I use a Mercurial Queues to create patches while I work on the repository.
So, let's say after I'm done with a patch, I do hg qrefresh and export the patch to some file I want.
So, now I have a patch file.
How do I view this visually view this patch, side by side , to know the changes I made to the original file(s) in the repository?
I know of one direct way: Keep copies of all the files before I edit and use kdiff3 or meld when I'm done. But this is clearly very time consuming and not straightforward.
If you still have the patch in MQ you can do a side-by-side view using the ExtDiff extension, which you already have installed but probably not enabled.
Then you'd:
hg extdiff .... -r revision_before_patch -r revision_including_patch
On the other hand if you want to be able to do it from just original files and a .patch file you'll need to find a diff program that takes an original and a patch instead of an original and a result. My (old!) favorite is xxdiff.