相关疑难解决方法(0)

我正在尝试将图像加载到canvas元素中,然后将数据拉出到toDataURL().

我的网站运行Ruby on Rails 2.3

我的图像来自aws s3.我有设置cors:

<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
  <CORSRule>
    <AllowedOrigin>*</AllowedOrigin>
    <AllowedMethod>GET</AllowedMethod>
    <AllowedMethod>HEAD</AllowedMethod>
    <MaxAgeSeconds>3000</MaxAgeSeconds>
    <AllowedHeader>*</AllowedHeader>
  </CORSRule>
</CORSConfiguration>

我有一个canvas元素:

<canvas id="explain_canvas"></canvas>

好的,所以有些背景.我最初尝试使用这样的代码,其中drawing_image只是图像的url.

var outlineImage = new Image();
outlineImage.crossOrigin = '';
outlineImage.src = drawing_image;
outlineImage.onload = function() {
  var canvas = document.getElementById('explain_canvas');
  var context = canvas.getContext("2d");
  context.drawImage(outlineImage, 10, 10, 600, 150);
}

但那不是发送原始标题.所以我以为我会通过jquery尝试ajax调用

var outlineImage = new Image();
$(outlineImage).attr('crossOrigin', '');
$.ajax({
    type: 'get',
    url : drawing_image,
    contentType: 'image/png',
    crossDomain: 'true',
    success: function() {
        $(outlineImage).attr("src", drawing_image);
    },
    error: function() {
        console.log('ah crap');
    } …