Fix invisibility of objects with no widht/height but strokewidth (#5382)

* added test

* fixed ellipse test

* fixed ellipse lint

src/shapes/object.class.js

@@ -1031,7 +1031,9 @@
      * @return {Boolean}
      */
     isNotVisible: function() {
-      return this.opacity === 0 || (this.width === 0 && this.height === 0) || !this.visible;
+      return this.opacity === 0 ||
+        (this.width === 0 && this.height === 0 && this.strokeWidth === 0) ||
+        !this.visible;
     },
 
     /**

test/unit/ellipse.js

@@ -83,18 +83,16 @@
     assert.deepEqual(ellipse.getRx(), ellipse.rx * ellipse.scaleX);
   });
 
-  QUnit.test('render', function(assert) {
+  QUnit.test('isNotVisible', function(assert) {
     var ellipse = new fabric.Ellipse();
     ellipse.set('rx', 0).set('ry', 0);
 
-    var wasRenderCalled = false;
+    assert.equal(ellipse.isNotVisible(), false, 'isNotVisible false when rx/ry are 0 because strokeWidth is > 0');
 
-    ellipse._render = function(){
-      wasRenderCalled = true;
-    };
-    ellipse.render({});
+    ellipse.set('strokeWidth', 0);
+
+    assert.equal(ellipse.isNotVisible(), true, 'should not render anymore with also strokeWidth 0');
 
-    assert.equal(wasRenderCalled, false, 'should not render when rx/ry are 0');
   });
 
   QUnit.test('toSVG', function(assert) {

test/unit/object.js

@@ -1249,4 +1249,16 @@
     object._set('fill', 'blue');
     assert.equal(object.dirty, false, 'dirty is not rised');
   });
+  QUnit.test('isNotVisible', function(assert) {
+    var object = new fabric.Object({ fill: 'blue', width: 100, height: 100 });
+    assert.equal(object.isNotVisible(), false, 'object is default visilbe');
+    object = new fabric.Object({ fill: 'blue', width: 0, height: 0, strokeWidth: 1 });
+    assert.equal(object.isNotVisible(), false, 'object is visilbe with width and height equal 0, but strokeWidth 1');
+    object = new fabric.Object({ opacity: 0, fill: 'blue' });
+    assert.equal(object.isNotVisible(), true, 'object is not visilbe with opacity 0');
+    object = new fabric.Object({ fill: 'blue', visible: false });
+    assert.equal(object.isNotVisible(), true, 'object is not visilbe with visible false');
+    object = new fabric.Object({ fill: 'blue', width: 0, height: 0, strokeWidth: 0 });
+    assert.equal(object.isNotVisible(), true, 'object is not visilbe with also strokeWidth equal 0');
+  });
 })();