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167 строки
4.4 KiB
167 строки
4.4 KiB
<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf-8">
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<style type="text/css">
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#c{
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border: 1px solid red;
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}
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</style>
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</head>
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<body>
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<input type="checkbox" id="er" >橡皮
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<br>
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颜色：黑<input type="radio" name="color" value="black" checked>红<input type="radio" name="color" value="red">蓝<input type="radio" name="color" value="blue">
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<br>
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<canvas id="c" width="400" height="400"></canvas>
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<br>
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<button id="clear">清空画布</button>
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<script src="http://cdn.bootcss.com/jquery/3.0.0-alpha1/jquery.min.js"></script>
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<script type="text/javascript" src="/socket.io/socket.io.js"></script>
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<script type="text/javascript">
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var socket = io.connect();
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//从服务器获得消息
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socket.on("message", function(msg){
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dealMsg(msg);
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});
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socket.on("load", function(data){
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for(var i = 0; i < data.msgs.length; i++){
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var m = data.msgs[i];
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dealMsg(m);
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}
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});
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function dealMsg(msg){
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if(msg.name == "line"){
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line(msg.x1, msg.y1, msg.x2, msg.y2, msg.color);
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}else if(msg.name == "text"){
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text(msg.x, msg.y, msg.text, msg.color);
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}else if(msg.name == "eraser"){
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eraser(msg.x1, msg.y1, msg.x2, msg.y2);
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}else if(msg.name == "clear"){
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clear();
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}
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}
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var er = $("#er");
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var c = $("#c");
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var cxt = c[0].getContext("2d");
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var drawing = false;
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var drawStartX = 0;
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var drawStartY = 0;
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var drawEndX = 0;
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var drawEndY = 0;
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var ering = false;
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var erStartX = 0;
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var erStartY = 0;
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var erEndX = 0;
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var erEndY = 0;
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c.mousedown(function(e){
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if(!er.is(":checked")){
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drawStartX = e.pageX - this.offsetLeft;
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drawStartY = e.pageY - this.offsetTop;
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drawing = true;
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}else{
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erStartX = e.pageX - this.offsetLeft;
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erStartY = e.pageY - this.offsetTop;
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ering = true;
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}
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});
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c.mouseup(function(e){
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if(!er.is(":checked")){
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drawEndX = e.pageX - this.offsetLeft;
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drawEndY = e.pageY - this.offsetTop;
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drawing = false;
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socket.emit("line", {
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x1 : drawStartX,
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y1 : drawStartY,
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x2 : drawEndX,
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y2 : drawEndY,
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color : color()
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});
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}else{
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erEndX = e.pageX - this.offsetLeft;
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erEndY = e.pageY - this.offsetTop;
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ering = false;
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socket.emit("eraser", {
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x1 : erStartX,
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y1 : erStartY,
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x2 : erEndX,
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y2 : erEndY
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});
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}
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});
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c.dblclick(function(e){
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var tx = e.pageX - this.offsetLeft;
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var ty = e.pageY - this.offsetTop;
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var txt = prompt("输入文字");
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socket.emit("text", {
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x : tx,
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y : ty,
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text : txt,
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color : color()
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});
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});
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$("#clear").click(function(){
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if(confirm("确定要清空画布？")){
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socket.emit("clear", {
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});
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}
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});
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//绘制....
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//绘制直线
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function line(x1, y1, x2, y2, c){
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cxt.strokeStyle = c;
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cxt.beginPath();
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cxt.moveTo(x1, y1);
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cxt.lineTo(x2, y2);
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cxt.closePath();
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cxt.stroke();
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}
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//绘制文字
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function text(x, y, t, c){
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cxt.fillStyle = c;
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cxt.fillText(t, x, y);
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}
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//橡皮擦（实际是绘制白色的矩形）
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function eraser(x1, y1, x2, y2){
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cxt.fillStyle = "#FFFFFF";
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cxt.fillRect(x1, y1, x2 - x1, y2 - y1);
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}
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//清空画布
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function clear(){
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cxt.clearRect(0, 0, 400, 400);
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}
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function color(){
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return $("[name=color]:checked").val();
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}
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//网页加载后读取已画图进度
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$(function(){
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socket.emit("load",{
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});
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});
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</script>
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</body>
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</html>
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