smelikecat

导航

[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>

 

posted on 2016-02-04 09:45  smelikecat  阅读(818)  评论(0)  编辑  收藏  举报