jquery.flot.orderBars.js

/*
 * Flot plugin to order bars side by side.
 *
 * Released under the MIT license by Benjamin BUFFET, 20-Sep-2010.
 * Modifications made by Steven Hall <github.com/emmerich>, 01-May-2013.
 *
 * This plugin is an alpha version.
 *
 * To activate the plugin you must specify the parameter "order" for the specific serie :
 *
 *  $.plot($("#placeholder"), [{ data: [ ... ], bars :{ order = null or integer }])
 *
 * If 2 series have the same order param, they are ordered by the position in the array;
 *
 * The plugin adjust the point by adding a value depanding of the barwidth
 * Exemple for 3 series (barwidth : 0.1) :
 *
 *          first bar décalage : -0.15
 *          second bar décalage : -0.05
 *          third bar décalage : 0.05
 *
 */

// INFO: decalage/decallage is French for gap. It's used to denote the spacing applied to each
// bar.
(function($){
    function init(plot){
        var orderedBarSeries;
        var nbOfBarsToOrder;
        var borderWidth;
        var borderWidthInXabsWidth;
        var pixelInXWidthEquivalent = 1;
        var isHorizontal = false;

        // A mapping of order integers to decallage.
        var decallageByOrder = {};

        /*
         * This method add shift to x values
         */
        function reOrderBars(plot, serie, datapoints){
            var shiftedPoints = null;

            if(serieNeedToBeReordered(serie)){
                checkIfGraphIsHorizontal(serie);
                calculPixel2XWidthConvert(plot);
                retrieveBarSeries(plot);
                calculBorderAndBarWidth(serie);

                if(nbOfBarsToOrder >= 2){
                    var position = findPosition(serie);
                    var decallage = 0;

                    var centerBarShift = calculCenterBarShift();

                    // If we haven't already calculated the decallage for this order value, do it.
                    if(typeof decallageByOrder[serie.bars.order] === 'undefined') {
                        if (isBarAtLeftOfCenter(position)){
                            decallageByOrder[serie.bars.order] = -1*(sumWidth(orderedBarSeries,position-1,Math.floor(nbOfBarsToOrder / 2)-1)) - centerBarShift;
                        }else{
                            decallageByOrder[serie.bars.order] = sumWidth(orderedBarSeries,Math.ceil(nbOfBarsToOrder / 2),position-2) + centerBarShift + borderWidthInXabsWidth*2;
                        }
                    }

                    // Lookup the decallage based on the series' order value.
                    decallage = decallageByOrder[serie.bars.order];

                    shiftedPoints = shiftPoints(datapoints,serie,decallage);
                    datapoints.points = shiftedPoints;
                }
            }
            return shiftedPoints;
        }

        function serieNeedToBeReordered(serie){
            return serie.bars != null
                && serie.bars.show
                && serie.bars.order != null;
        }

        function calculPixel2XWidthConvert(plot){
            var gridDimSize = isHorizontal ? plot.getPlaceholder().innerHeight() : plot.getPlaceholder().innerWidth();
            var minMaxValues = isHorizontal ? getAxeMinMaxValues(plot.getData(),1) : getAxeMinMaxValues(plot.getData(),0);
            var AxeSize = minMaxValues[1] - minMaxValues[0];
            pixelInXWidthEquivalent = AxeSize / gridDimSize;
        }

        function getAxeMinMaxValues(series,AxeIdx){
            var minMaxValues = new Array();
            for(var i = 0; i < series.length; i++){
                minMaxValues[0] = (series[i].data[0]) ? series[i].data[0][AxeIdx]: null;
                minMaxValues[1] = (series[i].data[series[i].data.length - 1]) ? series[i].data[series[i].data.length - 1][AxeIdx]: null;
            }
            return minMaxValues;
        }

        function retrieveBarSeries(plot){
            orderedBarSeries = findOthersBarsToReOrders(plot.getData());
            nbOfBarsToOrder = orderedBarSeries.length;
        }

        function findOthersBarsToReOrders(series){
            var retSeries = new Array();
            var orderValuesSeen = [];

            for(var i = 0; i < series.length; i++){
                if(series[i].bars.order != null && series[i].bars.show &&
                    orderValuesSeen.indexOf(series[i].bars.order) < 0){

                    orderValuesSeen.push(series[i].bars.order);
                    retSeries.push(series[i]);
                }
            }
            return retSeries.sort(sortByOrder);
        }

        function sortByOrder(serie1,serie2){
            var x = serie1.bars.order;
            var y = serie2.bars.order;
            return ((x < y) ? -1 : ((x > y) ? 1 : 0));
        }

        function  calculBorderAndBarWidth(serie){
            borderWidth = typeof serie.bars.lineWidth !== 'undefined' ? serie.bars.lineWidth  : 2;
            borderWidthInXabsWidth = borderWidth * pixelInXWidthEquivalent;
        }

        function checkIfGraphIsHorizontal(serie){
            if(serie.bars.horizontal){
                isHorizontal = true;
            }
        }

        function findPosition(serie){
            var pos = 0
            for (var i = 0; i < orderedBarSeries.length; ++i) {
                if (serie == orderedBarSeries[i]){
                    pos = i;
                    break;
                }
            }

            return pos+1;
        }

        function calculCenterBarShift(){
            var width = 0;

            if(nbOfBarsToOrder%2 != 0)
                width = (orderedBarSeries[Math.ceil(nbOfBarsToOrder / 2)].bars.barWidth)/2;

            return width;
        }

        function isBarAtLeftOfCenter(position){
            return position <= Math.ceil(nbOfBarsToOrder / 2);
        }

        function sumWidth(series,start,end){
            var totalWidth = 0;

            for(var i = start; i <= end; i++){
                totalWidth += series[i].bars.barWidth+borderWidthInXabsWidth*2;
            }

            return totalWidth;
        }

        function shiftPoints(datapoints,serie,dx){
            var ps = datapoints.pointsize;
            var points = datapoints.points;
            var j = 0;
            for(var i = isHorizontal ? 1 : 0;i < points.length; i += ps){
                points[i] += dx;
                //Adding the new x value in the serie to be abble to display the right tooltip value,
                //using the index 3 to not overide the third index.
                serie.data[j][3] = points[i];
                j++;
            }

            return points;
        }

        plot.hooks.processDatapoints.push(reOrderBars);

    }

    var options = {
        series : {
            bars: {order: null} // or number/string
        }
    };

    $.plot.plugins.push({
        init: init,
        options: options,
        name: "orderBars",
        version: "0.2"
    });

})(jQuery);