html5 canvas在线文本第二步设置（字体边框）等我全部写完，我会写在页面底部

时间：2021-09-30 19:15:29
<!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>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<title>html5 canvas文本处理</title>

<script src="js/modernizr.js"></script>

</head>

<body>

<script type="text/javascript">

window.addEventListener('load',eventWindowLoaded,false);

function eventWindowLoaded(){

    canvasApp();

}

function canvasSupport(){

    return Modernizr.canvas;

}

function eventWindowLoader(){

    canvasApp();

}

function canvasApp(){

    var message="JourneyYao";

    var fillOrStroke ="fill";

    if(!canvasSupport()){

        return;

    }

    var theCanvas = document.getElementById('canvas')

    var context = theCanvas.getContext("2d")

    var formElement = document.getElementById("textbox")

    formElement.addEventListener('keyup',textBoxChanged,false);

    var formElement = document.getElementById("fillorstroke")

    formElement.addEventListener('change',fillOrStrokeChanged,false);

    drawScreen()

    function drawScreen(){

        context.fillStyle = '#ffffaa';

        context.fillRect(0,0,theCanvas.width,theCanvas.height);

        context.strokeStyle = '#000';

        context.strokeRect(5,5,theCanvas.width-10,theCanvas.height-10);

        //字体大小

        context.font="50px serif";

        var metrics = context.measureText(message);

        //字体居中

        var textWidth= metrics.width;

        var xPosition=(theCanvas.width/2)-(textWidth/2);

        var yPosition=(theCanvas.height/2);

        //选择类型

        switch(fillOrStroke){

            case "fill":

                context.fillStyle="#ff0000";

                context.fillText(message,xPosition,yPosition);

                break;

            case "stroke":

                context.strokeStyle="#000000";

                context.strokeText(message,xPosition,yPosition);

                break;

            case "both":

                context.fillStyle="#ff0000";

                context.fillText(message,xPosition,yPosition);

                context.strokeStyle="#000000";

                context.strokeText(message,xPosition,yPosition);

                break;

        }

    }

    function textBoxChanged(e){

         var target = e.target;

         message=target.value;

         drawScreen();

    }

    function fillOrStrokeChanged(e){

         var target = e.target;

         fillOrStroke=target.value;

         drawScreen();

    }

}

</script>

<canvas id="canvas" width="500" height="300">

你的浏览器无法使用canvas

小白童鞋；你的支持是我最大的快乐！！

</canvas>

<form>

Text:<input id="textbox" placeholder="your text" /><br />

Fill Or Stroke:

<select id="fillorstroke">

  <option value="fill">fill</option>

  <option value="stroke">stroke</option>

  <option value="both">both</option>

</select>

</form>

</body>

</html>

html5 canvas在线文本第二步设置（字体边框）等我全部写完，我会写在页面底部

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