I'm using Chartjs to display a Line Chart and this works fine:
// get line chart canvas
var targetCanvas = document.getElementById('chartCanvas').getContext('2d');
// draw line chart
var chart = new Chart(targetCanvas).Line(chartData);
But the problem occurs when I try to change the data for the Chart. I update the graph by creating a new instance of a Chart with the new data points, and thus reinitializing the canvas.
This works fine. However, when I hover over the new chart, if I happen to go over specific locations corresponding to points displayed on the old chart, the hover/label is still triggered and suddenly the old chart is visible. It remains visible while my mouse is at this location and disappears when move off that point. I don't want the old chart to display. I want to remove it completely.
I've tried to clear both the canvas and the existing chart before loading the new one. Like:
targetCanvas.clearRect(0,0, targetCanvas.canvas.width, targetCanvas.canvas.height);
and
chart.clear();
But none of these have worked so far. Any ideas about how I can stop this from happening?
Best Answer
I had huge problems with this
First I tried
.clear()
then I tried.destroy()
and I tried setting my chart reference to nullWhat finally fixed the issue for me: deleting the
<canvas>
element and then reappending a new<canvas>
to the parent containerMy specific code (obviously there's a million ways to do this):