<!DOCTYPE html><html><head> ???<meta charset="UTF-8"> ???<title>canvas</title> ???<script type="text/javascript" src="../js/jQuery.js"></script> ???<style type="text/css"> ???????#canvas{ ???????????width: 7rem; ???????????margin: .25rem 0 0 1.5rem; ???????????border: 1px solid black; ???????????display: block; ???????} ???</style></head><body> ????<canvas id="canvas" width="1000" height="600"></canvas></body></html><script type="text/javascript"> ???/** ????* rem 布局初始化 ????*/ ???$(‘html‘).css(‘font-size‘, $(window).width()/10); ???/** ????* 获取 canvas 画布 ????* 获取 canvas 绘图上下文环境 ????*/ ???var canvas = $(‘#canvas‘)[0]; ???var cxt = canvas.getContext(‘2d‘); ???var balls = []; ???????/** ????* 事件交互, 点击事件为例 ????* isPointInPath(横坐标, 纵坐标) ????*/ ???for(var i = 0; i < 10; i++){ ???????var ball = { ???????????X: Math.random()*canvas.width, ???????????Y: Math.random()*canvas.height, ???????????R: Math.random()*50 + 20 ???????} ???????balls[i] = ball; ???} ???????draw(); ???$("#canvas").click(function(){ ???????//标准的获取鼠标点击相对于canvas画布的坐标公式 ???????var x = event.pageX - canvas.getBoundingClientRect().left; ???????var y = event.pageY - canvas.getBoundingClientRect().top; ???????for(var i = 0; i < balls.length; i++){ ???????????cxt.beginPath(); ???????????cxt.arc(balls[i].X, balls[i].Y, balls[i].R, 0, Math.PI*2); ???????????if(cxt.isPointInPath(x, y)){ ???????????????cxt.fillStyle = "red"; ???????????????cxt.fill(); ???????????} ???????} ???}); ???????function draw(){ ???????cxt.fillStyle = "blue"; ???????for(var i = 0; i < balls.length; i++){ ???????????cxt.beginPath(); ???????????cxt.arc(balls[i].X, balls[i].Y, balls[i].R, 0, Math.PI*2); ???????????cxt.fill(); ???????} ???}</script>原文地址:https://www.cnblogs.com/lovling/p/6657966.html
HTML5 Canvas ( 事件交互, 点击事件为例 ) isPointInPath(转)
原文地址：https://www.cnblogs.com/historylyt/p/9083105.html