Side-by-side diff and patch visualization

Does anybody know of any tools for doing side-by-side visualizations  
of diffs and patches which work well with Git?

By side-by-side I mean something like what's shown in this screen shot:

<http://wincent.com/images/side-by-side-diff.png>

For simple diffs there is little advantage here over a raw textual  
diff, but as patch complexity and size increase the side-by-side diff  
can sometimes prove itself to be more useful:

- totally flexible notion of context (you can scroll as far as you  
want in either direction)

- this flexibility comes with the same rapid movement between changes  
(ie. up/down cursor keys to jump between hunks no matter how far  
apart they are)

- for complex diffs, truly comprehending the nature of the changes  
may be easier in a side-by-side format

- as icing on cake, the implementation in the screenshot highlights  
the removed/added portions within each line

Now, that screenshot is actually of Apple's FileMerge app on Mac OS X  
and it would be fairly straightforward to write a dump wrapper script  
that either just interpreted the output of git-diff, or could be used  
in conjunction with GIT_EXTERNAL_DIFF, to feed files into opendiff  
two at a time, but that wouldn't allow you to easily visualize diffs  
which touch many paths.

So, can anyone recommend a tool which can do this kind of side-by- 
side visualization and plays nicely with Git? Experience with  
opendiff and git-mergetool has spoilt me here. For most cases I would  
continue to use vanilla git-diff (or gitk), but when I see a change  
that I'd like to visualize side-by-side I'd like to be able to use  
this alternative diff viewer (or can gitk already do side-by-side  
diffs and I just haven't seen how to turn them on?). Bonus points if  
I could not only view existing commits, but proposed commits too (ie.  
the ability to feed in a patch and see a side-by-side visualization  
of what the diff would look like if applied).

If nothing exists I will look at quickly hacking something together  
(most likely something that just reads the output of git-diff), but  
it will be just that, a quick hack.

Cheers,
Wincent

On Wed, Sep 19, 2007 at 01:40:17PM +0200, Wincent Colaiuta wrote:

Does anybody know of any tools for doing side-by-side visualizations of 
diffs and patches which work well with Git?

Have you tried kompare?

  git-diff HEAD~5 | kompare -

-Peff

El 19/9/2007, a las 14:09, Jeff King escribió:

On Wed, Sep 19, 2007 at 01:40:17PM +0200, Wincent Colaiuta wrote:

quoted

Does anybody know of any tools for doing side-by-side  
visualizations of
diffs and patches which work well with Git?

Have you tried kompare?

  git-diff HEAD~5 | kompare -

-Peff

Ah, didn't know about that one. From the look of it that is exactly  
the kind of extremely simple viewer that I was wanting.

Cheers,
Wincent

Wincent Colaiuta [off-list ref] writes:

Does anybody know of any tools for doing side-by-side visualizations
of diffs and patches which work well with Git?

So, can anyone recommend a tool which can do this kind of side-by- 
side visualization and plays nicely with Git?

I use M-x ediff-revision RET in Emacs for this.  There is also M-x
smerge-ediff RET for resolving a file with merge conflict markers, and
M-x ediff-merge-revisions-with-ancestor RET.

The side-by-side layout is chosen by typing | into the control window
for the merge.

Looking at a patch in respect of two versions can be done with M-x
ediff-patch-file RET.

-- 
David Kastrup

On Wednesday 2007 September 19, Jeff King wrote:

Have you tried kompare?

  git-diff HEAD~5 | kompare -

You can also throw in the "--unified" switch to see the whole file, rather 
than just the bits that have changed (if that's what you like).

 git-diff --unified=9999999 HEAD~5 | kompare -


Andy

-- 
Dr Andy Parkins, M Eng (hons), MIET
andyparkins@gmail.com