2022 SW 전문인재양성사업/웹 프로그래밍 기본

canvas (2) - 선 그리기

마루설아 2022. 7. 29. 12:06 
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        canvas#myCanvas{
            border: 1px solid blue;
        }
    </style>
</head>
<body>
    <canvas id="myCanvas" width="640" height="480"></canvas>

    <script>
        var canvas = document.querySelector("#myCanvas");
        var ctx = canvas.getContext("2d");
        var drawing = false;
        
        ctx.lineStyle = "black";
        ctx.lineWidth = 2;
        ctx.beginPath();

        canvas.addEventListener('mousedown', (e) => {
            drawing = true;
            ctx.moveTo(e.pageX, e.pageY);
        })

        canvas.addEventListener('mouseup', (e) => {
            drawing = false;
        })

        canvas.addEventListener('mousemove', (e) => {
            if(drawing){
                ctx.lineTo(e.offsetX, e.offsetY);
                ctx.stroke();
            };
        })
    </script>
</body>
</html>

 

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