裁剪浏览图像上的弹出

cropping browsed image on popup

本文关键字：浏览 图像 裁剪      更新时间：2023-09-26

请查看下面的代码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>

我上传的图像弹出，我想裁切的图像，为此我使用了JCrop。但这对我不起作用。我想在画布上显示那个图像。请帮帮我……我得到这个错误PM错误:NS_ERROR_INVALID_POINTER: Component returned failure code: 0x80004003 (NS_ERROR_INVALID_POINTER) [nsIDOMFileReader.readAsDataURL]提前感谢!

工作小提琴

JS变化

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，我已经添加了Jcrop插件到每个正在onloadend函数内加载的图像。我们还必须计算图像缩放了多少，因为canvas处理的是原始图像，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了。

showPreview回调已被修改为获取Jcrop传递的坐标以及被裁剪的图像和该图像的比例因子。

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