[Digikam-users] tool to view 4 images at once on screen (personal not related to dk)

[Jean-François Rabasse]

On Fri, 16 Sep 2011, Gilles Caulier wrote:

> And how to synchronize views to zoom and pan canvas at the same time ?
>
> How to image by pair to compare side by side ?
>
> Loading all images at the same time will not explode your memory ?
>
> What's about to show a preview of RAW image in gimp, without process
> demosaicing ?

Well, I didn't pretend GIMP was THE definitive solution to all problems:-)
My comment was rather to point out an alternative to Gwenview.
And, as usual, the best tool for someone will deeply depend on what you
expect to do with. But I can answer to your objections :


> And how to synchronize views to zoom and pan canvas at the same time ?

Synchronisation, you're right, this requires a single partitionned
window to handle that. With a "any windows number" tool, you don't get
synchronisation. But you're not stuck to 2, 4 or 6 images at a time.


> Loading all images at the same time will not explode your memory ?

Memory is not a software related issue but a computer issue.
Whatever tool you use, the max number of images you may be able to handle
at a time will depend on your computer RAM and swap.
If you can't open 10 images with GIMP, you won't open them with Gwenview,
or anything else, at least on the same machine.
(And swap memory is not a solution, it's too sloooooooow)

> What's about to show a preview of RAW image in gimp, without process
> demosaicing ?

RAW image ? Was that the initial issue ? I don't know raw images viewers,
or multiple raw images viewers, just raw images processors.
When I try to open with GIMP one of my .NEF file, GIMP fells back to
lauching ufraw (it's my KDE file association).
If I try to open it with Gwenview, I just get an error message
"cannot display documents of type image/x-nikon-nef"
So...


> How to image by pair to compare side by side ?

As for "compare side by side", it would probably require to define what
is "compare", what kind of comparision is awaited ? To have a global look
on similar images, composition, general coloured atmosphère, having
windows side by side is the same as having images side by side in a
single window.
In some other cases, images side by side will give nothing.
E.g. you wish to compare similar pictures (same subject, shot in the
same time interval) taken in low ambient light and at low shutter speed,
say 1/30 s or 1/15 s, and you suspect you may have some focus defects
due to slow speed and hand held camera. Side by side will give nothing,
exceptt if out of focus is obvious (and the image can be garbaged at 
once).
To do that kind of comparison, and as I'm a GIMP user, I select a small
area of each picture with fine details, and copy/paste into an empty work 
window as layers. Layers can be superimposed, switch on/off one by one,
it's possible to make one layer half transparent and compare with the
underlying one on really small details.
It becomes possible to have an accurate idea of the best focused shot,
but it takes a bit more time than just "have a glance".


But as I said above, there's never a definitive solution and each user
will have his preferred "modus operandi". Different software are never
stricly equivalent, so probably each user should test and try such and
such program, then select the best suited for particular needs.
I believe the question is not to decide which program is the best
(the answer will always be : hem, it depends...:-) but what can do
such or such program, can do very well, well, not very well, not at
all, then let users choose according to their needs.

Jean-François