How to optimize display & interactive with large svg image without Lag in FabricJS

Question

I have a fabricJS editor with some large svg files, therefore, when I interactive with ( move / drag ) items on the editor I fill it very lag & heavy.
How to optimize using large svg files with fabricJS ?

• big_image_1.svg: 4.4MB
  
• big_image_2.svg: 6.1MB
  
• big_image_3.svg: 4.1MB
  
• big_image_4.svg: 13.6MB
  

Here is my code:

var canvas;

var canvasObject = document.getElementById("editorCanvas");

// set canvas equal size with div
$(canvasObject).width($("#canvasContainer").width());
$(canvasObject).height($("#canvasContainer").height());

canvas = new fabric.Canvas('editorCanvas', {
  backgroundColor: 'white',
  selectionLineWidth: 2,
  width: $("#canvasContainer").width(),
  height: $("#canvasContainer").height()
});

for (var i = 0; i < 4; i++) {

  var bigImage = new fabric.Image();
  bigImage.left = 10 * (i + 1);
  bigImage.top = 10 * (i + 1);
  bigImage["objectCaching"] = true;
  canvas.add(bigImage);
  bigImage.setSrc('https://futushigame.firebaseapp.com/big_image/big_image_' + (i + 1) + '.svg', function(imageObject) {
    imageObject.set('dirty', true);
    canvas.renderAll();
    setObjectCoords();
  });

}

function setObjectCoords() {
  canvas.forEachObject(function(object) {
    object.setCoords();
  });
}

#canvasContainer {
  width: 100%;
  height: 100vh;
  background-color: gray;
}

<script src="https://code.jquery.com/jquery-3.3.1.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.4.3/fabric.js"></script>

<div id="canvasContainer">
  <canvas id="editorCanvas"></canvas>
</div>

Drag items are filling heavy & lag

Answer 1

You can rewrite needsItsOwnCache from fabric.Image class.

var canvasObject = document.getElementById("editorCanvas");

// set canvas equal size with div
$(canvasObject).width($("#canvasContainer").width());
$(canvasObject).height($("#canvasContainer").height());

canvas = new fabric.Canvas('editorCanvas', {
  backgroundColor: 'white',
  selectionLineWidth: 2,
  width: $("#canvasContainer").width(),
  height: $("#canvasContainer").height()
});

for (var i = 0; i < 4; i++) {

  var bigImage = new fabric.Image();
  bigImage.left = 10 * (i + 1);
  bigImage.top = 10 * (i + 1);
  //    bigImage["objectCaching"] = true;
  bigImage["ownCaching"] = true;
  //  bigImage["clipPath"] = [];
  canvas.add(bigImage);
  bigImage.setSrc('https://futushigame.firebaseapp.com/big_image/big_image_' + (i + 1) + '.svg', function(imageObject) {
    //imageObject.set('dirty', true);
    canvas.renderAll();
    setObjectCoords();
  });

}

function setObjectCoords() {
  canvas.forEachObject(function(object) {
    object.setCoords();
  });
}

fabric.Image.prototype.needsItsOwnCache = function() {
  return true
}

#canvasContainer {
  width: 100%;
  height: 100vh;
  background-color: gray;
}

<script src="https://code.jquery.com/jquery-3.3.1.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.4.3/fabric.js"></script>

<div id="canvasContainer">
  <canvas id="editorCanvas"></canvas>
</div>