/* Javascript plotting library for jQuery, v. 0.5.
 *
 * Released under the MIT license by IOLA, December 2007.
 *
 */

(function($) {
    function Plot(target, data_, options_, plugins) {
        // data is on the form:
        //   [ series1, series2 ... ]
        // where series is either just the data as [ [x1, y1], [x2, y2], ... ]
        // or { data: [ [x1, y1], [x2, y2], ... ], label: "some label", ... }
        
        var series = [],
            options = {
                // the color theme used for graphs
                colors: ["#edc240", "#afd8f8", "#cb4b4b", "#4da74d", "#9440ed"],
                legend: {
                    show: true,
                    noColumns: 1, // number of colums in legend table
                    labelFormatter: null, // fn: string -> string
                    labelBoxBorderColor: "#ccc", // border color for the little label boxes
                    container: null, // container (as jQuery object) to put legend in, null means default on top of graph
                    position: "ne", // position of default legend container within plot
                    margin: 5, // distance from grid edge to default legend container within plot
                    backgroundColor: null, // null means auto-detect
                    backgroundOpacity: 0.85 // set to 0 to avoid background
                },
                xaxis: {
                    mode: null, // null or "time"
                    min: null, // min. value to show, null means set automatically
                    max: null, // max. value to show, null means set automatically
                    autoscaleMargin: null, // margin in % to add if auto-setting min/max
                    ticks: null, // either [1, 3] or [[1, "a"], 3] or (fn: axis info -> ticks) or app. number of ticks for auto-ticks
                    tickFormatter: null, // fn: number -> string
                    labelWidth: null, // size of tick labels in pixels
                    labelHeight: null,
                    
                    // mode specific options
                    tickDecimals: null, // no. of decimals, null means auto
                    tickSize: null, // number or [number, "unit"]
                    minTickSize: null, // number or [number, "unit"]
                    monthNames: null, // list of names of months
                    timeformat: null // format string to use
                },
                yaxis: {
                    autoscaleMargin: 0.02
                },
                x2axis: {
                    autoscaleMargin: null
                },
                y2axis: {
                    autoscaleMargin: 0.02
                },
                series: {
                    points: {
                        show: false,
                        radius: 3,
                        lineWidth: 2, // in pixels
                        fill: true,
                        fillColor: "#ffffff"
                    },
                    lines: {
                        // we don't put in show: false so we can see
                        // whether lines were actively disabled 
                        lineWidth: 2, // in pixels
                        fill: false,
                        fillColor: null,
                        steps: false
                    },
                    bars: {
                        show: false,
                        lineWidth: 2, // in pixels
                        barWidth: 1, // in units of the x axis
                        fill: true,
                        fillColor: null,
                        align: "left", // or "center" 
                        horizontal: false // when horizontal, left is now top
                    },
                    shadowSize: 3
                },
                grid: {
                    show: true,
                    color: "#545454", // primary color used for outline and labels
                    backgroundColor: null, // null for transparent, else color
                    tickColor: "#dddddd", // color used for the ticks
                    labelMargin: 5, // in pixels
                    borderWidth: 2, // in pixels
                    borderColor: null, // set if different from the grid color
                    markings: null, // array of ranges or fn: axes -> array of ranges
                    markingsColor: "#f4f4f4",
                    markingsLineWidth: 2,
                    // interactive stuff
                    clickable: false,
                    hoverable: false,
                    autoHighlight: true, // highlight in case mouse is near
                    mouseActiveRadius: 10 // how far the mouse can be away to activate an item
                },
                selection: {
                    mode: null, // one of null, "x", "y" or "xy"
                    color: "#e8cfac"
                }
            },
        canvas = null,      // the canvas for the plot itself
        overlay = null,     // canvas for interactive stuff on top of plot
        eventHolder = null, // jQuery object that events should be bound to
        ctx = null, octx = null,
        axes = { xaxis: {}, yaxis: {}, x2axis: {}, y2axis: {} },
        plotOffset = { left: 0, right: 0, top: 0, bottom: 0},
        canvasWidth = 0, canvasHeight = 0,
        plotWidth = 0, plotHeight = 0,
        hooks = {
            processOptions: [],
            processRawData: [],
            processDatapoints: [],
            draw: [],
            bindEvents: [],
            drawOverlay: []
        },
        plot = this,
        // dedicated to storing data for buggy standard compliance cases
        workarounds = {};

        // public functions
        plot.setData = setData;
        plot.setupGrid = setupGrid;
        plot.draw = draw;
        plot.clearSelection = clearSelection;
        plot.setSelection = setSelection;
        plot.getSelection = getSelection;
        plot.getCanvas = function() { return canvas; };
        plot.getPlotOffset = function() { return plotOffset; };
        plot.width = function () { return plotWidth; }
        plot.height = function () { return plotHeight; }
        plot.offset = function () {
            var o = eventHolder.offset();
            o.left += plotOffset.left;
            o.top += plotOffset.top;
            return o;
        };
        plot.getData = function() { return series; };
        plot.getAxes = function() { return axes; };
        plot.getOptions = function() { return options; };
        plot.highlight = highlight;
        plot.unhighlight = unhighlight;
        plot.triggerRedrawOverlay = triggerRedrawOverlay;
        plot.pointOffset = function(point) {
            return { left: parseInt(axisSpecToRealAxis(point, "xaxis").p2c(+point.x) + plotOffset.left),
                     top: parseInt(axisSpecToRealAxis(point, "yaxis").p2c(+point.y) + plotOffset.top) };
        }
        

        // public attributes
        plot.hooks = hooks;
        
        // initialize
        initPlugins(plot);
        parseOptions(options_);
        constructCanvas();
        setData(data_);
        setupGrid();
        draw();
        bindEvents();


        function executeHooks(hook, args) {
            args = [plot].concat(args);
            for (var i = 0; i < hook.length; ++i)
                hook[i].apply(this, args);
        }

        function initPlugins() {
            for (var i = 0; i < plugins.length; ++i) {
                var p = plugins[i];
                p.init(plot);
                if (p.options)
                    $.extend(true, options, p.options);
            }
        }
        
        function parseOptions(opts) {
            $.extend(true, options, opts);
            if (options.grid.borderColor == null)
                options.grid.borderColor = options.grid.color
            // backwards compatibility, to be removed in future
            if (options.xaxis.noTicks && options.xaxis.ticks == null)
                options.xaxis.ticks = options.xaxis.noTicks;
            if (options.yaxis.noTicks && options.yaxis.ticks == null)
                options.yaxis.ticks = options.yaxis.noTicks;
            if (options.grid.coloredAreas)
                options.grid.markings = options.grid.coloredAreas;
            if (options.grid.coloredAreasColor)
                options.grid.markingsColor = options.grid.coloredAreasColor;
            if (options.lines)
                $.extend(true, options.series.lines, options.lines);
            if (options.points)
                $.extend(true, options.series.points, options.points);
            if (options.bars)
                $.extend(true, options.series.bars, options.bars);
            if (options.shadowSize)
                options.series.shadowSize = options.shadowSize;

            executeHooks(hooks.processOptions, [options]);
        }

        function setData(d) {
            series = parseData(d);
            fillInSeriesOptions();
            processData();
        }
        
        function parseData(d) {
            var res = [];
            for (var i = 0; i < d.length; ++i) {
                var s = $.extend(true, {}, options.series);

                if (d[i].data) {
                    s.data = d[i].data; // move the data instead of deep-copy
                    delete d[i].data;

                    $.extend(true, s, d[i]);

                    d[i].data = s.data;
                }
                else
                    s.data = d[i];
                res.push(s);
            }

            return res;
        }
        
        function axisSpecToRealAxis(obj, attr) {
            var a = obj[attr];
            if (!a || a == 1)
                return axes[attr];
            if (typeof a == "number")
                return axes[attr.charAt(0) + a + attr.slice(1)];
            return a; // assume it's OK
        }
        
        function fillInSeriesOptions() {
            var i;
            
            // collect what we already got of colors
            var neededColors = series.length,
                usedColors = [],
                assignedColors = [];
            for (i = 0; i < series.length; ++i) {
                var sc = series[i].color;
                if (sc != null) {
                    --neededColors;
                    if (typeof sc == "number")
                        assignedColors.push(sc);
                    else
                        usedColors.push(parseColor(series[i].color));
                }
            }
            
            // we might need to generate more colors if higher indices
            // are assigned
            for (i = 0; i < assignedColors.length; ++i) {
                neededColors = Math.max(neededColors, assignedColors[i] + 1);
            }

            // produce colors as needed
            var colors = [], variation = 0;
            i = 0;
            while (colors.length < neededColors) {
                var c;
                if (options.colors.length == i) // check degenerate case
                    c = new Color(100, 100, 100);
                else
                    c = parseColor(options.colors[i]);

                // vary color if needed
                var sign = variation % 2 == 1 ? -1 : 1;
                var factor = 1 + sign * Math.ceil(variation / 2) * 0.2;
                c.scale(factor, factor, factor);

                // FIXME: if we're getting to close to something else,
                // we should probably skip this one
                colors.push(c);
                
                ++i;
                if (i >= options.colors.length) {
                    i = 0;
                    ++variation;
                }
            }

            // fill in the options
            var colori = 0, s;
            for (i = 0; i < series.length; ++i) {
                s = series[i];
                
                // assign colors
                if (s.color == null) {
                    s.color = colors[colori].toString();
                    ++colori;
                }
                else if (typeof s.color == "number")
                    s.color = colors[s.color].toString();

                // turn on lines automatically in case nothing is set
                if (s.lines.show == null && !s.bars.show && !s.points.show)
                    s.lines.show = true;

                // setup axes
                s.xaxis = axisSpecToRealAxis(s, "xaxis");
                s.yaxis = axisSpecToRealAxis(s, "yaxis");
            }
        }
        
        function processData() {
            var topSentry = Number.POSITIVE_INFINITY,
                bottomSentry = Number.NEGATIVE_INFINITY,
                i, j, k, m, length,
                s, points, ps, x, y, axis;

            for (axis in axes) {
                axes[axis].datamin = topSentry;
                axes[axis].datamax = bottomSentry;
                axes[axis].min = options[axis].min;
                axes[axis].max = options[axis].max;
                axes[axis].used = false;
            }

            function updateAxis(axis, min, max) {
                if (min < axis.datamin)
                    axis.datamin = min;
                if (max > axis.datamax)
                    axis.datamax = max;
            }

            for (i = 0; i < series.length; ++i) {
                s = series[i];
                s.datapoints = { points: [] };
                
                executeHooks(hooks.processRawData, [ s, s.data, s.datapoints ]);
            }
            
            // first pass: clean and copy data
            for (i = 0; i < series.length; ++i) {
                s = series[i];

                if (s.datapoints.pointsize != null)
                    continue; // already filled in

                var data = s.data, format = [], p;

                // determine the point size
                if (s.bars.show) {
                    s.datapoints.pointsize = 3;
                    format.push({ d: 0 });
                }
                else
                    s.datapoints.pointsize = 2;
                
                /*
                // examine data to find out how to copy
                for (j = 0; j < data.length; ++j) {
                }*/
                
                ps = s.datapoints.pointsize;
                points = s.datapoints.points;

                insertSteps = s.lines.show && s.lines.steps;
                s.xaxis.used = s.yaxis.used = true;
                
                for (j = k = 0; j < data.length; ++j, k += ps) {
                    p = data[j];

                    if (p != null) {
                        x = p[0];
                        y = p[1];
                    }
                    else
                        y = x = null;

                    if (x != null) {
                        x = +x; // convert to number
                        if (isNaN(x))
                            x = null;
                    }

                    if (y != null) {
                        y = +y; // convert to number
                        if (isNaN(y))
                            y = null;
                    }

                    // check validity of point, making sure both are cleared
                    if (x == null && y != null) {
                        // extract min/max info before we whack
                        updateAxis(s.yaxis, y, y);
                        y = null;
                    }

                    if (y == null && x != null) {
                        updateAxis(s.xaxis, x, x);
                        x = null;
                    }
                    
                    if (insertSteps && x != null && k > 0
                        && points[k - ps] != null
                        && points[k - ps] != x && points[k - ps + 1] != y) {
                        points[k + 1] = points[k - ps + 1];
                        points[k] = x;
                            
                        // copy the remainding from real point
                        for (m = 2; m < ps; ++m)
                            points[k + m] = p[m] == null ? format[m-2].d : p[m];
                        k += ps;
                    }

                    for (m = 2; m < ps; ++m)
                        points[k + m] = p == null || p[m] == null ? format[m-2].d : p[m];
                    
                    points[k] = x;
                    points[k + 1] = y;
                }
            }

            for (i = 0; i < series.length; ++i) {
                s = series[i];
                
                executeHooks(hooks.processDatapoints, [ s, s.datapoints]);
            }

            // second pass: find datamax/datamin for auto-scaling
            for (i = 0; i < series.length; ++i) {
                s = series[i];
                points = s.datapoints.points,
                ps = s.datapoints.pointsize;

                var xmin = topSentry, ymin = topSentry,
                    xmax = bottomSentry, ymax = bottomSentry;
                
                for (j = 0; j < points.length; j += ps) {
                    x = points[j];

                    if (x == null)
                        continue;

                    if (x < xmin)
                        xmin = x;
                    if (x > xmax)
                        xmax = x;

                    y = points[j + 1];

                    if (y < ymin)
                        ymin = y;
                    if (y > ymax)
                        ymax = y;
                }
                
                if (s.bars.show) {
                    // make sure we got room for the bar on the dancing floor
                    var delta = s.bars.align == "left" ? 0 : -s.bars.barWidth/2;
                    if (s.bars.horizontal) {
                        ymin += delta;
                        ymax += delta + s.bars.barWidth;
                    }
                    else {
                        xmin += delta;
                        xmax += delta + s.bars.barWidth;
                    }
                }
                
                updateAxis(s.xaxis, xmin, xmax);
                updateAxis(s.yaxis, ymin, ymax);
            }

            for (axis in axes) {
                if (axes[axis].datamin == topSentry)
                    axes[axis].datamin = null;
                if (axes[axis].datamax == bottomSentry)
                    axes[axis].datamax = null;
            }
        }

        function constructCanvas() {
            function makeCanvas(width, height) {
                var c = document.createElement('canvas');
                c.width = width;
                c.height = height;
                if ($.browser.msie) // excanvas hack
                    c = window.G_vmlCanvasManager.initElement(c);
                return c;
            }
            
            canvasWidth = target.width();
            canvasHeight = target.height();
            target.html(""); // clear target
            if (target.css("position") == 'static')
                target.css("position", "relative"); // for positioning labels and overlay

            if (canvasWidth <= 0 || canvasHeight <= 0)
                throw "Invalid dimensions for plot, width = " + canvasWidth + ", height = " + canvasHeight;

            if ($.browser.msie) // excanvas hack
                window.G_vmlCanvasManager.init_(document); // make sure everything is setup
            
            // the canvas
            canvas = $(makeCanvas(canvasWidth, canvasHeight)).appendTo(target).get(0);
            ctx = canvas.getContext("2d");

            // overlay canvas for interactive features
            overlay = $(makeCanvas(canvasWidth, canvasHeight)).css({ position: 'absolute', left: 0, top: 0 }).appendTo(target).get(0);
            octx = overlay.getContext("2d");
            octx.stroke();
        }

        function bindEvents() {
            // we include the canvas in the event holder too, because IE 7
            // sometimes has trouble with the stacking order
            eventHolder = $([overlay, canvas]);

            // bind events
            if (options.selection.mode != null
                || options.grid.hoverable)
                eventHolder.mousemove(onMouseMove);

            if (options.selection.mode != null)
                eventHolder.mousedown(onMouseDown);

            if (options.grid.clickable)
                eventHolder.click(onClick);

            executeHooks(hooks.bindEvents, [eventHolder]);
        }

        function setupGrid() {
            function setTransformationHelpers(axis) {
                var s, m;
                    
                // add transformation helpers
                if (axis == axes.xaxis || axis == axes.x2axis) {
                    // precompute how much the axis is scaling a point
                    // in canvas space
                    s = axis.scale = plotWidth / (axis.max - axis.min);
                    m = axis.min;
                    
                    // data point to canvas coordinate
                    axis.p2c = function (p) { return (p - m) * s; };
                    // canvas coordinate to data point 
                    axis.c2p = function (c) { return m + c / s; };
                }
                else {
                    s = axis.scale = plotHeight / (axis.max - axis.min)
                    m = axis.max;
                    
                    axis.p2c = function (p) { return (m - p) * s; };
                    axis.c2p = function (p) { return m - p / s; };
                }
            }

            var axis;
            for (axis in axes)
                setRange(axes[axis], options[axis]);
            
            if (options.grid.show) {
                for (axis in axes) {
                    prepareTickGeneration(axes[axis], options[axis]);
                    setTicks(axes[axis], options[axis]);
                }                    

                setGridSpacing();
            }
            else {
                plotOffset.left = plotOffset.right = plotOffset.top = plotOffset.bottom = 0;
                plotWidth = canvasWidth;
                plotHeight = canvasHeight;
            }
            
            for (axis in axes)
                setTransformationHelpers(axes[axis]);

            if (options.grid.show)
                insertLabels();
            
            insertLegend();
        }
        
        function setRange(axis, axisOptions) {
            var min = +(axisOptions.min != null ? axisOptions.min : axis.datamin),
                max = +(axisOptions.max != null ? axisOptions.max : axis.datamax);

            if (max - min == 0.0) {
                // degenerate case
                var widen = max == 0 ? 1 : 0.01;

                if (axisOptions.min == null)
                    min -= widen;
                // alway widen max if we couldn't widen min to ensure we
                // don't fall into min == max which doesn't work
                if (axisOptions.max == null || axisOptions.min != null)
                    max += widen;
            }
            else {
                // consider autoscaling
                var margin = axisOptions.autoscaleMargin;
                if (margin != null) {
                    if (axisOptions.min == null) {
                        min -= (max - min) * margin;
                        // make sure we don't go below zero if all values
                        // are positive
                        if (min < 0 && axis.datamin != null && axis.datamin >= 0)
                            min = 0;
                    }
                    if (axisOptions.max == null) {
                        max += (max - min) * margin;
                        if (max > 0 && axis.datamax != null && axis.datamax <= 0)
                            max = 0;
                    }
                }
            }
            axis.min = min;
            axis.max = max;
        }

        function prepareTickGeneration(axis, axisOptions) {
            // estimate number of ticks
            var noTicks;
            if (typeof axisOptions.ticks == "number" && axisOptions.ticks > 0)
                noTicks = axisOptions.ticks;
            else if (axis == axes.xaxis || axis == axes.x2axis)
                noTicks = canvasWidth / 100;
            else
                noTicks = canvasHeight / 60;
            
            var delta = (axis.max - axis.min) / noTicks;
            var size, generator, unit, formatter, i, magn, norm;

            if (axisOptions.mode == "time") {
                // pretty handling of time
                
                // map of app. size of time units in milliseconds
                var timeUnitSize = {
                    "second": 1000,
                    "minute": 60 * 1000,
                    "hour": 60 * 60 * 1000,
                    "day": 24 * 60 * 60 * 1000,
                    "month": 30 * 24 * 60 * 60 * 1000,
                    "year": 365.2425 * 24 * 60 * 60 * 1000
                };


                // the allowed tick sizes, after 1 year we use
                // an integer algorithm
                var spec = [
                    [1, "second"], [2, "second"], [5, "second"], [10, "second"],
                    [30, "second"], 
                    [1, "minute"], [2, "minute"], [5, "minute"], [10, "minute"],
                    [30, "minute"], 
                    [1, "hour"], [2, "hour"], [4, "hour"],
                    [8, "hour"], [12, "hour"],
                    [1, "day"], [2, "day"], [3, "day"],
                    [0.25, "month"], [0.5, "month"], [1, "month"],
                    [2, "month"], [3, "month"], [6, "month"],
                    [1, "year"]
                ];

                var minSize = 0;
                if (axisOptions.minTickSize != null) {
                    if (typeof axisOptions.tickSize == "number")
                        minSize = axisOptions.tickSize;
                    else
                        minSize = axisOptions.minTickSize[0] * timeUnitSize[axisOptions.minTickSize[1]];
                }

                for (i = 0; i < spec.length - 1; ++i)
                    if (delta < (spec[i][0] * timeUnitSize[spec[i][1]]
                                 + spec[i + 1][0] * timeUnitSize[spec[i + 1][1]]) / 2
                       && spec[i][0] * timeUnitSize[spec[i][1]] >= minSize)
                        break;
                size = spec[i][0];
                unit = spec[i][1];
                
                // special-case the possibility of several years
                if (unit == "year") {
                    magn = Math.pow(10, Math.floor(Math.log(delta / timeUnitSize.year) / Math.LN10));
                    norm = (delta / timeUnitSize.year) / magn;
                    if (norm < 1.5)
                        size = 1;
                    else if (norm < 3)
                        size = 2;
                    else if (norm < 7.5)
                        size = 5;
                    else
                        size = 10;

                    size *= magn;
                }

                if (axisOptions.tickSize) {
                    size = axisOptions.tickSize[0];
                    unit = axisOptions.tickSize[1];
                }
                
                generator = function(axis) {
                    var ticks = [],
                        tickSize = axis.tickSize[0], unit = axis.tickSize[1],
                        d = new Date(axis.min);
                    
                    var step = tickSize * timeUnitSize[unit];

                    if (unit == "second")
                        d.setUTCSeconds(floorInBase(d.getUTCSeconds(), tickSize));
                    if (unit == "minute")
                        d.setUTCMinutes(floorInBase(d.getUTCMinutes(), tickSize));
                    if (unit == "hour")
                        d.setUTCHours(floorInBase(d.getUTCHours(), tickSize));
                    if (unit == "month")
                        d.setUTCMonth(floorInBase(d.getUTCMonth(), tickSize));
                    if (unit == "year")
                        d.setUTCFullYear(floorInBase(d.getUTCFullYear(), tickSize));
                    
                    // reset smaller components
                    d.setUTCMilliseconds(0);
                    if (step >= timeUnitSize.minute)
                        d.setUTCSeconds(0);
                    if (step >= timeUnitSize.hour)
                        d.setUTCMinutes(0);
                    if (step >= timeUnitSize.day)
                        d.setUTCHours(0);
                    if (step >= timeUnitSize.day * 4)
                        d.setUTCDate(1);
                    if (step >= timeUnitSize.year)
                        d.setUTCMonth(0);


                    var carry = 0, v = Number.NaN, prev;
                    do {
                        prev = v;
                        v = d.getTime();
                        ticks.push({ v: v, label: axis.tickFormatter(v, axis) });
                        if (unit == "month") {
                            if (tickSize < 1) {
                                // a bit complicated - we'll divide the month
                                // up but we need to take care of fractions
                                // so we don't end up in the middle of a day
                                d.setUTCDate(1);
                                var start = d.getTime();
                                d.setUTCMonth(d.getUTCMonth() + 1);
                                var end = d.getTime();
                                d.setTime(v + carry * timeUnitSize.hour + (end - start) * tickSize);
                                carry = d.getUTCHours();
                                d.setUTCHours(0);
                            }
                            else
                                d.setUTCMonth(d.getUTCMonth() + tickSize);
                        }
                        else if (unit == "year") {
                            d.setUTCFullYear(d.getUTCFullYear() + tickSize);
                        }
                        else
                            d.setTime(v + step);
                    } while (v < axis.max && v != prev);

                    return ticks;
                };

                formatter = function (v, axis) {
                    var d = new Date(v);

                    // first check global format
                    if (axisOptions.timeformat != null)
                        return $.plot.formatDate(d, axisOptions.timeformat, axisOptions.monthNames);
                    
                    var t = axis.tickSize[0] * timeUnitSize[axis.tickSize[1]];
                    var span = axis.max - axis.min;
                    
                    if (t < timeUnitSize.minute)
                        fmt = "%h:%M:%S";
                    else if (t < timeUnitSize.day) {
                        if (span < 2 * timeUnitSize.day)
                            fmt = "%h:%M";
                        else
                            fmt = "%b %d %h:%M";
                    }
                    else if (t < timeUnitSize.month)
                        fmt = "%b %d";
                    else if (t < timeUnitSize.year) {
                        if (span < timeUnitSize.year)
                            fmt = "%b";
                        else
                            fmt = "%b %y";
                    }
                    else
                        fmt = "%y";
                    
                    return $.plot.formatDate(d, fmt, axisOptions.monthNames);
                };
            }
            else {
                // pretty rounding of base-10 numbers
                var maxDec = axisOptions.tickDecimals;
                var dec = -Math.floor(Math.log(delta) / Math.LN10);
                if (maxDec != null && dec > maxDec)
                    dec = maxDec;
                
                magn = Math.pow(10, -dec);
                norm = delta / magn; // norm is between 1.0 and 10.0
                
                if (norm < 1.5)
                    size = 1;
                else if (norm < 3) {
                    size = 2;
                    // special case for 2.5, requires an extra decimal
                    if (norm > 2.25 && (maxDec == null || dec + 1 <= maxDec)) {
                        size = 2.5;
                        ++dec;
                    }
                }
                else if (norm < 7.5)
                    size = 5;
                else
                    size = 10;

                size *= magn;
                
                if (axisOptions.minTickSize != null && size < axisOptions.minTickSize)
                    size = axisOptions.minTickSize;

                if (axisOptions.tickSize != null)
                    size = axisOptions.tickSize;
                
                axis.tickDecimals = Math.max(0, (maxDec != null) ? maxDec : dec);
                
                generator = function (axis) {
                    var ticks = [];

                    // spew out all possible ticks
                    var start = floorInBase(axis.min, axis.tickSize),
                        i = 0, v = Number.NaN, prev;
                    do {
                        prev = v;
                        v = start + i * axis.tickSize;
                        ticks.push({ v: v, label: axis.tickFormatter(v, axis) });
                        ++i;
                    } while (v < axis.max && v != prev);
                    return ticks;
                };

                formatter = function (v, axis) {
                    return v.toFixed(axis.tickDecimals);
                };
            }

            axis.tickSize = unit ? [size, unit] : size;
            axis.tickGenerator = generator;
            if ($.isFunction(axisOptions.tickFormatter))
                axis.tickFormatter = function (v, axis) { return "" + axisOptions.tickFormatter(v, axis); };
            else
                axis.tickFormatter = formatter;
            if (axisOptions.labelWidth != null)
                axis.labelWidth = axisOptions.labelWidth;
            if (axisOptions.labelHeight != null)
                axis.labelHeight = axisOptions.labelHeight;
        }
        
        function setTicks(axis, axisOptions) {
            axis.ticks = [];

            if (!axis.used)
                return;
            
            if (axisOptions.ticks == null)
                axis.ticks = axis.tickGenerator(axis);
            else if (typeof axisOptions.ticks == "number") {
                if (axisOptions.ticks > 0)
                    axis.ticks = axis.tickGenerator(axis);
            }
            else if (axisOptions.ticks) {
                var ticks = axisOptions.ticks;

                if ($.isFunction(ticks))
                    // generate the ticks
                    ticks = ticks({ min: axis.min, max: axis.max });
                
                // clean up the user-supplied ticks, copy them over
                var i, v;
                for (i = 0; i < ticks.length; ++i) {
                    var label = null;
                    var t = ticks[i];
                    if (typeof t == "object") {
                        v = t[0];
                        if (t.length > 1)
                            label = t[1];
                    }
                    else
                        v = t;
                    if (label == null)
                        label = axis.tickFormatter(v, axis);
                    axis.ticks[i] = { v: v, label: label };
                }
            }

            if (axisOptions.autoscaleMargin != null && axis.ticks.length > 0) {
                // snap to ticks
                if (axisOptions.min == null)
                    axis.min = Math.min(axis.min, axis.ticks[0].v);
                if (axisOptions.max == null && axis.ticks.length > 1)
                    axis.max = Math.min(axis.max, axis.ticks[axis.ticks.length - 1].v);
            }
        }
        
        function setGridSpacing() {
            function measureXLabels(axis) {
                // to avoid measuring the widths of the labels, we
                // construct fixed-size boxes and put the labels inside
                // them, we don't need the exact figures and the
                // fixed-size box content is easy to center
                if (axis.labelWidth == null)
                    axis.labelWidth = canvasWidth / 6;

                // measure x label heights
                if (axis.labelHeight == null) {
                    labels = [];
                    for (i = 0; i < axis.ticks.length; ++i) {
                        l = axis.ticks[i].label;
                        if (l)
                            labels.push('<div class="tickLabel" style="float:left;width:' + axis.labelWidth + 'px">' + l + '</div>');
                    }
                    
                    axis.labelHeight = 0;
                    if (labels.length > 0) {
                        var dummyDiv = $('<div style="position:absolute;top:-10000px;width:10000px;font-size:smaller">'
                                         + labels.join("") + '<div style="clear:left"></div></div>').appendTo(target);
                        axis.labelHeight = dummyDiv.height();
                        dummyDiv.remove();
                    }
                }
            }
            
            function measureYLabels(axis) {
                if (axis.labelWidth == null || axis.labelHeight == null) {
                    var i, labels = [], l;
                    // calculate y label dimensions
                    for (i = 0; i < axis.ticks.length; ++i) {
                        l = axis.ticks[i].label;
                        if (l)
                            labels.push('<div class="tickLabel">' + l + '</div>');
                    }
                    
                    if (labels.length > 0) {
                        var dummyDiv = $('<div style="position:absolute;top:-10000px;font-size:smaller">'
                                         + labels.join("") + '</div>').appendTo(target);
                        if (axis.labelWidth == null)
                            axis.labelWidth = dummyDiv.width();
                        if (axis.labelHeight == null)
                            axis.labelHeight = dummyDiv.find("div").height();
                        dummyDiv.remove();
                    }
                    
                    if (axis.labelWidth == null)
                        axis.labelWidth = 0;
                    if (axis.labelHeight == null)
                        axis.labelHeight = 0;
                }
            }

            // get the most space needed around the grid for things
            // that may stick out
            var maxOutset = options.grid.borderWidth;
            for (i = 0; i < series.length; ++i)
                maxOutset = Math.max(maxOutset, 2 * (series[i].points.radius + series[i].points.lineWidth/2));
            
            plotOffset.left = plotOffset.right = plotOffset.top = plotOffset.bottom = maxOutset;
            
            var margin = options.grid.labelMargin + options.grid.borderWidth;
            
            measureXLabels(axes.xaxis);
            measureYLabels(axes.yaxis);
            measureXLabels(axes.x2axis);
            measureYLabels(axes.y2axis);
            
            if (axes.xaxis.labelHeight > 0)
                plotOffset.bottom = Math.max(maxOutset, axes.xaxis.labelHeight + margin);
            if (axes.yaxis.labelWidth > 0)
                    plotOffset.left = Math.max(maxOutset, axes.yaxis.labelWidth + margin);
            
            if (axes.x2axis.labelHeight > 0)
                plotOffset.top = Math.max(maxOutset, axes.x2axis.labelHeight + margin);
            
            if (axes.y2axis.labelWidth > 0)
                plotOffset.right = Math.max(maxOutset, axes.y2axis.labelWidth + margin);
            
            plotWidth = canvasWidth - plotOffset.left - plotOffset.right;
            plotHeight = canvasHeight - plotOffset.bottom - plotOffset.top;
        }
        
        function draw() {
            if (options.grid.show)
                drawGrid();

            for (var i = 0; i < series.length; ++i)
                drawSeries(series[i]);

            executeHooks(hooks.draw, [ctx]);
        }

        function extractRange(ranges, coord) {
            var firstAxis = coord + "axis",
                secondaryAxis = coord + "2axis",
                axis, from, to, reverse;

            if (ranges[firstAxis]) {
                axis = axes[firstAxis];
                from = ranges[firstAxis].from;
                to = ranges[firstAxis].to;
            }
            else if (ranges[secondaryAxis]) {
                axis = axes[secondaryAxis];
                from = ranges[secondaryAxis].from;
                to = ranges[secondaryAxis].to;
            }
            else {
                // backwards-compat stuff - to be removed in future
                axis = axes[firstAxis];
                from = ranges[coord + "1"];
                to = ranges[coord + "2"];
            }

            // auto-reverse as an added bonus
            if (from != null && to != null && from > to)
                return { from: to, to: from, axis: axis };
            
            return { from: from, to: to, axis: axis };
        }
        
        function drawGrid() {
            var i;
            
            ctx.save();
            ctx.clearRect(0, 0, canvasWidth, canvasHeight);
            ctx.translate(plotOffset.left, plotOffset.top);

            // draw background, if any
            if (options.grid.backgroundColor) {
                ctx.fillStyle = getColorOrGradient(options.grid.backgroundColor, plotHeight, 0, "rgba(255, 255, 255, 0)");
                ctx.fillRect(0, 0, plotWidth, plotHeight);
            }

            // draw markings
            var markings = options.grid.markings;
            if (markings) {
                if ($.isFunction(markings))
                    // xmin etc. are backwards-compatible, to be removed in future
                    markings = markings({ xmin: axes.xaxis.min, xmax: axes.xaxis.max, ymin: axes.yaxis.min, ymax: axes.yaxis.max, xaxis: axes.xaxis, yaxis: axes.yaxis, x2axis: axes.x2axis, y2axis: axes.y2axis });

                for (i = 0; i < markings.length; ++i) {
                    var m = markings[i],
                        xrange = extractRange(m, "x"),
                        yrange = extractRange(m, "y");

                    // fill in missing
                    if (xrange.from == null)
                        xrange.from = xrange.axis.min;
                    if (xrange.to == null)
                        xrange.to = xrange.axis.max;
                    if (yrange.from == null)
                        yrange.from = yrange.axis.min;
                    if (yrange.to == null)
                        yrange.to = yrange.axis.max;

                    // clip
                    if (xrange.to < xrange.axis.min || xrange.from > xrange.axis.max ||
                        yrange.to < yrange.axis.min || yrange.from > yrange.axis.max)
                        continue;

                    xrange.from = Math.max(xrange.from, xrange.axis.min);
                    xrange.to = Math.min(xrange.to, xrange.axis.max);
                    yrange.from = Math.max(yrange.from, yrange.axis.min);
                    yrange.to = Math.min(yrange.to, yrange.axis.max);

                    if (xrange.from == xrange.to && yrange.from == yrange.to)
                        continue;

                    // then draw
                    xrange.from = xrange.axis.p2c(xrange.from);
                    xrange.to = xrange.axis.p2c(xrange.to);
                    yrange.from = yrange.axis.p2c(yrange.from);
                    yrange.to = yrange.axis.p2c(yrange.to);
                    
                    if (xrange.from == xrange.to || yrange.from == yrange.to) {
                        // draw line
                        ctx.strokeStyle = m.color || options.grid.markingsColor;
                        ctx.beginPath();
                        ctx.lineWidth = m.lineWidth || options.grid.markingsLineWidth;
                        //ctx.moveTo(Math.floor(xrange.from), yrange.from);
                        //ctx.lineTo(Math.floor(xrange.to), yrange.to);
                        ctx.moveTo(xrange.from, yrange.from);
                        ctx.lineTo(xrange.to, yrange.to);
                        ctx.stroke();
                    }
                    else {
                        // fill area
                        ctx.fillStyle = m.color || options.grid.markingsColor;
                        ctx.fillRect(xrange.from, yrange.to,
                                     xrange.to - xrange.from,
                                     yrange.from - yrange.to);
                    }
                }
            }
            
            // draw the inner grid
            ctx.lineWidth = 1;
            ctx.strokeStyle = options.grid.tickColor;
            ctx.beginPath();
            var v, axis = axes.xaxis;
            for (i = 0; i < axis.ticks.length; ++i) {
                v = axis.ticks[i].v;
                if (v <= axis.min || v >= axes.xaxis.max)
                    continue;   // skip those lying on the axes

                ctx.moveTo(Math.floor(axis.p2c(v)) + ctx.lineWidth/2, 0);
                ctx.lineTo(Math.floor(axis.p2c(v)) + ctx.lineWidth/2, plotHeight);
            }

            axis = axes.yaxis;
            for (i = 0; i < axis.ticks.length; ++i) {
                v = axis.ticks[i].v;
                if (v <= axis.min || v >= axis.max)
                    continue;

                ctx.moveTo(0, Math.floor(axis.p2c(v)) + ctx.lineWidth/2);
                ctx.lineTo(plotWidth, Math.floor(axis.p2c(v)) + ctx.lineWidth/2);
            }

            axis = axes.x2axis;
            for (i = 0; i < axis.ticks.length; ++i) {
                v = axis.ticks[i].v;
                if (v <= axis.min || v >= axis.max)
                    continue;
    
                ctx.moveTo(Math.floor(axis.p2c(v)) + ctx.lineWidth/2, -5);
                ctx.lineTo(Math.floor(axis.p2c(v)) + ctx.lineWidth/2, 5);
            }

            axis = axes.y2axis;
            for (i = 0; i < axis.ticks.length; ++i) {
                v = axis.ticks[i].v;
                if (v <= axis.min || v >= axis.max)
                    continue;

                ctx.moveTo(plotWidth-5, Math.floor(axis.p2c(v)) + ctx.lineWidth/2);
                ctx.lineTo(plotWidth+5, Math.floor(axis.p2c(v)) + ctx.lineWidth/2);
            }
            
            ctx.stroke();
            
            if (options.grid.borderWidth) {
                // draw border
                var bw = options.grid.borderWidth;
                ctx.lineWidth = bw;
                ctx.strokeStyle = options.grid.borderColor;
                ctx.strokeRect(-bw/2, -bw/2, plotWidth + bw, plotHeight + bw);
            }

            ctx.restore();
        }

        function insertLabels() {
            target.find(".tickLabels").remove();
            
            var html = ['<div class="tickLabels" style="font-size:smaller;color:' + options.grid.color + '">'];

            function addLabels(axis, labelGenerator) {
                for (var i = 0; i < axis.ticks.length; ++i) {
                    var tick = axis.ticks[i];
                    if (!tick.label || tick.v < axis.min || tick.v > axis.max)
                        continue;
                    html.push(labelGenerator(tick, axis));
                }
            }

            var margin = options.grid.labelMargin + options.grid.borderWidth;
            
            addLabels(axes.xaxis, function (tick, axis) {
                return '<div style="position:absolute;top:' + (plotOffset.top + plotHeight + margin) + 'px;left:' + Math.round(plotOffset.left + axis.p2c(tick.v) - axis.labelWidth/2) + 'px;width:' + axis.labelWidth + 'px;text-align:center" class="tickLabel">' + tick.label + "</div>";
            });
            
            
            addLabels(axes.yaxis, function (tick, axis) {
                return '<div style="position:absolute;top:' + Math.round(plotOffset.top + axis.p2c(tick.v) - axis.labelHeight/2) + 'px;right:' + (plotOffset.right + plotWidth + margin) + 'px;width:' + axis.labelWidth + 'px;text-align:right" class="tickLabel">' + tick.label + "</div>";
            });
            
            addLabels(axes.x2axis, function (tick, axis) {
                return '<div style="position:absolute;bottom:' + (plotOffset.bottom + plotHeight + margin) + 'px;left:' + Math.round(plotOffset.left + axis.p2c(tick.v) - axis.labelWidth/2) + 'px;width:' + axis.labelWidth + 'px;text-align:center" class="tickLabel">' + tick.label + "</div>";
            });
            
            addLabels(axes.y2axis, function (tick, axis) {
                return '<div style="position:absolute;top:' + Math.round(plotOffset.top + axis.p2c(tick.v) - axis.labelHeight/2) + 'px;left:' + (plotOffset.left + plotWidth + margin) +'px;width:' + axis.labelWidth + 'px;text-align:left" class="tickLabel">' + tick.label + "</div>";
            });

            html.push('</div>');
            
            target.append(html.join(""));
        }

        function drawSeries(series) {
            if (series.lines.show)
                drawSeriesLines(series);
            if (series.bars.show)
                drawSeriesBars(series);
            if (series.points.show)
                drawSeriesPoints(series);
        }
        
        function drawSeriesLines(series) {
            function plotLine(datapoints, xoffset, yoffset, axisx, axisy) {
                var points = datapoints.points,
                    ps = datapoints.pointsize,
                    prevx = null, prevy = null;
                
                ctx.beginPath();
                for (var i = ps; i < points.length; i += ps) {
                    var x1 = points[i - ps], y1 = points[i - ps + 1],
                        x2 = points[i], y2 = points[i + 1];
                    
                    if (x1 == null || x2 == null)
                        continue;

                    // clip with ymin
                    if (y1 <= y2 && y1 < axisy.min) {
                        if (y2 < axisy.min)
                            continue;   // line segment is outside
                        // compute new intersection point
                        x1 = (axisy.min - y1) / (y2 - y1) * (x2 - x1) + x1;
                        y1 = axisy.min;
                    }
                    else if (y2 <= y1 && y2 < axisy.min) {
                        if (y1 < axisy.min)
                            continue;
                        x2 = (axisy.min - y1) / (y2 - y1) * (x2 - x1) + x1;
                        y2 = axisy.min;
                    }

                    // clip with ymax
                    if (y1 >= y2 && y1 > axisy.max) {
                        if (y2 > axisy.max)
                            continue;
                        x1 = (axisy.max - y1) / (y2 - y1) * (x2 - x1) + x1;
                        y1 = axisy.max;
                    }
                    else if (y2 >= y1 && y2 > axisy.max) {
                        if (y1 > axisy.max)
                            continue;
                        x2 = (axisy.max - y1) / (y2 - y1) * (x2 - x1) + x1;
                        y2 = axisy.max;
                    }

                    // clip with xmin
                    if (x1 <= x2 && x1 < axisx.min) {
                        if (x2 < axisx.min)
                            continue;
                        y1 = (axisx.min - x1) / (x2 - x1) * (y2 - y1) + y1;
                        x1 = axisx.min;
                    }
                    else if (x2 <= x1 && x2 < axisx.min) {
                        if (x1 < axisx.min)
                            continue;
                        y2 = (axisx.min - x1) / (x2 - x1) * (y2 - y1) + y1;
                        x2 = axisx.min;
                    }

                    // clip with xmax
                    if (x1 >= x2 && x1 > axisx.max) {
                        if (x2 > axisx.max)
                            continue;
                        y1 = (axisx.max - x1) / (x2 - x1) * (y2 - y1) + y1;
                        x1 = axisx.max;
                    }
                    else if (x2 >= x1 && x2 > axisx.max) {
                        if (x1 > axisx.max)
                            continue;
                        y2 = (axisx.max - x1) / (x2 - x1) * (y2 - y1) + y1;
                        x2 = axisx.max;
                    }

                    if (x1 != prevx || y1 != prevy)
                        ctx.moveTo(axisx.p2c(x1) + xoffset, axisy.p2c(y1) + yoffset);
                    
                    prevx = x2;
                    prevy = y2;
                    ctx.lineTo(axisx.p2c(x2) + xoffset, axisy.p2c(y2) + yoffset);
                }
                ctx.stroke();
            }

            function plotLineArea(datapoints, axisx, axisy) {
                var points = datapoints.points,
                    ps = datapoints.pointsize,
                    bottom = Math.min(Math.max(0, axisy.min), axisy.max),
                    top, lastX = 0, areaOpen = false;
                
                for (var i = ps; i < points.length; i += ps) {
                    var x1 = points[i - ps], y1 = points[i - ps + 1],
                        x2 = points[i], y2 = points[i + 1];
                    
                    if (areaOpen && x1 != null && x2 == null) {
                        // close area
                        ctx.lineTo(axisx.p2c(lastX), axisy.p2c(bottom));
                        ctx.fill();
                        areaOpen = false;
                        continue;
                    }

                    if (x1 == null || x2 == null)
                        continue;

                    // clip x values
                    
                    // clip with xmin
                    if (x1 <= x2 && x1 < axisx.min) {
                        if (x2 < axisx.min)
                            continue;
                        y1 = (axisx.min - x1) / (x2 - x1) * (y2 - y1) + y1;
                        x1 = axisx.min;
                    }
                    else if (x2 <= x1 && x2 < axisx.min) {
                        if (x1 < axisx.min)
                            continue;
                        y2 = (axisx.min - x1) / (x2 - x1) * (y2 - y1) + y1;
                        x2 = axisx.min;
                    }

                    // clip with xmax
                    if (x1 >= x2 && x1 > axisx.max) {
                        if (x2 > axisx.max)
                            continue;
                        y1 = (axisx.max - x1) / (x2 - x1) * (y2 - y1) + y1;
                        x1 = axisx.max;
                    }
                    else if (x2 >= x1 && x2 > axisx.max) {
                        if (x1 > axisx.max)
                            continue;
                        y2 = (axisx.max - x1) / (x2 - x1) * (y2 - y1) + y1;
                        x2 = axisx.max;
                    }

                    if (!areaOpen) {
                        // open area
                        ctx.beginPath();
                        ctx.moveTo(axisx.p2c(x1), axisy.p2c(bottom));
                        areaOpen = true;
                    }
                    
                    // now first check the case where both is outside
                    if (y1 >= axisy.max && y2 >= axisy.max) {
                        ctx.lineTo(axisx.p2c(x1), axisy.p2c(axisy.max));
                        ctx.lineTo(axisx.p2c(x2), axisy.p2c(axisy.max));
                        lastX = x2;
                        continue;
                    }
                    else if (y1 <= axisy.min && y2 <= axisy.min) {
                        ctx.lineTo(axisx.p2c(x1), axisy.p2c(axisy.min));
                        ctx.lineTo(axisx.p2c(x2), axisy.p2c(axisy.min));
                        lastX = x2;
                        continue;
                    }
                    
                    // else it's a bit more complicated, there might
                    // be two rectangles and two triangles we need to fill
                    // in; to find these keep track of the current x values
                    var x1old = x1, x2old = x2;

                    // and clip the y values, without shortcutting
                    
                    // clip with ymin
                    if (y1 <= y2 && y1 < axisy.min && y2 >= axisy.min) {
                        x1 = (axisy.min - y1) / (y2 - y1) * (x2 - x1) + x1;
                        y1 = axisy.min;
                    }
                    else if (y2 <= y1 && y2 < axisy.min && y1 >= axisy.min) {
                        x2 = (axisy.min - y1) / (y2 - y1) * (x2 - x1) + x1;
                        y2 = axisy.min;
                    }

                    // clip with ymax
                    if (y1 >= y2 && y1 > axisy.max && y2 <= axisy.max) {
                        x1 = (axisy.max - y1) / (y2 - y1) * (x2 - x1) + x1;
                        y1 = axisy.max;
                    }
                    else if (y2 >= y1 && y2 > axisy.max && y1 <= axisy.max) {
                        x2 = (axisy.max - y1) / (y2 - y1) * (x2 - x1) + x1;
                        y2 = axisy.max;
                    }


                    // if the x value was changed we got a rectangle
                    // to fill
                    if (x1 != x1old) {
                        if (y1 <= axisy.min)
                            top = axisy.min;
                        else
                            top = axisy.max;
                        
                        ctx.lineTo(axisx.p2c(x1old), axisy.p2c(top));
                        ctx.lineTo(axisx.p2c(x1), axisy.p2c(top));
                    }
                    
                    // fill the triangles
                    ctx.lineTo(axisx.p2c(x1), axisy.p2c(y1));
                    ctx.lineTo(axisx.p2c(x2), axisy.p2c(y2));

                    // fill the other rectangle if it's there
                    if (x2 != x2old) {
                        if (y2 <= axisy.min)
                            top = axisy.min;
                        else
                            top = axisy.max;
                        
                        ctx.lineTo(axisx.p2c(x2), axisy.p2c(top));
                        ctx.lineTo(axisx.p2c(x2old), axisy.p2c(top));
                    }

                    lastX = Math.max(x2, x2old);
                }

                if (areaOpen) {
                    ctx.lineTo(axisx.p2c(lastX), axisy.p2c(bottom));
                    ctx.fill();
                }
            }
            
            ctx.save();
            ctx.translate(plotOffset.left, plotOffset.top);
            ctx.lineJoin = "round";

            var lw = series.lines.lineWidth,
                sw = series.shadowSize;
            // FIXME: consider another form of shadow when filling is turned on
            if (lw > 0 && sw > 0) {
                // draw shadow as a thick and thin line with transparency
                ctx.lineWidth = sw;
                ctx.strokeStyle = "rgba(0,0,0,0.1)";
                // position shadow at angle from the mid of line
                var angle = Math.PI/18;
                plotLine(series.datapoints, Math.sin(angle) * (lw/2 + sw/2), Math.cos(angle) * (lw/2 + sw/2), series.xaxis, series.yaxis);
                ctx.lineWidth = sw/2;
                plotLine(series.datapoints, Math.sin(angle) * (lw/2 + sw/4), Math.cos(angle) * (lw/2 + sw/4), series.xaxis, series.yaxis);
            }

            ctx.lineWidth = lw;
            ctx.strokeStyle = series.color;
            var fillStyle = getFillStyle(series.lines, series.color, 0, plotHeight);
            if (fillStyle) {
                ctx.fillStyle = fillStyle;
                plotLineArea(series.datapoints, series.xaxis, series.yaxis);
            }

            if (lw > 0)
                plotLine(series.datapoints, 0, 0, series.xaxis, series.yaxis);
            ctx.restore();
        }

        function drawSeriesPoints(series) {
            function plotPoints(datapoints, radius, fillStyle, offset, circumference, axisx, axisy) {
                var points = datapoints.points, ps = datapoints.pointsize;
                
                for (var i = 0; i < points.length; i += ps) {
                    var x = points[i], y = points[i + 1];
                    if (x == null || x < axisx.min || x > axisx.max || y < axisy.min || y > axisy.max)
                        continue;
                    
                    ctx.beginPath();
                    ctx.arc(axisx.p2c(x), axisy.p2c(y) + offset, radius, 0, circumference, false);
                    if (fillStyle) {
                        ctx.fillStyle = fillStyle;
                        ctx.fill();
                    }
                    ctx.stroke();
                }
            }
            
            ctx.save();
            ctx.translate(plotOffset.left, plotOffset.top);

            var lw = series.lines.lineWidth,
                sw = series.shadowSize,
                radius = series.points.radius;
            if (lw > 0 && sw > 0) {
                // draw shadow in two steps
                var w = sw / 2;
                ctx.lineWidth = w;
                ctx.strokeStyle = "rgba(0,0,0,0.1)";
                plotPoints(series.datapoints, radius, null, w + w/2, Math.PI,
                           series.xaxis, series.yaxis);

                ctx.strokeStyle = "rgba(0,0,0,0.2)";
                plotPoints(series.datapoints, radius, null, w/2, Math.PI,
                           series.xaxis, series.yaxis);
            }

            ctx.lineWidth = lw;
            ctx.strokeStyle = series.color;
            plotPoints(series.datapoints, radius,
                       getFillStyle(series.points, series.color), 0, 2 * Math.PI,
                       series.xaxis, series.yaxis);
            ctx.restore();
        }

        function drawBar(x, y, b, barLeft, barRight, offset, fillStyleCallback, axisx, axisy, c, horizontal) {
            var left, right, bottom, top,
                drawLeft, drawRight, drawTop, drawBottom,
                tmp;

            if (horizontal) {
                drawBottom = drawRight = drawTop = true;
                drawLeft = false;
                left = b;
                right = x;
                top = y + barLeft;
                bottom = y + barRight;

                // account for negative bars
                if (right < left) {
                    tmp = right;
                    right = left;
                    left = tmp;
                    drawLeft = true;
                    drawRight = false;
                }
            }
            else {
                drawLeft = drawRight = drawTop = true;
                drawBottom = false;
                left = x + barLeft;
                right = x + barRight;
                bottom = b;
                top = y;

                // account for negative bars
                if (top < bottom) {
                    tmp = top;
                    top = bottom;
                    bottom = tmp;
                    drawBottom = true;
                    drawTop = false;
                }
            }
           
            // clip
            if (right < axisx.min || left > axisx.max ||
                top < axisy.min || bottom > axisy.max)
                return;
            
            if (left < axisx.min) {
                left = axisx.min;
                drawLeft = false;
            }

            if (right > axisx.max) {
                right = axisx.max;
                drawRight = false;
            }

            if (bottom < axisy.min) {
                bottom = axisy.min;
                drawBottom = false;
            }
            
            if (top > axisy.max) {
                top = axisy.max;
                drawTop = false;
            }

            left = axisx.p2c(left);
            bottom = axisy.p2c(bottom);
            right = axisx.p2c(right);
            top = axisy.p2c(top);
            
            // fill the bar
            if (fillStyleCallback) {
                c.beginPath();
                c.moveTo(left, bottom);
                c.lineTo(left, top);
                c.lineTo(right, top);
                c.lineTo(right, bottom);
                c.fillStyle = fillStyleCallback(bottom, top);
                c.fill();
            }

            // draw outline
            if (drawLeft || drawRight || drawTop || drawBottom) {
                c.beginPath();

                // FIXME: inline moveTo is buggy with excanvas
                c.moveTo(left, bottom + offset);
                if (drawLeft)
                    c.lineTo(left, top + offset);
                else
                    c.moveTo(left, top + offset);
                if (drawTop)
                    c.lineTo(right, top + offset);
                else
                    c.moveTo(right, top + offset);
                if (drawRight)
                    c.lineTo(right, bottom + offset);
                else
                    c.moveTo(right, bottom + offset);
                if (drawBottom)
                    c.lineTo(left, bottom + offset);
                else
                    c.moveTo(left, bottom + offset);
                c.stroke();
            }
        }
        
        function drawSeriesBars(series) {
            function plotBars(datapoints, barLeft, barRight, offset, fillStyleCallback, axisx, axisy) {
                var points = datapoints.points, ps = datapoints.pointsize;
                
                for (var i = 0; i < points.length; i += ps) {
                    if (points[i] == null)
                        continue;
                    drawBar(points[i], points[i + 1], points[i + 2], barLeft, barRight, offset, fillStyleCallback, axisx, axisy, ctx, series.bars.horizontal);
                }
            }

            ctx.save();
            ctx.translate(plotOffset.left, plotOffset.top);

            // FIXME: figure out a way to add shadows (for instance along the right edge)
            ctx.lineWidth = series.bars.lineWidth;
            ctx.strokeStyle = series.color;
            var barLeft = series.bars.align == "left" ? 0 : -series.bars.barWidth/2;
            var fillStyleCallback = series.bars.fill ? function (bottom, top) { return getFillStyle(series.bars, series.color, bottom, top); } : null;
            plotBars(series.datapoints, barLeft, barLeft + series.bars.barWidth, 0, fillStyleCallback, series.xaxis, series.yaxis);
            ctx.restore();
        }

        function getFillStyle(filloptions, seriesColor, bottom, top) {
            var fill = filloptions.fill;
            if (!fill)
                return null;

            if (filloptions.fillColor)
                return getColorOrGradient(filloptions.fillColor, bottom, top, seriesColor);
            
            var c = parseColor(seriesColor);
            c.a = typeof fill == "number" ? fill : 0.4;
            c.normalize();
            return c.toString();
        }
        
        function insertLegend() {
            target.find(".legend").remove();

            if (!options.legend.show)
                return;
            
            var fragments = [], rowStarted = false,
                lf = options.legend.labelFormatter, s, label;
            for (i = 0; i < series.length; ++i) {
                s = series[i];
                label = s.label;
                if (!label)
                    continue;
                
                if (i % options.legend.noColumns == 0) {
                    if (rowStarted)
                        fragments.push('</tr>');
                    fragments.push('<tr>');
                    rowStarted = true;
                }

                if (lf)
                    label = lf(label, s);
                
                fragments.push(
                    '<td class="legendColorBox"><div style="border:1px solid ' + options.legend.labelBoxBorderColor + ';padding:1px"><div style="width:4px;height:0;border:5px solid ' + s.color + ';overflow:hidden"></div></div></td>' +
                    '<td class="legendLabel">' + label + '</td>');
            }
            if (rowStarted)
                fragments.push('</tr>');
            
            if (fragments.length == 0)
                return;

            var table = '<table style="font-size:smaller;color:' + options.grid.color + '">' + fragments.join("") + '</table>';
            if (options.legend.container != null)
                $(options.legend.container).html(table);
            else {
                var pos = "",
                    p = options.legend.position,
                    m = options.legend.margin;
                if (m[0] == null)
                    m = [m, m];
                if (p.charAt(0) == "n")
                    pos += 'top:' + (m[1] + plotOffset.top) + 'px;';
                else if (p.charAt(0) == "s")
                    pos += 'bottom:' + (m[1] + plotOffset.bottom) + 'px;';
                if (p.charAt(1) == "e")
                    pos += 'right:' + (m[0] + plotOffset.right) + 'px;';
                else if (p.charAt(1) == "w")
                    pos += 'left:' + (m[0] + plotOffset.left) + 'px;';
                var legend = $('<div class="legend">' + table.replace('style="', 'style="position:absolute;' + pos +';') + '</div>').appendTo(target);
                if (options.legend.backgroundOpacity != 0.0) {
                    // put in the transparent background
                    // separately to avoid blended labels and
                    // label boxes
                    var c = options.legend.backgroundColor;
                    if (c == null) {
                        var tmp;
                        if (options.grid.backgroundColor && typeof options.grid.backgroundColor == "string")
                            tmp = options.grid.backgroundColor;
                        else
                            tmp = extractColor(legend);
                        c = parseColor(tmp).adjust(null, null, null, 1).toString();
                    }
                    var div = legend.children();
                    $('<div style="position:absolute;width:' + div.width() + 'px;height:' + div.height() + 'px;' + pos +'background-color:' + c + ';"> </div>').prependTo(legend).css('opacity', options.legend.backgroundOpacity);
                }
            }
        }


        // interactive features
        
        var lastMousePos = { pageX: null, pageY: null },
            selection = {
                first: { x: -1, y: -1}, second: { x: -1, y: -1},
                show: false,
                active: false
            },
            highlights = [],
            clickIsMouseUp = false,
            redrawTimeout = null,
            hoverTimeout = null;
        
        // returns the data item the mouse is over, or null if none is found
        function findNearbyItem(mouseX, mouseY, seriesFilter) {
            var maxDistance = options.grid.mouseActiveRadius,
                lowestDistance = maxDistance * maxDistance + 1,
                item = null, foundPoint = false, i, j;

            for (var i = 0; i < series.length; ++i) {
                if (!seriesFilter(series[i]))
                    continue;
                
                var s = series[i],
                    axisx = s.xaxis,
                    axisy = s.yaxis,
                    points = s.datapoints.points,
                    ps = s.datapoints.pointsize,
                    mx = axisx.c2p(mouseX), // precompute some stuff to make the loop faster
                    my = axisy.c2p(mouseY),
                    maxx = maxDistance / axisx.scale,
                    maxy = maxDistance / axisy.scale;

                if (s.lines.show || s.points.show) {
                    for (j = 0; j < points.length; j += ps) {
                        var x = points[j], y = points[j + 1];
                        if (x == null)
                            continue;
                        
                        // For points and lines, the cursor must be within a
                        // certain distance to the data point
                        if (x - mx > maxx || x - mx < -maxx ||
                            y - my > maxy || y - my < -maxy)
                            continue;

                        // We have to calculate distances in pixels, not in
                        // data units, because the scales of the axes may be different
                        var dx = Math.abs(axisx.p2c(x) - mouseX),
                            dy = Math.abs(axisy.p2c(y) - mouseY),
                            dist = dx * dx + dy * dy; // no idea in taking sqrt
                        if (dist < lowestDistance) {
                            lowestDistance = dist;
                            item = [i, j / ps];
                        }
                    }
                }
                    
                if (s.bars.show && !item) { // no other point can be nearby
                    var barLeft = s.bars.align == "left" ? 0 : -s.bars.barWidth/2,
                        barRight = barLeft + s.bars.barWidth;
                    
                    for (j = 0; j < points.length; j += ps) {
                        var x = points[j], y = points[j + 1], b = points[j + 2];
                        if (x == null)
                            continue;
  
                        // for a bar graph, the cursor must be inside the bar
                        if (series[i].bars.horizontal ? 
                            (mx <= Math.max(b, x) && mx >= Math.min(b, x) && 
                             my >= y + barLeft && my <= y + barRight) :
                            (mx >= x + barLeft && mx <= x + barRight &&
                             my >= Math.min(b, y) && my <= Math.max(b, y)))
                                item = [i, j / ps];
                    }
                }
            }

            if (item) {
                i = item[0];
                j = item[1];
                
                return { datapoint: series[i].datapoints.points.slice(j * ps, (j + 1) * ps),
                         dataIndex: j,
                         series: series[i],
                         seriesIndex: i };
            }
            
            return null;
        }

        function onMouseMove(e) {
            lastMousePos.pageX = e.pageX;
            lastMousePos.pageY = e.pageY;
            
            if (options.grid.hoverable)
                triggerClickHoverEvent("plothover", lastMousePos,
                                       function (s) { return s["hoverable"] != false; });

            if (selection.active) {
                target.trigger("plotselecting", [ getSelection() ]);

                updateSelection(lastMousePos);
            }
        }
        
        function onMouseDown(e) {
            if (e.which != 1)  // only accept left-click
                return;
            
            // cancel out any text selections
            document.body.focus();

            // prevent text selection and drag in old-school browsers
            if (document.onselectstart !== undefined && workarounds.onselectstart == null) {
                workarounds.onselectstart = document.onselectstart;
                document.onselectstart = function () { return false; };
            }
            if (document.ondrag !== undefined && workarounds.ondrag == null) {
                workarounds.ondrag = document.ondrag;
                document.ondrag = function () { return false; };
            }
            
            setSelectionPos(selection.first, e);
                
            lastMousePos.pageX = null;
            selection.active = true;
            $(document).one("mouseup", onSelectionMouseUp);
        }

        function onClick(e) {
            if (clickIsMouseUp) {
                clickIsMouseUp = false;
                return;
            }

            triggerClickHoverEvent("plotclick", e,
                                   function (s) { return s["clickable"] != false; });
        }

        // trigger click or hover event (they send the same parameters
        // so we share their code)
        function triggerClickHoverEvent(eventname, event, seriesFilter) {
            var offset = eventHolder.offset(),
                pos = { pageX: event.pageX, pageY: event.pageY },
                canvasX = event.pageX - offset.left - plotOffset.left,
                canvasY = event.pageY - offset.top - plotOffset.top;

            if (axes.xaxis.used)
                pos.x = axes.xaxis.c2p(canvasX);
            if (axes.yaxis.used)
                pos.y = axes.yaxis.c2p(canvasY);
            if (axes.x2axis.used)
                pos.x2 = axes.x2axis.c2p(canvasX);
            if (axes.y2axis.used)
                pos.y2 = axes.y2axis.c2p(canvasY);

            var item = findNearbyItem(canvasX, canvasY, seriesFilter);

            if (item) {
                // fill in mouse pos for any listeners out there
                item.pageX = parseInt(item.series.xaxis.p2c(item.datapoint[0]) + offset.left + plotOffset.left);
                item.pageY = parseInt(item.series.yaxis.p2c(item.datapoint[1]) + offset.top + plotOffset.top);
            }

            if (options.grid.autoHighlight) {
                // clear auto-highlights
                for (var i = 0; i < highlights.length; ++i) {
                    var h = highlights[i];
                    if (h.auto == eventname &&
                        !(item && h.series == item.series && h.point == item.datapoint))
                        unhighlight(h.series, h.point);
                }
                
                if (item)
                    highlight(item.series, item.datapoint, eventname);
            }
            
            target.trigger(eventname, [ pos, item ]);
        }

        function triggerRedrawOverlay() {
            if (!redrawTimeout)
                redrawTimeout = setTimeout(drawOverlay, 30);
        }

        function drawOverlay() {
            redrawTimeout = null;

            // draw highlights
            octx.save();
            octx.clearRect(0, 0, canvasWidth, canvasHeight);
            octx.translate(plotOffset.left, plotOffset.top);
            
            var i, hi;
            for (i = 0; i < highlights.length; ++i) {
                hi = highlights[i];

                if (hi.series.bars.show)
                    drawBarHighlight(hi.series, hi.point);
                else
                    drawPointHighlight(hi.series, hi.point);
            }

            // draw selection
            if (selection.show && selectionIsSane()) {
                octx.strokeStyle = parseColor(options.selection.color).scale(null, null, null, 0.8).toString();
                octx.lineWidth = 1;
                ctx.lineJoin = "round";
                octx.fillStyle = parseColor(options.selection.color).scale(null, null, null, 0.4).toString();
                
                var x = Math.min(selection.first.x, selection.second.x),
                    y = Math.min(selection.first.y, selection.second.y),
                    w = Math.abs(selection.second.x - selection.first.x),
                    h = Math.abs(selection.second.y - selection.first.y);
                
                octx.fillRect(x, y, w, h);
                octx.strokeRect(x, y, w, h);
            }
            octx.restore();
            
            executeHooks(hooks.drawOverlay, [octx]);
        }
        
        function highlight(s, point, auto) {
            if (typeof s == "number")
                s = series[s];

            if (typeof point == "number")
                point = s.data[point];

            var i = indexOfHighlight(s, point);
            if (i == -1) {
                highlights.push({ series: s, point: point, auto: auto });

                triggerRedrawOverlay();
            }
            else if (!auto)
                highlights[i].auto = false;
        }
            
        function unhighlight(s, point) {
            if (s == null && point == null) {
                highlights = [];
                triggerRedrawOverlay();
            }
            
            if (typeof s == "number")
                s = series[s];

            if (typeof point == "number")
                point = s.data[point];

            var i = indexOfHighlight(s, point);
            if (i != -1) {
                highlights.splice(i, 1);

                triggerRedrawOverlay();
            }
        }
        
        function indexOfHighlight(s, p) {
            for (var i = 0; i < highlights.length; ++i) {
                var h = highlights[i];
                if (h.series == s && h.point[0] == p[0]
                    && h.point[1] == p[1])
                    return i;
            }
            return -1;
        }
        
        function drawPointHighlight(series, point) {
            var x = point[0], y = point[1],
                axisx = series.xaxis, axisy = series.yaxis;
            
            if (x < axisx.min || x > axisx.max || y < axisy.min || y > axisy.max)
                return;
            
            var pointRadius = series.points.radius + series.points.lineWidth / 2;
            octx.lineWidth = pointRadius;
            octx.strokeStyle = parseColor(series.color).scale(1, 1, 1, 0.5).toString();
            var radius = 1.5 * pointRadius;
            octx.beginPath();
            octx.arc(axisx.p2c(x), axisy.p2c(y), radius, 0, 2 * Math.PI, false);
            octx.stroke();
        }

        function drawBarHighlight(series, point) {
            octx.lineWidth = series.bars.lineWidth;
            octx.strokeStyle = parseColor(series.color).scale(1, 1, 1, 0.5).toString();
            var fillStyle = parseColor(series.color).scale(1, 1, 1, 0.5).toString();
            var barLeft = series.bars.align == "left" ? 0 : -series.bars.barWidth/2;
            drawBar(point[0], point[1], point[2] || 0, barLeft, barLeft + series.bars.barWidth,
                    0, function () { return fillStyle; }, series.xaxis, series.yaxis, octx, series.bars.horizontal);
        }

        function getSelection() {
            if (!selectionIsSane())
                return null;
            
            var x1 = Math.min(selection.first.x, selection.second.x),
                x2 = Math.max(selection.first.x, selection.second.x),
                y1 = Math.max(selection.first.y, selection.second.y),
                y2 = Math.min(selection.first.y, selection.second.y);

            var r = {};
            if (axes.xaxis.used)
                r.xaxis = { from: axes.xaxis.c2p(x1), to: axes.xaxis.c2p(x2) };
            if (axes.x2axis.used)
                r.x2axis = { from: axes.x2axis.c2p(x1), to: axes.x2axis.c2p(x2) };
            if (axes.yaxis.used)
                r.yaxis = { from: axes.yaxis.c2p(y1), to: axes.yaxis.c2p(y2) };
            if (axes.y2axis.used)
                r.y2axis = { from: axes.y2axis.c2p(y1), to: axes.y2axis.c2p(y2) };
            return r;
        }
        
        function triggerSelectedEvent() {
            var r = getSelection();
            
            target.trigger("plotselected", [ r ]);

            // backwards-compat stuff, to be removed in future
            if (axes.xaxis.used && axes.yaxis.used)
                target.trigger("selected", [ { x1: r.xaxis.from, y1: r.yaxis.from, x2: r.xaxis.to, y2: r.yaxis.to } ]);
        }
        
        function onSelectionMouseUp(e) {
            // revert drag stuff for old-school browsers
            if (document.onselectstart !== undefined)
                document.onselectstart = workarounds.onselectstart;
            if (document.ondrag !== undefined)
                document.ondrag = workarounds.ondrag;
            
            // no more draggy-dee-drag
            selection.active = false;
            updateSelection(e);
            
            if (selectionIsSane()) {
                triggerSelectedEvent();
                clickIsMouseUp = true;
            }
            else {
                // this counts as a clear
                target.trigger("plotunselected", [ ]);
                target.trigger("plotselecting", [ null ]);
            }
            
            return false;
        }

        function setSelectionPos(pos, e) {
            var offset = eventHolder.offset();
            pos.x = clamp(0, e.pageX - offset.left - plotOffset.left, plotWidth);
            pos.y = clamp(0, e.pageY - offset.top - plotOffset.top, plotHeight);
            
            if (options.selection.mode == "y") {
                if (pos == selection.first)
                    pos.x = 0;
                else
                    pos.x = plotWidth;
            }

            if (options.selection.mode == "x") {
                if (pos == selection.first)
                    pos.y = 0;
                else
                    pos.y = plotHeight;
            }
        }

        function updateSelection(pos) {
            if (pos.pageX == null)
                return;

            setSelectionPos(selection.second, pos);
            if (selectionIsSane()) {
                selection.show = true;
                triggerRedrawOverlay();
            }
            else
                clearSelection(true);
        }

        function clearSelection(preventEvent) {
            if (selection.show) {
                selection.show = false;
                triggerRedrawOverlay();
                if (!preventEvent)
                    target.trigger("plotunselected", [ ]);
            }
        }

        function setSelection(ranges, preventEvent) {
            var range;
            
            if (options.selection.mode == "y") {
                selection.first.x = 0;
                selection.second.x = plotWidth;
            }
            else {
                range = extractRange(ranges, "x");
                
                selection.first.x = range.axis.p2c(range.from);
                selection.second.x = range.axis.p2c(range.to);
            }
            
            if (options.selection.mode == "x") {
                selection.first.y = 0;
                selection.second.y = plotHeight;
            }
            else {
                range = extractRange(ranges, "y");
                
                selection.first.y = range.axis.p2c(range.from);
                selection.second.y = range.axis.p2c(range.to);
            }

            selection.show = true;
            triggerRedrawOverlay();
            if (!preventEvent)
                triggerSelectedEvent();
        }
        
        function selectionIsSane() {
            var minSize = 5;
            return Math.abs(selection.second.x - selection.first.x) >= minSize &&
                Math.abs(selection.second.y - selection.first.y) >= minSize;
        }
        
        function getColorOrGradient(spec, bottom, top, defaultColor) {
            if (typeof spec == "string")
                return spec;
            else {
                // assume this is a gradient spec; IE currently only
                // supports a simple vertical gradient properly, so that's
                // what we support too
                var gradient = ctx.createLinearGradient(0, top, 0, bottom);
                
                for (var i = 0, l = spec.colors.length; i < l; ++i) {
                    var c = spec.colors[i];
                    gradient.addColorStop(i / (l - 1), typeof c == "string" ? c : parseColor(defaultColor).scale(c.brightness, c.brightness, c.brightness, c.opacity));
                }
                
                return gradient;
            }
        }
    }

    $.plot = function(target, data, options) {
        var plot = new Plot($(target), data, options, $.plot.plugins);
        /*var t0 = new Date();
        var t1 = new Date();
        var tstr = "time used (msecs): " + (t1.getTime() - t0.getTime())
        if (window.console)
            console.log(tstr);
        else
            alert(tstr);*/
        return plot;
    };

    $.plot.plugins = [];

    // returns a string with the date d formatted according to fmt
    $.plot.formatDate = function(d, fmt, monthNames) {
        var leftPad = function(n) {
            n = "" + n;
            return n.length == 1 ? "0" + n : n;
        };
        
        var r = [];
        var escape = false;
        if (monthNames == null)
            monthNames = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
        for (var i = 0; i < fmt.length; ++i) {
            var c = fmt.charAt(i);
            
            if (escape) {
                switch (c) {
                case 'h': c = "" + d.getUTCHours(); break;
                case 'H': c = leftPad(d.getUTCHours()); break;
                case 'M': c = leftPad(d.getUTCMinutes()); break;
                case 'S': c = leftPad(d.getUTCSeconds()); break;
                case 'd': c = "" + d.getUTCDate(); break;
                case 'm': c = "" + (d.getUTCMonth() + 1); break;
                case 'y': c = "" + d.getUTCFullYear(); break;
                case 'b': c = "" + monthNames[d.getUTCMonth()]; break;
                }
                r.push(c);
                escape = false;
            }
            else {
                if (c == "%")
                    escape = true;
                else
                    r.push(c);
            }
        }
        return r.join("");
    };
    
    // round to nearby lower multiple of base
    function floorInBase(n, base) {
        return base * Math.floor(n / base);
    }
    
    function clamp(min, value, max) {
        if (value < min)
            return min;
        else if (value > max)
            return max;
        else
            return value;
    }
    
    // color helpers, inspiration from the jquery color animation
    // plugin by John Resig
    function Color (r, g, b, a) {
       
        var rgba = ['r','g','b','a'];
        var x = 4; //rgba.length
       
        while (-1<--x) {
            this[rgba[x]] = arguments[x] || ((x==3) ? 1.0 : 0);
        }
       
        this.toString = function() {
            if (this.a >= 1.0) {
                return "rgb("+[this.r,this.g,this.b].join(",")+")";
            } else {
                return "rgba("+[this.r,this.g,this.b,this.a].join(",")+")";
            }
        };

        this.scale = function(rf, gf, bf, af) {
            x = 4; //rgba.length
            while (-1<--x) {
                if (arguments[x] != null)
                    this[rgba[x]] *= arguments[x];
            }
            return this.normalize();
        };

        this.adjust = function(rd, gd, bd, ad) {
            x = 4; //rgba.length
            while (-1<--x) {
                if (arguments[x] != null)
                    this[rgba[x]] += arguments[x];
            }
            return this.normalize();
        };

        this.clone = function() {
            return new Color(this.r, this.b, this.g, this.a);
        };

        var limit = function(val,minVal,maxVal) {
            return Math.max(Math.min(val, maxVal), minVal);
        };

        this.normalize = function() {
            this.r = clamp(0, parseInt(this.r), 255);
            this.g = clamp(0, parseInt(this.g), 255);
            this.b = clamp(0, parseInt(this.b), 255);
            this.a = clamp(0, this.a, 1);
            return this;
        };

        this.normalize();
    }
    
    var lookupColors = {
        aqua:[0,255,255],
        azure:[240,255,255],
        beige:[245,245,220],
        black:[0,0,0],
        blue:[0,0,255],
        brown:[165,42,42],
        cyan:[0,255,255],
        darkblue:[0,0,139],
        darkcyan:[0,139,139],
        darkgrey:[169,169,169],
        darkgreen:[0,100,0],
        darkkhaki:[189,183,107],
        darkmagenta:[139,0,139],
        darkolivegreen:[85,107,47],
        darkorange:[255,140,0],
        darkorchid:[153,50,204],
        darkred:[139,0,0],
        darksalmon:[233,150,122],
        darkviolet:[148,0,211],
        fuchsia:[255,0,255],
        gold:[255,215,0],
        green:[0,128,0],
        indigo:[75,0,130],
        khaki:[240,230,140],
        lightblue:[173,216,230],
        lightcyan:[224,255,255],
        lightgreen:[144,238,144],
        lightgrey:[211,211,211],
        lightpink:[255,182,193],
        lightyellow:[255,255,224],
        lime:[0,255,0],
        magenta:[255,0,255],
        maroon:[128,0,0],
        navy:[0,0,128],
        olive:[128,128,0],
        orange:[255,165,0],
        pink:[255,192,203],
        purple:[128,0,128],
        violet:[128,0,128],
        red:[255,0,0],
        silver:[192,192,192],
        white:[255,255,255],
        yellow:[255,255,0]
    };    

    function extractColor(element) {
        var color, elem = element;
        do {
            color = elem.css("background-color").toLowerCase();
            // keep going until we find an element that has color, or
            // we hit the body
            if (color != '' && color != 'transparent')
                break;
            elem = elem.parent();
        } while (!$.nodeName(elem.get(0), "body"));

        // catch Safari's way of signalling transparent
        if (color == "rgba(0, 0, 0, 0)")
            return "transparent";
        
        return color;
    }
    
    // parse string, returns Color
    function parseColor(str) {
        var result;

        // Look for rgb(num,num,num)
        if (result = /rgb\(\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*\)/.exec(str))
            return new Color(parseInt(result[1], 10), parseInt(result[2], 10), parseInt(result[3], 10));
        
        // Look for rgba(num,num,num,num)
        if (result = /rgba\(\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]+(?:\.[0-9]+)?)\s*\)/.exec(str))
            return new Color(parseInt(result[1], 10), parseInt(result[2], 10), parseInt(result[3], 10), parseFloat(result[4]));
            
        // Look for rgb(num%,num%,num%)
        if (result = /rgb\(\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*\)/.exec(str))
            return new Color(parseFloat(result[1])*2.55, parseFloat(result[2])*2.55, parseFloat(result[3])*2.55);

        // Look for rgba(num%,num%,num%,num)
        if (result = /rgba\(\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\s*\)/.exec(str))
            return new Color(parseFloat(result[1])*2.55, parseFloat(result[2])*2.55, parseFloat(result[3])*2.55, parseFloat(result[4]));
        
        // Look for #a0b1c2
        if (result = /#([a-fA-F0-9]{2})([a-fA-F0-9]{2})([a-fA-F0-9]{2})/.exec(str))
            return new Color(parseInt(result[1], 16), parseInt(result[2], 16), parseInt(result[3], 16));

        // Look for #fff
        if (result = /#([a-fA-F0-9])([a-fA-F0-9])([a-fA-F0-9])/.exec(str))
            return new Color(parseInt(result[1]+result[1], 16), parseInt(result[2]+result[2], 16), parseInt(result[3]+result[3], 16));

        // Otherwise, we're most likely dealing with a named color
        var name = $.trim(str).toLowerCase();
        if (name == "transparent")
            return new Color(255, 255, 255, 0);
        else {
            result = lookupColors[name];
            return new Color(result[0], result[1], result[2]);
        }
    }
        
})(jQuery);
