我的画布绘图界面在桌面上运行良好，但在 iPhone 上无法运行。
当我尝试画画时，它只会在我的拇指所在的地方画一个点。当我拖动拇指时，没有线条并且页面继续滚动......
代码：
var clearButton = document.getElementById('doodle-bin');
var canvascontainer = document.getElementById('doodle-canvas-container');
var canvas = document.getElementById('doodle-canvas');
var context = canvas.getContext('2d');
var radius = (document.getElementById('doodle-canvas-container').clientWidth + document.getElementById('doodle-canvas-container').clientHeight) / 150;
var dragging = false;
function getMousePosition(e) {
var mouseX = e.offsetX * canvas.width / canvas.clientWidth | 0;
var mouseY = e.offsetY * canvas.height / canvas.clientHeight | 0;
return {x: mouseX, y: mouseY};
}
context.mozImageSmoothingEnabled = false;
context.imageSmoothingEnabled = false;
canvas.width = 1280;
canvas.height = 720;
canvas.style.width = '100%';
canvas.style.height = '100%'; …我有一个绘图界面，绘图需要以 1280x720px 保存。但是，我希望画布能够根据该纵横比进行缩放。一个问题是，当我绘制时，路径的起点不在光标上。
我到处找，找不到解决办法。这是javascript：
var clearButton = document.getElementById('doodle-bin');
var canvascontainer = document.getElementById('doodle-canvas-container');
var canvas = document.getElementById('doodle-canvas');
var context = canvas.getContext('2d');
var radius = (document.getElementById('doodle-canvas-container').clientWidth + document.getElementById('doodle-canvas-container').clientHeight)/150;
var dragging = false;
context.mozImageSmoothingEnabled = false;
context.imageSmoothingEnabled = false;
canvas.width = 1280;
canvas.height = 720;
canvas.style.width = '100%';
canvas.style.height = '100%';
/* CLEAR CANVAS */
function clearCanvas() {
context.clearRect(0, 0, canvas.width, canvas.height);
}
clearButton.addEventListener('click', clearCanvas);
var putPoint = function (e) {
if (dragging) {
context.lineTo(e.offsetX, e.offsetY);
context.lineWidth = radius * 2;
context.stroke();
context.beginPath(); …