How to clear a chart from a canvas so that hover events cannot be triggered?
I had huge problems with this
First I tried .clear()
then I tried .destroy()
and I tried setting my chart reference to null
What finally fixed the issue for me: deleting the <canvas>
element and then reappending a new <canvas>
to the parent container
My specific code (obviously there's a million ways to do this):
var resetCanvas = function(){
$('#results-graph').remove(); // this is my <canvas> element
$('#graph-container').append('<canvas id="results-graph"><canvas>');
canvas = document.querySelector('#results-graph');
ctx = canvas.getContext('2d');
ctx.canvas.width = $('#graph').width(); // resize to parent width
ctx.canvas.height = $('#graph').height(); // resize to parent height
var x = canvas.width/2;
var y = canvas.height/2;
ctx.font = '10pt Verdana';
ctx.textAlign = 'center';
ctx.fillText('This text is centered on the canvas', x, y);
};
var myPieChart=null;
function drawChart(objChart,data){
if(myPieChart!=null){
myPieChart.destroy();
}
// Get the context of the canvas element we want to select
var ctx = objChart.getContext("2d");
myPieChart = new Chart(ctx).Pie(data, {animateScale: true});
}
I have faced the same problem few hours ago.
The ".clear()" method actually clears the canvas, but (evidently) it leaves the object alive and reactive.
Reading carefully the official documentation, in the "Advanced usage" section, I have noticed the method ".destroy()", described as follows:
"Use this to destroy any chart instances that are created. This will clean up any references stored to the chart object within Chart.js, along with any associated event listeners attached by Chart.js."
It actually does what it claims and it has worked fine for me, I suggest you to give it a try.
This is the only thing that worked for me:
document.getElementById("chartContainer").innerHTML = ' ';
document.getElementById("chartContainer").innerHTML = '<canvas id="myCanvas"></canvas>';
var ctx = document.getElementById("myCanvas").getContext("2d");