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Re: TortoiseIDiff "compare" vs. "show difference"

From: Lorenz <lorenznl_at_yahoo.com>
Date: 2007-07-20 08:29:06 CEST

Simon Large wrote:
>On 19/07/07, Stefan Küng <tortoisesvn@gmail.com> wrote:
>> On 7/19/07, Simon Large <simon.tortoisesvn@googlemail.com> wrote:
>> > On 19/07/07, Stefan Küng <tortoisesvn@gmail.com> wrote:
>> > > On 7/19/07, Lorenz <lorenznl@yahoo.com> wrote:
>> > >
>> > > > The layout editor (circuit diagrams and board layouts) we are using
>> > > > (cadsofts EAGLE) has no diff tool of its own, so I'm exporting to bmps
>> > > > and comparing them.
>> > >
>> > > I know that one very well :)

so you suffer from not being able to use svn:keywords too 8-(

>> > > > For that purpose it would be nice if TortoiseIDiff could not only show
>> > > > an overlay of both bmps, but also a difference bmp (numerical,
>> > > > per-pixel difference).
>> > > > One then could locate differing section easyly, zoom-in and switch
>> > > > back to the overlay mode to examine in-detail.
>> > > >
>> > > > Any change such thing could be implemented?
>> > >
>> > > I'm sorry, but I don't understand what you mean with "difference bmp".
>> > > Do you maybe mean instead of alpha-blending the two images over one
>> > > another use maybe XOR (or some other combining algorithm) to 'merge'
>> > > the images together?
>> >
>> > Blending = (pixelA + pixelB) / 2;
>> >
>> > Difference = func(pixelA - pixelB);

PixD = (PixA != PixB) ? #FFF : #000

in combination with a toggle button to switch between overlay and diff
views would be sufficient for locating the differences.

>> > or something like that, so you get plain areas where the content is
>> > identical, and hotspots where there are differences. Maybe this can be
>> > done by making one of the images negative and using 50% alpha blend?
>> >
>> > That sounds like a useful feature for quickly finding what has changed
>> > in a graphic file.
>>
>> you mean this?
>> http://issues.tortoisesvn.net/index.php?do=details&task_id=300
>
>Well naturally I like my idea better ;-)
>
>PCB (gerber) viewers tend to use bright primary colours for the
>layers, so using a bright colour to indicate change may not be that
>useful, unless you also reduce the brightness/contrast of the rest of
>the image at the same time.
>
>Another method is to display the absolute difference between pixels.
>This might work well with a blend slider, as you get pure image at
>either end of the slide scale, pure difference in the middle, and a
>mix in between.

Do you mean alpha blending from the first image to the difference in
the first half of the blend silder scale and from the difference to
the second image in the second half?

That would be consistent with the current user interface (but using
three images instead of two) and would only nead a new "compare"
button in addition to the already existing "overlay" button .

Perhaps we should make it two new modes though,

for locating differences I would prefere:

         PixD = (PixA != PixB) ? #FFF : #000

but if someone wants to get an impression about how much two versions
of an image differ

        PixD = abs(PixA - PixB)

is much more significant.

Lorenz

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Received on Fri Jul 20 08:28:04 2007

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