Clear NSImage's specified rect

Hi, I want to clear specified rect of NSImage.

I make a small program to draw mouse cursor, there is need to erase mouse cursor on NSImage.

Drawing mouse cursor is easy.

But it is hard to erase mouse cursor from NSImage.

How do I do it ?

Model: MacBook Pro 2012
AppleScript: 2.7
Browser: Safari 13.0.1
Operating System: macOS 10.14

We solved this.