diff --git a/lib/modifiedAPI.js b/lib/modifiedAPI.js
index 931bf7a..91b368b 100644
--- a/lib/modifiedAPI.js
+++ b/lib/modifiedAPI.js
@@ -31,8 +31,8 @@
 		var imageData;
 		var source;
 		if ((context.canvas.width || 0) * (context.canvas.height || 0) === 0){
-			imageData  = new getWrapped(window).ImageData(0, 0);
-			source  = new getWrapped(window).ImageData(0, 0);
+			imageData  = new (getWrapped(window).ImageData)(0, 0);
+			source  = new (getWrapped(window).ImageData)(0, 0);
 		}
 		else if (context instanceof window.CanvasRenderingContext2D){
 			imageData = window.CanvasRenderingContext2D.prototype.getImageData.call(
@@ -43,9 +43,13 @@
 			source = imageData.data;
 		}
 		else {
-			imageData  = new getWrapped(window).ImageData(context.canvas.width, context.canvas.height);
+			imageData  = new (getWrapped(window).ImageData)(context.canvas.width, context.canvas.height);
 			source = new Uint8Array(imageData.data.length);
-			window.WebGLRenderingContext.prototype.readPixels.call(
+			(
+				context instanceof window.WebGLRenderingContext?
+					window.WebGLRenderingContext:
+					window.WebGL2RenderingContext
+			).prototype.readPixels.call(
 				context,
 				0, 0, context.canvas.width, context.canvas.height,
 				context.RGBA, context.UNSIGNED_BYTE,