これは、特大のキャンバスを使用し、CSS マージンを調整してマウスの動きに合わせてスクロールするデモです: https://jsfiddle.net/ax7n8944/
HTML:
<div id="canvasdiv" style="width: 500px; height: 250px; overflow: hidden">
<canvas id="canvas" width="10000px" height="250px"></canvas>
</div>
JS:
var canvas = document.getElementById("canvas");
var context = canvas.getContext('2d');
var dragging = false;
var lastX;
var marginLeft = 0;
for (var i = 0; i < 1000; i++) {
context.beginPath();
context.arc(Math.random() * 10000, Math.random() * 250, 20.0, 0, 2 * Math.PI, false);
context.stroke();
}
canvas.addEventListener('mousedown', function(e) {
var evt = e || event;
dragging = true;
lastX = evt.clientX;
e.preventDefault();
}, false);
window.addEventListener('mousemove', function(e) {
var evt = e || event;
if (dragging) {
var delta = evt.clientX - lastX;
lastX = evt.clientX;
marginLeft += delta;
canvas.style.marginLeft = marginLeft + "px";
}
e.preventDefault();
}, false);
window.addEventListener('mouseup', function() {
dragging = false;
}, false);