#76 Add live diff feature

[Ben Gardner]

Sometimes it isn't easy to see exactly what an option changes.

It would be nice to have something that highlights the lines that changed when an option is altered.

Perhaps put an icon next to the line number or highlight the whole line?

Along with that, it would be nice to be able to take a 'snapshot' of the output and config file, and have the diff be against that.

[Roland Illig]

+1. This is exactly what I would like to have. Before even downloading the program, I thought: This would be the killer feature.

In more detail, the workflow for establishing an indenter style in a project could look like this:

1. I load an original file. UIGUI automatically marks this as the “original” snapshot.
2. I choose an indenter and its settings.
3. I play a little with the settings, looking at the output.
4. To see what has changed, I switch into “diff mode”.
5. I’m satisfied with the result, so I take a snapshot. I can give it a name if I want. The list of snapshots appears in the toolbar, or somewhere else where I can quickly access it. The base version for showing the diffs doesn’t change, so it is still the original.
6. I want to experiment further, so I change some other options. The diff is getting larger, and it’s hard to see what my recent experiments changed.
7. Therefore I click on the snapshot that I just took and select that as the base for the diffs. Now the diffs are nice and short again.
8. I like the changes, so I take another snapshot.
9. I notice that the first snapshot wasn’t too good, and I don’t need it anymore. Therefore I delete it.
10. I do some more experiments, creating several more snapshots.
11. I want to discuss the snapshots with my team colleagues. Therefore I need to save the snapshots, so they don’t get lost.