[javascript-snippet]使用javascript+html5实现图片的灰度处理

// 源码出自：潇湘夜雨
<!DOCTYPE>

<html>

<head>

<meta charset="utf-8"/>

</head>

<body>

<img src="" id='stuPic' style="display:none">

<input type="file" id="loadFile">

<canvas id="canvas" width="600" height="600"></canvas>

<script src="http://code.jquery.com/jquery-latest.js"></script>

<script>

    var canvas = document.getElementById('canvas');

    var context = canvas.getContext('2d');

    function grey(image){

        var imagedata = context.getImageData(0,0,image.width,image.height);

        var imagedata1 = context.createImageData(image.width,image.height);

        var pix = imagedata.data;

        for (var i = 0, n = pix.length; i < n; i += 4) {

        var grayscale = pix[i] * .3 + pix[i+1] * .59 + pix[i+2] * .11;

        pix[i] = grayscale;     // red

        pix[i+1] = grayscale;     // green

        pix[i+2] = grayscale;     // blue

        // alpha

        }

        context.putImageData(imagedata, 0, 0);

    }

    $("#loadFile").change(function(){

        var file = $(this)[0].files[0];

        var fReader = new FileReader();

        fReader.readAsDataURL(file);

        fReader.onload = function (e){

            $("#stuPic").attr("src", this.result).load(function(){

                context.drawImage(this,0,0);

                var s = context.getImageData(100,50,350,150);

                grey(this);

                context.putImageData(s,100,50);

            });

        };

    });

</script>

</body>

</html>
PIX

[javascript-snippet]使用javascript+html5实现图片的灰度处理
