 'fill', color);
249                 node.setAttributeNS(null, 'fill-opacity', opacity);
250 
251                 // This is the stroke-width of the arrow head.
252                 // Should be zero to make the positioning easy
253                 node.setAttributeNS(null, 'stroke-width', 0);
254             }
255         },
256 
257         /* ******************************** *
258          *  This renderer does not need to
259          *  override draw/update* methods
260          *  since it provides draw/update*Prim
261          *  methods except for some cases like
262          *  internal texts or images.
263          * ******************************** */
264 
265         /* **************************
266          *    Lines
267          * **************************/
268 
269         // documented in AbstractRenderer
270         updateTicks: function (ticks, dxMaj, dyMaj, dxMin, dyMin, minStyle, majStyle) {
271             var i, c, node, x, y,
272                 tickStr = '',
273                 len = ticks.ticks.length;
274 
275             for (i = 0; i < len; i++) {
276                 c = ticks.ticks[i];
277                 x = c[0];
278                 y = c[1];
279 
280                 if (typeof x[0] === 'number' && typeof x[1] === 'number') {
281                     tickStr += "M " + (x[0]) + " " + (y[0]) + " L " + (x[1]) + " " + (y[1]) + " ";
282                 }
283             }
284 
285             node = ticks.rendNode;
286 
287             if (!Type.exists(node)) {
288                 node = this.createPrim('path', ticks.id);
289                 this.appendChildPrim(node, ticks.visProp.layer);
290                 ticks.rendNode = node;
291             }
292 
293             node.setAttributeNS(null, 'stroke', ticks.visProp.strokecolor);
294             node.setAttributeNS(null, 'stroke-opacity', ticks.visProp.strokeopacity);
295             node.setAttributeNS(null, 'stroke-width', ticks.visProp.strokewidth);
296             this.updatePathPrim(node, tickStr, ticks.board);
297         },
298 
299         /* **************************
300          *    Text related stuff
301          * **************************/
302 
303         // already documented in JXG.AbstractRenderer
304         displayCopyright: function (str, fontsize) {
305             var node = this.createPrim('text', 'licenseText'),
306                 t;
307             node.setAttributeNS(null, 'x', '20px');
308             node.setAttributeNS(null, 'y', (2 + fontsize) + 'px');
309             node.setAttributeNS(null, "style", "font-family:Arial,Helvetica,sans-serif; font-size:" + fontsize + "px; fill:#356AA0;  opacity:0.3;");
310             t = document.createTextNode(str);
311             node.appendChild(t);
312             this.appendChildPrim(node, 0);
313         },
314 
315         // already documented in JXG.AbstractRenderer
316         drawInternalText: function (el) {
317             var node = this.createPrim('text', el.id);
318 
319             node.setAttributeNS(null, "class", el.visProp.cssclass);
320             //node.setAttributeNS(null, "style", "alignment-baseline:middle"); // Not yet supported by Firefox
321             el.rendNodeText = document.createTextNode('');
322             node.appendChild(el.rendNodeText);
323             this.appendChildPrim(node,  el.visProp.layer);
324 
325             return node;
326         },
327 
328         // already documented in JXG.AbstractRenderer
329         updateInternalText: function (el) {
330             var content = el.plaintext, v;
331 
332             // el.rendNode.setAttributeNS(null, "class", el.visProp.cssclass);
333             if (!isNaN(el.coords.scrCoords[1] + el.coords.scrCoords[2])) {
334 
335                 v = el.coords.scrCoords[1];
336                 if (el.visPropOld.left !== el.visProp.anchorx + v) {
337                     el.rendNode.setAttributeNS(null, 'x', v + 'px');
338 
339                     if (el.visProp.anchorx === 'left') {
340                         el.rendNode.setAttributeNS(null, 'text-anchor', 'start');
341                     } else if (el.visProp.anchorx === 'right') {
342                         el.rendNode.setAttributeNS(null, 'text-anchor', 'end');
343                     } else if (el.visProp.anchorx === 'middle') {
344                         el.rendNode.setAttributeNS(null, 'text-anchor', 'middle');
345                     }
346                     el.visPropOld.left = el.visProp.anchorx + v;
347                 }
348 
349                 v = el.coords.scrCoords[2];
350                 if (el.visPropOld.top !== el.visProp.anchory + v) {
351                     el.rendNode.setAttributeNS(null, 'y', (el.coords.scrCoords[2] + this.vOffsetText * 0.5) + 'px');
352 
353                     if (el.visProp.anchory === 'bottom') {
354                         el.rendNode.setAttributeNS(null, 'dominant-baseline', 'text-after-edge');
355                     } else if (el.visProp.anchory === 'top') {
356                         el.rendNode.setAttributeNS(null, 'dominant-baseline', 'text-before-edge');
357                     } else if (el.visProp.anchory === 'middle') {
358                         el.rendNode.setAttributeNS(null, 'dominant-baseline', 'middle');
359                     }
360                     el.visPropOld.top = el.visProp.anchory + v;
361                 }
362             }
363             if (el.htmlStr !== content) {
364                 el.rendNodeText.data = content;
365                 el.htmlStr = content;
366             }
367             this.transformImage(el, el.transformations);
368         },
369 
370         /**
371          * Set color and opacity of internal texts.
372          * SVG needs its own version.
373          * @private
374          * @see JXG.AbstractRenderer#updateTextStyle
375          * @see JXG.AbstractRenderer#updateInternalTextStyle
376          */
377         updateInternalTextStyle: function (element, strokeColor, strokeOpacity) {
378             this.setObjectFillColor(element, strokeColor, strokeOpacity);
379         },
380 
381         /* **************************
382          *    Image related stuff
383          * **************************/
384 
385         // already documented in JXG.AbstractRenderer
386         drawImage: function (el) {
387             var node = this.createPrim('image', el.id);
388 
389             node.setAttributeNS(null, 'preserveAspectRatio', 'none');
390             this.appendChildPrim(node, el.visProp.layer);
391             el.rendNode = node;
392 
393             this.updateImage(el);
394         },
395 
396         // already documented in JXG.AbstractRenderer
397         transformImage: function (el, t) {
398             var s, m,
399                 node = el.rendNode,
400                 str = "",
401                 len = t.length;
402 
403             if (len > 0) {
404                 m = this.joinTransforms(el, t);
405                 s = [m[1][1], m[2][1], m[1][2], m[2][2], m[1][0], m[2][0]].join(',');
406                 str += ' matrix(' + s + ') ';
407                 node.setAttributeNS(null, 'transform', str);
408             }
409         },
410 
411         // already documented in JXG.AbstractRenderer
412         updateImageURL: function (el) {
413             var url = Type.evaluate(el.url);
414 
415             el.rendNode.setAttributeNS(this.xlinkNamespace, 'xlink:href', url);
416         },
417 
418         // already documented in JXG.AbstractRenderer
419         updateImageStyle: function (el, doHighlight) {
420             var css = doHighlight ? el.visProp.highlightcssclass : el.visProp.cssclass;
421 
422             el.rendNode.setAttributeNS(null, 'class', css);
423         },
424 
425         /* **************************
426          * Render primitive objects
427          * **************************/
428 
429         // already documented in JXG.AbstractRenderer
430         appendChildPrim: function (node, level) {
431             if (!Type.exists(level)) { // trace nodes have level not set
432                 level = 0;
433             } else if (level >= Options.layer.numlayers) {
434                 level = Options.layer.numlayers - 1;
435             }
436 
437             this.layer[level].appendChild(node);
438 
439             return node;
440         },
441 
442         // already documented in JXG.AbstractRenderer
443         /*
444         appendNodesToElement: function (element) {
445             element.rendNode = this.getElementById(element.id);
446         },
447         */
448 
449         // already documented in JXG.AbstractRenderer
450         createPrim: function (type, id) {
451             var node = this.container.ownerDocument.createElementNS(this.svgNamespace, type);
452             node.setAttributeNS(null, 'id', this.container.id + '_' + id);
453             node.style.position = 'absolute';
454             if (type === 'path') {
455                 node.setAttributeNS(null, 'stroke-linecap', 'butt');
456                 node.setAttributeNS(null, 'stroke-linejoin', 'round');
457             }
458             return node;
459         },
460 
461         // already documented in JXG.AbstractRenderer
462         remove: function (shape) {
463             if (Type.exists(shape) && Type.exists(shape.parentNode)) {
464                 shape.parentNode.removeChild(shape);
465             }
466         },
467 
468         // already documented in JXG.AbstractRenderer
469         makeArrows: function (el) {
470             var node2;
471 
472             if (el.visPropOld.firstarrow === el.visProp.firstarrow && el.visPropOld.lastarrow === el.visProp.lastarrow) {
473                 return;
474             }
475 
476             if (el.visProp.firstarrow) {
477                 node2 = el.rendNodeTriangleStart;
478                 if (!Type.exists(node2)) {
479                     node2 = this._createArrowHead(el, 'End');
480                     this.defs.appendChild(node2);
481                     el.rendNodeTriangleStart = node2;
482                     el.rendNode.setAttributeNS(null, 'marker-start', 'url(#' + this.container.id + '_' + el.id + 'TriangleEnd)');
483                 } else {
484                     this.defs.appendChild(node2);
485                 }
486             } else {
487                 node2 = el.rendNodeTriangleStart;
488                 if (Type.exists(node2)) {
489                     this.remove(node2);
490                 }
491             }
492             if (el.visProp.lastarrow) {
493                 node2 = el.rendNodeTriangleEnd;
494                 if (!Type.exists(node2)) {
495                     node2 = this._createArrowHead(el, 'Start');
496                     this.defs.appendChild(node2);
497                     el.rendNodeTriangleEnd = node2;
498                     el.rendNode.setAttributeNS(null, 'marker-end', 'url(#' + this.container.id + '_' + el.id + 'TriangleStart)');
499                 } else {
500                     this.defs.appendChild(node2);
501                 }
502             } else {
503                 node2 = el.rendNodeTriangleEnd;
504                 if (Type.exists(node2)) {
505                     this.remove(node2);
506                 }
507             }
508             el.visPropOld.firstarrow = el.visProp.firstarrow;
509             el.visPropOld.lastarrow = el.visProp.lastarrow;
510         },
511 
512         // already documented in JXG.AbstractRenderer
513         updateEllipsePrim: function (node, x, y, rx, ry) {
514             var huge = 1000000;
515 
516             // webkit does not like huge values if the object is dashed
517             x = Math.abs(x) < huge ? x : huge * x / Math.abs(x);
518             y = Math.abs(y) < huge ? y : huge * y / Math.abs(y);
519             rx = Math.abs(rx) < huge ? rx : huge * rx / Math.abs(rx);
520             ry = Math.abs(ry) < huge ? ry : huge * ry / Math.abs(ry);
521 
522             node.setAttributeNS(null, 'cx', x);
523             node.setAttributeNS(null, 'cy', y);
524             node.setAttributeNS(null, 'rx', Math.abs(rx));
525             node.setAttributeNS(null, 'ry', Math.abs(ry));
526         },
527 
528         // already documented in JXG.AbstractRenderer
529         updateLinePrim: function (node, p1x, p1y, p2x, p2y) {
530             var huge = 1000000;
531 
532             if (!isNaN(p1x + p1y + p2x + p2y)) {
533                 // webkit does not like huge values if the object is dashed
534                 p1x = Math.abs(p1x) < huge ? p1x : huge * p1x / Math.abs(p1x);
535                 p1y = Math.abs(p1y) < huge ? p1y : huge * p1y / Math.abs(p1y);
536                 p2x = Math.abs(p2x) < huge ? p2x : huge * p2x / Math.abs(p2x);
537                 p2y = Math.abs(p2y) < huge ? p2y : huge * p2y / Math.abs(p2y);
538 
539                 node.setAttributeNS(null, 'x1', p1x);
540                 node.setAttributeNS(null, 'y1', p1y);
541                 node.setAttributeNS(null, 'x2', p2x);
542                 node.setAttributeNS(null, 'y2', p2y);
543             }
544         },
545 
546         // already documented in JXG.AbstractRenderer
547         updatePathPrim: function (node, pointString) {
548             if (pointString === '') {
549                 pointString = 'M 0 0';
550             }
551             node.setAttributeNS(null, 'd', pointString);
552         },
553 
554         // already documented in JXG.AbstractRenderer
555         updatePathStringPoint: function (el, size, type) {
556             var s = '',
557                 scr = el.coords.scrCoords,
558                 sqrt32 = size * Math.sqrt(3) * 0.5,
559                 s05 = size * 0.5;
560 
561             if (type === 'x') {
562                 s = ' M ' + (scr[1] - size) + ' ' + (scr[2] - size) +
563                     ' L ' + (scr[1] + size) + ' ' + (scr[2] + size) +
564                     ' M ' + (scr[1] + size) + ' ' + (scr[2] - size) +
565                     ' L ' + (scr[1] - size) + ' ' + (scr[2] + size);
566             } else if (type === '+') {
567                 s = ' M ' + (scr[1] - size) + ' ' + (scr[2]) +
568                     ' L ' + (scr[1] + size) + ' ' + (scr[2]) +
569                     ' M ' + (scr[1])        + ' ' + (scr[2] - size) +
570                     ' L ' + (scr[1])        + ' ' + (scr[2] + size);
571             } else if (type === '<>') {
572                 s = ' M ' + (scr[1] - size) + ' ' + (scr[2]) +
573                     ' L ' + (scr[1])        + ' ' + (scr[2] + size) +
574                     ' L ' + (scr[1] + size) + ' ' + (scr[2]) +
575                     ' L ' + (scr[1])        + ' ' + (scr[2] - size) + ' Z ';
576             } else if (type === '^') {
577                 s = ' M ' + (scr[1])          + ' ' + (scr[2] - size) +
578                     ' L ' + (scr[1] - sqrt32) + ' ' + (scr[2] + s05) +
579                     ' L ' + (scr[1] + sqrt32) + ' ' + (scr[2] + s05) +
580                     ' Z ';  // close path
581             } else if (type === 'v') {
582                 s = ' M ' + (scr[1])          + ' ' + (scr[2] + size) +
583                     ' L ' + (scr[1] - sqrt32) + ' ' + (scr[2] - s05) +
584                     ' L ' + (scr[1] + sqrt32) + ' ' + (scr[2] - s05) +
585                     ' Z ';
586             } else if (type === '>') {
587                 s = ' M ' + (scr[1] + size) + ' ' + (scr[2]) +
588                     ' L ' + (scr[1] - s05)  + ' ' + (scr[2] - sqrt32) +
589                     ' L ' + (scr[1] - s05)  + ' ' + (scr[2] + sqrt32) +
590                     ' Z ';
591             } else if (type === '<') {
592                 s = ' M ' + (scr[1] - size) + ' ' + (scr[2]) +
593                     ' L ' + (scr[1] + s05)  + ' ' + (scr[2] - sqrt32) +
594                     ' L ' + (scr[1] + s05)  + ' ' + (scr[2] + sqrt32) +
595                     ' Z ';
596             }
597             return s;
598         },
599 
600         // already documented in JXG.AbstractRenderer
601         updatePathStringPrim: function (el) {
602             var i, scr, len,
603                 symbm = ' M ',
604                 symbl = ' L ',
605                 symbc = ' C ',
606                 nextSymb = symbm,
607                 maxSize = 5000.0,
608                 pStr = '',
609                 isNotPlot = (el.visProp.curvetype !== 'plot');
610 
611             if (el.numberPoints <= 0) {
612                 return '';
613             }
614 
615             len = Math.min(el.points.length, el.numberPoints);
616 
617             if (el.bezierDegree === 1) {
618                 if (isNotPlot && el.board.options.curve.RDPsmoothing) {
619                     el.points = Numerics.RamerDouglasPeuker(el.points, 0.5);
620                 }
621 
622                 for (i = 0; i < len; i++) {
623                     scr = el.points[i].scrCoords;
624                     if (isNaN(scr[1]) || isNaN(scr[2])) {  // PenUp
625                         nextSymb = symbm;
626                     } else {
627                         // Chrome has problems with values being too far away.
628                         if (scr[1] > maxSize) {
629                             scr[1] = maxSize;
630                         } else if (scr[1] < -maxSize) {
631                             scr[1] = -maxSize;
632                         }
633 
634                         if (scr[2] > maxSize) {
635                             scr[2] = maxSize;
636                         } else if (scr[2] < -maxSize) {
637                             scr[2] = -maxSize;
638                         }
639                         // Attention: first coordinate may be inaccurate if far way
640                         //pStr += [nextSymb, scr[1], ' ', scr[2]].join('');
641                         pStr += nextSymb + scr[1] + ' ' + scr[2];   // Seems to be faster on now (webkit and firefox)
642                         nextSymb = symbl;
643                     }
644                 }
645             } else if (el.bezierDegree === 3) {
646                 i = 0;
647                 while (i < len) {
648                     scr = el.points[i].scrCoords;
649                     if (isNaN(scr[1]) || isNaN(scr[2])) {  // PenUp
650                         nextSymb = symbm;
651                     } else {
652                         pStr += nextSymb + scr[1] + ' ' + scr[2];
653                         if (nextSymb === symbc) {
654                             i += 1;
655                             scr = el.points[i].scrCoords;
656                             pStr += ' ' + scr[1] + ' ' + scr[2];
657                             i += 1;
658                             scr = el.points[i].scrCoords;
659                             pStr += ' ' + scr[1] + ' ' + scr[2];
660                         }
661                         nextSymb = symbc;
662                     }
663                     i += 1;
664                 }
665             }
666             return pStr;
667         },
668 
669         // already documented in JXG.AbstractRenderer
670         updatePathStringBezierPrim: function (el) {
671             var i, j, k, scr, lx, ly, len,
672                 symbm = ' M ',
673                 symbl = ' C ',
674                 nextSymb = symbm,
675                 maxSize = 5000.0,
676                 pStr = '',
677                 f = el.visProp.strokewidth,
678                 isNoPlot = (el.visProp.curvetype !== 'plot');
679 
680             if (el.numberPoints <= 0) {
681                 return '';
682             }
683 
684             if (isNoPlot && el.board.options.curve.RDPsmoothing) {
685                 el.points = Numerics.RamerDouglasPeuker(el.points, 0.5);
686             }
687 
688             len = Math.min(el.points.length, el.numberPoints);
689             for (j = 1; j < 3; j++) {
690                 nextSymb = symbm;
691                 for (i = 0; i < len; i++) {
692                     scr = el.points[i].scrCoords;
693 
694                     if (isNaN(scr[1]) || isNaN(scr[2])) {  // PenUp
695                         nextSymb = symbm;
696                     } else {
697                         // Chrome has problems with values being too far away.
698                         if (scr[1] > maxSize) {
699                             scr[1] = maxSize;
700                         } else if (scr[1] < -maxSize) {
701                             scr[1] = -maxSize;
702                         }
703 
704                         if (scr[2] > maxSize) {
705                             scr[2] = maxSize;
706                         } else if (scr[2] < -maxSize) {
707                             scr[2] = -maxSize;
708                         }
709 
710                         // Attention: first coordinate may be inaccurate if far way
711                         if (nextSymb === symbm) {
712                             pStr += [nextSymb, scr[1], ' ', scr[2]].join('');
713                         } else {
714                             k = 2 * j;
715                             pStr += [nextSymb,
716                                 (lx + (scr[1] - lx) * 0.333 + f * (k * Math.random() - j)), ' ',
717                                 (ly + (scr[2] - ly) * 0.333 + f * (k * Math.random() - j)), ' ',
718                                 (lx + (scr[1] - lx) * 0.666 + f * (k * Math.random() - j)), ' ',
719                                 (ly + (scr[2] - ly) * 0.666 + f * (k * Math.random() - j)), ' ',
720                                 scr[1], ' ', scr[2]].join('');
721                         }
722 
723                         nextSymb = symbl;
724                         lx = scr[1];
725                         ly = scr[2];
726                     }
727                 }
728             }
729             return pStr;
730         },
731 
732         // already documented in JXG.AbstractRenderer
733         updatePolygonPrim: function (node, el) {
734             var i,
735                 pStr = '',
736                 scrCoords,
737                 len = el.vertices.length;
738 
739             node.setAttributeNS(null, 'stroke', 'none');
740 
741             for (i = 0; i < len - 1; i++) {
742                 if (el.vertices[i].isReal) {
743                     scrCoords = el.vertices[i].coords.scrCoords;
744                     pStr = pStr + scrCoords[1] + "," + scrCoords[2];
745                 } else {
746                     node.setAttributeNS(null, 'points', '');
747                     return;
748                 }
749 
750                 if (i < len - 2) {
751                     pStr += " ";
752                 }
753             }
754             if (pStr.indexOf('NaN') === -1) {
755                 node.setAttributeNS(null, 'points', pStr);
756             }
757         },
758 
759         // already documented in JXG.AbstractRenderer
760         updateRectPrim: function (node, x, y, w, h) {
761             node.setAttributeNS(null, 'x', x);
762             node.setAttributeNS(null, 'y', y);
763             node.setAttributeNS(null, 'width', w);
764             node.setAttributeNS(null, 'height', h);
765         },
766 
767         /* **************************
768          *  Set Attributes
769          * **************************/
770 
771         // documented in JXG.AbstractRenderer
772         setPropertyPrim: function (node, key, val) {
773             if (key === 'stroked') {
774                 return;
775             }
776             node.setAttributeNS(null, key, val);
777         },
778 
779         // documented in JXG.AbstractRenderer
780         show: function (el) {
781             var node;
782 
783             if (el && el.rendNode) {
784                 node = el.rendNode;
785                 node.setAttributeNS(null, 'display', 'inline');
786                 node.style.visibility = "inherit";
787             }
788         },
789 
790         // documented in JXG.AbstractRenderer
791         hide: function (el) {
792             var node;
793 
794             if (el && el.rendNode) {
795                 node = el.rendNode;
796                 node.setAttributeNS(null, 'display', 'none');
797                 node.style.visibility = "hidden";
798             }
799         },
800 
801         // documented in JXG.AbstractRenderer
802         setBuffering: function (el, type) {
803             el.rendNode.setAttribute('buffered-rendering', type);
804         },
805 
806         // documented in JXG.AbstractRenderer
807         setDashStyle: function (el) {
808             var dashStyle = el.visProp.dash, node = el.rendNode;
809 
810             if (el.visProp.dash > 0) {
811                 node.setAttributeNS(null, 'stroke-dasharray', this.dashArray[dashStyle - 1]);
812             } else {
813                 if (node.hasAttributeNS(null, 'stroke-dasharray')) {
814                     node.removeAttributeNS(null, 'stroke-dasharray');
815                 }
816             }
817         },
818 
819         // documented in JXG.AbstractRenderer
820         setGradient: function (el) {
821             var fillNode = el.rendNode, col, op,
822                 node, node2, node3, x1, x2, y1, y2;
823 
824             op = Type.evaluate(el.visProp.fillopacity);
825             op = (op > 0) ? op : 0;
826 
827             col = Type.evaluate(el.visProp.fillcolor);
828 
829             if (el.visProp.gradient === 'linear') {
830                 node = this.createPrim('linearGradient', el.id + '_gradient');
831                 x1 = '0%';
832                 x2 = '100%';
833                 y1 = '0%';
834                 y2 = '0%';
835 
836                 node.setAttributeNS(null, 'x1', x1);
837                 node.setAttributeNS(null, 'x2', x2);
838                 node.setAttributeNS(null, 'y1', y1);
839                 node.setAttributeNS(null, 'y2', y2);
840                 node2 = this.createPrim('stop', el.id + '_gradient1');
841                 node2.setAttributeNS(null, 'offset', '0%');
842                 node2.setAttributeNS(null, 'style', 'stop-color:' + col + ';stop-opacity:' + op);
843                 node3 = this.createPrim('stop', el.id + '_gradient2');
844                 node3.setAttributeNS(null, 'offset', '100%');
845                 node3.setAttributeNS(null, 'style', 'stop-color:' + el.visProp.gradientsecondcolor + ';stop-opacity:' + el.visProp.gradientsecondopacity);
846                 node.appendChild(node2);
847                 node.appendChild(node3);
848                 this.defs.appendChild(node);
849                 fillNode.setAttributeNS(null, 'style', 'fill:url(#' + this.container.id + '_' + el.id + '_gradient)');
850                 el.gradNode1 = node2;
851                 el.gradNode2 = node3;
852             } else if (el.visProp.gradient === 'radial') {
853                 node = this.createPrim('radialGradient', el.id + '_gradient');
854 
855                 node.setAttributeNS(null, 'cx', '50%');
856                 node.setAttributeNS(null, 'cy', '50%');
857                 node.setAttributeNS(null, 'r', '50%');
858                 node.setAttributeNS(null, 'fx', el.visProp.gradientpositionx * 100 + '%');
859                 node.setAttributeNS(null, 'fy', el.visProp.gradientpositiony * 100 + '%');
860 
861                 node2 = this.createPrim('stop', el.id + '_gradient1');
862                 node2.setAttributeNS(null, 'offset', '0%');
863                 node2.setAttributeNS(null, 'style', 'stop-color:' + el.visProp.gradientsecondcolor + ';stop-opacity:' + el.visProp.gradientsecondopacity);
864                 node3 = this.createPrim('stop', el.id + '_gradient2');
865                 node3.setAttributeNS(null, 'offset', '100%');
866                 node3.setAttributeNS(null, 'style', 'stop-color:' + col + ';stop-opacity:' + op);
867 
868                 node.appendChild(node2);
869                 node.appendChild(node3);
870                 this.defs.appendChild(node);
871                 fillNode.setAttributeNS(null, 'style', 'fill:url(#' + this.container.id + '_' + el.id + '_gradient)');
872                 el.gradNode1 = node2;
873                 el.gradNode2 = node3;
874             } else {
875                 fillNode.removeAttributeNS(null, 'style');
876             }
877         },
878 
879         // documented in JXG.AbstractRenderer
880         updateGradient: function (el) {
881             var col, op,
882                 node2 = el.gradNode1,
883                 node3 = el.gradNode2;
884 
885             if (!Type.exists(node2) || !Type.exists(node3)) {
886                 return;
887             }
888 
889             op = Type.evaluate(el.visProp.fillopacity);
890             op = (op > 0) ? op : 0;
891 
892             col = Type.evaluate(el.visProp.fillcolor);
893 
894             if (el.visProp.gradient === 'linear') {
895                 node2.setAttributeNS(null, 'style', 'stop-color:' + col + ';stop-opacity:' + op);
896                 node3.setAttributeNS(null, 'style', 'stop-color:' + el.visProp.gradientsecondcolor + ';stop-opacity:' + el.visProp.gradientsecondopacity);
897             } else if (el.visProp.gradient === 'radial') {
898                 node2.setAttributeNS(null, 'style', 'stop-color:' + el.visProp.gradientsecondcolor + ';stop-opacity:' + el.visProp.gradientsecondopacity);
899                 node3.setAttributeNS(null, 'style', 'stop-color:' + col + ';stop-opacity:' + op);
900             }
901         },
902 
903         // documented in JXG.AbstractRenderer
904         setObjectFillColor: function (el, color, opacity) {
905             var node, c, rgbo, oo,
906                 rgba = Type.evaluate(color),
907                 o = Type.evaluate(opacity);
908 
909             o = (o > 0) ? o : 0;
910 
911             if (el.visPropOld.fillcolor === rgba && el.visPropOld.fillopacity === o) {
912                 return;
913             }
914             if (Type.exists(rgba) && rgba !== false) {
915                 if (rgba.length !== 9) {          // RGB, not RGBA
916                     c = rgba;
917                     oo = o;
918                 } else {                       // True RGBA, not RGB
919                     rgbo = Color.rgba2rgbo(rgba);
920                     c = rgbo[0];
921                     oo = o * rgbo[1];
922                 }
923 
924                 node = el.rendNode;
925 
926                 if (c !== 'none') {               // problem in firefox 17
927                     node.setAttributeNS(null, 'fill', c);
928                 } else {
929                     oo = 0;
930                 }
931 
932                 if (el.type === JXG.OBJECT_TYPE_IMAGE) {
933                     node.setAttributeNS(null, 'opacity', oo);
934                 } else {
935                     node.setAttributeNS(null, 'fill-opacity', oo);
936                 }
937 
938                 if (Type.exists(el.visProp.gradient)) {
939                     this.updateGradient(el);
940                 }
941             }
942             el.visPropOld.fillcolor = rgba;
943             el.visPropOld.fillopacity = o;
944         },
945 
946         // documented in JXG.AbstractRenderer
947         setObjectStrokeColor: function (el, color, opacity) {
948             var rgba = Type.evaluate(color), c, rgbo,
949                 o = Type.evaluate(opacity), oo,
950                 node;
951 
952             o = (o > 0) ? o : 0;
953 
954             if (el.visPropOld.strokecolor === rgba && el.visPropOld.strokeopacity === o) {
955                 return;
956             }
957 
958             if (Type.exists(rgba) && rgba !== false) {
959                 if (rgba.length !== 9) {          // RGB, not RGBA
960                     c = rgba;
961                     oo = o;
962                 } else {                       // True RGBA, not RGB
963                     rgbo = Color.rgba2rgbo(rgba);
964                     c = rgbo[0];
965                     oo = o * rgbo[1];
966                 }
967 
968                 node = el.rendNode;
969 
970                 if (el.type === Const.OBJECT_TYPE_TEXT) {
971                     if (el.visProp.display === 'html') {
972                         node.style.color = c;
973                         node.style.opacity = oo;
974                     } else {
975                         node.setAttributeNS(null, "style", "fill:" + c);
976                         node.setAttributeNS(null, "style", "fill-opacity:" + oo);
977                     }
978                 } else {
979                     node.setAttributeNS(null, 'stroke', c);
980                     node.setAttributeNS(null, 'stroke-opacity', oo);
981                 }
982 
983                 if (el.type === Const.OBJECT_TYPE_ARROW) {
984                     this._setArrowAtts(el.rendNodeTriangle, c, oo, el.visProp.strokewidth);
985                 } else if (el.elementClass === Const.OBJECT_CLASS_CURVE || el.elementClass === Const.OBJECT_CLASS_LINE) {
986                     if (el.visProp.firstarrow) {
987                         this._setArrowAtts(el.rendNodeTriangleStart, c, oo, el.visProp.strokewidth);
988                     }
989 
990                     if (el.visProp.lastarrow) {
991                         this._setArrowAtts(el.rendNodeTriangleEnd, c, oo, el.visProp.strokewidth);
992                     }
993                 }
994             }
995 
996             el.visPropOld.strokecolor = rgba;
997             el.visPropOld.strokeopacity = o;
998         },
999 
1000         // documented in JXG.AbstractRenderer
1001         setObjectStrokeWidth: function (el, width) {
1002             var node,
1003                 w = Type.evaluate(width);
1004 
1005             if (isNaN(w) || el.visPropOld.strokewidth === w) {
1006                 return;
1007             }
1008 
1009             node = el.rendNode;
1010             this.setPropertyPrim(node, 'stroked', 'true');
1011             if (Type.exists(w)) {
1012                 this.setPropertyPrim(node, 'stroke-width', w + 'px');
1013 
1014                 if (el.type === Const.OBJECT_TYPE_ARROW) {
1015                     this._setArrowAtts(el.rendNodeTriangle, el.visProp.strokecolor, el.visProp.strokeopacity, w);
1016                 } else if (el.elementClass === Const.OBJECT_CLASS_CURVE || el.elementClass === Const.OBJECT_CLASS_LINE) {
1017                     if (el.visProp.firstarrow) {
1018                         this._setArrowAtts(el.rendNodeTriangleStart, el.visProp.strokecolor, el.visProp.strokeopacity, w);
1019                     }
1020 
1021                     if (el.visProp.lastarrow) {
1022                         this._setArrowAtts(el.rendNodeTriangleEnd, el.visProp.strokecolor, el.visProp.strokeopacity, w);
1023                     }
1024                 }
1025             }
1026             el.visPropOld.strokewidth = w;
1027         },
1028 
1029         // documented in JXG.AbstractRenderer
1030         setShadow: function (el) {
1031             if (el.visPropOld.shadow === el.visProp.shadow) {
1032                 return;
1033             }
1034 
1035             if (Type.exists(el.rendNode)) {
1036                 if (el.visProp.shadow) {
1037                     el.rendNode.setAttributeNS(null, 'filter', 'url(#' + this.container.id + '_' + 'f1)');
1038                 } else {
1039                     el.rendNode.removeAttributeNS(null, 'filter');
1040                 }
1041             }
1042             el.visPropOld.shadow = el.visProp.shadow;
1043         },
1044 
1045         /* **************************
1046          * renderer control
1047          * **************************/
1048 
1049         // documented in JXG.AbstractRenderer
1050         suspendRedraw: function () {
1051             // It seems to be important for the Linux version of firefox
1052             //this.suspendHandle = this.svgRoot.suspendRedraw(10000);
1053         },
1054 
1055         // documented in JXG.AbstractRenderer
1056         unsuspendRedraw: function () {
1057             //this.svgRoot.unsuspendRedraw(this.suspendHandle);
1058             //this.svgRoot.unsuspendRedrawAll();
1059             //this.svgRoot.forceRedraw();
1060         },
1061 
1062         // documented in AbstractRenderer
1063         resize: function (w, h) {
1064             this.svgRoot.style.width = parseFloat(w) + 'px';
1065             this.svgRoot.style.height = parseFloat(h) + 'px';
1066         },
1067 
1068         // documented in JXG.AbstractRenderer
1069         createTouchpoints: function (n) {
1070             var i, na1, na2, node;
1071             this.touchpoints = [];
1072             for (i = 0; i < n; i++) {
1073                 na1 = 'touchpoint1_' + i;
1074                 node = this.createPrim('path', na1);
1075                 this.appendChildPrim(node, 19);
1076                 node.setAttributeNS(null, 'd', 'M 0 0');
1077                 this.touchpoints.push(node);
1078 
1079                 this.setPropertyPrim(node, 'stroked', 'true');
1080                 this.setPropertyPrim(node, 'stroke-width', '1px');
1081                 node.setAttributeNS(null, 'stroke', '#000000');
1082                 node.setAttributeNS(null, 'stroke-opacity', 1.0);
1083                 node.setAttributeNS(null, 'display', 'none');
1084 
1085                 na2 = 'touchpoint2_' + i;
1086                 node = this.createPrim('ellipse', na2);
1087                 this.appendChildPrim(node, 19);
1088                 this.updateEllipsePrim(node, 0, 0, 0, 0);
1089                 this.touchpoints.push(node);
1090 
1091                 this.setPropertyPrim(node, 'stroked', 'true');
1092                 this.setPropertyPrim(node, 'stroke-width', '1px');
1093                 node.setAttributeNS(null, 'stroke', '#000000');
1094                 node.setAttributeNS(null, 'stroke-opacity', 1.0);
1095                 node.setAttributeNS(null, 'fill', '#ffffff');
1096                 node.setAttributeNS(null, 'fill-opacity', 0.0);
1097 
1098                 node.setAttributeNS(null, 'display', 'none');
1099             }
1100         },
1101 
1102         // documented in JXG.AbstractRenderer
1103         showTouchpoint: function (i) {
1104             if (this.touchpoints && i >= 0 && 2 * i < this.touchpoints.length) {
1105                 this.touchpoints[2 * i].setAttributeNS(null, 'display', 'inline');
1106                 this.touchpoints[2 * i + 1].setAttributeNS(null, 'display', 'inline');
1107             }
1108         },
1109 
1110         // documented in JXG.AbstractRenderer
1111         hideTouchpoint: function (i) {
1112             if (this.touchpoints && i >= 0 && 2 * i < this.touchpoints.length) {
1113                 this.touchpoints[2 * i].setAttributeNS(null, 'display', 'none');
1114                 this.touchpoints[2 * i + 1].setAttributeNS(null, 'display', 'none');
1115             }
1116         },
1117 
1118         // documented in JXG.AbstractRenderer
1119         updateTouchpoint: function (i, pos) {
1120             var x, y,
1121                 d = 37;
1122 
1123             if (this.touchpoints && i >= 0 && 2 * i < this.touchpoints.length) {
1124                 x = pos[0];
1125                 y = pos[1];
1126 
1127                 this.touchpoints[2 * i].setAttributeNS(null, 'd', 'M ' + (x - d) + ' ' + y + ' ' +
1128                     'L ' + (x + d) + ' ' + y + ' ' +
1129                     'M ' + x + ' ' + (y - d) + ' ' +
1130                     'L ' + x + ' ' + (y + d));
1131                 this.updateEllipsePrim(this.touchpoints[2 * i + 1], pos[0], pos[1], 25, 25);
1132             }
1133         }
1134     });
1135 
1136     return JXG.SVGRenderer;
1137 });
1138