From 4f446020baff4b8d1b3ec98d65f743210e81baa0 Mon Sep 17 00:00:00 2001
From: Andrea Bogazzi <andreabogazzi79@gmail.com>
Date: Fri, 26 Jan 2018 11:12:27 +0100
Subject: [PATCH] added a simple test (#4647)

---
 src/shapes/object.class.js | 12 +++++++++---
 test/unit/image.js         | 12 ++++++++++++
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/shapes/object.class.js b/src/shapes/object.class.js
index 9bbe5cdc..b633010f 100644
--- a/src/shapes/object.class.js
+++ b/src/shapes/object.class.js
@@ -1429,7 +1429,11 @@
       el.width = boundingRect.width;
       el.height = boundingRect.height;
       fabric.util.wrapElement(el, 'div');
-      var canvas = new fabric.StaticCanvas(el, { enableRetinaScaling: options.enableRetinaScaling });
+      var canvas = new fabric.StaticCanvas(el, {
+        enableRetinaScaling: options.enableRetinaScaling,
+        renderOnAddRemove: false,
+        skipOffscreen: false,
+      });
       // to avoid common confusion https://github.com/kangax/fabric.js/issues/806
       if (options.format === 'jpg') {
         options.format = 'jpeg';
@@ -1449,10 +1453,12 @@
       var originalCanvas = this.canvas;
       canvas.add(this);
       var data = canvas.toDataURL(options);
-
       this.set(origParams).setCoords();
       this.canvas = originalCanvas;
-
+      // canvas.dispose will call image.dispose that will nullify the elements
+      // since this canvas is a simple element for the process, we remove references
+      // to objects in this way in order to avoid object trashing.
+      canvas._objects = [];
       canvas.dispose();
       canvas = null;
 
diff --git a/test/unit/image.js b/test/unit/image.js
index b7768e4b..679a4ca8 100644
--- a/test/unit/image.js
+++ b/test/unit/image.js
@@ -567,4 +567,16 @@
       done();
     });
   });
+
+  QUnit.test('consecutive dataURLs give same result.', function(assert) {
+    var done = assert.async();
+    createImageObject(function(image) {
+      var data1 = image.toDataURL();
+      var data2 = image.toDataURL();
+      var data3 = image.toDataURL();
+      assert.equal(data1, data2, 'dataurl does not change 1');
+      assert.equal(data1, data3, 'dataurl does not change 2');
+      done();
+    });
+  });
 })();