canvas画板！随意画！！

news2025/7/16 20:33:29

希望你天天开心

在这里插入图片描述

代码：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>绘画板</title>
    <style>
        #canvas {
            border: 1px solid black;
            border-radius: 5px;
        }

        .menu {
            display: flex;
        }

        .button {
            margin: 5px;
        }
    </style>
</head>

<body>
    <div class="menu">
        <div class="button">画板</div>
        <div class="button" id="clear">重置</div>
        <div class="button" id="save">保存</div>
    </div>
    <div class="window">
        <div class="top">
            <div class="button"></div>
            <div class="button"></div>
            <div class="button"></div>
        </div>
    </div>
    <canvas id="canvas" width="500" height="500"></canvas>
    <script>
        let painting = false; // 记录绘画
        let startPoint = { x: undefined, y: undefined }; // 记录起点的位置

        const canvas = document.getElementById("canvas");
        const ctx = canvas.getContext("2d");

        // 鼠标点击
        canvas.onmousedown = (e) => {
            let x = e.offsetX;
            let y = e.offsetY;
            startPoint = { x: x, y: y };
            painting = true;
        }

        // 鼠标移动
        canvas.onmousemove = (e) => {
            let x = e.offsetX;
            let y = e.offsetY;
            let newPoint = { x: x, y: y };
            if (painting) {
                drawLine(startPoint.x, startPoint.y, newPoint.x, newPoint.y);
                startPoint = newPoint;
            }
        }

        // 鼠标离开
        canvas.onmouseup = () => {
            painting = false;
        }

        // 绘制方法
        function drawLine(xStart, yStart, xEnd, yEnd) {
            ctx.beginPath();
            ctx.lineWidth = 3;
            ctx.moveTo(xStart, yStart);
            ctx.lineTo(xEnd, yEnd);
            ctx.stroke();
            ctx.closePath();
        }

        clear.onclick = () => {
            ctx.fillStyle = "#fff";
            ctx.clearRect(0, 0, canvas.width, canvas.height);
            // ctx.fillRect(0, 0, canvas.width, canvas.height); // 同上面效果一致
        }

        save.onclick = () => {
            const url = canvas.toDataURL("image/jpg");
            const a = document.createElement("a");
            a.href = url;
            a.download = "画板";
            a.target = "_blank";
            a.click();
        }
    </script>
</body>

</html>