在php上载之前，多个图像调整了fileReader的大小

Question

我在php中有一个很好的工作多上计划脚本(还有一些javaScript(。问题是，用户直接从相机拍摄图片，因此图像大小是大的，移动频带很小。

所以我搜索了一个解决方案来调整图像端端的大小，并找到了一些与帖子相关的fileReader和canvas。

我的问题是如何使用我的PHP上传脚本上传FileReader的"结果"。

这就是我所拥有的：

html：

<input id="fileupload" type="file" name="images[]" multiple/>

javascript到动态添加上传字段和预览上传：

var abc = 0; 
$(document).ready(function() {
$('#add-file-field').click(function() {
 $("#newrow").append("<div class='col-sm-4'><div id='newrow' class='card'><div class='card-body'><input id='fileupload' type='file' name='images[]' multiple/></div></div></div>");
});
$('body').on('change', '#fileupload', function(){
  if (this.files && this.files[0]) {
       abc += 1; 
      var z = abc - 1;
      var x = $(this).parent().find('#previewimg' + z).remove();
      $(this).before("<div id='abcd"+ abc +"' class='card-img-top abcd'><img id='previewimg" + abc + "' src='' style='width:100%; height:100%;'/></div>");
      var reader = new FileReader();
      reader.onload = imageIsLoaded;
      reader.readAsDataURL(this.files[0]);
      $(this).hide();
      $("#abcd"+ abc).append($("<img/>", {id: 'delete', src: 'x.png', alt: 'delete'}).click(function() {
      $(this).parent().parent().parent().remove();
      }));
  }
});
//To preview image     
function imageIsLoaded(e) {
      $('#previewimg' + abc).attr('src', e.target.result);
  };
  $('#upload').click(function(e) {
  var name = $(":file").val();
  if (!name)
  {
      alert("First Image Must Be Selected");
      e.preventDefault();
  }
  });
});   

和php脚本：

$lastpositionid = $_SESSION['lastpositionid'];
$query = "INSERT INTO media (posid,orderid,name,image,created,tag,type) VALUES('$lastpositionid',$position->order_id,?,?,'$date','Vorher',?)";
$stmt = $con->prepare($query);
if(isset($_FILES['images'])){
        $countfiles = count($_FILES['images']['name']);
        $target_directory = "../uploads/". $position->order_id;
        $file_upload_error_messages="";
        for($i=0;$i<$countfiles;$i++){
            if(!is_dir($target_directory)){
               mkdir($target_directory, 0777, true);
            }
            $filename = $_FILES['images']['name'][$i];
            $shafilename = sha1_file($_FILES['images']['tmp_name'][$i]) . "-" . date('d-m-Y-H-i-s') . "-" . basename($_FILES["images"]["name"][$i]);
            $media->image = $filename[$i];
            $file_size = $_FILES['images']['size'][$i];
            $ext = end((explode(".", $filename)));
            $valid_ext = array('jpg','JPG','jpeg','JPEG','png','PNG','gif','GIF','mov','MOV','mp4','MP4');

        if(!empty($_FILES["images"]["tmp_name"][$i])){
            if($file_size > 104857600){
                $file_upload_error_messages.= "<div class="alert alert-danger alert-dismissable">";
                $file_upload_error_messages.= "</div>";
            }   
            if(in_array($ext, $valid_ext)){
               }
               else{
                    $file_upload_error_messages.= "<div class="alert alert-danger alert-dismissable">";
                    $file_upload_error_messages.= "</div>";
               }
            if(!empty($file_upload_error_messages)){
                $file_upload_error_messages.= "<div class="alert alert-danger alert-dismissable">";
                $file_upload_error_messages.= "</div>";
            }       
            if(empty($file_upload_error_messages)){
                    if(move_uploaded_file($_FILES['images']['tmp_name'][$i],$target_directory."/".$shafilename)){
                        echo "<div class="alert alert-success alert-dismissable">";
                        echo "<button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>";
                        echo "</div>";
                             // Execute query
                             $stmt->execute(array($shafilename,'uploads/'.$position->order_id.'/'.$shafilename,$ext));
                }
            }
        } 
    }
    print_r($file_upload_error_messages);
}

现在我认为我可以使用此脚本(或在此处找到类似的脚本(：

function handleFiles()
{
    var filesToUpload = document.getElementById('fileupload').files;
    var file = filesToUpload[0];
    // Create an image
    var img = document.createElement("img");
    // Create a file reader
    var reader = new FileReader();
    // Set the image once loaded into file reader
    reader.onload = function(e)
    {
        img.src = e.target.result;
        var canvas = document.createElement("canvas");
        //var canvas = $("<canvas>", {"id":"testing"})[0];
        var ctx = canvas.getContext("2d");
        ctx.drawImage(img, 0, 0);
        var MAX_WIDTH = 400;
        var MAX_HEIGHT = 300;
        var width = img.width;
        var height = img.height;
        if (width > height) {
          if (width > MAX_WIDTH) {
            height *= MAX_WIDTH / width;
            width = MAX_WIDTH;
          }
        } else {
          if (height > MAX_HEIGHT) {
            width *= MAX_HEIGHT / height;
            height = MAX_HEIGHT;
          }
        }
        canvas.width = width;
        canvas.height = height;
        var ctx = canvas.getContext("2d");
        ctx.drawImage(img, 0, 0, width, height);
        var dataurl = canvas.toDataURL("image/png");
        document.getElementById('image').src = dataurl;     
    }
    // Load files into file reader
    reader.readAsDataURL(file);
}

FileReader的脚本对我来说很清楚，除了如何使用PHP再次上传的部分。顺便说一句，我比JS更熟悉PHP，另一个问题是如何将此功能整合到我现有的脚本中...

我没有外部上传脚本，它全部都在同一PHP文件中。

谢谢。

Answer 1

您无法在客户端缩小图像并将其上传为文件，但是您可以缩小图像，然后获取Shurnken Image的数据图，然后将其上传为字符串，然后将其转换回服务器端的图像。

var maxWidth = 100;
var maxHeight = 100;
document.getElementById("myfile").onchange = function() {
  var reader = new FileReader();
  reader.onload = function(e) {
    var img = new Image();
    img.onload = function() {
      var cnvs = document.createElement('canvas');
      var rectRatio = img.width / img.height;
      var boundsRatio = maxWidth / maxHeight;
      var w, h;
      if (rectRatio > boundsRatio) {
        w = maxWidth;
        h = img.height * (maxWidth / img.width);
      } else {
        w = img.width * (maxHeight / img.height);
        h = maxHeight;
      }
      cnvs.width = w;
      cnvs.height = h;
      var ctx = cnvs.getContext('2d');
      ctx.drawImage(img, 0, 0, w, h);
      var uri = cnvs.toDataURL();
      // Do something here to upload the smaller verion of the datauri
      // for now i'm just putting it on the page though
      document.body.innerHTML = '<img src="' + uri + '">';
    };
    img.src = e.target.result;
  };
  reader.readAsDataURL(this.files[0]);
}

<input type=file id=myfile accept=".png">

然后在PHP侧您可以将其保存为实际图像，例如此

$data = $_POST['mydatauri'];
$encodedData = str_replace(' ','+',substr($data,strpos($data,",")+1));
$decodedData = base64_decode($encodedData);
file_put_contents("myUploadImage.png", $decodedData);