graph_interact.js

/**
* Copyright 2012-2015, Plotly, Inc.
* All rights reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/


'use strict';

var Plotly = require('../../plotly');
var d3 = require('d3');
var tinycolor = require('tinycolor2');
var isNumeric = require('fast-isnumeric');
var Events = require('../../lib/events');
var prepSelect = require('./select');

var fx = module.exports = {};

fx.layoutAttributes = {
    dragmode: {
        valType: 'enumerated',
        role: 'info',
        values: ['zoom', 'pan', 'select', 'lasso', 'orbit', 'turntable'],
        description: 'Determines the mode of drag interactions.'
    },
    hovermode: {
        valType: 'enumerated',
        role: 'info',
        values: ['x', 'y', 'closest', false],
        description: 'Determines the mode of hover interactions.'
    }
};

fx.supplyLayoutDefaults = function(layoutIn, layoutOut, fullData) {
    var isHoriz, hovermodeDflt;

    function coerce(attr, dflt) {
        return Plotly.Lib.coerce(layoutIn, layoutOut,
                                 fx.layoutAttributes,
                                 attr, dflt);
    }

    coerce('dragmode', layoutOut._hasGL3D ? 'turntable' : 'zoom');

    if(layoutOut._hasCartesian) {
        // flag for 'horizontal' plots:
        // determines the state of the mode bar 'compare' hovermode button
        isHoriz = layoutOut._isHoriz = fx.isHoriz(fullData);
        hovermodeDflt = isHoriz ? 'y' : 'x';
    }
    else hovermodeDflt = 'closest';

    coerce('hovermode', hovermodeDflt);
};

fx.isHoriz = function(fullData) {
    var isHoriz = true;
    var i, trace;
    for (i = 0; i < fullData.length; i++) {
        trace = fullData[i];
        if (trace.orientation !== 'h') {
            isHoriz = false;
            break;
        }
    }
    return isHoriz;
};

// ms between first mousedown and 2nd mouseup to constitute dblclick...
// we don't seem to have access to the system setting
fx.DBLCLICKDELAY = 600;

// pixels to move mouse before you stop clamping to starting point
fx.MINDRAG = 8;

// smallest dimension allowed for a zoombox
fx.MINZOOM = 20;

// width of axis drag regions
var DRAGGERSIZE = 20;

fx.init = function(gd) {
    var fullLayout = gd._fullLayout;

    if(fullLayout._hasGL3D || fullLayout._hasGeo || gd._context.staticPlot) return;

    var subplots = Object.keys(fullLayout._plots || {}).sort(function(a,b) {
        // sort overlays last, then by x axis number, then y axis number
        if( (fullLayout._plots[a].mainplot && true) ===
                (fullLayout._plots[b].mainplot && true) ) {
            var aParts = a.split('y'),
                bParts = b.split('y');
            return (aParts[0]===bParts[0]) ?
                (Number(aParts[1]||1) - Number(bParts[1]||1)) :
                (Number(aParts[0]||1) - Number(bParts[0]||1));
        }
        return fullLayout._plots[a].mainplot ? 1 : -1;
    });

    subplots.forEach(function(subplot) {
        var plotinfo = fullLayout._plots[subplot];

        if(!fullLayout._hasCartesian) return;

        var xa = plotinfo.x(),
            ya = plotinfo.y(),

            // the y position of the main x axis line
            y0 = (xa._linepositions[subplot]||[])[3],

            // the x position of the main y axis line
            x0 = (ya._linepositions[subplot]||[])[3];

        if(isNumeric(y0) && xa.side==='top') y0 -= DRAGGERSIZE;
        if(isNumeric(x0) && ya.side!=='right') x0 -= DRAGGERSIZE;

        // main and corner draggers need not be repeated for
        // overlaid subplots - these draggers drag them all
        if(!plotinfo.mainplot) {
            // main dragger goes over the grids and data, so we use its
            // mousemove events for all data hover effects
            var maindrag = dragBox(gd, plotinfo, 0, 0,
                xa._length, ya._length,'ns','ew');

            maindrag.onmousemove = function(evt) {
                fx.hover(gd, evt, subplot);
                fullLayout._lasthover = maindrag;
                fullLayout._hoversubplot = subplot;
            };

            /*
             * IMPORTANT:
             * We must check for the presence of the drag cover here.
             * If we don't, a 'mouseout' event is triggered on the
             * maindrag before each 'click' event, which has the effect
             * of clearing the hoverdata; thus, cancelling the click event.
             */
            maindrag.onmouseout = function(evt) {
                if(gd._dragging) return;

                fx.unhover(gd, evt);
            };

            maindrag.onclick = function(evt) {
                fx.click(gd, evt);
            };

            // corner draggers
            dragBox(gd, plotinfo, -DRAGGERSIZE, -DRAGGERSIZE,
                DRAGGERSIZE, DRAGGERSIZE, 'n', 'w');
            dragBox(gd, plotinfo, xa._length,   -DRAGGERSIZE,
                DRAGGERSIZE, DRAGGERSIZE, 'n', 'e');
            dragBox(gd, plotinfo, -DRAGGERSIZE, ya._length,
                DRAGGERSIZE, DRAGGERSIZE, 's', 'w');
            dragBox(gd, plotinfo, xa._length,   ya._length,
                DRAGGERSIZE, DRAGGERSIZE, 's', 'e');
        }

        // x axis draggers - if you have overlaid plots,
        // these drag each axis separately
        if(isNumeric(y0)) {
            if(xa.anchor==='free') y0 -= fullLayout._size.h*(1-ya.domain[1]);
            dragBox(gd, plotinfo, xa._length*0.1, y0,
                xa._length*0.8, DRAGGERSIZE, '', 'ew');
            dragBox(gd, plotinfo, 0, y0,
                xa._length*0.1, DRAGGERSIZE, '', 'w');
            dragBox(gd, plotinfo, xa._length*0.9, y0,
                xa._length*0.1, DRAGGERSIZE, '', 'e');
        }
        // y axis draggers
        if(isNumeric(x0)) {
            if(ya.anchor==='free') x0 -= fullLayout._size.w*xa.domain[0];
            dragBox(gd, plotinfo, x0, ya._length*0.1,
                DRAGGERSIZE, ya._length*0.8, 'ns', '');
            dragBox(gd, plotinfo, x0, ya._length*0.9,
                DRAGGERSIZE, ya._length*0.1, 's', '');
            dragBox(gd, plotinfo, x0, 0,
                DRAGGERSIZE, ya._length*0.1, 'n', '');
        }
    });

    // In case you mousemove over some hovertext, send it to fx.hover too
    // we do this so that we can put the hover text in front of everything,
    // but still be able to interact with everything as if it isn't there
    var hoverLayer = fullLayout._hoverlayer.node();

    hoverLayer.onmousemove = function(evt) {
        evt.target = fullLayout._lasthover;
        fx.hover(gd, evt, fullLayout._hoversubplot);
    };

    hoverLayer.onclick = function(evt) {
        evt.target = fullLayout._lasthover;
        fx.click(gd, evt);
    };

    // also delegate mousedowns... TODO: does this actually work?
    hoverLayer.onmousedown = function(evt) {
        fullLayout._lasthover.onmousedown(evt);
    };
};

// hover labels for multiple horizontal bars get tilted by some angle,
// then need to be offset differently if they overlap
var YANGLE = 60,
    YA_RADIANS = Math.PI*YANGLE/180,

    // expansion of projected height
    YFACTOR = 1/Math.sin(YA_RADIANS),

    // to make the appropriate post-rotation x offset,
    // you need both x and y offsets
    YSHIFTX = Math.cos(YA_RADIANS),
    YSHIFTY = Math.sin(YA_RADIANS);

// convenience functions for mapping all relevant axes
function flat(subplots, v) {
    var out = [];
    for(var i=subplots.length; i>0; i--) out.push(v);
    return out;
}

function p2c(axArray, v) {
    var out = [];
    for(var i=0; i<axArray.length; i++) out.push(axArray[i].p2c(v));
    return out;
}

function quadrature(dx, dy) {
    return function(di){
        var x = dx(di),
            y = dy(di);
        return Math.sqrt(x*x + y*y);
    };
}

// size and display constants for hover text
var HOVERARROWSIZE = 6, // pixel size of hover arrows
    HOVERTEXTPAD = 3, // pixels padding around text
    HOVERFONTSIZE = 13,
    HOVERFONT = 'Arial, sans-serif';

// max pixels away from mouse to allow a point to highlight
fx.MAXDIST = 20;

// fx.hover: highlight data on hover
// evt can be a mousemove event, or an object with data about what points
//   to hover on
//      {xpx,ypx[,hovermode]} - pixel locations from top left
//          (with optional overriding hovermode)
//      {xval,yval[,hovermode]} - data values
//      [{curveNumber,(pointNumber|xval and/or yval)}] -
//              array of specific points to highlight
//          pointNumber is a single integer if gd.data[curveNumber] is 1D,
//              or a two-element array if it's 2D
//          xval and yval are data values,
//              1D data may specify either or both,
//              2D data must specify both
// subplot is an id string (default "xy")
// makes use of gl.hovermode, which can be:
//      x (find the points with the closest x values, ie a column),
//      closest (find the single closest point)
//    internally there are two more that occasionally get used:
//      y (pick out a row - only used for multiple horizontal bar charts)
//      array (used when the user specifies an explicit
//          array of points to hover on)
//
// We wrap the hovers in a timer, to limit their frequency.
// The actual rendering is done by private functions
// hover() and unhover().

var HOVERMINTIME = 100; // minimum time between hover calls

fx.hover = function (gd, evt, subplot) {
    if(typeof gd === 'string') gd = document.getElementById(gd);
    if(gd._lastHoverTime === undefined) gd._lastHoverTime = 0;

    // If we have an update queued, discard it now
    if (gd._hoverTimer !== undefined) {
        clearTimeout(gd._hoverTimer);
        gd._hoverTimer = undefined;
    }
    // Is it more than 100ms since the last update?  If so, force
    // an update now (synchronously) and exit
    if (Date.now() > gd._lastHoverTime + HOVERMINTIME) {
        hover(gd,evt,subplot);
        gd._lastHoverTime = Date.now();
        return;
    }
    // Queue up the next hover for 100ms from now (if no further events)
    gd._hoverTimer = setTimeout(function () {
        hover(gd,evt,subplot);
        gd._lastHoverTime = Date.now();
        gd._hoverTimer = undefined;
    }, HOVERMINTIME);
};

fx.unhover = function (gd, evt, subplot) {
    if(typeof gd === 'string') gd = document.getElementById(gd);
    // Important, clear any queued hovers
    if (gd._hoverTimer) {
        clearTimeout(gd._hoverTimer);
        gd._hoverTimer = undefined;
    }
    unhover(gd,evt,subplot);
};

// The actual implementation is here:

function hover(gd, evt, subplot){
    if(!subplot) subplot = 'xy';

    var fullLayout = gd._fullLayout,
        plotinfo = fullLayout._plots[subplot],
        // list of all overlaid subplots to look at
        subplots = [subplot].concat(plotinfo.overlays
            .map(function(pi){ return pi.id; })),
        xaArray = subplots.map(function(spId) {
            return Plotly.Axes.getFromId(gd, spId, 'x');
        }),
        yaArray = subplots.map(function(spId) {
            return Plotly.Axes.getFromId(gd, spId, 'y');
        }),
        hovermode = evt.hovermode || fullLayout.hovermode;

    if(['x','y','closest'].indexOf(hovermode)===-1 || !gd.calcdata ||
            gd.querySelector('.zoombox') || gd._dragging) {
        return unhover(gd, evt);
    }

        // hoverData: the set of candidate points we've found to highlight
    var hoverData = [],

        // searchData: the data to search in. Mostly this is just a copy of
        // gd.calcdata, filtered to the subplot and overlays we're on
        // but if a point array is supplied it will be a mapping
        // of indicated curves
        searchData = [],

        // [x|y]valArray: the axis values of the hover event
        // mapped onto each of the currently selected overlaid subplots
        xvalArray,
        yvalArray,

        // used in loops
        itemnum,
        curvenum,
        cd,
        trace,
        subploti,
        mode,
        xval,
        yval,
        pointData,
        closedataPreviousLength;

    // Figure out what we're hovering on:
    // mouse location or user-supplied data

    if(Array.isArray(evt)){
        // user specified an array of points to highlight
        hovermode = 'array';
        for(itemnum = 0; itemnum<evt.length; itemnum++) {
            cd = gd.calcdata[evt[itemnum].curveNumber||0];
            if(cd[0].trace.hoverinfo!=='none') searchData.push(cd);
        }
    }
    else {
        for(curvenum = 0; curvenum<gd.calcdata.length; curvenum++) {
            cd = gd.calcdata[curvenum];
            trace = cd[0].trace;
            if(trace.hoverinfo!=='none' && subplots.indexOf(trace.xaxis + trace.yaxis)!==-1) {
                searchData.push(cd);
            }
        }

        // [x|y]px: the pixels (from top left) of the mouse location
        // on the currently selected plot area
        var xpx, ypx;

        // mouse event? ie is there a target element with
        // clientX and clientY values?
        if(evt.target && ('clientX' in evt) && ('clientY' in evt)) {

            // fire the beforehover event and quit if it returns false
            // note that we're only calling this on real mouse events, so
            // manual calls to fx.hover will always run.
            if(Events.triggerHandler(gd, 'plotly_beforehover', evt)===false) {
                return;
            }

            var dbb = evt.target.getBoundingClientRect();

            xpx = evt.clientX - dbb.left;
            ypx = evt.clientY - dbb.top;

            // in case hover was called from mouseout into hovertext,
            // it's possible you're not actually over the plot anymore
            if(xpx<0 || xpx>dbb.width || ypx<0 || ypx>dbb.height) {
                return unhover(gd,evt);
            }
        }
        else {
            if('xpx' in evt) xpx = evt.xpx;
            else xpx = xaArray[0]._length/2;

            if('ypx' in evt) ypx = evt.ypx;
            else ypx = yaArray[0]._length/2;
        }

        if('xval' in evt) xvalArray = flat(subplots, evt.xval);
        else xvalArray = p2c(xaArray, xpx);

        if('yval' in evt) yvalArray = flat(subplots, evt.yval);
        else yvalArray = p2c(yaArray, ypx);

        if(!isNumeric(xvalArray[0]) || !isNumeric(yvalArray[0])) {
            console.log('Plotly.Fx.hover failed', evt, gd);
            return unhover(gd, evt);
        }
    }

    // the pixel distance to beat as a matching point
    // in 'x' or 'y' mode this resets for each trace
    var distance = Infinity;

    // find the closest point in each trace
    // this is minimum dx and/or dy, depending on mode
    // and the pixel position for the label (labelXpx, labelYpx)
    for(curvenum = 0; curvenum<searchData.length; curvenum++) {
        cd = searchData[curvenum];

        // filter out invisible or broken data
        if(!cd || !cd[0] || !cd[0].trace || cd[0].trace.visible !== true) continue;

        trace = cd[0].trace;
        subploti = subplots.indexOf(trace.xaxis + trace.yaxis);

        // within one trace mode can sometimes be overridden
        mode = hovermode;

        // container for new point, also used to pass info into module.hoverPoints
        pointData = {
            // trace properties
            cd: cd,
            trace: trace,
            xa: xaArray[subploti],
            ya: yaArray[subploti],
            name: (gd.data.length>1 || trace.hoverinfo.indexOf('name')!==-1) ? trace.name : undefined,
            // point properties - override all of these
            index: false, // point index in trace - only used by plotly.js hoverdata consumers
            distance: Math.min(distance, fx.MAXDIST), // pixel distance or pseudo-distance
            color: Plotly.Color.defaultLine, // trace color
            x0: undefined,
            x1: undefined,
            y0: undefined,
            y1: undefined,
            xLabelVal: undefined,
            yLabelVal: undefined,
            zLabelVal: undefined,
            text: undefined
        };

        closedataPreviousLength = hoverData.length;

        // for a highlighting array, figure out what
        // we're searching for with this element
        if(mode==='array') {
            var selection = evt[curvenum];
            if('pointNumber' in selection) {
                pointData.index = selection.pointNumber;
                mode = 'closest';
            }
            else {
                mode = '';
                if('xval' in selection) {
                    xval = selection.xval;
                    mode = 'x';
                }
                if('yval' in selection) {
                    yval = selection.yval;
                    mode = mode ? 'closest' : 'y';
                }
            }
        }
        else {
            xval = xvalArray[subploti];
            yval = yvalArray[subploti];
        }

        // Now find the points.
        if(trace._module && trace._module.hoverPoints) {
            var newPoints = trace._module.hoverPoints(pointData, xval, yval, mode);
            if(newPoints) {
                var newPoint;
                for(var newPointNum=0; newPointNum<newPoints.length; newPointNum++) {
                    newPoint = newPoints[newPointNum];
                    if(isNumeric(newPoint.x0) && isNumeric(newPoint.y0)) {
                        hoverData.push(cleanPoint(newPoint, hovermode));
                    }
                }
            }
        }
        else {
            console.log('unrecognized trace type in hover', trace);
        }

        // in closest mode, remove any existing (farther) points
        // and don't look any farther than this latest point (or points, if boxes)
        if(hovermode==='closest' && hoverData.length > closedataPreviousLength) {
            hoverData.splice(0, closedataPreviousLength);
            distance = hoverData[0].distance;
        }

    }

    // nothing left: remove all labels and quit
    if(hoverData.length===0) return unhover(gd,evt);

    // if there's more than one horz bar trace,
    // rotate the labels so they don't overlap
    var rotateLabels = hovermode==='y' && searchData.length>1;

    hoverData.sort(function(d1, d2) { return d1.distance - d2.distance; });

    var labelOpts = {
        hovermode: hovermode,
        rotateLabels: rotateLabels,
        bgColor: Plotly.Color.combine(fullLayout.plot_bgcolor, fullLayout.paper_bgcolor),
        container: fullLayout._hoverlayer,
        outerContainer: fullLayout._paperdiv
    };
    var hoverLabels = createHoverText(hoverData, labelOpts);

    hoverAvoidOverlaps(hoverData, rotateLabels ? xaArray[0] : yaArray[0]);

    alignHoverText(hoverLabels, rotateLabels);

    // lastly, emit custom hover/unhover events
    var oldhoverdata = gd._hoverdata,
        newhoverdata = [];

    // pull out just the data that's useful to
    // other people and send it to the event
    for(itemnum = 0; itemnum<hoverData.length; itemnum++) {
        var pt = hoverData[itemnum];
        var out = {
            data: pt.trace._input,
            fullData: pt.trace,
            curveNumber: pt.trace.index,
            pointNumber: pt.index,
            x: pt.xVal,
            y: pt.yVal,
            xaxis: pt.xa,
            yaxis: pt.ya
        };
        if(pt.zLabelVal!==undefined) out.z = pt.zLabelVal;
        newhoverdata.push(out);
    }
    gd._hoverdata = newhoverdata;

    if(!hoverChanged(gd, evt, oldhoverdata)) return;

    /* Emit the custom hover handler. Bind this like:
     *  gd.on('hover.plotly', function(extras) {
     *      // do something with extras.data
     *  });
     */
    if(oldhoverdata) {
        gd.emit('plotly_unhover', { points: oldhoverdata });
    }
    gd.emit('plotly_hover', {
        points: gd._hoverdata,
        xaxes: xaArray,
        yaxes: yaArray,
        xvals: xvalArray,
        yvals: yvalArray
    });
}

fx.getDistanceFunction = function(mode, dx, dy, dxy) {
    if(mode==='closest') return dxy || quadrature(dx, dy);
    return mode==='x' ? dx : dy;
};

fx.getClosest = function(cd, distfn, pointData) {
    // do we already have a point number? (array mode only)
    if(pointData.index!==false) {
        if(pointData.index>=0 && pointData.index<cd.length) {
            pointData.distance = 0;
        }
        else pointData.index = false;
    }
    else {
        // apply the distance function to each data point
        // this is the longest loop... if this bogs down, we may need
        // to create pre-sorted data (by x or y), not sure how to
        // do this for 'closest'
        for(var i=0; i<cd.length; i++) {
            var newDistance = distfn(cd[i]);
            if(newDistance < pointData.distance) {
                pointData.index = i;
                pointData.distance = newDistance;
            }
        }
    }
    return pointData;
};

function cleanPoint(d, hovermode) {
    d.posref = hovermode==='y' ? (d.x0+d.x1)/2 : (d.y0+d.y1)/2;

    // then constrain all the positions to be on the plot
    d.x0 = Plotly.Lib.constrain(d.x0, 0, d.xa._length);
    d.x1 = Plotly.Lib.constrain(d.x1, 0, d.xa._length);
    d.y0 = Plotly.Lib.constrain(d.y0, 0, d.ya._length);
    d.y1 = Plotly.Lib.constrain(d.y1, 0, d.ya._length);

    // and convert the x and y label values into objects
    // formatted as text, with font info
    var logOffScale;
    if(d.xLabelVal!==undefined) {
        logOffScale = (d.xa.type==='log' && d.xLabelVal<=0);
        var xLabelObj = Plotly.Axes.tickText(d.xa,
                d.xa.c2l(logOffScale ? -d.xLabelVal : d.xLabelVal), 'hover');
        if(logOffScale) {
            if(d.xLabelVal===0) d.xLabel = '0';
            else d.xLabel = '-' + xLabelObj.text;
        }
        else d.xLabel = xLabelObj.text;
        d.xVal = d.xa.c2d(d.xLabelVal);
    }

    if(d.yLabelVal!==undefined) {
        logOffScale = (d.ya.type==='log' && d.yLabelVal<=0);
        var yLabelObj = Plotly.Axes.tickText(d.ya,
                d.ya.c2l(logOffScale ? -d.yLabelVal : d.yLabelVal), 'hover');
        if(logOffScale) {
            if(d.yLabelVal===0) d.yLabel = '0';
            else d.yLabel = '-' + yLabelObj.text;
        }
        else d.yLabel = yLabelObj.text;
        d.yVal = d.ya.c2d(d.yLabelVal);
    }

    if(d.zLabelVal!==undefined) d.zLabel = String(d.zLabelVal);

    // for box means and error bars, add the range to the label
    if(d.xerr!==undefined) {
        var xeText = Plotly.Axes.tickText(d.xa, d.xa.c2l(d.xerr), 'hover').text;
        if(d.xerrneg!==undefined) {
            d.xLabel += ' +' + xeText + ' / -' +
                Plotly.Axes.tickText(d.xa, d.xa.c2l(d.xerrneg), 'hover').text;
        }
        else d.xLabel += ' &plusmn; ' + xeText;

        // small distance penalty for error bars, so that if there are
        // traces with errors and some without, the error bar label will
        // hoist up to the point
        if(hovermode==='x') d.distance += 1;
    }
    if(d.yerr!==undefined) {
        var yeText = Plotly.Axes.tickText(d.ya, d.ya.c2l(d.yerr), 'hover').text;
        if(d.yerrneg!==undefined) {
            d.yLabel += ' +' + yeText + ' / -' +
                Plotly.Axes.tickText(d.ya, d.ya.c2l(d.yerrneg), 'hover').text;
        }
        else d.yLabel += ' &plusmn; ' + yeText;

        if(hovermode==='y') d.distance += 1;
    }

    var infomode = d.trace.hoverinfo;
    if(infomode!=='all') {
        infomode = infomode.split('+');
        if(infomode.indexOf('x')===-1) d.xLabel = undefined;
        if(infomode.indexOf('y')===-1) d.yLabel = undefined;
        if(infomode.indexOf('z')===-1) d.zLabel = undefined;
        if(infomode.indexOf('text')===-1) d.text = undefined;
        if(infomode.indexOf('name')===-1) d.name = undefined;
    }
    return d;
}

fx.loneHover = function(hoverItem, opts) {
    // draw a single hover item in a pre-existing svg container somewhere
    // hoverItem should have keys:
    //    - x and y (or x0, x1, y0, and y1):
    //      the pixel position to mark, relative to opts.container
    //    - xLabel, yLabel, zLabel, text, and name:
    //      info to go in the label
    //    - color:
    //      the background color for the label. text & outline color will
    //      be chosen black or white to contrast with this
    // opts should have keys:
    //    - bgColor:
    //      the background color this is against, used if the trace is
    //      non-opaque, and for the name, which goes outside the box
    //    - container:
    //      a dom <svg> element - must be big enough to contain the whole
    //      hover label
    var pointData = {
        color: hoverItem.color || Plotly.Color.defaultLine,
        x0: hoverItem.x0 || hoverItem.x || 0,
        x1: hoverItem.x1 || hoverItem.x || 0,
        y0: hoverItem.y0 || hoverItem.y || 0,
        y1: hoverItem.y1 || hoverItem.y || 0,
        xLabel: hoverItem.xLabel,
        yLabel: hoverItem.yLabel,
        zLabel: hoverItem.zLabel,
        text: hoverItem.text,
        name: hoverItem.name,
        idealAlign: hoverItem.idealAlign,

        // filler to make createHoverText happy
        trace: {
          index: 0,
          hoverinfo: ''
        },
        xa: {_offset:0},
        ya: {_offset:0},
        index: 0
    };

    var container3 = d3.select(opts.container),
        outerContainer3 = opts.outerContainer ?
            d3.select(opts.outerContainer) : container3;

    var fullOpts = {
        hovermode: 'closest',
        rotateLabels: false,
        bgColor: opts.bgColor || Plotly.Color.background,
        container: container3,
        outerContainer: outerContainer3
    };

    var hoverLabel = createHoverText([pointData], fullOpts);
    alignHoverText(hoverLabel, fullOpts.rotateLabels);

    return hoverLabel.node();
};

fx.loneUnhover = function(containerOrSelection) {
    var selection = containerOrSelection instanceof d3.selection ?
            containerOrSelection :
            d3.select(containerOrSelection);

    selection.selectAll('g.hovertext').remove();
};

function createHoverText(hoverData, opts) {
    var hovermode = opts.hovermode,
        rotateLabels = opts.rotateLabels,
        bgColor = opts.bgColor,
        container = opts.container,
        outerContainer = opts.outerContainer,

        c0 = hoverData[0],
        xa = c0.xa,
        ya = c0.ya,
        commonAttr = hovermode==='y' ? 'yLabel' : 'xLabel',
        t0 = c0[commonAttr],
        t00 = (String(t0)||'').split(' ')[0],
        outerContainerBB = outerContainer.node().getBoundingClientRect(),
        outerTop = outerContainerBB.top,
        outerWidth = outerContainerBB.width,
        outerHeight = outerContainerBB.height;

    // show the common label, if any, on the axis
    // never show a common label in array mode,
    // even if sometimes there could be one
    var showCommonLabel = c0.distance<=fx.MAXDIST &&
                          (hovermode==='x' || hovermode==='y');

    // all hover traces hoverinfo must contain the hovermode
    // to have common labels
    var i, traceHoverinfo;
    for (i = 0; i < hoverData.length; i++) {
        traceHoverinfo = hoverData[i].trace.hoverinfo;
        var parts = traceHoverinfo.split('+');
        if (parts.indexOf('all') === -1 &&
            parts.indexOf(hovermode) === -1) {
            showCommonLabel = false;
            break;
        }
    }

    var commonLabel = container.selectAll('g.axistext')
        .data(showCommonLabel ? [0] : []);
    commonLabel.enter().append('g')
        .classed('axistext', true);
    commonLabel.exit().remove();

    commonLabel.each(function() {
        var label = d3.select(this),
            lpath = label.selectAll('path').data([0]),
            ltext = label.selectAll('text').data([0]);

        lpath.enter().append('path')
            .style({fill: Plotly.Color.defaultLine, 'stroke-width': '1px', stroke: Plotly.Color.background});
        ltext.enter().append('text')
            .call(Plotly.Drawing.font, HOVERFONT, HOVERFONTSIZE, Plotly.Color.background)
            // prohibit tex interpretation until we can handle
            // tex and regular text together
            .attr('data-notex',1);

        ltext.text(t0)
            .call(Plotly.util.convertToTspans)
            .call(Plotly.Drawing.setPosition, 0, 0)
          .selectAll('tspan.line')
            .call(Plotly.Drawing.setPosition, 0, 0);
        label.attr('transform','');

        var tbb = ltext.node().getBoundingClientRect();
        if(hovermode==='x'){
            ltext.attr('text-anchor','middle')
                .call(Plotly.Drawing.setPosition,0,(xa.side==='top' ?
                    (outerTop-tbb.bottom-HOVERARROWSIZE-HOVERTEXTPAD) :
                    (outerTop-tbb.top+HOVERARROWSIZE+HOVERTEXTPAD)))
                .selectAll('tspan.line')
                    .attr({x:ltext.attr('x'), y:ltext.attr('y')});

            var topsign = xa.side==='top' ? '-' : '';
            lpath.attr('d','M0,0'+
                'L'+HOVERARROWSIZE+','+topsign+HOVERARROWSIZE+
                'H'+(HOVERTEXTPAD+tbb.width/2)+
                'v'+topsign+(HOVERTEXTPAD*2+tbb.height)+
                'H-'+(HOVERTEXTPAD+tbb.width/2)+
                'V'+topsign+HOVERARROWSIZE+'H-'+HOVERARROWSIZE+'Z');

            label.attr('transform','translate(' +
                (xa._offset+(c0.x0+c0.x1)/2)+',' +
                (ya._offset + (xa.side==='top' ? 0 : ya._length))+')');
        }
        else {
            ltext.attr('text-anchor',ya.side==='right' ? 'start' : 'end')
                .call(Plotly.Drawing.setPosition,
                    (ya.side==='right' ? 1 : -1)*(HOVERTEXTPAD+HOVERARROWSIZE),
                    outerTop-tbb.top-tbb.height/2)
                .selectAll('tspan.line')
                    .attr({x:ltext.attr('x'), y:ltext.attr('y')});

            var leftsign = ya.side==='right' ? '' : '-';
            lpath.attr('d','M0,0'+
                'L'+leftsign+HOVERARROWSIZE+','+HOVERARROWSIZE+
                'V'+(HOVERTEXTPAD+tbb.height/2)+
                'h'+leftsign+(HOVERTEXTPAD*2+tbb.width)+
                'V-'+(HOVERTEXTPAD+tbb.height/2)+
                'H'+leftsign+HOVERARROWSIZE+'V-'+HOVERARROWSIZE+'Z');

            label.attr('transform','translate(' +
                (xa._offset+(ya.side==='right' ? xa._length : 0))+',' +
                (ya._offset+(c0.y0+c0.y1)/2)+')');
        }
        // remove the "close but not quite" points
        // because of error bars, only take up to a space
        hoverData = hoverData.filter(function(d){
            return (d.zLabelVal!==undefined) ||
                (d[commonAttr]||'').split(' ')[0]===t00;
        });
    });

    // show all the individual labels

    // first create the objects
    var hoverLabels = container.selectAll('g.hovertext')
        .data(hoverData,function(d){
            return [d.trace.index,d.index,d.x0,d.y0,d.name,d.attr||''].join(',');
        });
    hoverLabels.enter().append('g')
        .classed('hovertext',true)
        .each(function() {
            var g = d3.select(this);
            // trace name label (rect and text.name)
            g.append('rect')
                .call(Plotly.Color.fill,
                    Plotly.Color.addOpacity(bgColor, 0.8));
            g.append('text').classed('name',true)
                .call(Plotly.Drawing.font,HOVERFONT,HOVERFONTSIZE);
            // trace data label (path and text.nums)
            g.append('path')
                .style('stroke-width','1px');
            g.append('text').classed('nums',true)
                .call(Plotly.Drawing.font,HOVERFONT,HOVERFONTSIZE);
        });
    hoverLabels.exit().remove();

    // then put the text in, position the pointer to the data,
    // and figure out sizes
    hoverLabels.each(function(d){
        var g = d3.select(this).attr('transform', ''),
            name = '',
            text = '',
            // combine possible non-opaque trace color with bgColor
            baseColor = Plotly.Color.opacity(d.color) ?
                d.color : Plotly.Color.defaultLine,
            traceColor = Plotly.Color.combine(baseColor, bgColor),

            // find a contrasting color for border and text
            contrastColor = tinycolor(traceColor).getBrightness()>128 ?
                '#000' : Plotly.Color.background;


        if(d.name && d.zLabelVal===undefined) {
            // strip out any html elements from d.name (if it exists at all)
            // Note that this isn't an XSS vector, only because it never gets
            // attached to the DOM
            var tmp = document.createElement('p');
            tmp.innerHTML = d.name;
            name = tmp.textContent||'';

            if(name.length>15) name = name.substr(0,12)+'...';
        }

        if(d.zLabel!==undefined) {
            if(d.xLabel!==undefined) text += 'x: ' + d.xLabel + '<br>';
            if(d.yLabel!==undefined) text += 'y: ' + d.yLabel + '<br>';
            text += (text ? 'z: ' : '') + d.zLabel;
        }
        else if(showCommonLabel && d[hovermode+'Label']===t0) {
            text = d[(hovermode==='x' ? 'y' : 'x') + 'Label'] || '';
        }
        else if(d.xLabel===undefined) {
            if(d.yLabel!==undefined) text = d.yLabel;
        }
        else if(d.yLabel===undefined) text = d.xLabel;
        else text = '('+d.xLabel+', '+d.yLabel+')';

        if(d.text) text += (text ? '<br>' : '') + d.text;

        // if 'text' is empty at this point,
        // put 'name' in main label and don't show secondary label
        if (text === '') {
            // if 'name' is also empty, remove entire label
            if (name === '') g.remove();
            text = name;
        }

        // main label
        var tx = g.select('text.nums')
            .style('fill',contrastColor)
            .call(Plotly.Drawing.setPosition,0,0)
            .text(text)
            .attr('data-notex',1)
            .call(Plotly.util.convertToTspans);
        tx.selectAll('tspan.line')
            .call(Plotly.Drawing.setPosition,0,0);

        var tx2 = g.select('text.name'),
            tx2width = 0;

        // secondary label for non-empty 'name'
        if (name && name!==text) {
            tx2.style('fill',traceColor)
                .text(name)
                .call(Plotly.Drawing.setPosition,0,0)
                .attr('data-notex',1)
                .call(Plotly.util.convertToTspans);
            tx2.selectAll('tspan.line')
                .call(Plotly.Drawing.setPosition,0,0);
            tx2width = tx2.node().getBoundingClientRect().width+2*HOVERTEXTPAD;
        }
        else {
            tx2.remove();
            g.select('rect').remove();
        }

        g.select('path')
            .style({fill:traceColor, stroke:contrastColor});
        var tbb = tx.node().getBoundingClientRect(),
            htx = xa._offset+(d.x0+d.x1)/2,
            hty = ya._offset+(d.y0+d.y1)/2,
            dx = Math.abs(d.x1-d.x0),
            dy = Math.abs(d.y1-d.y0),
            txTotalWidth = tbb.width+HOVERARROWSIZE+HOVERTEXTPAD+tx2width,
            anchorStartOK,
            anchorEndOK;

        d.ty0 = outerTop-tbb.top;
        d.bx = tbb.width+2*HOVERTEXTPAD;
        d.by = tbb.height+2*HOVERTEXTPAD;
        d.anchor = 'start';
        d.txwidth = tbb.width;
        d.tx2width = tx2width;
        d.offset = 0;

        if(rotateLabels) {
            d.pos = htx;
            anchorStartOK = hty + dy / 2 + txTotalWidth <= outerHeight;
            anchorEndOK = hty - dy / 2 - txTotalWidth >= 0;
            if((d.idealAlign === 'top' || !anchorStartOK) && anchorEndOK) {
                hty -= dy / 2;
                d.anchor = 'end';
            } else if(anchorStartOK) {
                hty += dy / 2;
                d.anchor = 'start';
            } else d.anchor = 'middle';
        }
        else {
            d.pos = hty;
            anchorStartOK = htx + dx / 2 + txTotalWidth <= outerWidth;
            anchorEndOK = htx - dx / 2 - txTotalWidth >= 0;
            if((d.idealAlign === 'left' || !anchorStartOK) && anchorEndOK) {
                htx -= dx / 2;
                d.anchor = 'end';
            } else if(anchorStartOK) {
                htx += dx / 2;
                d.anchor = 'start';
            } else d.anchor = 'middle';
        }

        tx.attr('text-anchor',d.anchor);
        if(tx2width) tx2.attr('text-anchor',d.anchor);
        g.attr('transform','translate('+htx+','+hty+')'+
            (rotateLabels ? 'rotate('+YANGLE+')' : ''));
    });

    return hoverLabels;
}

// Make groups of touching points, and within each group
// move each point so that no labels overlap, but the average
// label position is the same as it was before moving. Indicentally,
// this is equivalent to saying all the labels are on equal linear
// springs about their initial position. Initially, each point is
// its own group, but as we find overlaps we will clump the points.
//
// Also, there are hard constraints at the edges of the graphs,
// that push all groups to the middle so they are visible. I don't
// know what happens if the group spans all the way from one edge to
// the other, though it hardly matters - there's just too much
// information then.
function hoverAvoidOverlaps(hoverData, ax) {
    var nummoves = 0,
        pmin = ax._offset,
        pmax = ax._offset+ax._length,

        // make groups of touching points
        pointgroups = hoverData
            .map(function(d,i){
                return [{
                    i: i,
                    dp: 0,
                    pos: d.pos,
                    posref: d.posref,
                    size: d.by*(ax._id.charAt(0)==='x' ? YFACTOR : 1)/2
                }];
            })
            .sort(function(a,b){ return a[0].posref-b[0].posref; }),
        donepositioning,
        topOverlap,
        bottomOverlap,
        i, j,
        pti,
        sumdp;

    function constrainGroup(grp){
        var minPt = grp[0],
            maxPt = grp[grp.length-1];

        // overlap with the top - positive vals are overlaps
        topOverlap = pmin-minPt.pos-minPt.dp+minPt.size;

        // overlap with the bottom - positive vals are overlaps
        bottomOverlap = maxPt.pos+maxPt.dp+maxPt.size-pmax;

        // check for min overlap first, so that we always
        // see the largest labels
        // allow for .01px overlap, so we don't get an
        // infinite loop from rounding errors
        if(topOverlap>0.01) {
            for(j=grp.length-1; j>=0; j--) grp[j].dp += topOverlap;
            donepositioning = false;
        }
        if(bottomOverlap<0.01) return;
        if(topOverlap<-0.01) {
            // make sure we're not pushing back and forth
            for(j=grp.length-1; j>=0; j--) grp[j].dp -= bottomOverlap;
            donepositioning = false;
        }
        if(!donepositioning) return;

        // no room to fix positioning, delete off-screen points

        // first see how many points we need to delete
        var deleteCount = 0;
        for(i=0; i<grp.length; i++) {
            pti = grp[i];
            if(pti.pos+pti.dp+pti.size>pmax) deleteCount++;
        }

        // start by deleting points whose data is off screen
        for(i=grp.length-1; i>=0; i--) {
            if(deleteCount<=0) break;
            pti = grp[i];

            // pos has already been constrained to [pmin,pmax]
            // so look for points close to that to delete
            if(pti.pos>pmax-1) {
                pti.del = true;
                deleteCount--;
            }
        }
        for(i=0; i<grp.length; i++) {
            if(deleteCount<=0) break;
            pti = grp[i];

            // pos has already been constrained to [pmin,pmax]
            // so look for points close to that to delete
            if(pti.pos<pmin+1) {
                pti.del = true;
                deleteCount--;

                // shift the whole group minus into this new space
                bottomOverlap = pti.size*2;
                for(j=grp.length-1; j>=0; j--) grp[j].dp -= bottomOverlap;
            }
        }
        // then delete points that go off the bottom
        for(i=grp.length-1; i>=0; i--) {
            if(deleteCount<=0) break;
            pti = grp[i];
            if(pti.pos+pti.dp+pti.size>pmax) {
                pti.del = true;
                deleteCount--;
            }
        }
    }

    // loop through groups, combining them if they overlap,
    // until nothing moves
    while(!donepositioning && nummoves<=hoverData.length) {
        // to avoid infinite loops, don't move more times
        // than there are traces
        nummoves++;

        // assume nothing will move in this iteration,
        // reverse this if it does
        donepositioning = true;
        i = 0;
        while(i<pointgroups.length-1) {
                // the higher (g0) and lower (g1) point group
            var g0 = pointgroups[i],
                g1 = pointgroups[i+1],

                // the lowest point in the higher group (p0)
                // the highest point in the lower group (p1)
                p0 = g0[g0.length-1],
                p1 = g1[0];
            topOverlap = p0.pos+p0.dp+p0.size-p1.pos-p1.dp+p1.size;
            if(topOverlap>0.01) {
                // push the new point(s) added to this group out of the way
                for(j=g1.length-1; j>=0; j--) g1[j].dp += topOverlap;

                // add them to the group
                g0.push.apply(g0,g1);
                pointgroups.splice(i+1,1);

                // adjust for minimum average movement
                sumdp = 0;
                for(j=g0.length-1; j>=0; j--) sumdp += g0[j].dp;
                bottomOverlap = sumdp/g0.length;
                for(j=g0.length-1; j>=0; j--) g0[j].dp -= bottomOverlap;
                donepositioning = false;
            }
            else i++;
        }

        // check if we're going off the plot on either side and fix
        pointgroups.forEach(constrainGroup);
    }

    // now put these offsets into hoverData
    for(i=pointgroups.length-1; i>=0; i--) {
        var grp = pointgroups[i];
        for(j=grp.length-1; j>=0; j--) {
            var pt = grp[j],
                hoverPt = hoverData[pt.i];
            hoverPt.offset = pt.dp;
            hoverPt.del = pt.del;
        }
    }
}

function alignHoverText(hoverLabels, rotateLabels) {
    // finally set the text positioning relative to the data and draw the
    // box around it
    hoverLabels.each(function(d){
        var g = d3.select(this);
        if(d.del) {
            g.remove();
            return;
        }
        var horzSign = d.anchor==='end' ? -1 : 1,
            tx = g.select('text.nums'),
            alignShift = {start:1,end:-1,middle:0}[d.anchor],
            txx = alignShift*(HOVERARROWSIZE+HOVERTEXTPAD),
            tx2x = txx+alignShift*(d.txwidth+HOVERTEXTPAD),
            offsetX = 0,
            offsetY = d.offset;
        if(d.anchor==='middle') {
            txx-=d.tx2width/2;
            tx2x-=d.tx2width/2;
        }
        if(rotateLabels) {
            offsetY *= -YSHIFTY;
            offsetX = d.offset*YSHIFTX;
        }

        g.select('path').attr('d',d.anchor==='middle' ?
            // middle aligned: rect centered on data
            ('M-'+(d.bx/2)+',-'+(d.by/2)+'h'+d.bx+'v'+d.by+'h-'+d.bx+'Z') :
            // left or right aligned: side rect with arrow to data
            ('M0,0L'+(horzSign*HOVERARROWSIZE+offsetX)+','+(HOVERARROWSIZE+offsetY)+
                'v'+(d.by/2-HOVERARROWSIZE)+
                'h'+(horzSign*d.bx)+
                'v-'+d.by+
                'H'+(horzSign*HOVERARROWSIZE+offsetX)+
                'V'+(offsetY-HOVERARROWSIZE)+
                'Z'));

        tx.call(Plotly.Drawing.setPosition,
                txx+offsetX, offsetY+d.ty0-d.by/2+HOVERTEXTPAD)
            .selectAll('tspan.line')
                .attr({x:tx.attr('x'), y:tx.attr('y')});

        if(d.tx2width) {
            g.select('text.name, text.name tspan.line')
                .call(Plotly.Drawing.setPosition,
                    tx2x+alignShift*HOVERTEXTPAD+offsetX,
                    offsetY+d.ty0-d.by/2+HOVERTEXTPAD);
            g.select('rect')
                .call(Plotly.Drawing.setRect,
                    tx2x+(alignShift-1)*d.tx2width/2+offsetX,
                    offsetY-d.by/2-1,
                    d.tx2width, d.by+2);
        }
    });
}

function hoverChanged(gd, evt, oldhoverdata) {
    // don't emit any events if nothing changed or
    // if fx.hover was called manually
    if(!evt.target) return false;
    if(!oldhoverdata || oldhoverdata.length!==gd._hoverdata.length) return true;

    for(var i = oldhoverdata.length-1; i>=0; i--) {
        var oldPt = oldhoverdata[i],
            newPt = gd._hoverdata[i];
        if(oldPt.curveNumber!==newPt.curveNumber ||
                String(oldPt.pointNumber)!==String(newPt.pointNumber)) {
            return true;
        }
    }
    return false;
}

// remove hover effects on mouse out, and emit unhover event
function unhover(gd, evt){
    var fullLayout = gd._fullLayout;
    if(!evt) evt = {};
    if(evt.target &&
       Events.triggerHandler(gd, 'plotly_beforehover', evt) === false) {
        return;
    }
    fullLayout._hoverlayer.selectAll('g').remove();
    if(evt.target && gd._hoverdata) {
        gd.emit('plotly_unhover', {points: gd._hoverdata});
    }
    gd._hoverdata = undefined;
}

// on click
fx.click = function(gd,evt){
    if(gd._hoverdata && evt && evt.target) {
        gd.emit('plotly_click', {points: gd._hoverdata});
        // why do we get a double event without this???
        if(evt.stopImmediatePropagation) evt.stopImmediatePropagation();
    }
};


// ----------------------------------------------------
// Axis dragging functions
// ----------------------------------------------------

function getDragCursor(nsew, dragmode) {
    if(!nsew) return 'pointer';
    if(nsew === 'nsew') {
        if(dragmode === 'pan') return 'move';
        return 'crosshair';
    }
    return nsew.toLowerCase() + '-resize';
}

// flag for showing "doubleclick to zoom out" only at the beginning
var SHOWZOOMOUTTIP = true;

// dragBox: create an element to drag one or more axis ends
// inputs:
//      plotinfo - which subplot are we making dragboxes on?
//      x,y,w,h - left, top, width, height of the box
//      ns - how does this drag the vertical axis?
//          'n' - top only
//          's' - bottom only
//          'ns' - top and bottom together, difference unchanged
//      ew - same for horizontal axis
function dragBox(gd, plotinfo, x, y, w, h, ns, ew) {
    // mouseDown stores ms of first mousedown event in the last
    // DBLCLICKDELAY ms on the drag bars
    // numClicks stores how many mousedowns have been seen
    // within DBLCLICKDELAY so we can check for click or doubleclick events
    // dragged stores whether a drag has occurred, so we don't have to
    // redraw unnecessarily, ie if no move bigger than MINDRAG or MINZOOM px
    var fullLayout = gd._fullLayout,
        // if we're dragging two axes at once, also drag overlays
        subplots = [plotinfo].concat((ns && ew) ? plotinfo.overlays : []),
        xa = [plotinfo.x()],
        ya = [plotinfo.y()],
        pw = xa[0]._length,
        ph = ya[0]._length,
        i,
        subplotXa,
        subplotYa;

    for(i = 1; i < subplots.length; i++) {
        subplotXa = subplots[i].x();
        subplotYa = subplots[i].y();
        if(xa.indexOf(subplotXa) === -1) xa.push(subplotXa);
        if(ya.indexOf(subplotYa) === -1) ya.push(subplotYa);
    }

    function isDirectionActive(axList, activeVal) {
        for(i = 0; i < axList.length; i++) {
            if(!axList[i].fixedrange) return activeVal;
        }
        return '';
    }

    var allaxes = xa.concat(ya),
        xActive = isDirectionActive(xa, ew),
        yActive = isDirectionActive(ya, ns),
        cursor = getDragCursor(yActive + xActive, fullLayout.dragmode),
        dragClass = ns + ew + 'drag';

    var dragger3 = plotinfo.draglayer.selectAll('.' + dragClass).data([0]);
    dragger3.enter().append('rect')
        .classed('drag', true)
        .classed(dragClass, true)
        .style({fill: 'transparent', 'stroke-width': 0})
        .attr('data-subplot', plotinfo.id);
    dragger3.call(Plotly.Drawing.setRect, x, y, w, h)
        .call(fx.setCursor,cursor);
    var dragger = dragger3.node();

    // still need to make the element if the axes are disabled
    // but nuke its events (except for maindrag which needs them for hover)
    // and stop there
    if(!yActive && !xActive) {
        dragger.onmousedown = null;
        dragger.style.pointerEvents = (ns + ew === 'nsew') ? 'all' : 'none';
        return dragger;
    }

    function forceNumbers(axRange) {
        axRange[0] = Number(axRange[0]);
        axRange[1] = Number(axRange[1]);
    }

    var dragOptions = {
        element: dragger,
        gd: gd,
        plotinfo: plotinfo,
        xaxes: xa,
        yaxes: ya,
        doubleclick: doubleClick,
        prepFn: function(e, startX, startY) {
            fx.unhover(gd); // we want a clear plot for dragging
            var dragModeNow = gd._fullLayout.dragmode;
            if(ns + ew === 'nsew') {
                // main dragger handles all drag modes, and changes
                // to pan (or to zoom if it already is pan) on shift
                if(e.shiftKey) {
                    if(dragModeNow === 'pan') dragModeNow = 'zoom';
                    else dragModeNow = 'pan';
                }
            }
            // all other draggers just pan
            else dragModeNow = 'pan';

            if(dragModeNow === 'lasso') dragOptions.minDrag = 1;
            else dragOptions.minDrag = undefined;

            if(dragModeNow === 'zoom') {
                dragOptions.moveFn = zoomMove;
                dragOptions.doneFn = zoomDone;
                zoomPrep(e, startX, startY);
            }
            else if(dragModeNow === 'pan') {
                dragOptions.moveFn = plotDrag;
                dragOptions.doneFn = dragDone;
            }
            else if(dragModeNow === 'select' || dragModeNow === 'lasso') {
                prepSelect(e, startX, startY, dragOptions, dragModeNow);
            }
        }
    };

    fx.dragElement(dragOptions);

    var x0,
        y0,
        box,
        lum,
        path0,
        dimmed,
        zoomMode,
        zb,
        corners;

    function zoomPrep(e, startX, startY) {
        var dragBBox = dragger.getBoundingClientRect();
        x0 = startX - dragBBox.left;
        y0 = startY - dragBBox.top;
        box = {l: x0, r: x0, w: 0, t: y0, b: y0, h: 0};
        lum = gd._hmpixcount ?
            (gd._hmlumcount / gd._hmpixcount) :
            tinycolor(gd._fullLayout.plot_bgcolor).getLuminance();
        path0 = path0 = 'M0,0H'+pw+'V'+ph+'H0V0';
        dimmed = false;
        zoomMode = 'xy';

        zb = plotinfo.plot.append('path')
            .attr('class', 'zoombox')
            .style({
                'fill': lum>0.2 ? 'rgba(0,0,0,0)' : 'rgba(255,255,255,0)',
                'stroke-width': 0
            })
            .attr('d', path0 + 'Z');

        corners = plotinfo.plot.append('path')
            .attr('class', 'zoombox-corners')
            .style({
                fill: Plotly.Color.background,
                stroke: Plotly.Color.defaultLine,
                'stroke-width': 1,
                opacity: 0
            })
            .attr('d','M0,0Z');

        for(i = 0; i < allaxes.length; i++) forceNumbers(allaxes[i].range);
    }

    function zoomMove(dx0, dy0) {
        var x1 = Math.max(0, Math.min(pw, dx0 + x0)),
            y1 = Math.max(0, Math.min(ph, dy0 + y0)),
            dx = Math.abs(x1 - x0),
            dy = Math.abs(y1 - y0),
            clen = Math.floor(Math.min(dy, dx, fx.MINZOOM) / 2);

        box.l = Math.min(x0, x1);
        box.r = Math.max(x0, x1);
        box.t = Math.min(y0, y1);
        box.b = Math.max(y0, y1);

        // look for small drags in one direction or the other,
        // and only drag the other axis
        if(!yActive || dy < Math.min(Math.max(dx * 0.6, fx.MINDRAG), fx.MINZOOM)) {
            if(dx < fx.MINDRAG) {
                zoomMode = '';
                box.r = box.l;
                box.t = box.b;
                corners.attr('d', 'M0,0Z');
            }
            else {
                box.t = 0;
                box.b = ph;
                zoomMode = 'x';
                corners.attr('d',
                    'M'+(box.l-0.5)+','+(y0-fx.MINZOOM-0.5)+
                    'h-3v'+(2*fx.MINZOOM+1)+'h3ZM'+
                    (box.r+0.5)+','+(y0-fx.MINZOOM-0.5)+
                    'h3v'+(2*fx.MINZOOM+1)+'h-3Z');
            }
        }
        else if(!xActive || dx < Math.min(dy * 0.6, fx.MINZOOM)) {
            box.l = 0;
            box.r = pw;
            zoomMode = 'y';
            corners.attr('d',
                'M'+(x0-fx.MINZOOM-0.5)+','+(box.t-0.5)+
                'v-3h'+(2*fx.MINZOOM+1)+'v3ZM'+
                (x0-fx.MINZOOM-0.5)+','+(box.b+0.5)+
                'v3h'+(2*fx.MINZOOM+1)+'v-3Z');
        }
        else {
            zoomMode = 'xy';
            corners.attr('d',
                'M'+(box.l-3.5)+','+(box.t-0.5+clen)+'h3v'+(-clen)+
                        'h'+clen+'v-3h-'+(clen+3)+'ZM'+
                    (box.r+3.5)+','+(box.t-0.5+clen)+'h-3v'+(-clen)+
                        'h'+(-clen)+'v-3h'+(clen+3)+'ZM'+
                    (box.r+3.5)+','+(box.b+0.5-clen)+'h-3v'+clen+
                        'h'+(-clen)+'v3h'+(clen+3)+'ZM'+
                    (box.l-3.5)+','+(box.b+0.5-clen)+'h3v'+clen+
                        'h'+clen+'v3h-'+(clen+3)+'Z');
        }
        box.w = box.r - box.l;
        box.h = box.b - box.t;

        // Not sure about the addition of window.scrollX/Y...
        // seems to work but doesn't seem robust.
        zb.attr('d',
            path0+'M'+(box.l)+','+(box.t)+'v'+(box.h)+
            'h'+(box.w)+'v-'+(box.h)+'h-'+(box.w)+'Z');
        if(!dimmed) {
            zb.transition()
                .style('fill', lum>0.2 ? 'rgba(0,0,0,0.4)' :
                    'rgba(255,255,255,0.3)')
                .duration(200);
            corners.transition()
                .style('opacity',1)
                .duration(200);
            dimmed = true;
        }
    }

    function zoomAxRanges(axList, r0Fraction, r1Fraction) {
        var i,
            axi,
            axRange;

        for(i = 0; i < axList.length; i++) {
            axi = axList[i];
            if(axi.fixedrange) continue;

            axRange = axi.range;
            axi.range = [
                axRange[0] + (axRange[1] - axRange[0]) * r0Fraction,
                axRange[0] + (axRange[1] - axRange[0]) * r1Fraction
            ];
        }
    }

    function zoomDone(dragged, numClicks) {
        if(Math.min(box.h, box.w) < fx.MINDRAG * 2) {
            if(numClicks === 2) doubleClick();
            else pauseForDrag(gd);

            return removeZoombox(gd);
        }

        if(zoomMode === 'xy' || zoomMode === 'x') zoomAxRanges(xa, box.l / pw, box.r / pw);
        if(zoomMode === 'xy' || zoomMode === 'y') zoomAxRanges(ya, (ph - box.b) / ph, (ph - box.t) / ph);

        removeZoombox(gd);
        dragTail(zoomMode);

        if(SHOWZOOMOUTTIP && gd.data && gd._context.showTips) {
            Plotly.Lib.notifier('Double-click to<br>zoom back out','long');
            SHOWZOOMOUTTIP = false;
        }
    }

    function dragDone(dragged, numClicks) {
        var singleEnd = (ns + ew).length === 1;
        if(dragged) dragTail();
        else if(numClicks === 2 && !singleEnd) doubleClick();
        else if(numClicks === 1 && singleEnd) {
            var ax = ns ? ya[0] : xa[0],
                end = (ns==='s' || ew==='w') ? 0 : 1,
                attrStr = ax._name + '.range[' + end + ']',
                initialText = getEndText(ax, end),
                hAlign = 'left',
                vAlign = 'middle';

            if(ax.fixedrange) return;

            if(ns) {
                vAlign = (ns === 'n') ? 'top' : 'bottom';
                if(ax.side === 'right') hAlign = 'right';
            }
            else if(ew === 'e') hAlign = 'right';

            dragger3
                .call(Plotly.util.makeEditable, null, {
                    immediate: true,
                    background: fullLayout.paper_bgcolor,
                    text: String(initialText),
                    fill: ax.tickfont ? ax.tickfont.color : '#444',
                    horizontalAlign: hAlign,
                    verticalAlign: vAlign
                })
                .on('edit', function(text) {
                    var v = ax.type==='category' ? ax.c2l(text) : ax.d2l(text);
                    if(v !== undefined) {
                        Plotly.relayout(gd, attrStr, v);
                    }
                });
        }
        else pauseForDrag(gd);
    }

    // scroll zoom, on all draggers except corners
    var scrollViewBox = [0,0,pw,ph],
        // wait a little after scrolling before redrawing
        redrawTimer = null,
        REDRAWDELAY = 300,
        mainplot = plotinfo.mainplot ?
            fullLayout._plots[plotinfo.mainplot] : plotinfo;

    function zoomWheel(e) {
        // deactivate mousewheel scrolling on embedded graphs
        // devs can override this with layout._enablescrollzoom,
        // but _ ensures this setting won't leave their page
        if(!gd._context.scrollZoom && !fullLayout._enablescrollzoom) {
            return;
        }
        var pc = gd.querySelector('.plotly');

        // if the plot has scrollbars (more than a tiny excess)
        // disable scrollzoom too.
        if(pc.scrollHeight-pc.clientHeight>10 ||
                pc.scrollWidth-pc.clientWidth>10) {
            return;
        }

        clearTimeout(redrawTimer);

        var wheelDelta = -e.deltaY;
        if(!isFinite(wheelDelta)) wheelDelta = e.wheelDelta / 10;
        if(!isFinite(wheelDelta)) {
            console.log('did not find wheel motion attributes', e);
            return;
        }

        var zoom = Math.exp(-Math.min(Math.max(wheelDelta, -20), 20) / 100),
            gbb = mainplot.draglayer.select('.nsewdrag')
                .node().getBoundingClientRect(),
            xfrac = (e.clientX - gbb.left) / gbb.width,
            vbx0 = scrollViewBox[0] + scrollViewBox[2]*xfrac,
            yfrac = (gbb.bottom - e.clientY)/gbb.height,
            vby0 = scrollViewBox[1]+scrollViewBox[3]*(1-yfrac),
            i;

        function zoomWheelOneAxis(ax, centerFraction, zoom) {
            if(ax.fixedrange) return;
            forceNumbers(ax.range);
            var axRange = ax.range,
                v0 = axRange[0] + (axRange[1] - axRange[0]) * centerFraction;
            ax.range = [v0 + (axRange[0] - v0) * zoom, v0 + (axRange[1] - v0) * zoom];
        }

        if(ew) {
            for(i = 0; i < xa.length; i++) zoomWheelOneAxis(xa[i], xfrac, zoom);
            scrollViewBox[2] *= zoom;
            scrollViewBox[0] = vbx0 - scrollViewBox[2] * xfrac;
        }
        if(ns) {
            for(i = 0; i < ya.length; i++) zoomWheelOneAxis(ya[i], yfrac, zoom);
            scrollViewBox[3] *= zoom;
            scrollViewBox[1] = vby0 - scrollViewBox[3] * (1 - yfrac);
        }

        // viewbox redraw at first
        updateViewBoxes(scrollViewBox);
        ticksAndAnnotations(ns,ew);

        // then replot after a delay to make sure
        // no more scrolling is coming
        redrawTimer = setTimeout(function(){
            scrollViewBox = [0,0,pw,ph];
            dragTail();
        }, REDRAWDELAY);

        return Plotly.Lib.pauseEvent(e);
    }

    // everything but the corners gets wheel zoom
    if(ns.length*ew.length!==1) {
        // still seems to be some confusion about onwheel vs onmousewheel...
        if(dragger.onwheel!==undefined) dragger.onwheel = zoomWheel;
        else if(dragger.onmousewheel!==undefined) dragger.onmousewheel = zoomWheel;
    }

    // plotDrag: move the plot in response to a drag
    function plotDrag(dx,dy) {
        function dragAxList(axList, pix) {
            for(var i = 0; i < axList.length; i++) {
                var axi = axList[i];
                if(!axi.fixedrange) {
                    axi.range = [axi._r[0] - pix / axi._m, axi._r[1] - pix / axi._m];
                }
            }
        }

        if(xActive === 'ew' || yActive === 'ns') {
            if(xActive) dragAxList(xa, dx);
            if(yActive) dragAxList(ya, dy);
            updateViewBoxes([xActive ? -dx : 0, yActive ? -dy : 0, pw, ph]);
            ticksAndAnnotations(yActive, xActive);
            return;
        }

        // common transform for dragging one end of an axis
        // d>0 is compressing scale (cursor is over the plot,
        //  the axis end should move with the cursor)
        // d<0 is expanding (cursor is off the plot, axis end moves
        //  nonlinearly so you can expand far)
        function dZoom(d) {
            return 1-((d>=0) ? Math.min(d,0.9) :
                1/(1/Math.max(d,-0.3)+3.222));
        }

        // dz: set a new value for one end (0 or 1) of an axis array ax,
        // and return a pixel shift for that end for the viewbox
        // based on pixel drag distance d
        // TODO: this makes (generally non-fatal) errors when you get
        // near floating point limits
        function dz(ax, end, d) {
            var otherEnd = 1 - end,
                movedi = 0;
            for(var i = 0; i < ax.length; i++) {
                var axi = ax[i];
                if(axi.fixedrange) continue;
                movedi = i;
                axi.range[end] = axi._r[otherEnd] +
                    (axi._r[end] - axi._r[otherEnd]) / dZoom(d / axi._length);
            }
            return ax[movedi]._length * (ax[movedi]._r[end] - ax[movedi].range[end]) /
                (ax[movedi]._r[end] - ax[movedi]._r[otherEnd]);
        }

        if(xActive === 'w') dx = dz(xa, 0, dx);
        else if(xActive === 'e') dx = dz(xa, 1, -dx);
        else if(!xActive) dx = 0;

        if(yActive === 'n') dy = dz(ya, 1, dy);
        else if(yActive === 's') dy = dz(ya, 0, -dy);
        else if(!yActive) dy = 0;

        updateViewBoxes([
            (xActive === 'w') ? dx : 0,
            (yActive === 'n') ? dy : 0,
            pw - dx,
            ph - dy
        ]);
        ticksAndAnnotations(yActive, xActive);
    }

    function ticksAndAnnotations(ns, ew){
        var activeAxIds = [],
            i;

        function pushActiveAxIds(axList) {
            for(i = 0; i < axList.length; i++) {
                if(!axList[i].fixedrange) activeAxIds.push(axList[i]._id);
            }
        }

        if(ew) pushActiveAxIds(xa);
        if(ns) pushActiveAxIds(ya);

        for(i = 0; i < activeAxIds.length; i++) {
            Plotly.Axes.doTicks(gd, activeAxIds[i], true);
        }

        function redrawObjs(objArray, module) {
            var obji;
            for(i = 0; i < objArray.length; i++) {
                obji = objArray[i];
                if( (ew && activeAxIds.indexOf(obji.xref) !== -1) ||
                        (ns && activeAxIds.indexOf(obji.yref) !== -1) ) {
                    module.draw(gd, i);
                }
            }
        }

        redrawObjs(fullLayout.annotations || [], Plotly.Annotations);
        redrawObjs(fullLayout.shapes || [], Plotly.Shapes);
    }

    function doubleClick() {
        var doubleClickConfig = gd._context.doubleClick,
            axList = (xActive ? xa : []).concat(yActive ? ya : []),
            attrs = {};

        var ax, i;

        if(doubleClickConfig === 'autosize') {
            for(i = 0; i < axList.length; i++) {
                ax = axList[i];
                if(!ax.fixedrange) attrs[ax._name + '.autorange'] = true;
            }
        }
        else if(doubleClickConfig === 'reset') {
            for(i = 0; i < axList.length; i++) {
                ax = axList[i];
                attrs[ax._name + '.range'] = ax._rangeInitial.slice();
            }
        }
        else if(doubleClickConfig === 'reset+autosize') {
            for(i = 0; i < axList.length; i++) {
                ax = axList[i];
                if(ax.fixedrange) continue;
                if(ax._rangeInitial === undefined ||
                    ax.range[0]===ax._rangeInitial[0] && ax.range[1]===ax._rangeInitial[1]) {
                    attrs[ax._name + '.autorange'] = true;
                }
                else attrs[ax._name + '.range'] = ax._rangeInitial.slice();
            }
        }

        Plotly.relayout(gd, attrs);
    }

    // dragTail - finish a drag event with a redraw
    function dragTail(zoommode) {
        var attrs = {};
        // revert to the previous axis settings, then apply the new ones
        // through relayout - this lets relayout manage undo/redo
        for(var i = 0; i < allaxes.length; i++) {
            var axi = allaxes[i];
            if(zoommode && zoommode.indexOf(axi._id.charAt(0))===-1) {
                continue;
            }
            if(axi._r[0] !== axi.range[0]) attrs[axi._name+'.range[0]'] = axi.range[0];
            if(axi._r[1] !== axi.range[1]) attrs[axi._name+'.range[1]'] = axi.range[1];

            axi.range=axi._r.slice();
        }

        updateViewBoxes([0,0,pw,ph]);
        Plotly.relayout(gd,attrs);
    }

    // updateViewBoxes - find all plot viewboxes that should be
    // affected by this drag, and update them. look for all plots
    // sharing an affected axis (including the one being dragged)
    function updateViewBoxes(viewBox) {
        var plotinfos = fullLayout._plots,
            subplots = Object.keys(plotinfos),
            i,
            plotinfo2,
            xa2,
            ya2,
            editX,
            editY;

        for(i = 0; i < subplots.length; i++) {
            plotinfo2 = plotinfos[subplots[i]];
            xa2 = plotinfo2.x();
            ya2 = plotinfo2.y();
            editX = ew && xa.indexOf(xa2)!==-1 && !xa2.fixedrange;
            editY = ns && ya.indexOf(ya2)!==-1 && !ya2.fixedrange;

            if(editX || editY) {
                var newVB = [0,0,xa2._length,ya2._length];
                if(editX) {
                    newVB[0] = viewBox[0];
                    newVB[2] = viewBox[2];
                }
                if(editY) {
                    newVB[1] = viewBox[1];
                    newVB[3] = viewBox[3];
                }
                plotinfo2.plot.attr('viewBox',newVB.join(' '));
            }
        }
    }

    return dragger;
}

function getEndText(ax, end) {
    var initialVal = ax.range[end],
        diff = Math.abs(initialVal - ax.range[1 - end]),
        dig;

    if(ax.type === 'date'){
        return Plotly.Lib.ms2DateTime(initialVal, diff);
    }
    else if(ax.type==='log') {
        dig = Math.ceil(Math.max(0, -Math.log(diff) / Math.LN10)) + 3;
        return d3.format('.' + dig + 'g')(Math.pow(10, initialVal));
    }
    else { // linear numeric (or category... but just show numbers here)
        dig = Math.floor(Math.log(Math.abs(initialVal)) / Math.LN10) -
            Math.floor(Math.log(diff) / Math.LN10) + 4;
        return d3.format('.'+String(dig)+'g')(initialVal);
    }
}

function pauseForDrag(gd) {
    // prevent more redraws until we know if a doubleclick
    // has occurred
    gd._dragging = true;
    var deferredReplot = gd._replotPending;
    gd._replotPending = false;

    setTimeout(function() {
            gd._replotPending = deferredReplot;
            finishDrag(gd);
        },
        fx.DBLCLICKDELAY);
}

function finishDrag(gd) {
    gd._dragging = false;
    if(gd._replotPending) Plotly.plot(gd);
}

function removeZoombox(gd) {
    d3.select(gd)
        .selectAll('.zoombox,.js-zoombox-backdrop,.js-zoombox-menu,.zoombox-corners')
        .remove();
}

// for automatic alignment on dragging, <1/3 means left align,
// >2/3 means right, and between is center. Pick the right fraction
// based on where you are, and return the fraction corresponding to
// that position on the object
fx.dragAlign = function(v, dv, v0, v1, anchor) {
    var vmin = (v-v0)/(v1-v0),
        vmax = vmin+dv/(v1-v0),
        vc = (vmin+vmax)/2;

    // explicitly specified anchor
    if(anchor==='left' || anchor==='bottom') return vmin;
    if(anchor==='center' || anchor==='middle') return vc;
    if(anchor==='right' || anchor==='top') return vmax;

    // automatic based on position
    if(vmin<(2/3)-vc) return vmin;
    if(vmax>(4/3)-vc) return vmax;
    return vc;
};


// set cursors pointing toward the closest corner/side,
// to indicate alignment
// x and y are 0-1, fractions of the plot area
var cursorset = [['sw-resize','s-resize','se-resize'],
            ['w-resize','move','e-resize'],
            ['nw-resize','n-resize','ne-resize']];
fx.dragCursors = function(x,y,xanchor,yanchor){
    if(xanchor==='left') x=0;
    else if(xanchor==='center') x=1;
    else if(xanchor==='right') x=2;
    else x = Plotly.Lib.constrain(Math.floor(x*3),0,2);

    if(yanchor==='bottom') y=0;
    else if(yanchor==='middle') y=1;
    else if(yanchor==='top') y=2;
    else y = Plotly.Lib.constrain(Math.floor(y*3),0,2);

    return cursorset[y][x];
};

/**
 * Abstracts click & drag interactions
 * @param {object} options with keys:
 *      element (required) the DOM element to drag
 *      prepFn (optional) function(event, startX, startY)
 *          executed on mousedown
 *          startX and startY are the clientX and clientY pixel position
 *          of the mousedown event
 *      moveFn (optional) function(dx, dy, dragged)
 *          executed on move
 *          dx and dy are the net pixel offset of the drag,
 *          dragged is true/false, has the mouse moved enough to
 *          constitute a drag
 *      doneFn (optional) function(dragged, numClicks)
 *          executed on mouseup, or mouseout of window since
 *          we don't get events after that
 *          dragged is as in moveFn
 *          numClicks is how many clicks we've registered within
 *          a doubleclick time
 */
fx.dragElement = function(options) {
    var gd = Plotly.Lib.getPlotDiv(options.element) || {},
        numClicks = 1,
        startX,
        startY,
        newMouseDownTime,
        dragCover,
        initialTarget;

    if(!gd._mouseDownTime) gd._mouseDownTime = 0;

    function onStart(e) {
        // because we cancel event bubbling,
        // explicitly trigger input blur event.
        var inputBox = document.querySelector('.plugin-editable');
        if(inputBox) d3.select(inputBox).on('blur').call(inputBox);

        // make dragging and dragged into properties of gd
        // so that others can look at and modify them
        gd._dragged = false;
        gd._dragging = true;
        startX = e.clientX;
        startY = e.clientY;
        initialTarget = e.target;

        newMouseDownTime = (new Date()).getTime();
        if(newMouseDownTime - gd._mouseDownTime < fx.DBLCLICKDELAY) {
            // in a click train
            numClicks += 1;
        }
        else {
            // new click train
            numClicks = 1;
            gd._mouseDownTime = newMouseDownTime;
        }

        if(options.prepFn) options.prepFn(e, startX, startY);

        dragCover = coverSlip();

        dragCover.onmousemove = onMove;
        dragCover.onmouseup = onDone;
        dragCover.onmouseout = onDone;

        dragCover.style.cursor = window.getComputedStyle(options.element).cursor;

        return Plotly.Lib.pauseEvent(e);
    }

    function onMove(e) {
        var dx = e.clientX - startX,
            dy = e.clientY - startY,
            minDrag = options.minDrag || fx.MINDRAG;

        if(Math.abs(dx) < minDrag) dx = 0;
        if(Math.abs(dy) < minDrag) dy = 0;
        if(dx||dy) gd._dragged = true;

        if(options.moveFn) options.moveFn(dx, dy, gd._dragged);

        return Plotly.Lib.pauseEvent(e);
    }

    function onDone(e) {
        dragCover.onmousemove = null;
        dragCover.onmouseup = null;
        dragCover.onmouseout = null;
        Plotly.Lib.removeElement(dragCover);

        if(!gd._dragging) {
            gd._dragged = false;
            return;
        }
        gd._dragging = false;

        // don't count as a dblClick unless the mouseUp is also within
        // the dblclick delay
        if((new Date()).getTime() - gd._mouseDownTime > fx.DBLCLICKDELAY) {
            numClicks = Math.max(numClicks - 1, 1);
        }

        if(options.doneFn) options.doneFn(gd._dragged, numClicks);

        if(!gd._dragged) {
            var e2 = document.createEvent('MouseEvents');
            e2.initEvent('click', true, true);
            initialTarget.dispatchEvent(e2);
        }

        finishDrag(gd);

        gd._dragged = false;

        return Plotly.Lib.pauseEvent(e);
    }

    options.element.onmousedown = onStart;
    options.element.style.pointerEvents = 'all';
};

function coverSlip() {
    var cover = document.createElement('div');

    cover.className = 'dragcover';
    var cStyle = cover.style;
    cStyle.position = 'fixed';
    cStyle.left = 0;
    cStyle.right = 0;
    cStyle.top = 0;
    cStyle.bottom = 0;
    cStyle.zIndex = 999999999;
    cStyle.background = 'none';

    document.body.appendChild(cover);

    return cover;
}

fx.setCursor = function(el3,csr) {
    (el3.attr('class')||'').split(' ').forEach(function(cls){
        if(cls.indexOf('cursor-')===0) { el3.classed(cls,false); }
    });
    if(csr) { el3.classed('cursor-'+csr, true); }
};

// for bar charts and others with finite-size objects: you must be inside
// it to see its hover info, so distance is infinite outside.
// But make distance inside be at least 1/4 MAXDIST, and a little bigger
// for bigger bars, to prioritize scatter and smaller bars over big bars

// note that for closest mode, two inbox's will get added in quadrature
// args are (signed) difference from the two opposite edges
// count one edge as in, so that over continuous ranges you never get a gap
fx.inbox = function(v0,v1){
    if(v0*v1<0 || v0===0) {
        return fx.MAXDIST*(0.6-0.3/Math.max(3,Math.abs(v0-v1)));
    }
    return Infinity;
};