Function prepSelect

src/components/selections/select.js:58–493

(evt, startX, startY, dragOptions, mode)

}

function prepSelect(evt, startX, startY, dragOptions, mode) {
    var isCartesian = !hasSubplot(dragOptions);

    var isFreeMode = freeMode(mode);
    var isRectMode = rectMode(mode);
    var isOpenMode = openMode(mode);
    var isDrawMode = drawMode(mode);
    var isSelectMode = selectMode(mode);

    var isLine = mode === 'drawline';
    var isEllipse = mode === 'drawcircle';
    var isLineOrEllipse = isLine || isEllipse; // cases with two start & end positions

    var gd = dragOptions.gd;
    var fullLayout = gd._fullLayout;
    var immediateSelect = isSelectMode && fullLayout.newselection.mode === 'immediate' &&
        isCartesian; // N.B. only cartesian subplots have persistent selection

    var zoomLayer = fullLayout._zoomlayer;
    var dragBBox = dragOptions.element.getBoundingClientRect();
    var plotinfo = dragOptions.plotinfo;
    var transform = getTransform(plotinfo);
    var x0 = startX - dragBBox.left;
    var y0 = startY - dragBBox.top;

    fullLayout._calcInverseTransform(gd);
    var transformedCoords = Lib.apply3DTransform(fullLayout._invTransform)(x0, y0);
    x0 = transformedCoords[0];
    y0 = transformedCoords[1];
    var scaleX = fullLayout._invScaleX;
    var scaleY = fullLayout._invScaleY;

    var x1 = x0;
    var y1 = y0;
    var path0 = 'M' + x0 + ',' + y0;
    var xAxis = dragOptions.xaxes[0];
    var yAxis = dragOptions.yaxes[0];
    var pw = xAxis._length;
    var ph = yAxis._length;

    var subtract = evt.altKey &&
        !(drawMode(mode) && isOpenMode);

    var filterPoly, selectionTesters, mergedPolygons, currentPolygon;
    var i, searchInfo, eventData;

    coerceSelectionsCache(evt, gd, dragOptions);

    if(isFreeMode) {
        filterPoly = filteredPolygon([[x0, y0]], constants.BENDPX);
    }

    var outlines = zoomLayer.selectAll('path.select-outline-' + plotinfo.id).data([1]);
    var newStyle = isDrawMode ?
        fullLayout.newshape :
        fullLayout.newselection;

    if(isDrawMode) {