getCoalescedEvents()
Parameters
None.
Return value
A sequence of PointerEvent
instances.
Example
HTML
<canvas id="target" width="600" height="300"></canvas>
JavaScript
const canvas = document.getElementById("target");
const ctx = canvas.getContext("2d");
const pointerEvents = [];
function drawCircle(x, y, color) {
ctx.clearRect(0, 0, canvas.width, canvas.height);
/ draw the last 20 events
if (pointerEvents.length > 20) {
pointerEvents.shift();
}
pointerEvents.push({ x, y, color });
for (const pointerEvent of pointerEvents) {
ctx.beginPath();
ctx.arc(pointerEvent.x, pointerEvent.y, 10, 0, 2 * Math.PI);
ctx.strokeStyle = pointerEvent.color;
ctx.stroke();
}
}
canvas.addEventListener("pointermove", (e) => {
/ draw a circle for the current event
drawCircle(e.clientX, e.clientY, "black");
const coalescedEvents = e.getCoalescedEvents();
for (let coalescedEvent of coalescedEvents) {
/ give it an offset so we can see the difference and color it red
drawCircle(coalescedEvent.clientX + 20, coalescedEvent.clientY + 20, "red");
}
});