7

请检查以下代码http://jsfiddle.net/UmJtB/18/

<script type="text/javascript">
$(document).ready( function() {
$(".uploadphoto").click(function() {
    if(document.getElementById('files').files.length == 0){
      alert('Select an Image first');
      return false;
      }else {
         // When upload button is pressed, load the Popupbox First
       loadPopupBox();
              }
        $('#popupBoxClose').click( function() {           
            unloadPopupBox();
        });

        $('#container').click( function() {
            unloadPopupBox();
        });

        function unloadPopupBox() {    // TO Unload the Popupbox
            $('#popup_box').fadeOut("slow");
            $("#container").css({ // this is just for style       
                "opacity": "1" 
            });
        }   
        function loadPopupBox() {    // To Load the Popupbox
            $('#popup_box').fadeIn("slow");
            $("#container").css({ // this is just for style
                "opacity": "1.5" 
            });        
        }  
    });

//$('.FieldRequired').attr('id','files');
// set up variables
var reader = new FileReader(),
    i=0,
    numFiles = 0,
    imageFiles;

// use the FileReader to read image i
function readFile() {
    reader.readAsDataURL(imageFiles[i])
}
// define function to be run when the File
// reader has finished reading the file
reader.onloadend = function(e) {

    // make an image and append it to the div
    var image = $('<img>').attr('src', e.target.result);
    var imgdiv = $('#popup_box');
    $(imgdiv).append(image);
 // if there are more files run the file reader again
    if (i < numFiles) {
        i++;
        readFile();
    }
};
$(".uploadphoto").click(function() {

    imageFiles = document.getElementById('files').files
    // get the number of files
    numFiles = imageFiles.length;
    readFile();           

});

$(function(){

    $('#popup_box img').Jcrop({
        onChange: showPreview,
        onSelect: showPreview,
        aspectRatio: 1
    });

});
function showPreview(coords)
{
    var rx = 100 / coords.w;
    var ry = 100 / coords.h;

    $('#preview').css({
        width: Math.round(rx * 500) + 'px',
        height: Math.round(ry * 370) + 'px',
        marginLeft: '-' + Math.round(rx * coords.x) + 'px',
        marginTop: '-' + Math.round(ry * coords.y) + 'px'
    });
}


});
</script>
</head>
<body>
<input type="file" value="" size="" class="Textbox FieldRequired" name="ProductFields[3]" id="files">
<input type="submit" value="upload" class="uploadphoto"/>
<div id="popup_box"> <!-- OUR PopupBox DIV--> 
<canvas id="preview" style="width:150px;height:150px;overflow:hidden;"></canvas>  
<a id="popupBoxClose">close</a> </div>
<div id="container"> <!-- Main Page --> 

</div>
</body>
</html>
<style type="text/css">
/* popup_box DIV-Styles*/
#popup_box {
    display:none; /* Hide the DIV */
    position:fixed;
    _position:absolute; /* hack for internet explorer 6 */
    height:600px;
    width:600px;
    background:#FFFFFF;
    left: 300px;
    top: 150px;
    z-index:100; /* Layering ( on-top of others), if you have lots of layers: I just maximized, you can change it yourself */
    margin-left: 15px;
    /* additional features, can be omitted */
    border:2px solid #ff0000;
    padding:15px;
    font-size:15px;
    -moz-box-shadow: 0 0 5px #ff0000;
    -webkit-box-shadow: 0 0 5px #ff0000;
    box-shadow: 0 0 5px #ff0000;
}
#popup_box img {
    height:600px;
    width:600px
}
#container {
    background: #d2d2d2; /*Sample*/
    width:100%;
    height:100%;
}
a {
    cursor: pointer;
    text-decoration:none;
}
/* This is for the positioning of the Close Link */
#popupBoxClose {
    background: url("close.png") no-repeat scroll 0 0 transparent;
    color: transparent;
    font-size: 20px;
    line-height: 26px;
    position: absolute;
    right: -28px;
    top: -14px;
}
</style>

我在弹出窗口上传图像，我想裁剪该图像，因为我使用了 JCrop。但这对我不起作用。我想在该弹出窗口的画布中显示该图像。请帮帮我..我收到此错误 PM 错误：NS_ERROR_INVALID_POINTER：组件返回失败代码：0x80004003 (NS_ERROR_INVALID_POINTER) [nsIDOMFileReader.readAsDataURL]提前致谢！

4

1 回答 1

3

工作小提琴

JS 更改

reader.onloadend = function (e) {

    // make an image and append it to the div
    var image = $('<img>').attr('src', e.target.result);
    var theImage = new Image();
    theImage.src = e.target.result;
    var imageWidth = theImage.width;
    var imageHeight = theImage.height;
    var imgdiv = $('#popup_box');
    $(imgdiv).append(image);
    image.Jcrop({
        /*onChange: function(coords){showPreview(coords, image);}, */
        onSelect: function(coords){showPreview(coords, image, imageWidth / image.width(), imageHeight / image.height());},
        aspectRatio: 1
    });
    // if there are more files run the file reader again
    if (i < numFiles) {
        i++;
        readFile();
    }
};

和

function showPreview(coords, image, width_scale, height_scale) {        
        var c=document.getElementById("preview");
        var ctx=c.getContext("2d");
        var img=image[0];
        if(coords.w > 0 && coords.h > 0)
            ctx.drawImage(img,coords.x * width_scale,coords.y * height_scale,coords.w * width_scale, coords.h * height_scale, 0 , 0, 300, 150);        
    }

首先，我已将 Jcrop 插件添加到 onloadend 函数中正在加载的每个图像中。我们还必须计算图像缩放了多少，因为 canvas 使用的是原始图像而不是渲染的 html 图像。我删除了 onChange 回调函数，因为每次 onChange 事件触发时绘制画布可能有点太昂贵而无法运行。

showPreview 回调已修改为获取 Jcrop 传递的坐标以及正在裁剪的图像和该图像的比例因子。

于 2013-08-28T13:30:00.800 回答