ChartJS place y-axis labels between ticks

Question

I have the following graph:

However, i'd like to shift the y axis labels to be the following:

Is it possible to move the y axis labels in between the tick marks with ChartJS, like shown in the example image above?

Functionality is similar to the options.scales.yAxes[].ticks.position option, except currently it is defined as in the x direction for the y axis , where as I need it in the y direction for the y axis. And better yet, automatically centered.

Answer 1

Unfortunately, there is no built-in method in ChartJS for this, at the moment.

You would rather need to create a chart plugin to achieve that.

plugins: [{
   beforeDraw: function(chart) {
      var ctx = chart.ctx;
      var yAxis = chart.scales['y-axis-0'];
      var tickGap = yAxis.getPixelForTick(1) - yAxis.getPixelForTick(0);
      yAxis.options.ticks.fontColor = 'transparent'; // hide original tick
      // loop through ticks array
      Chart.helpers.each(yAxis.ticks, function(tick, index) {
         if (index === yAxis.ticks.length - 1) return;
         var xPos = yAxis.right;
         var yPos = yAxis.getPixelForTick(index);
         var xPadding = 10;
         // draw tick
         ctx.save();
         ctx.textBaseline = 'middle';
         ctx.textAlign = 'right';
         ctx.fillStyle = 'rgba(0, 0, 0, 0.8)';
         ctx.fillText(tick, xPos - xPadding, yPos + tickGap / 2);
         ctx.restore();
      });
   }
}]

^{note: this will hide the first tick (which begins at 0)}

ᴡᴏʀᴋɪɴɢ ᴇxᴀᴍᴘʟᴇ ⧩

 var barChart = new Chart(ctx, { type: 'bar', data: { labels: ['Jan', 'Feb', 'Mar'], datasets: [{ label: 'BAR', data: [10, 20, 30], backgroundColor: 'rgba(0, 119, 204, 0.5)' }] }, options: { responsive: false, scales: { yAxes: [{ ticks: { beginAtZero: true } }] } }, plugins: [{ beforeDraw: function(chart) { var ctx = chart.ctx; var yAxis = chart.scales['y-axis-0']; var tickGap = yAxis.getPixelForTick(1) - yAxis.getPixelForTick(0); yAxis.options.ticks.fontColor = 'transparent'; // hide original tick // loop through ticks array Chart.helpers.each(yAxis.ticks, function(tick, index) { if (index === yAxis.ticks.length - 1) return; var xPos = yAxis.right; var yPos = yAxis.getPixelForTick(index); var xPadding = 10; // draw tick ctx.save(); ctx.textBaseline = 'middle'; ctx.textAlign = 'right'; ctx.fillStyle = 'rgba(0, 0, 0, 0.8)'; ctx.fillText(tick, xPos - xPadding, yPos + tickGap / 2); ctx.restore(); }); } }] });

 <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.min.js"></script> <canvas id="ctx" height="200"></canvas>

Answer 2

I think you can use: yAxes: [{gridLines: { offsetGridLines: true }}] to do this. The label value will be the avg between the thicks.