放大混乱的画布区域请点击

Question

下面是我页面的简化版本。在下面的演示中，单击一个圆圈，应打印出在div中单击的圆圈的名称。我有2个问题。  1）当我放大页面时（Chrome似乎在加载页面时自动在页面上执行此操作，因此，当使用Chrome浏览器时，我目前必须缩小以使可点击区域起作用），按像素点击检测不更长的作品。我通过检查距圆心的距离（以像素为单位）来检测是否在三个圆之一内发生了单击。您可以尝试放大并查看单击圆圈是否产生预期的结果。

2）有时不显示圆圈右边的文本，我必须手动刷新一次页面（第一次加载后），以查看文本出现在圆圈旁边。

定义点击的代码位于脚本部分的底部。 建议您整页查看下面的页面。

var total_vap_count = 12;
var total_sta_count = 3;


//ac
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(175,50,30,0,2*Math.PI);
ctx.fillStyle = "#004379";
ctx.font = "14px Lato";
if ("1" < 2){
    ctx.fillText("1" + " AC", 211, 50);
} else {
    ctx.fillText("2" + " ACs", 211, 50);
}
ctx.fill();




//sta
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(175,300,30,0,2*Math.PI);
ctx.fillStyle = "#004379";
ctx.font = "14px Lato";
if (total_sta_count < 2){
    ctx.fillText("" + total_sta_count + " device", 211, 300);
} else {
    ctx.fillText("" + total_sta_count + " devices", 211, 300);
}
ctx.fillText("connected", 211, 315);
ctx.fill();

//ssid
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(50,175,30,0,2*Math.PI);
ctx.fillStyle = "#004379";
ctx.font = "14px Lato";
if (total_vap_count < 2){
    ctx.fillText("" + total_vap_count + " SSID", 86, 175);
} else {
    ctx.fillText("" + total_vap_count + " SSIDs", 86, 175);
}
ctx.fill();




// ssid status
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(50 + Math.sin(Math.PI/4) * 30,175-Math.cos(Math.PI/4) * 30,8,0,2*Math.PI);
if (total_vap_count){
    ctx.fillStyle = "#4caf50";
} else {
    ctx.fillStyle = "#ff0000";
}
ctx.fill();

// sta status
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(175 + Math.sin(Math.PI/4) * 30,300 - Math.cos(Math.PI/4) * 30,8,0,2*Math.PI);
if (total_sta_count){
    ctx.fillStyle = "#4caf50";
} else {
    ctx.fillStyle = "#ff0000";
}
ctx.fill();

// ac status
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(175 + Math.sin(Math.PI/4) * 30,50 - Math.cos(Math.PI/4) * 30,8,0,2*Math.PI);
if (parseInt("1") > 0){
    ctx.fillStyle = "#4caf50";
} else {
    ctx.fillStyle = "#ff0000";
}
//ctx.fillStyle = "#e9ebee";
ctx.fill();

// Lines.
if (parseInt("1") > 0){
    var canvas = document.getElementById("myCanvas");
    var ctx = canvas.getContext("2d");
    ctx.beginPath();
    ctx.moveTo(50 + Math.sin(Math.PI/4) * 30+10,175-Math.cos(Math.PI/4) * 30-10);
    ctx.lineTo(175 - Math.sin(Math.PI/4) * 30-5,50 + Math.cos(Math.PI/4) * 30+5);
    ctx.lineWidth = 3;
    ctx.strokeStyle = "#004379"
    ctx.stroke();
}

if (total_vap_count && total_sta_count){
    var canvas = document.getElementById("myCanvas");
    var ctx = canvas.getContext("2d");
    ctx.beginPath();
    ctx.moveTo(50 + Math.sin(Math.PI/4) * 30+5,175+Math.cos(Math.PI/4) * 30+ 5);
    ctx.lineTo(175 - Math.sin(Math.PI/4) * 30-5,300 - Math.cos(Math.PI/4) * 30-5);
    ctx.lineWidth = 3;
    ctx.strokeStyle = "#004379"
    ctx.stroke();
}






$(document).ready(function() {

 var canvas=document.getElementById("myCanvas");
    var ctx=canvas.getContext("2d");
    
    var paint1 = setTimeout(()=>{
        ctx.font="16px FontAwesome";
        ctx.fillStyle = "white";
        ctx.fillText('\uf0ac',170, 55);
    },2000);

    
    var canvas=document.getElementById("myCanvas");
    var ctx=canvas.getContext("2d");
    
    var paint2 = setTimeout(()=>{
        ctx.font="16px FontAwesome";
        ctx.fillStyle = "white";
        ctx.fillText('\uf10b',170, 305);
    },2000);

 
    var canvas=document.getElementById("myCanvas");
    var ctx=canvas.getContext("2d");
    
    var paint3 = setTimeout(()=>{
        ctx.font="16px FontAwesome";
        ctx.fillStyle = "white";
        ctx.fillText('\uf012',45, 180);
    },2000);


    $('#myCanvas').click(function(e){
        var x = e.clientX;
        var y = e.clientY;
        console.log("inside click");
        console.log(x);
        console.log(y);
        //x start: 5, y start: 213 for canvas
        if (Math.pow(x-55, 2) + Math.pow(y-175-213, 2) < Math.pow(30, 2)){
            //$j("#overview_page").hide();
            //openNav();
            $("#demo").empty().append("ssid clicked");
            
        }

        if (Math.pow(x-175, 2) + Math.pow(y-300-213, 2) < Math.pow(30, 2)){
            //$j("#overview_page").hide();
            //openNav_sta();
            $("#demo").empty().append("sta clicked");
            
        }

        if (Math.pow(x-175, 2) + Math.pow(y-50-213, 2) < Math.pow(30, 2)){
            //$j("#overview_page").hide();
            //openNav_ac();
            $("#demo").empty().append("ac clicked");
        }


    });

})

#left_menu {
    list-style-type: none;
    margin: 0;
    padding: 0;
    width: 330px;
    background-color: #e9ebee;
    position: fixed;
    height: 100%;
    overflow: auto;
    border: 1px solid #e9ebee;
    border-radius: 6px;
    font-family: 'Lato', Helvetica, sans-serif;
    font-size: 18px;
}

li a {
    display: block;
    color: #000;
    padding: 8px 18px;
    text-decoration: none;
}

li a.active {
    background-color: #008b10;
    color: white;
}

li a:hover:not(.active) {
    background-color: #555;
    color: white;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.3.1/css/all.css" integrity="sha384-mzrmE5qonljUremFsqc01SB46JvROS7bZs3IO2EmfFsd15uHvIt+Y8vEf7N7fWAU" crossorigin="anonymous">
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css" rel="stylesheet"/>


<ul id="left_menu">
        <li><div><a id="tab_wireless" href="#"><i class="fas fa-chart-line"></i>&nbsp;&nbsp;System Status</a></div></li>
        <li><div><a id="tab_system" href="#"><i class="fa fa-laptop" aria-hidden="true"></i>&nbsp;Network Configuration</a></div></li>

  <li><div><a id="radio_list" href="#"><i class="fas fa-broadcast-tower"></i>&nbsp;Radio Information</a></div></li>
  <!--<li><a id="search" href="#">Search</a></li>-->
  <li><canvas id="myCanvas" width="310" height="400" style="position: relative; top: 110px; left: 5px;">
Your browser does not support the canvas element.
</canvas></li>
</ul>





<div id="demo" style="margin-left:330px;padding:1px 16px;border:1px solid #e9ebee; border-radius:6px;">hello world</div>

Answer 1

我只是在这里使用offsetX和offsetY作为快速解决方案，但是如果要在生产中使用，您需要一种更安全的方法来获得鼠标相对于画布的点击位置。当您单击画布的左上角时，您需要将鼠标位置设置为[0，0]。

var total_vap_count = 12;
var total_sta_count = 3;


//ac
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(175,50,30,0,2*Math.PI);
ctx.fillStyle = "#004379";
ctx.font = "14px Lato";
if ("1" < 2){
    ctx.fillText("1" + " AC", 211, 50);
} else {
    ctx.fillText("2" + " ACs", 211, 50);
}
ctx.fill();




//sta
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(175,300,30,0,2*Math.PI);
ctx.fillStyle = "#004379";
ctx.font = "14px Lato";
if (total_sta_count < 2){
    ctx.fillText("" + total_sta_count + " device", 211, 300);
} else {
    ctx.fillText("" + total_sta_count + " devices", 211, 300);
}
ctx.fillText("connected", 211, 315);
ctx.fill();

//ssid
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(50,175,30,0,2*Math.PI);
ctx.fillStyle = "#004379";
ctx.font = "14px Lato";
if (total_vap_count < 2){
    ctx.fillText("" + total_vap_count + " SSID", 86, 175);
} else {
    ctx.fillText("" + total_vap_count + " SSIDs", 86, 175);
}
ctx.fill();




// ssid status
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(50 + Math.sin(Math.PI/4) * 30,175-Math.cos(Math.PI/4) * 30,8,0,2*Math.PI);
if (total_vap_count){
    ctx.fillStyle = "#4caf50";
} else {
    ctx.fillStyle = "#ff0000";
}
ctx.fill();

// sta status
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(175 + Math.sin(Math.PI/4) * 30,300 - Math.cos(Math.PI/4) * 30,8,0,2*Math.PI);
if (total_sta_count){
    ctx.fillStyle = "#4caf50";
} else {
    ctx.fillStyle = "#ff0000";
}
ctx.fill();

// ac status
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(175 + Math.sin(Math.PI/4) * 30,50 - Math.cos(Math.PI/4) * 30,8,0,2*Math.PI);
if (parseInt("1") > 0){
    ctx.fillStyle = "#4caf50";
} else {
    ctx.fillStyle = "#ff0000";
}
//ctx.fillStyle = "#e9ebee";
ctx.fill();

// Lines.
if (parseInt("1") > 0){
    var canvas = document.getElementById("myCanvas");
    var ctx = canvas.getContext("2d");
    ctx.beginPath();
    ctx.moveTo(50 + Math.sin(Math.PI/4) * 30+10,175-Math.cos(Math.PI/4) * 30-10);
    ctx.lineTo(175 - Math.sin(Math.PI/4) * 30-5,50 + Math.cos(Math.PI/4) * 30+5);
    ctx.lineWidth = 3;
    ctx.strokeStyle = "#004379"
    ctx.stroke();
}

if (total_vap_count && total_sta_count){
    var canvas = document.getElementById("myCanvas");
    var ctx = canvas.getContext("2d");
    ctx.beginPath();
    ctx.moveTo(50 + Math.sin(Math.PI/4) * 30+5,175+Math.cos(Math.PI/4) * 30+ 5);
    ctx.lineTo(175 - Math.sin(Math.PI/4) * 30-5,300 - Math.cos(Math.PI/4) * 30-5);
    ctx.lineWidth = 3;
    ctx.strokeStyle = "#004379"
    ctx.stroke();
}






$(document).ready(function() {

 var canvas=document.getElementById("myCanvas");
    var ctx=canvas.getContext("2d");
    
    var paint1 = setTimeout(()=>{
        ctx.font="16px FontAwesome";
        ctx.fillStyle = "white";
        ctx.fillText('\uf0ac',170, 55);
    },2000);

    
    var canvas=document.getElementById("myCanvas");
    var ctx=canvas.getContext("2d");
    
    var paint2 = setTimeout(()=>{
        ctx.font="16px FontAwesome";
        ctx.fillStyle = "white";
        ctx.fillText('\uf10b',170, 305);
    },2000);

 
    var canvas=document.getElementById("myCanvas");
    var ctx=canvas.getContext("2d");
    
    var paint3 = setTimeout(()=>{
        ctx.font="16px FontAwesome";
        ctx.fillStyle = "white";
        ctx.fillText('\uf012',45, 180);
    },2000);


    $('#myCanvas').click(function(e){
        var x = e.offsetX;
        var y = e.offsetY;

        //x start: 5, y start: 213 for canvas
        if (pointInCircle(x, y, 50, 175, 30)){
            //$j("#overview_page").hide();
            //openNav();
            $("#demo").empty().append("ssid clicked");
            
        }

        if (pointInCircle(x, y, 175, 300, 30)){
            //$j("#overview_page").hide();
            //openNav_sta();
            $("#demo").empty().append("sta clicked");
            
        }

        if (pointInCircle(x, y, 175, 50, 30)){
            //$j("#overview_page").hide();
            //openNav_ac();
            $("#demo").empty().append("ac clicked");
        }


    });

})

function pointInCircle(x, y, cx, cy, radius) {
  var distancesquared = (x - cx) * (x - cx) + (y - cy) * (y - cy);
  return distancesquared <= radius * radius;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.3.1/css/all.css" integrity="sha384-mzrmE5qonljUremFsqc01SB46JvROS7bZs3IO2EmfFsd15uHvIt+Y8vEf7N7fWAU" crossorigin="anonymous">
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css" rel="stylesheet"/>
<canvas id="myCanvas" width="310" height="400" style="position: relative; top: 110px; left: 5px;">
Your browser does not support the canvas element.
</canvas>

<div id="demo"></div>