There's no option to do that in X. But, that is technically possible using CSS filters. Just note that this requires custom development which is outside the scope of our support. I could point you to the right direction though.
You will need to apply the filter to the background element like this:
If you wish to apply that to a specific row, you will need to add a class (see Adding Classess and IDs to V2 Elements) to the row and add the class in the selector like this
.my-class .x-bg. You can also use the Element CSS method. The only difference between the methods is using a class, you can use it globally while the element CSS is only per page.