ISSUE-5952 fix toCanvasElement of objects in group (fabricjs#5962)

* fix toCanvasElement of objects in group

* added test

* lint

src/shapes/object.class.js

@@ -1719,9 +1719,10 @@
       options || (options = { });
 
       var utils = fabric.util, origParams = utils.saveObjectTransform(this),
+          originalGroup = this.group,
           originalShadow = this.shadow, abs = Math.abs,
           multiplier = (options.multiplier || 1) * (options.enableRetinaScaling ? fabric.devicePixelRatio : 1);
-
+      delete this.group;
       if (options.withoutTransform) {
         utils.resetObjectTransform(this);
       }
@@ -1743,6 +1744,7 @@
         else {
           scaling = this.getObjectScaling();
         }
+        // consider non scaling shadow.
         shadowOffset.x = 2 * Math.round(abs(shadow.offsetX) + shadowBlur) * (abs(scaling.scaleX));
         shadowOffset.y = 2 * Math.round(abs(shadow.offsetY) + shadowBlur) * (abs(scaling.scaleY));
       }
@@ -1765,6 +1767,9 @@
       var canvasEl = canvas.toCanvasElement(multiplier || 1, options);
       this.shadow = originalShadow;
       this.canvas = originalCanvas;
+      if (originalGroup) {
+        this.group = originalGroup;
+      }
       this.set(origParams).setCoords();
       // canvas.dispose will call image.dispose that will nullify the elements
       // since this canvas is a simple element for the process, we remove references

test/visual/generic_rendering.js

@@ -242,5 +242,23 @@
     height: 300,
   });
 
+  function objectsInActiveSelections(canvas, callback) {
+    canvas.setZoom(0.1);
+    var rect1 = new fabric.Rect({ fill: 'purple', top: 30, left: 50, width: 30, height: 100, angle: 10 });
+    var rect2 = new fabric.Rect({ fill: 'green', top: 150, left: 10, width: 300, height: 30, angle: -10 });
+    new fabric.ActiveSelection([rect1, rect2]);
+    var output = rect1.toCanvasElement();
+    callback(output);
+  }
+
+  tests.push({
+    test: 'objects in activeSelection toCanvasElement',
+    code: objectsInActiveSelections,
+    golden: 'objectsInActiveSelections.png',
+    percentage: 0.09,
+    width: 300,
+    height: 300,
+  });
+
   tests.forEach(visualTestLoop(QUnit));
 })();