一个简单的html5画板
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Paint</title> <script type="text/javascript" src="draw.js" language="javascript"></script> </head> <body> <div> <canvas id="myCanvas" style="border: 2px solid red; background-image:url(juren.jpg)" height="349px" width="349px"></canvas> </div> <select name="kind" id="k" onchange="KarlChangeColor()"> <option value="black">黑色</option> <option value="blue">蓝色</option> <option value="red">红色</option> <option value="green">绿色</option> <option value="yellow">黄色</option> <option value="purple">紫色</option> <option value="white">橡皮</option> </select> <input type="text" value="4" id="karlline" onchange="KarlChangeLineWidth()"/> </body> </html>这是js文件：
// JavaScript Document var colorKarlDraw = "black"; var LineWidth = 4; function KarlChangeLineWidth() { var KarlColorWidth = document.getElementById("karlline").value; LineWidth = KarlColorWidth; } function KarlChangeColor() { var KarlColor = document.getElementById("k").value; colorKarlDraw = KarlColor; } window.onload = function () { var canvas = document.getElementById("myCanvas"); var ctx = canvas.getContext("2d"); //鼠标左键按下 canvas.onmousedown = function (e) { //开始记录路径 ctx.beginPath(); //将光标焦点移动到鼠标点击的位置 ctx.moveTo(e.clientX - 10, e.clientY - 10); //设置当前绘线的粗细(默认1.0)[由于画布的坐标和像素并不是直接对应的，所以，此属性会有0.5像素的偏差] ctx.lineWidth = LineWidth; //设置绘线颜色 ctx.strokeStyle = colorKarlDraw; // //设置渐变(会替换掉绘线颜色) // var lingrad = ctx.createLinearGradient(0, 0, 0, 600); // lingrad.addColorStop(0, "#00ABEB"); // lingrad.addColorStop(0.5, "#fff"); // lingrad.addColorStop(1, "#66CC00"); // ctx.strokeStyle = lingrad; //设置绘线透明度(0.0-1.0默认1.0) ctx.globalAlpha = 1.0; //设置绘线端点显示的样子(round/butt/square) ctx.lineCap = "round"; //设置线段拐角连接处显示的样子(round/bevel/miter默认) ctx.lineJoin = "round"; //当鼠标左键按下时，监听鼠标移动事件 canvas.onmousemove = function (e) { //用线段连接点 ctx.lineTo(e.clientX - 10, e.clientY - 10); //用笔画描绘路径[可以试一下fill(),看看是什么效果哦] ctx.stroke(); } } //当鼠标按下后，释放鼠标时，停止监听鼠标移动事件 canvas.onmouseup = function (e) { canvas.onmousemove = null; } //直线渐变的示例 function drawLinear() { // Create gradients(x1,y1,x2,y2) var lingrad = ctx.createLinearGradient(0, 0, 0, 150); //上色(position,color)[position value between 0.0 and 1.0] lingrad.addColorStop(0, 'blue'); lingrad.addColorStop(0.5, '#fff'); lingrad.addColorStop(0.5, '#66CC00'); lingrad.addColorStop(1, 'red'); var lingrad2 = ctx.createLinearGradient(0, 50, 0, 95); lingrad2.addColorStop(0.5, '#000'); lingrad2.addColorStop(1, 'rgba(0,0,0,0)'); // assign gradients to fill and stroke styles ctx.fillStyle = lingrad; ctx.strokeStyle = lingrad2; // draw shapes ctx.fillRect(10, 10, 130, 130); ctx.strokeRect(50, 50, 50, 50); } //径向渐变的示例 function drawRadial() { var ctx = document.getElementById('myCanvas').getContext('2d'); // Create gradients（x1,y1,r1,x2,y2,r2） var radgrad = ctx.createRadialGradient(45, 45, 10, 52, 50, 30); radgrad.addColorStop(0, '#A7D30C'); radgrad.addColorStop(0.9, '#019F62'); radgrad.addColorStop(1, 'rgba(1,159,98,0)'); var radgrad2 = ctx.createRadialGradient(105, 105, 20, 112, 120, 50); radgrad2.addColorStop(0, '#FF5F98'); radgrad2.addColorStop(0.75, '#FF0188'); radgrad2.addColorStop(1, 'rgba(255,1,136,0)'); var radgrad3 = ctx.createRadialGradient(95, 15, 15, 102, 20, 40); radgrad3.addColorStop(0, '#00C9FF'); radgrad3.addColorStop(0.8, '#00B5E2'); radgrad3.addColorStop(1, 'rgba(0,201,255,0)'); var radgrad4 = ctx.createRadialGradient(0, 150, 50, 0, 140, 90); radgrad4.addColorStop(0, '#F4F201'); radgrad4.addColorStop(0.8, '#E4C700'); radgrad4.addColorStop(1, 'rgba(228,199,0,0)'); // draw shapes ctx.fillStyle = radgrad4; ctx.fillRect(0, 0, 150, 150); ctx.fillStyle = radgrad3; ctx.fillRect(0, 0, 150, 150); ctx.fillStyle = radgrad2; ctx.fillRect(0, 0, 150, 150); ctx.fillStyle = radgrad; ctx.fillRect(0, 0, 150, 150); } //用图案填充画布的示例 function drawImage() { var ctx = document.getElementById("myCanvas").getContext("2d"); var img = new Image(); img.src = "Images/1.jpg"; img.onload = function () { var ptrn = ctx.createPattern(img, "repeat"); ctx.fillStyle = ptrn; ctx.fillRect(0, 0, 400, 400); } } //设置阴影的示例 function drawText() { var ctx = document.getElementById('myCanvas').getContext('2d'); ctx.shadowOffsetX = 2; ctx.shadowOffsetY = 2; ctx.shadowBlur = 2; ctx.shadowColor = "lime"; ctx.font = "20px Times New Roman"; ctx.fillStyle = "black"; ctx.fillText("Sample String", 5, 30); } } 本文由用户 jopen 自行上传分享，仅供网友学习交流。所有权归原作者，若您的权利被侵害，请联系管理员。
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