[Digikam-devel] [Bug 135048] easy comparing similar pictures using a lighttable

[Arnd Baecker]

Hey, this looks close to useable!
(Compile went fine and no crashes so far ;-)

Some thoughts (feel free to ignore if they are premature;
I know the light-table is alpha)
- the light-table has to work with non-scaled images
  (i.e. like the image editor); otherwise
  a control of the quality is not possible.
- joint zooming and joint panning is essential
  (I agree with Mikolaj that for images not idential in size
   this should just be disabled;
   maybe there is a way to deal with this, but this
   really looks like a rare situation)

  In addition, even for similar pictures, the
  subject of interest might not be at the same place.
  For this the possibility to create an additional shift
  (while still keeping the linked panning and zooming) would
  be helpful. This could be achieved by declaring
  the left image as master and the right one just follows
  any zoom and pan.
  If one pans in the right image, only this one is
  affected. If one then pans in the left one,
  the right one follows, as before, but with
  the additional shift
  (there might be some issues near the borders, but
   one thing after another ;-).
- the whole process feels too complicated:
  a) select images
  b) add them to the light-table
  c) in the light-table:
     select image for the left view
     select image for the right view
  There is not much one can do about a) and b),
  apart from maybe providing a keyboard short-cut
  at some later stage.
  For c): what about displaying the first two images
  directly as left and right one?
  (maybe they should also be marked as selected ones,
   with different colors?)

  (Gilles, here should really stop reading, because
   the rest is even more like feature wishes...)
  - Maybe drag-and-drop from the thumbs would be helpful.
  - Then, to go through a sequence of similar
    images, a kind of "Next - two" comparison would
    speed up things considerably.
    Here the right image becomes the left one and
    the next thumb becomes the new right image.
    (The same for "Previus Two")

What I am not sure about concerns the simultaneous comparison
of more than two images (3, 4, ....)?
Whether this is useful or not, presumably depends
on the size of the screen. For a small 12'' laptop
anything more than 2 might not work out, whereas on a
large 20'' display much more is possible.

OK, I will shut up now.

Keep on this great work on the light-table - it
looks extremely promising!!!

Best, Arnd