Remove duplicates on canvas

[iwandejong]

There has been an issue where the canvas shows a duplicate. This has been fixed by creating a temporary canvas first then transposing the image later on to the original canvas

[rogeriopvl]

Hi @iwandejong

Thanks for both pull requests. I'm glad to merge them, can you just please make sure the tests pass? I've added a github action to run them automatically on pull requests for convenience.

Thanks!