转换的图片应该有一些小的网址，而不是BaseCode [英] Converted image should have some small url instead of BaseCode

问题描述

现在我将图片上传到画布，上传图片后，通过toDataURl将画布转换为图片。如果我通过toDataURL将画布转换为图像，然后我得到基本代码（基本代码会大）。我想要一些小的网址而不是BaseCode。

Right now i am uploading image into canvas and after uploaded image, canvas converted into image by toDataURl. If i am converting canvas into image by toDataURL then i am getting base code(Base Code will be big). I want some small url instead of BaseCode.

var canvas = new fabric.Canvas('canvas');
document.getElementById('file').addEventListener("change", function (e) {
  var file = e.target.files[0];
  var reader = new FileReader();
  reader.onload = function (f) {  
    var data = f.target.result;  
    var img = document.createElement('img');
                    img.src = data;
                    img.onload = function () {
                        if (img.width < 300 || img.height < 300)
                        {
                            alert("upload image should be greater");
                            canvas.getActiveObject().remove();
                        }
                    };
    
    fabric.Image.fromURL(data, function (img) {
      var oImg = img.set({left: 50, top: 100,width:100, height:100, angle: 00}).scale(0.9);
      canvas.add(oImg).renderAll();
      var a = canvas.setActiveObject(oImg);
      var dataURL = canvas.toDataURL({format: 'png', quality: 0.8});
      console.log("aaaaaaaaaaa" + dataURL);

      //                        console.log("Canvas Image " + dataURL);
      //                        document.getElementById('txt').href = dataURL;

    });
  };
  reader.readAsDataURL(file);
});
document.querySelector('#txt').onclick = function (e) {
  e.preventDefault();
  canvas.deactivateAll().renderAll();
  document.querySelector('#preview').src = canvas.toDataURL();
  var b= canvas.toDataURL();
  console.log(b);
}

canvas{
  border: 1px solid black;
}

<script src="https://rawgit.com/kangax/fabric.js/master/dist/fabric.min.js"></script>
<input type="file" id="file">
<canvas id="canvas" width="400" height="400"></canvas>
<a href='' id='txt' target="_blank">Click Me!!</a>
<br />
<img id="preview" />

JSFiddle： https://jsfiddle.net/varunPes/8gt6d7op/23/ p>

JSFiddle: https://jsfiddle.net/varunPes/8gt6d7op/23/

推荐答案

如果你想避免发送dataURL，可以使用这个函数将它转换成DataForm：

If you want to avoid send dataURL, you can convert it into DataForm using this function:

function dataURItoBlob(dataURI) {
    // convert base64/URLEncoded data component to raw binary data held in a string
    var byteString;
    if (dataURI.split(',')[0].indexOf('base64') >= 0)
        byteString = atob(dataURI.split(',')[1]);
    else
        byteString = unescape(dataURI.split(',')[1]);

    // separate out the mime component
    var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];

    // write the bytes of the string to a typed array
    var ia = new Uint8Array(byteString.length);
    for (var i = 0; i < byteString.length; i++) {
        ia[i] = byteString.charCodeAt(i);
    }

    return new Blob([ia], {type:mimeString});
}

然后，调用它：

var dataURL = canvas.toDataURL('image/jpeg', 0.5);
var blob = dataURItoBlob(dataURL);
var fd = new FormData(document.forms[0]);
fd.append("canvasImage", blob);

最后，发送此表单（常规或ajax）。

Finally, send this form (regular or ajax).

来源答案

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