Add initial fix for npe

[aidenkeating]

Ignore the formatting changes, my editor auto-fixes stuff. I'll comment the main part that was causing the issue.

As a side note, depending on the image you use you'll notice the rectangles you add to pane might be off in your UI. This is because if you pick a large image, JavaFX is scaling it down in the image view. but your Rectangle coordinates are based on the full sized image.

Two ways to approach this:

• Scale the rectangle coordinates with the ratio between the original image size and the displayed image size in JavaFX
• Draw the rectangles to a BufferedImage (or any other Image class) and then update the ImageView with that image. Then the rectangles will be scaled too because they'll actually be drawn to the image.

[aidenkeating]

I didn't read the code too much. But from that it looks like this logic was adding a Rectangle to a list and then adding it as a child of the Pane. The list of Rectangle doesn't seem to be used. So just add the Rectangle directly.

Also, as a side note, index++ is done twice here. index++ changes index, so this code is essentially adding 2 to index every time it gets to this point. I assume this wasn't the intention?