js实现图片区域可点击大小随意改变(适用移动端)代码实例

时间：2021-05-26

实现图片区域可点击，实际上使用map是可以的，但是适配效果并不好，图片只能是固定大小的值，而且点都被写死了。

在这里，我使用的js基于canvas写的一个小工具。可以圈出你需要点击的部分，然后生成一串json，在预览页面就可以看见效果了；

在实际应用中，只要用工具处理一下图片，再把数据存入数据库，就很方便了；

使用工具时，先上传图片。然后就可以圈了，圈完一定要记得，点击保存数据，，，接着就可以预览了，预览点击的效果，可以看控制台，

首先是工具

首先工具的html

<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> <style type="text/css"> *{ padding: 0; margin: 0; font-family: "微软雅黑"; } .hide{ display: none; } canvas{ border: 1px solid red; display: block; margin: 0 auto; background-position: 0 0; background-repeat: no-repeat; background-size: 100% 100%; } .cover{ position: absolute; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.4); } .cover p{ text-align: center; } .btn{ width: 800px; margin: 0 auto; padding-top: 10px; } .btn p{ padding-bottom: 10px; } a{ text-decoration: none; color: #000; } button{ line-height: 30px; padding: 0 10px; cursor: pointer; border-radius: 4px; background: #449d44; color: #fff; border: none; } </style> </head> <body> <div class="btn"> <p> <button onclick="saveData()">保存数据</button> <button onclick="getData()">导入数据</button> <button onclick="seeData(true)">查看数据</button> <a href="preview.html" rel="external nofollow" target="_blank"><button>预览效果</button></a> </p> <p> <input type="file" name="imgload" id="imgload" value="上传图片" /> </p> <p> <button onclick="reduo()">撤销</button> <button onclick="clearAll()">清除</button> </p> <p> 基础宽度:<input type="text" name="width" id="width" value="800" /> </p> <p> 基础高度:<input type="text" name="width" id="height" value="600" /> </p> </div> <canvas id="canvas" width="800" height="600"></canvas> <div class="cover hide"> <p> <span>url地址:</span> <input type="text" name="" id="urlAddress" value="" /> </p> <p> <span>描述:</span> <input type="text" name="dec" id="dec" value="" /> </p> <p> <button class="contain">确认</button> </p> </div> </body> <script type="text/javascript" src="js/jquery.js"></script> <script type="text/javascript" src="js/index.js"></script></html>

接着是工具的js代码

var canvas = document.getElementById('canvas'); var ctx = canvas.getContext('2d');ctx.lineWidth = 1;ctx.strokeStyle="green";var run = false;var moduleList = [];var path = [];var $baseImg = ''; var $cover = $(".cover");var $urlAddress = $('#urlAddress');var $dec = $("#dec"); var $baseWidth = $('#width');var $baseHeight = $('#height'); canvas.onmousedown = function(e){ //console.log(e.clientX); //console.log(e.offsetX); ctx.beginPath(); ctx.moveTo(e.offsetX, e.offsetY); path.push({ x:e.offsetX, y:e.offsetY }); run = true;} canvas.onmousemove = function(e){ //var x = e.offsetX; if(run){ ctx.lineTo(e.offsetX, e.offsetY); ctx.stroke(); path.push({ x:e.offsetX, y:e.offsetY }); }}canvas.onmouseup = function(e){ run = false; ctx.closePath(); if(path.length > 10){ $cover.removeClass('hide'); }else{ path = []; }} //保存数据function saveData(){ var data = { "dec":"图片点击", "version":"1", "img":$baseImg, "module":moduleList, "baseWidth":$baseWidth.val(), "baseHeight":$baseHeight.val() } console.log(JSON.stringify(data)); localStorage.setItem("data",JSON.stringify(data));}//查看数据function seeData(flag){ var data = { "dec":"图片点击", "version":"1", "img":$baseImg, "module":moduleList, "baseWidth":$baseWidth.val(), "baseHeight":$baseHeight.val() } if(flag){ console.log(JSON.stringify(data)); } return data;} //图片背景$('#imgload').on('change',function(){ imgToBase64(this.files[0],function(result){ console.log(result); var base64Data = 'url(' + result + ')'; $(canvas).css({'background-image': base64Data}); $baseImg = result; }); }); //转化为base64function imgToBase64(file,callback){ var reader = new FileReader(); reader.onload = function (e) { callback(e.target.result); }; reader.readAsDataURL(file); // 读取完后会调用onload方法} //确认信息$cover.on('click','.contain',function(){ if($urlAddress.val() == ''){ alert('地址不能为空'); }else{ moduleList.push({ id:getName(), path:path, url:$urlAddress.val(), dec:$dec.val() }); path = []; $cover.addClass('hide'); }}); //修改高度和宽度$baseWidth.on('change',function(){ $(canvas).css({'width': $(this).val()});});$baseHeight.on('change',function(){ $(canvas).css({'height': $(this).val()});}); //随机获取名称function getName(){ var timer = new Date(); var arr = JSON.stringify(timer).replace(/:|-|"/g ,'').split('.'); var str = arr.join(''); return str;} //导入模板function getData(){ var data = JSON.parse(localStorage.getItem("data")); if(data){ moduleList = data.module;; $baseImg = data.img; drawn(data); }else{ alert('没有模板数据.'); }} //撤销function reduo(){ moduleList.pop(); ctx.clearRect(0, 0, canvas.width, canvas.height); drawn(seeData());} //清除所有function clearAll(){ moduleList = []; ctx.clearRect(0, 0, canvas.width, canvas.height);} //给数据，画出来function drawn(data){ ctx.clearRect(0, 0, canvas.width, canvas.height); var module = data.module; var base64Data = 'url(' + data.img + ')'; $(canvas).css({'background-image': base64Data}); $baseWidth.val(data.baseWidth); $baseHeight.val(data.baseHeight); $(canvas).css({'width': data.baseWidth,'height':data.baseHeight}); //开始画 for(var i = 0; i < module.length;i++){ var path = module[i].path; ctx.beginPath(); ctx.moveTo(path[0].x, path[0].y); for(var j = 1; j < path.length; j++){ ctx.lineTo(path[j].x, path[j].y); ctx.stroke(); } ctx.closePath(); }}

最后是preview.html预览

<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" /> <style type="text/css"> *{ padding: 0; margin: 0; } body,html{ width: 100%; height: 100%; } canvas{ background-position: 0 0; background-repeat: no-repeat; background-size: 100% 100%; width: 100%; height: 100%; } .wrap{ border: 1px solid red; margin: 0 auto; width: 800px; height: 600px; } </style> </head> <body> <div class="wrap"> <canvas id="canvas" ></canvas> </div> </body> <script type="text/javascript" src="js/jquery.js"></script> <script type="text/javascript"> var $canvas = $('#canvas'); var canvas = $canvas[0]; var data = JSON.parse(localStorage.getItem("data")); var ctx = canvas.getContext('2d'); ctx.lineWidth = 1; ctx.strokeStyle="rgba(0,0,0,0)"; var module = data.module; var rateWidth = $canvas.width()/data.baseWidth; var rateHeight = $canvas.height()/data.baseHeight; var base64Data = 'url(' + data.img + ')'; $canvas.css({'background-image': base64Data}); console.log(rateWidth); console.log(rateHeight); //判断点击了图片的某个地方 canvas.onclick = function(e){ var x = event.pageX - canvas.getBoundingClientRect().left; var y = event.pageY - canvas.getBoundingClientRect().top; for(var i = 0; i < module.length;i++){ var path = module[i].path; ctx.beginPath(); ctx.moveTo(path[0].x*rateWidth, path[0].y*rateHeight); for(var j = 1; j < path.length; j++){ ctx.lineTo(path[j].x*rateWidth, path[j].y*rateHeight); } ctx.closePath(); if(ctx.isPointInPath(x, y)){ clickCall(module[i]); return; } } }; //点击中了选中的区域 function clickCall(result){ console.log(result.dec); console.log(result.url); } </script></html>

效果

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。

声明：本页内容来源网络，仅供用户参考；我单位不保证亦不表示资料全面及准确无误，也不保证亦不表示这些资料为最新信息，如因任何原因，本网内容或者用户因倚赖本网内容造成任何损失或损害，我单位将不会负任何法律责任。如涉及版权问题，请提交至online#300.cn邮箱联系删除。

相关文章