Dynamically set dragmax using dragable points for Highcharts

Question

I am using highcharts with dragable points for highcharts. I want to be able to drag the chart points, but not past the next point. Their website shows demos of how dragMaxX can be set, but not dynamically: http://www.highcharts.com/plugin-registry/single/3/Draggable%20Points

This fiddle shows how I have set the Highchart settings, without setting dragMax : http://jsfiddle.net/AyUbx/3263/

I want to limit the user to not be able to drag a point past the next point. Something like this:

var thisX = this.series.xData.indexOf(this.x);
var nextX = this.series.xData[thisX+1];
this.series.dragMaxX = nextX;

Except this doesn't work. Does anyone know if this is possible or how it can be done? I have looked at the API for Highcharts but couldn't find something that worked.

Answer 1

I have changed this plugin a little bit to give you the possibility for setting max distance between points. I have added new parameter, named dragMaxToPoint, you can use it in series.

Here you can see function I have changed:

function getNewPos(e) {
  toClose = false;
  var originalEvent = e.originalEvent || e,
    pageX = originalEvent.changedTouches ? originalEvent.changedTouches[0].pageX : e.pageX,
    pageY = originalEvent.changedTouches ? originalEvent.changedTouches[0].pageY : e.pageY,
    series = dragPoint.series,
    draggableX = series.options.draggableX && dragPoint.draggableX !== false,
    draggableY = series.options.draggableY && dragPoint.draggableY !== false,
    dragSensitivity = pick(series.options.dragSensitiviy, 1),
    dragMaxToPoint = pick(series.options.dragMaxToPoint, 0.3),
    deltaX = draggableX ? dragX - pageX : 0,
    deltaY = draggableY ? dragY - pageY : 0,
    newPlotX = dragPlotX - deltaX,
    newPlotY = dragPlotY - deltaY,
    newX = dragX === undefined ? dragPoint.x : series.xAxis.toValue(newPlotX, true),
    newY = dragY === undefined ? dragPoint.y : series.yAxis.toValue(newPlotY, true),
    ret;
  newX = filterRange(newX, series, 'X');
  newY = filterRange(newY, series, 'Y');
  Highcharts.each(dragPoint.series.data, function(p, i) {
    if ((dragPoint.x - p.x) !== 0 && (dragPoint.y - p.y) !== 0) {
      if (Math.abs(newX - p.x) < dragMaxToPoint && Math.abs(newY - p.y) < dragMaxToPoint) {
        toClose = true;
      }
    }
  });
  if (!toClose && Math.sqrt(Math.pow(deltaX, 2) + Math.pow(deltaY, 2)) > dragSensitivity) {
    return {
      x: draggableX ? newX : dragPoint.x,
      y: draggableY ? newY : dragPoint.y
    };
  } else {
    return null;
  }
}

Here you can see an example how it can work: http://jsfiddle.net/AyUbx/3269/

Best regards.

EDIT: If you want to stop the drag if the point you are dragging gets a higher x value than the next point, you can change the same function a little bit. You can add if statement similar to:

  if (dragPoint.index > 0 && (newX - dragPoint.series.data[dragPoint.index - 1].x) < dragMaxToPoint || dragPoint.index < dragPoint.series.data.length - 1 && (newX - dragPoint.series.data[dragPoint.index + 1].x) > -dragMaxToPoint) {
    toClose = true;
  }

Here you can see an example how it can work: http://jsfiddle.net/AyUbx/3270/