Highlight Major Value Grid Lines - amcharts

Question

Is there a setting that I'm missing to highlight major axis grid lines? I've mocked up an example of what I'm trying to do below. The arrows point to what I want, the circle shows what I have. The axis value highlights the day of the week, but not the grid line. I have a feeling that it is considering the 12 pm's as major axis grid lines too.
Here is what I have for the categoryAxis:
"categoryAxis" :
{
"equalSpacing" : true,
"minPeriod" : "hh",
"parseDates" : true,
"fontSize" : 24,
"dateFormats" : [
{
period : 'fff',
format : 'JJ:NN:SS'
},
{
period : 'ss',
format : 'JJ:NN:SS'
},
{
period : 'mm',
format : 'JJ:NN'
},
{
period : 'hh',
format : 'L A'
},
{
period : 'DD',
format : 'MMM DD\n L A'
},
{
period : 'WW',
format : 'MMM DD\n L A'
},
{
period : 'MM',
format : 'MMM DD\n L A'
},
{
period : 'YYYY',
format : 'MMM DD\n L A'
}]
},

Answer 1

No, there isn't a setting that highlights those lines automatically. You can use a guide to highlight those times by drawing a darker line.
Typically, this is done manually, however you can use the init event to automatically do this by having it read the category axis' internal start and end dates and placing the guides as needed:
var chart = AmCharts.makeChart("chartdiv", {
// ...
"listeners": [{
"event": "init",
"method": function(e) {
//get the start and end date objects from the categoryAxis' internal data array
var startDate = new Date(e.chart.categoryAxis.data[0].category);
var endDate = new Date(e.chart.categoryAxis.data[e.chart.categoryAxis.data.length - 1].category);
var guides = [];
var guideDate;
//start at midnight
startDate.setHours(0, 0, 0, 0);
while (startDate.getTime() <= endDate.getTime()) {
guideDate = new Date(startDate);
guides.push({
"lineAlpha": 1,
"lineColor": "#000",
"date": guideDate
});
startDate.setDate(startDate.getDate() + 1);
}
//remove the first guide if it falls outside of the full date range of the axis
if (guides[0].date.getTime() < e.chart.categoryAxis.data[0].category.getTime()) {
guides.shift();
}
e.chart.categoryAxis.guides = guides;
e.chart.validateNow(); //draw the guides
}
}]
});
Demo