/*
    Copyright 2008-2018
        Matthias Ehmann,
        Michael Gerhaeuser,
        Carsten Miller,
        Bianca Valentin,
        Alfred Wassermann,
        Peter Wilfahrt

    This file is part of JSXGraph.

    JSXGraph is free software dual licensed under the GNU LGPL or MIT License.

    You can redistribute it and/or modify it under the terms of the

      * GNU Lesser General Public License as published by
        the Free Software Foundation, either version 3 of the License, or
        (at your option) any later version
      OR
      * MIT License: https://github.com/jsxgraph/jsxgraph/blob/master/LICENSE.MIT

    JSXGraph is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License and
    the MIT License along with JSXGraph. If not, see <http://www.gnu.org/licenses/>
    and <http://opensource.org/licenses/MIT/>.
 */


/*global JXG: true, define: true, AMprocessNode: true, MathJax: true, document: true */
/*jslint nomen: true, plusplus: true, newcap:true*/

/* depends:
 jxg
 renderer/abstract
 base/constants
 utils/type
 utils/color
 math/math
 math/numerics
*/

define([
    'jxg', 'renderer/abstract', 'base/constants', 'utils/type', 'utils/color', 'math/math', 'math/numerics'
], function (JXG, AbstractRenderer, Const, Type, Color, Mat, Numerics) {

    "use strict";

    /**
     * Uses VML to implement the rendering methods defined in {@link JXG.AbstractRenderer}.
     * @class JXG.AbstractRenderer
     * @augments JXG.AbstractRenderer
     * @param {Node} container Reference to a DOM node containing the board.
     * @see JXG.AbstractRenderer
     */
    JXG.VMLRenderer = function (container) {
        this.type = 'vml';

        this.container = container;
        this.container.style.overflow = 'hidden';
        if (this.container.style.position === '') {
            this.container.style.position = 'relative';
        }
        this.container.onselectstart = function () {
            return false;
        };

        this.resolution = 10; // Paths are drawn with a a resolution of this.resolution/pixel.

        // Add VML includes and namespace
        // Original: IE <=7
        //container.ownerDocument.createStyleSheet().addRule("v\\:*", "behavior: url(#default#VML);");
        if (!Type.exists(JXG.vmlStylesheet)) {
            container.ownerDocument.namespaces.add("jxgvml", "urn:schemas-microsoft-com:vml");
            JXG.vmlStylesheet = this.container.ownerDocument.createStyleSheet();
            JXG.vmlStylesheet.addRule(".jxgvml", "behavior:url(#default#VML)");
        }

        try {
            if (!container.ownerDocument.namespaces.jxgvml) {
                container.ownerDocument.namespaces.add("jxgvml", "urn:schemas-microsoft-com:vml");
            }

            this.createNode = function (tagName) {
                return container.ownerDocument.createElement('<jxgvml:' + tagName + ' class="jxgvml">');
            };
        } catch (e) {
            this.createNode = function (tagName) {
                return container.ownerDocument.createElement('<' + tagName + ' xmlns="urn:schemas-microsoft.com:vml" class="jxgvml">');
            };
        }

        // dash styles
        this.dashArray = ['Solid', '1 1', 'ShortDash', 'Dash', 'LongDash', 'ShortDashDot', 'LongDashDot'];
    };

    JXG.VMLRenderer.prototype = new AbstractRenderer();

    JXG.extend(JXG.VMLRenderer.prototype, /** @lends JXG.VMLRenderer */ {

        /**
         * Sets attribute <tt>key</tt> of node <tt>node</tt> to <tt>value</tt>.
         * @param {Node} node A DOM node.
         * @param {String} key Name of the attribute.
         * @param {String} val New value of the attribute.
         * @param {Boolean} [iFlag=false] If false, the attribute's name is case insensitive.
         */
        _setAttr: function (node, key, val, iFlag) {
            try {
                if (this.container.ownerDocument.documentMode === 8) {
                    node[key] = val;
                } else {
                    node.setAttribute(key, val, iFlag);
                }
            } catch (e) {
                JXG.debug('_setAttr:'/*node.id*/ + ' ' + key + ' ' + val + '<br>\n');
            }
        },

        /* ******************************** *
         *  This renderer does not need to
         *  override draw/update* methods
         *  since it provides draw/update*Prim
         *  methods.
         * ******************************** */

        /* **************************
         *    Lines
         * **************************/

        // documented in AbstractRenderer
        updateTicks: function (ticks) {
            var i, len, c, x, y,
                r = this.resolution,
                tickArr = [];

            len = ticks.ticks.length;
            for (i = 0; i < len; i++) {
                c = ticks.ticks[i];
                x = c[0];
                y = c[1];

                if (Type.isNumber(x[0]) && Type.isNumber(x[1])) {
                    tickArr.push(' m ' + Math.round(r * x[0]) + ', ' + Math.round(r * y[0]) +
                        ' l ' + Math.round(r * x[1]) + ', ' + Math.round(r * y[1]) + ' ');
                }
            }

            if (!Type.exists(ticks.rendNode)) {
                ticks.rendNode = this.createPrim('path', ticks.id);
                this.appendChildPrim(ticks.rendNode, Type.evaluate(ticks.visProp.layer));
            }

            this._setAttr(ticks.rendNode, 'stroked', 'true');
            this._setAttr(ticks.rendNode, 'strokecolor', Type.evaluate(ticks.visProp.strokecolor), 1);
            this._setAttr(ticks.rendNode, 'strokeweight', Type.evaluate(ticks.visProp.strokewidth));
            this._setAttr(ticks.rendNodeStroke, 'opacity', (Type.evaluate(ticks.visProp.strokeopacity) * 100) + '%');
            this.updatePathPrim(ticks.rendNode, tickArr, ticks.board);
        },

        /* **************************
         *    Text related stuff
         * **************************/

        // already documented in JXG.AbstractRenderer
        displayCopyright: function (str, fontsize) {
            var node, t;

            node = this.createNode('textbox');
            node.style.position = 'absolute';
            this._setAttr(node, 'id', this.container.id + '_' + 'licenseText');

            node.style.left = 20;
            node.style.top = 2;
            node.style.fontSize = fontsize;
            node.style.color = '#356AA0';
            node.style.fontFamily = 'Arial,Helvetica,sans-serif';
            this._setAttr(node, 'opacity', '30%');
            node.style.filter = "progid:DXImageTransform.Microsoft.Matrix(M11='1.0', sizingMethod='auto expand', enabled = false) progid:DXImageTransform.Microsoft.Alpha(opacity = 30, enabled = true)";

            t = this.container.ownerDocument.createTextNode(str);
            node.appendChild(t);
            this.appendChildPrim(node, 0);
        },

        // documented in AbstractRenderer
        drawInternalText: function (el) {
            var node;
            node = this.createNode('textbox');
            node.style.position = 'absolute';
            el.rendNodeText = this.container.ownerDocument.createTextNode('');
            node.appendChild(el.rendNodeText);
            this.appendChildPrim(node, 9);
            node.style.filter = "progid:DXImageTransform.Microsoft.Matrix(M11='1.0', sizingMethod='auto expand', enabled = false) progid:DXImageTransform.Microsoft.Alpha(opacity = 100, enabled = false)";

            return node;
        },

        // documented in AbstractRenderer
        updateInternalText: function (el) {
            var v, content = el.plaintext,
                m = this.joinTransforms(el, el.transformations),
                offset = [0, 0],
                maxX, maxY, minX, minY, i,
                node = el.rendNode,
                p = [],
                ev_ax = el.getAnchorX(),
                ev_ay = el.getAnchorY();

            if (!isNaN(el.coords.scrCoords[1] + el.coords.scrCoords[2])) {
                // Horizontal
                if (ev_ax === 'right') {
                    offset[0] = 1;
                } else if (ev_ax === 'middle') {
                    offset[0] = 0.5;
                } // default (ev_ax === 'left') offset[0] = 0;

                // Vertical
                if (ev_ay === 'bottom') {
                    offset[1] = 1;
                } else if (ev_ay === 'middle') {
                    offset[1] = 0.5;
                } // default (ev_ay === 'top') offset[1] = 0;

                // Compute maxX, maxY, minX, minY
                p[0] = Mat.matVecMult(m, [1,
                                          el.coords.scrCoords[1] - offset[0] * el.size[0],
                                          el.coords.scrCoords[2] + (1 - offset[1]) * el.size[1] + this.vOffsetText]);
                p[0][1] /= p[0][0];
                p[0][2] /= p[0][0];
                p[1] = Mat.matVecMult(m, [1,
                                          el.coords.scrCoords[1] + (1 - offset[0]) * el.size[0],
                                          el.coords.scrCoords[2] + (1 - offset[1]) * el.size[1] + this.vOffsetText]);
                p[1][1] /= p[1][0];
                p[1][2] /= p[1][0];
                p[2] = Mat.matVecMult(m, [1,
                                          el.coords.scrCoords[1] + (1 - offset[0]) * el.size[0],
                                          el.coords.scrCoords[2] - offset[1] * el.size[1] + this.vOffsetText]);
                p[2][1] /= p[2][0];
                p[2][2] /= p[2][0];
                p[3] = Mat.matVecMult(m, [1,
                                          el.coords.scrCoords[1] - offset[0] * el.size[0],
                                          el.coords.scrCoords[2] - offset[1] * el.size[1] + this.vOffsetText]);
                p[3][1] /= p[3][0];
                p[3][2] /= p[3][0];
                maxX = p[0][1];
                minX = p[0][1];
                maxY = p[0][2];
                minY = p[0][2];

                for (i = 1; i < 4; i++) {
                    maxX = Math.max(maxX, p[i][1]);
                    minX = Math.min(minX, p[i][1]);
                    maxY = Math.max(maxY, p[i][2]);
                    minY = Math.min(minY, p[i][2]);
                }

                // Horizontal
                v = offset[0] === 1 ? Math.floor(el.board.canvasWidth - maxX) : Math.floor(minX);
                if (el.visPropOld.left !== (ev_ax + v)) {
                    if (offset[0] === 1) {
                        el.rendNode.style.right = v + 'px';
                        el.rendNode.style.left = 'auto';
                    } else {
                        el.rendNode.style.left = v + 'px';
                        el.rendNode.style.right = 'auto';
                    }
                    el.visPropOld.left = ev_ax + v;
                }

                // Vertical
                v = offset[1] === 1 ? Math.floor(el.board.canvasHeight - maxY) : Math.floor(minY);
                if (el.visPropOld.top !== (ev_ay + v)) {
                    if (offset[1] === 1) {
                        el.rendNode.style.bottom = v + 'px';
                        el.rendNode.style.top = 'auto';
                    } else {
                        el.rendNode.style.top = v + 'px';
                        el.rendNode.style.bottom = 'auto';
                    }
                    el.visPropOld.top = ev_ay + v;
                }

            }

            if (el.htmlStr !== content) {
                el.rendNodeText.data = content;
                el.htmlStr = content;
            }

            //this.transformImage(el, el.transformations);
            node.filters.item(0).M11 = m[1][1];
            node.filters.item(0).M12 = m[1][2];
            node.filters.item(0).M21 = m[2][1];
            node.filters.item(0).M22 = m[2][2];
            node.filters.item(0).enabled = true;
        },

        /* **************************
         *    Image related stuff
         * **************************/

        // already documented in JXG.AbstractRenderer
        drawImage: function (el) {
            // IE 8: Bilder ueber data URIs werden bis 32kB unterstuetzt.
            var node;

            node = this.container.ownerDocument.createElement('img');
            node.style.position = 'absolute';
            this._setAttr(node, 'id', this.container.id + '_' + el.id);

            this.container.appendChild(node);
            this.appendChildPrim(node, Type.evaluate(el.visProp.layer));

            // Adding the rotation filter. This is always filter item 0:
            // node.filters.item(0), see transformImage
            // Also add the alpha filter. This is always filter item 1
            // node.filters.item(1), see setObjectFillColor and setObjectSTrokeColor
            //node.style.filter = node.style['-ms-filter'] = "progid:DXImageTransform.Microsoft.Matrix(M11='1.0', sizingMethod='auto expand')";
            node.style.filter = "progid:DXImageTransform.Microsoft.Matrix(M11='1.0', sizingMethod='auto expand') progid:DXImageTransform.Microsoft.Alpha(opacity = 100, enabled = false)";
            el.rendNode = node;
            this.updateImage(el);
        },

        // already documented in JXG.AbstractRenderer
        transformImage: function (el, t) {
            var m, s, maxX, maxY, minX, minY, i, nt,
                node = el.rendNode,
                p = [],
                len = t.length;

            if (len > 0) {
                /*
                nt = el.rendNode.style.filter.toString();
                if (!nt.match(/DXImageTransform/)) {
                    node.style.filter = "progid:DXImageTransform.Microsoft.Matrix(M11='1.0', sizingMethod='auto expand') " + nt;
                }
                */

                m = this.joinTransforms(el, t);
                p[0] = Mat.matVecMult(m, el.coords.scrCoords);
                p[0][1] /= p[0][0];
                p[0][2] /= p[0][0];
                p[1] = Mat.matVecMult(m, [1, el.coords.scrCoords[1] + el.size[0], el.coords.scrCoords[2]]);
                p[1][1] /= p[1][0];
                p[1][2] /= p[1][0];
                p[2] = Mat.matVecMult(m, [1, el.coords.scrCoords[1] + el.size[0], el.coords.scrCoords[2] - el.size[1]]);
                p[2][1] /= p[2][0];
                p[2][2] /= p[2][0];
                p[3] = Mat.matVecMult(m, [1, el.coords.scrCoords[1], el.coords.scrCoords[2] - el.size[1]]);
                p[3][1] /= p[3][0];
                p[3][2] /= p[3][0];
                maxX = p[0][1];
                minX = p[0][1];
                maxY = p[0][2];
                minY = p[0][2];

                for (i = 1; i < 4; i++) {
                    maxX = Math.max(maxX, p[i][1]);
                    minX = Math.min(minX, p[i][1]);
                    maxY = Math.max(maxY, p[i][2]);
                    minY = Math.min(minY, p[i][2]);
                }
                node.style.left = Math.floor(minX) + 'px';
                node.style.top  = Math.floor(minY) + 'px';

                node.filters.item(0).M11 = m[1][1];
                node.filters.item(0).M12 = m[1][2];
                node.filters.item(0).M21 = m[2][1];
                node.filters.item(0).M22 = m[2][2];
                node.filters.item(0).enabled = true;
            }
        },

        // already documented in JXG.AbstractRenderer
        updateImageURL: function (el) {
            var url = Type.evaluate(el.url);

            this._setAttr(el.rendNode, 'src', url);
        },

        /* **************************
         * Render primitive objects
         * **************************/

        // already documented in JXG.AbstractRenderer
        appendChildPrim: function (node, level) {
            // For trace nodes
            if (!Type.exists(level)) {
                level = 0;
            }

            node.style.zIndex = level;
            this.container.appendChild(node);

            return node;
        },

        // already documented in JXG.AbstractRenderer
        appendNodesToElement: function (el, type) {
            if (type === 'shape' || type === 'path' || type === 'polygon') {
                el.rendNodePath = this.getElementById(el.id + '_path');
            }
            el.rendNodeFill = this.getElementById(el.id + '_fill');
            el.rendNodeStroke = this.getElementById(el.id + '_stroke');
            el.rendNodeShadow = this.getElementById(el.id + '_shadow');
            el.rendNode = this.getElementById(el.id);
        },

        // already documented in JXG.AbstractRenderer
        createPrim: function (type, id) {
            var node, pathNode,
                fillNode = this.createNode('fill'),
                strokeNode = this.createNode('stroke'),
                shadowNode = this.createNode('shadow');

            this._setAttr(fillNode, 'id', this.container.id + '_' + id + '_fill');
            this._setAttr(strokeNode, 'id', this.container.id + '_' + id + '_stroke');
            this._setAttr(shadowNode, 'id', this.container.id + '_' + id + '_shadow');

            if (type === 'circle' || type === 'ellipse') {
                node = this.createNode('oval');
                node.appendChild(fillNode);
                node.appendChild(strokeNode);
                node.appendChild(shadowNode);
            } else if (type === 'polygon' || type === 'path' || type === 'shape' || type === 'line') {
                node = this.createNode('shape');
                node.appendChild(fillNode);
                node.appendChild(strokeNode);
                node.appendChild(shadowNode);
                pathNode = this.createNode('path');
                this._setAttr(pathNode, 'id', this.container.id + '_' + id + '_path');
                node.appendChild(pathNode);
            } else {
                node = this.createNode(type);
                node.appendChild(fillNode);
                node.appendChild(strokeNode);
                node.appendChild(shadowNode);
            }

            node.style.position = 'absolute';
            node.style.left = '0px';
            node.style.top = '0px';
            this._setAttr(node, 'id', this.container.id + '_' + id);

            return node;
        },

        // already documented in JXG.AbstractRenderer
        remove: function (node) {
            if (Type.exists(node)) {
                node.removeNode(true);
            }
        },

        // already documented in JXG.AbstractRenderer
        makeArrows: function (el) {
            var nodeStroke,
                ev_fa = Type.evaluate(el.visProp.firstarrow),
                ev_la = Type.evaluate(el.visProp.lastarrow);

            if (el.visPropOld.firstarrow === ev_fa && el.visPropOld.lastarrow === ev_la) {
                return;
            }

            if (ev_fa) {
                nodeStroke = el.rendNodeStroke;
                this._setAttr(nodeStroke, 'startarrow', 'block');
                this._setAttr(nodeStroke, 'startarrowlength', 'long');
            } else {
                nodeStroke = el.rendNodeStroke;
                if (Type.exists(nodeStroke)) {
                    this._setAttr(nodeStroke, 'startarrow', 'none');
                }
            }

            if (ev_la) {
                nodeStroke = el.rendNodeStroke;
                this._setAttr(nodeStroke, 'id', this.container.id + '_' + el.id + "stroke");
                this._setAttr(nodeStroke, 'endarrow', 'block');
                this._setAttr(nodeStroke, 'endarrowlength', 'long');
            } else {
                nodeStroke = el.rendNodeStroke;
                if (Type.exists(nodeStroke)) {
                    this._setAttr(nodeStroke, 'endarrow', 'none');
                }
            }
            el.visPropOld.firstarrow = ev_fa;
            el.visPropOld.lastarrow = ev_la;
        },

        // already documented in JXG.AbstractRenderer
        updateEllipsePrim: function (node, x, y, rx, ry) {
            node.style.left = Math.floor(x - rx) + 'px';
            node.style.top =  Math.floor(y - ry) + 'px';
            node.style.width = Math.floor(Math.abs(rx) * 2) + 'px';
            node.style.height = Math.floor(Math.abs(ry) * 2) + 'px';
        },

        // already documented in JXG.AbstractRenderer
        updateLinePrim: function (node, p1x, p1y, p2x, p2y, board) {
            var s, r = this.resolution;

            if (!isNaN(p1x + p1y + p2x + p2y)) {
                s = ['m ', Math.floor(r * p1x), ', ', Math.floor(r * p1y), ' l ', Math.floor(r * p2x), ', ', Math.floor(r * p2y)];
                this.updatePathPrim(node, s, board);
            }
        },

        // already documented in JXG.AbstractRenderer
        updatePathPrim: function (node, pointString, board) {
            var x = board.canvasWidth,
                y = board.canvasHeight;
            if (pointString.length <= 0) {
                pointString = ['m 0,0'];
            }
            node.style.width = x;
            node.style.height = y;
            this._setAttr(node, 'coordsize', [Math.floor(this.resolution * x), Math.floor(this.resolution * y)].join(','));
            this._setAttr(node, 'path', pointString.join(""));
        },

        // already documented in JXG.AbstractRenderer
        updatePathStringPoint: function (el, size, type) {
            var s = [],
                mround = Math.round,
                scr = el.coords.scrCoords,
                sqrt32 = size * Math.sqrt(3) * 0.5,
                s05 = size * 0.5,
                r = this.resolution;

            if (type === 'x') {
                s.push([
                    ' m ', mround(r * (scr[1] - size)), ', ', mround(r * (scr[2] - size)),
                    ' l ', mround(r * (scr[1] + size)), ', ', mround(r * (scr[2] + size)),
                    ' m ', mround(r * (scr[1] + size)), ', ', mround(r * (scr[2] - size)),
                    ' l ', mround(r * (scr[1] - size)), ', ', mround(r * (scr[2] + size))
                ].join(''));
            } else if (type === '+') {
                s.push([
                    ' m ', mround(r * (scr[1] - size)), ', ', mround(r * (scr[2])),
                    ' l ', mround(r * (scr[1] + size)), ', ', mround(r * (scr[2])),
                    ' m ', mround(r * (scr[1])),        ', ', mround(r * (scr[2] - size)),
                    ' l ', mround(r * (scr[1])),        ', ', mround(r * (scr[2] + size))
                ].join(''));
            } else if (type === '<>') {

                s.push([
                    ' m ', mround(r * (scr[1] - size)), ', ', mround(r * (scr[2])),
                    ' l ', mround(r * (scr[1])),        ', ', mround(r * (scr[2] + size)),
                    ' l ', mround(r * (scr[1] + size)), ', ', mround(r * (scr[2])),
                    ' l ', mround(r * (scr[1])),        ', ', mround(r * (scr[2] - size)),
                    ' x e '
                ].join(''));
            } else if (type === '^') {
                s.push([
                    ' m ', mround(r * (scr[1])),          ', ', mround(r * (scr[2] - size)),
                    ' l ', mround(r * (scr[1] - sqrt32)), ', ', mround(r * (scr[2] + s05)),
                    ' l ', mround(r * (scr[1] + sqrt32)), ', ', mround(r * (scr[2] + s05)),
                    ' x e '
                ].join(''));
            } else if (type === 'v') {
                s.push([
                    ' m ', mround(r * (scr[1])),          ', ', mround(r * (scr[2] + size)),
                    ' l ', mround(r * (scr[1] - sqrt32)), ', ', mround(r * (scr[2] - s05)),
                    ' l ', mround(r * (scr[1] + sqrt32)), ', ', mround(r * (scr[2] - s05)),
                    ' x e '
                ].join(''));
            } else if (type === '>') {
                s.push([
                    ' m ', mround(r * (scr[1] + size)), ', ', mround(r * (scr[2])),
                    ' l ', mround(r * (scr[1] - s05)),  ', ', mround(r * (scr[2] - sqrt32)),
                    ' l ', mround(r * (scr[1] - s05)),  ', ', mround(r * (scr[2] + sqrt32)),
                    ' l ', mround(r * (scr[1] + size)), ', ', mround(r * (scr[2]))
                ].join(''));
            } else if (type === '<') {
                s.push([
                    ' m ', mround(r * (scr[1] - size)), ', ', mround(r * (scr[2])),
                    ' l ', mround(r * (scr[1] + s05)),  ', ', mround(r * (scr[2] - sqrt32)),
                    ' l ', mround(r * (scr[1] + s05)),  ', ', mround(r * (scr[2] + sqrt32)),
                    ' x e '
                ].join(''));
            }

            return s;
        },

        // already documented in JXG.AbstractRenderer
        updatePathStringPrim: function (el) {
            var i, scr,
                pStr = [],
                r = this.resolution,
                mround = Math.round,
                symbm = ' m ',
                symbl = ' l ',
                symbc = ' c ',
                nextSymb = symbm,
                len = Math.min(el.numberPoints, 8192); // otherwise IE 7 crashes in hilbert.html

            if (el.numberPoints <= 0) {
                return '';
            }
            len = Math.min(len, el.points.length);

            if (el.bezierDegree === 1) {
                /*
                if (isNotPlot && el.board.options.curve.RDPsmoothing) {
                    el.points = Numerics.RamerDouglasPeucker(el.points, 1.0);
                }
                */

                for (i = 0; i < len; i++) {
                    scr = el.points[i].scrCoords;
                    if (isNaN(scr[1]) || isNaN(scr[2])) {  // PenUp
                        nextSymb = symbm;
                    } else {
                        // IE has problems with values  being too far away.
                        if (scr[1] > 20000.0) {
                            scr[1] = 20000.0;
                        } else if (scr[1] < -20000.0) {
                            scr[1] = -20000.0;
                        }

                        if (scr[2] > 20000.0) {
                            scr[2] = 20000.0;
                        } else if (scr[2] < -20000.0) {
                            scr[2] = -20000.0;
                        }

                        pStr.push([nextSymb, mround(r * scr[1]), ', ', mround(r * scr[2])].join(''));
                        nextSymb = symbl;
                    }
                }
            } else if (el.bezierDegree === 3) {
                i = 0;
                while (i < len) {
                    scr = el.points[i].scrCoords;
                    if (isNaN(scr[1]) || isNaN(scr[2])) {  // PenUp
                        nextSymb = symbm;
                    } else {
                        pStr.push([nextSymb, mround(r * scr[1]), ', ', mround(r * scr[2])].join(''));
                        if (nextSymb === symbc) {
                            i += 1;
                            scr = el.points[i].scrCoords;
                            pStr.push([' ', mround(r * scr[1]), ', ', mround(r * scr[2])].join(''));
                            i += 1;
                            scr = el.points[i].scrCoords;
                            pStr.push([' ', mround(r * scr[1]), ', ', mround(r * scr[2])].join(''));
                        }
                        nextSymb = symbc;
                    }
                    i += 1;
                }
            }
            pStr.push(' e');
            return pStr;
        },

        // already documented in JXG.AbstractRenderer
        updatePathStringBezierPrim: function (el) {
            var i, j, k, scr, lx, ly,
                pStr = [],
                f = Type.evaluate(el.visProp.strokewidth),
                r = this.resolution,
                mround = Math.round,
                symbm = ' m ',
                symbl = ' c ',
                nextSymb = symbm,
                isNoPlot = (Type.evaluate(el.visProp.curvetype) !== 'plot'),
                len = Math.min(el.numberPoints, 8192); // otherwise IE 7 crashes in hilbert.html

            if (el.numberPoints <= 0) {
                return '';
            }
            if (isNoPlot && el.board.options.curve.RDPsmoothing) {
                el.points = Numerics.RamerDouglasPeucker(el.points, 1.0);
            }
            len = Math.min(len, el.points.length);

            for (j = 1; j < 3; j++) {
                nextSymb = symbm;
                for (i = 0; i < len; i++) {
                    scr = el.points[i].scrCoords;
                    if (isNaN(scr[1]) || isNaN(scr[2])) {  // PenUp
                        nextSymb = symbm;
                    } else {
                        // IE has problems with values  being too far away.
                        if (scr[1] > 20000.0) {
                            scr[1] = 20000.0;
                        } else if (scr[1] < -20000.0) {
                            scr[1] = -20000.0;
                        }

                        if (scr[2] > 20000.0) {
                            scr[2] = 20000.0;
                        } else if (scr[2] < -20000.0) {
                            scr[2] = -20000.0;
                        }

                        if (nextSymb === symbm) {
                            pStr.push([nextSymb,
                                mround(r * (scr[1])), ' ', mround(r * (scr[2]))].join(''));
                        } else {
                            k = 2 * j;
                            pStr.push([nextSymb,
                                mround(r * (lx + (scr[1] - lx) * 0.333 + f * (k * Math.random() - j))), ' ',
                                mround(r * (ly + (scr[2] - ly) * 0.333 + f * (k * Math.random() - j))), ' ',
                                mround(r * (lx + (scr[1] - lx) * 0.666 + f * (k * Math.random() - j))), ' ',
                                mround(r * (ly + (scr[2] - ly) * 0.666 + f * (k * Math.random() - j))), ' ',
                                mround(r * scr[1]), ' ',
                                mround(r * scr[2])].join(''));
                        }
                        nextSymb = symbl;
                        lx = scr[1];
                        ly = scr[2];
                    }
                }
            }
            pStr.push(' e');
            return pStr;
        },

        // already documented in JXG.AbstractRenderer
        updatePolygonPrim: function (node, el) {
            var i,
                len = el.vertices.length,
                r = this.resolution,
                scr,
                pStr = [];

            this._setAttr(node, 'stroked', 'false');
            scr = el.vertices[0].coords.scrCoords;

            if (isNaN(scr[1] + scr[2])) {
                return;
            }

            pStr.push(["m ", Math.floor(r * scr[1]), ",", Math.floor(r * scr[2]), " l "].join(''));

            for (i = 1; i < len - 1; i++) {
                if (el.vertices[i].isReal) {
                    scr = el.vertices[i].coords.scrCoords;

                    if (isNaN(scr[1] + scr[2])) {
                        return;
                    }

                    pStr.push(Math.floor(r * scr[1]) + "," + Math.floor(r * scr[2]));
                } else {
                    this.updatePathPrim(node, '', el.board);
                    return;
                }
                if (i < len - 2) {
                    pStr.push(", ");
                }
            }
            pStr.push(" x e");
            this.updatePathPrim(node, pStr, el.board);
        },

        // already documented in JXG.AbstractRenderer
        updateRectPrim: function (node, x, y, w, h) {
            node.style.left = Math.floor(x) + 'px';
            node.style.top = Math.floor(y) + 'px';

            if (w >= 0) {
                node.style.width = w + 'px';
            }

            if (h >= 0) {
                node.style.height = h + 'px';
            }
        },

        /* **************************
         *  Set Attributes
         * **************************/

        // already documented in JXG.AbstractRenderer
        setPropertyPrim: function (node, key, val) {
            var keyVml = '',
                v;

            switch (key) {
            case 'stroke':
                keyVml = 'strokecolor';
                break;
            case 'stroke-width':
                keyVml = 'strokeweight';
                break;
            case 'stroke-dasharray':
                keyVml = 'dashstyle';
                break;
            }

            if (keyVml !== '') {
                v = Type.evaluate(val);
                this._setAttr(node, keyVml, v);
            }
        },

        // already documented in JXG.AbstractRenderer
        display: function(el, val) {
            if (el && el.rendNode) {
                el.visPropOld.visible = val;
                if (val) {
                    el.rendNode.style.visibility = "inherit";
                } else {
                    el.rendNode.style.visibility = "hidden";
                }
            }
        },

        // already documented in JXG.AbstractRenderer
        show: function (el) {
            JXG.deprecated('Board.renderer.show()', 'Board.renderer.display()');

            if (el && el.rendNode) {
                el.rendNode.style.visibility = "inherit";
            }
        },

        // already documented in JXG.AbstractRenderer
        hide: function (el) {
            JXG.deprecated('Board.renderer.hide()', 'Board.renderer.display()');

            if (el && el.rendNode) {
                el.rendNode.style.visibility = "hidden";
            }
        },

        // already documented in JXG.AbstractRenderer
        setDashStyle: function (el, visProp) {
            var node;
            if (visProp.dash >= 0) {
                node = el.rendNodeStroke;
                this._setAttr(node, 'dashstyle', this.dashArray[visProp.dash]);
            }
        },

        // already documented in JXG.AbstractRenderer
        setGradient: function (el) {
            var nodeFill = el.rendNodeFill,
                ev_g = Type.evaluate(el.visProp.gradient);

            if (ev_g === 'linear') {
                this._setAttr(nodeFill, 'type', 'gradient');
                this._setAttr(nodeFill, 'color2', Type.evaluate(el.visProp.gradientsecondcolor));
                this._setAttr(nodeFill, 'opacity2', Type.evaluate(el.visProp.gradientsecondopacity));
                this._setAttr(nodeFill, 'angle', Type.evaluate(el.visProp.gradientangle));
            } else if (ev_g === 'radial') {
                this._setAttr(nodeFill, 'type', 'gradientradial');
                this._setAttr(nodeFill, 'color2', Type.evaluate(el.visProp.gradientsecondcolor));
                this._setAttr(nodeFill, 'opacity2', Type.evaluate(el.visProp.gradientsecondopacity));
                this._setAttr(nodeFill, 'focusposition', Type.evaluate(el.visProp.gradientpositionx) * 100 + '%,' +
                            Type.evaluate(el.visProp.gradientpositiony) * 100 + '%');
                this._setAttr(nodeFill, 'focussize', '0,0');
            } else {
                this._setAttr(nodeFill, 'type', 'solid');
            }
        },

        // already documented in JXG.AbstractRenderer
        setObjectFillColor: function (el, color, opacity) {
            var rgba = Type.evaluate(color), c, rgbo,
                o = Type.evaluate(opacity), oo,
                node = el.rendNode,
                t;

            o = (o > 0) ? o : 0;

            if (el.visPropOld.fillcolor === rgba && el.visPropOld.fillopacity === o) {
                return;
            }

            if (Type.exists(rgba) && rgba !== false) {
                // RGB, not RGBA
                if (rgba.length !== 9) {
                    c = rgba;
                    oo = o;
                // True RGBA, not RGB
                } else {
                    rgbo = Color.rgba2rgbo(rgba);
                    c = rgbo[0];
                    oo = o * rgbo[1];
                }
                if (c === 'none' || c === false) {
                    this._setAttr(el.rendNode, 'filled', 'false');
                } else {
                    this._setAttr(el.rendNode, 'filled', 'true');
                    this._setAttr(el.rendNode, 'fillcolor', c);

                    if (Type.exists(oo) && el.rendNodeFill) {
                        this._setAttr(el.rendNodeFill, 'opacity', (oo * 100) + '%');
                    }
                }
                if (el.type === Const.OBJECT_TYPE_IMAGE) {
                    /*
                    t = el.rendNode.style.filter.toString();
                    if (t.match(/alpha/)) {
                        el.rendNode.style.filter = t.replace(/alpha\(opacity *= *[0-9\.]+\)/, 'alpha(opacity = ' + (oo * 100) + ')');
                    } else {
                        el.rendNode.style.filter += ' alpha(opacity = ' + (oo * 100) + ')';
                    }
                    */
                    if (node.filters.length > 1) {
                        // Why am I sometimes seeing node.filters.length==0 here when I move the pointer around near [0,0]?
                        // Setting axes:true shows text labels!
                        node.filters.item(1).opacity = Math.round(oo * 100); // Why does setObjectFillColor not use Math.round?
                        node.filters.item(1).enabled = true;
                    }
                }
            }
            el.visPropOld.fillcolor = rgba;
            el.visPropOld.fillopacity = o;
        },

        // already documented in JXG.AbstractRenderer
        setObjectStrokeColor: function (el, color, opacity) {
            var rgba = Type.evaluate(color), c, rgbo, t,
                o = Type.evaluate(opacity), oo,
                node = el.rendNode, nodeStroke;

            o = (o > 0) ? o : 0;

            if (el.visPropOld.strokecolor === rgba && el.visPropOld.strokeopacity === o) {
                return;
            }

            // this looks like it could be merged with parts of VMLRenderer.setObjectFillColor

            if (Type.exists(rgba) && rgba !== false) {
                // RGB, not RGBA
                if (rgba.length !== 9) {
                    c = rgba;
                    oo = o;
                // True RGBA, not RGB
                } else {
                    rgbo = color.rgba2rgbo(rgba);
                    c = rgbo[0];
                    oo = o * rgbo[1];
                }
                if (el.elementClass === Const.OBJECT_CLASS_TEXT) {
                    //node.style.filter = ' alpha(opacity = ' + oo + ')';
                    /*
                    t = node.style.filter.toString();
                    if (t.match(/alpha/)) {
                        node.style.filter =
                        t.replace(/alpha\(opacity *= *[0-9\.]+\)/, 'alpha(opacity = ' + oo + ')');
                    } else {
                        node.style.filter += ' alpha(opacity = ' + oo + ')';
                    }
                    */
                    if (node.filters.length > 1) {
                        // Why am I sometimes seeing node.filters.length==0 here when I move the pointer around near [0,0]?
                        // Setting axes:true shows text labels!
                        node.filters.item(1).opacity = Math.round(oo * 100);
                        node.filters.item(1).enabled = true;
                    }

                    node.style.color = c;
                } else {
                    if (c !== false) {
                        this._setAttr(node, 'stroked', 'true');
                        this._setAttr(node, 'strokecolor', c);
                    }

                    nodeStroke = el.rendNodeStroke;
                    if (Type.exists(oo) && el.type !== Const.OBJECT_TYPE_IMAGE) {
                        this._setAttr(nodeStroke, 'opacity', (oo * 100) + '%');
                    }
                }
            }
            el.visPropOld.strokecolor = rgba;
            el.visPropOld.strokeopacity = o;
        },

        // already documented in JXG.AbstractRenderer
        setObjectStrokeWidth: function (el, width) {
            var w = Type.evaluate(width),
                node;

            if (isNaN(w) || el.visPropOld.strokewidth === w) {
                return;
            }

            node = el.rendNode;
            this.setPropertyPrim(node, 'stroked', 'true');

            if (Type.exists(w)) {

                this.setPropertyPrim(node, 'stroke-width', w);
                if (w === 0 && Type.exists(el.rendNodeStroke)) {
                    this._setAttr(node, 'stroked', 'false');
                }
            }

            el.visPropOld.strokewidth = w;

        },

        // already documented in JXG.AbstractRenderer
        setShadow: function (el) {
            var nodeShadow = el.rendNodeShadow,
                ev_s = Type.evaluate(el.visProp.shadow);

            if (!nodeShadow || el.visPropOld.shadow === ev_s) {
                return;
            }

            if (ev_s) {
                this._setAttr(nodeShadow, 'On', 'True');
                this._setAttr(nodeShadow, 'Offset', '3pt,3pt');
                this._setAttr(nodeShadow, 'Opacity', '60%');
                this._setAttr(nodeShadow, 'Color', '#aaaaaa');
            } else {
                this._setAttr(nodeShadow, 'On', 'False');
            }

            el.visPropOld.shadow = ev_s;
        },

        /* **************************
         * renderer control
         * **************************/

        // already documented in JXG.AbstractRenderer
        suspendRedraw: function () {
            this.container.style.display = 'none';
        },

        // already documented in JXG.AbstractRenderer
        unsuspendRedraw: function () {
            this.container.style.display = '';
        }
    });

    return JXG.VMLRenderer;
});
