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Canvas 颜色反转

时间:2015-07-24 12:05:11      阅读:174      评论:0      收藏:0      [点我收藏+]

ImageData中的元素反转颜色 255-data[i,i+1,i+2]

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

<head>
    <meta charset="UTF-8">
    <title>converse color</title>
</head>

<body>
    <canvas id=‘myCanvas‘ width=‘800‘ height=‘600‘>
        your browser does not support canvas
    </canvas>
    <script type="text/javascript">
    var c = document.getElementById(myCanvas);
    var ctx = c.getContext(2d);
    var img = new Image();
    img.src = face.jpg;
    img.onload = function() {
        ctx.drawImage(img, 0, 0);
        var imgData = ctx.getImageData(0, 0, 250, 250);
        var pixels = imgData.data;
        for (var i = 0, n = pixels.length; i < n; i += 4) {
            pixels[i] = 255 - pixels[i];
            pixels[i + 1] = 255 - pixels[i + 1];
            pixels[i + 2] = 255 - pixels[i + 2];
        }
        ctx.putImageData(imgData, 250, 0);
    };
    </script>
</body>

</html>

 

Canvas 颜色反转

原文:http://www.cnblogs.com/stono/p/4672756.html

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