3

我正在努力实现,如何使用cropper.js,到目前为止它看起来还不错,但是......当我尝试裁剪图像时,如何将结果放回我的表单?

我的输入有 id 'profile_avatar'。所以我尝试将更新的图像放在那里,但不能。

$('#cut_button').click(function(e) {
  e.preventDefault();
  var croppedImageDataURL = cropper.getCroppedCanvas()
  $('#profile_avatar').val(croppedImageDataURL.toDataURL("image/png"))
});

但是当我点击“剪切按钮”时,我得到了

InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable

在控制台中。我究竟做错了什么?我试图打败它几个小时。太感谢了!

带有视图的苗条文件

  = form_for @profile do |f|
    = f.label :avatar
      = f.file_field :avatar
      .canvas_window
        canvas id='canvas'
      .preview
      = link_to('Cut', '', id: 'cut_button')
      = f.label :photos
      = f.file_field :photos, multiple: true
      = f.label :description
      = f.text_area :description
      = @profile.errors.messages[:description].presence
      = hidden_field :dimensions, ''
      = f.submit I18n.t('user.forms.buttons.submit')

javascript:
  var canvas  = $("#canvas"),
      context = canvas.get(0).getContext("2d"),
      $result = $('#result');

  $('#profile_avatar').on( 'change', function(){
    console.log('start')
    if (this.files && this.files[0]) {
      if ( this.files[0].type.match(/^image\//) ) {
        var reader = new FileReader();
        reader.onload = function(evt) {
          var img = new Image();
          img.onload = function() {
            context.canvas.height = img.height;
            context.canvas.width  = img.width;
            context.drawImage(img, 0, 0);
            const image = document.getElementById('canvas');
            const cropper = new Cropper(image, {
              preview: '.preview',
              aspectRatio: 16 / 9,
              crop(event) {
                dimensions = event.detail.width + 'x' + event.detail.width + '+' + event.detail.x + '+' + event.detail.y
                $('#new_profile input#dimensions_').val(dimensions)
                console.log(dimensions);
                console.log(event.detail.x);
                console.log(event.detail.y);
                console.log(event.detail.width);
                console.log(event.detail.height);
              },
            });

            $('#cut_button').click(function(e) {
              e.preventDefault();
              var croppedImageDataURL = cropper.getCroppedCanvas()
              HERE IS ERROR \/
              $('#profile_avatar').val(croppedImageDataURL.toDataURL("image/png"))
              console.log(croppedImageDataURL.toDataURL("image/png"))
             });
           };
           img.src = evt.target.result;
        };
        reader.readAsDataURL(this.files[0]);
      }
      else {
        alert("Invalid file type! Please select an image file.");
      }
    }
    else {
      alert('No file(s) selected.');
    }
  });

html

<form class="new_profile" id="new_profile" enctype="multipart/form-data" action="/profiles" accept-charset="UTF-8" method="post">
  <input type="hidden" name="authenticity_token" value="j53mqq1th1kb17ynj2jxIMcPFRC210EQVLBSgEu2n4FLOONtFBH3Vu7wrjc+iDrogn99H/emvN5qUdyZo2pAkg==">
  <label for="profile_avatar">Avatar</label>
  <input type="file" name="profile[avatar]" id="profile_avatar">
  <div class="canvas_window">
    <canvas id="canvas"></canvas>
  </div>
  <div class="preview"></div>
  <a id="cut_button" href="">Cut</a>
  <label for="profile_photos">Photos</label>
  <input multiple="multiple" type="file" name="profile[photos][]" id="profile_photos">
  <label for="profile_description">Description</label>
  <textarea name="profile[description]" id="profile_description"></textarea>
  <input type="hidden" name="dimensions[]" id="dimensions_">
  <input type="submit" name="commit" value="Submit" data-disable-with="Submit">
</form>
4

2 回答 2

1

突出的一件事是您需要将图像的源设置为toDataUrl(). 例如:

HTML:

<img id="cropped_image" src="/blank.gif"></img>

JS:

$("#cropped_image").attr("src", croppedImageDataURL.toDataURL("image/png"));

您可以使用 JavaScript 即时创建该图像,或者<img/>在您的标记中包含空白图像或隐藏的标记(在添加裁剪图像后显示它)。

要在表单中传递图像,您应该使用输入字段,因为此时的值是一个字符串(例如“data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNby”)。

HTML:

<input id="cropped_image" type="hidden" />

JS:

$("#cropped_image").val(croppedImageDataURL.toDataURL("image/png"));
于 2020-05-22T15:51:19.730 回答
0

如果您的服务器需要文件作为输入,请检查此链接。

整体流程是:CroppedData() -> Base64 image -> Blob -> File ===> Send to Server

于 2020-07-11T07:49:11.983 回答