Add possibility to change style for each of the ticks

[moviesound]

It would be great if in future there is a possibility to change style (color, bgcolor, font-weight) for each of the ticks. For example if one needs to show in XAxes that 7 May 2016 and 8 May 2016 are holidays on the linear graph - changes the style for this ticks on the XAxes. Now style is set once for all ticks.

[etimberg]

@moviesound this is a good idea. For anyone who comes across this, I'd be happy to merge a PR adding this.

[moviesound]

This is an example. There may be placed array in fontColor (only for XAxes). The amount of color elements must be equal to the amount of the elements in data.labels.

<canvas id="graph-canvas" width="800" height="400"></canvas>

<script>
data = {
    labels: ["26 Apr","27 Apr","28 Apr","29 Apr","30 Apr","01 May","02 May","03 May"],
    datasets: [{
        label: "total",
        data: [2, 3, 4, 2, 3, 5, 6, 3]
        }]
};

var ctx = document.getElementById("graph-canvas");
var myLineChart = new Chart(ctx, {
    type: 'line',
    data,
    options: {
        scales: {
            xAxes: [{
                ticks: {
                    fontColor:['rgba(44,44,44,0.8)','rgba(44,44,44,0.8)','rgba(44,44,44,0.8)','rgba(178,31,31,1)','rgba(44,44,44,0.8)','rgba(44,44,44,0.8)','rgba(44,44,44,0.8)','rgba(44,44,44,0.8)'],
                    callback: function(tickValue, index, ticks) {
                        return tickValue;
                    }
                }
            }]
        }
    }
});
</script>

Then in chart.js near the row 6349 after the
helpers.each(this.ticks, function(label, index) {
there can be placed

if(Object.prototype.toString.call( tickFontColor ) === '[object Array]'){
    this.ctx.fillStyle = tickFontColor[index];
}

[ortichon]

for chart.js 2.6.0 you should do the change @moviesound suggested, but in:
chart.js/src/core/core.scale.js at line 830, change:

context.fillStyle = itemToDraw.major ? majorTickFontColor : tickFontColor;

to

if (Object.prototype.toString.call( tickFontColor ) === '[object Array]') {
    context.fillStyle = itemToDraw.major ? majorTickFontColor[index] : tickFontColor[index];
} else {
    context.fillStyle = itemToDraw.major ? majorTickFontColor : tickFontColor;
}

and in line 798 change:

helpers.each(itemsToDraw, function(itemToDraw) {

to:

helpers.each(itemsToDraw, function(itemToDraw, index) {