[Digikam-devel] [Bug 140131] No zoom in image preview

[Gilles Caulier]

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http://bugs.kde.org/show_bug.cgi?id=140131         




------- Additional Comments From caulier.gilles gmail com  2007-04-10 14:57 -------
To Arnd, #11 :

>Wow - that zooming looks absolutely great!!!!

Thanks

>Some observations and comments:
>- I also observe artefacts at different zoom-levels
>  (eg. at 92 % and at 397%, but these values differ from image to
>  image; also this only seems to happen when using CTRL+ and CTRL-,
>  but not the slider?)

Artifact are give from FastScale algorithm from Antonio Larrossa. Investigation are under progress to fix it.

Slider step is more fine than CTRL+/- or mouse wheel. This is why you can see a diff.

>- pressing F4 to open the image editor: the zoom in the album view
>   is undone (however, moving the slider afterwards shows, that it is
>   still zoomed in)

Hum, fixed in svn i think.

>- maybe related: somehow the previous zoom-level is memorized:
>  F3 for an image and zoom in (e.g. 1000%)
>  ESC to leave
>  F3 again: the image is displayed to fit the available space,
>  but the slider is still on 1000%.

Right, i will fix it.

>- the zoom percentages do not seem to match with the values in
>  the image editor (but maybe I am wrong): I.e.,
>  shouldn't 100% mean that one image pixel corresponds one
>  display pixel?

100% is the real image size on the screen.

>- Maybe just a personal problem: I always find my to press CTRL-Q
>  to leave the large view (obviously because of the large display
>  some corner of my brain thinks that this must be the image editor),
>  but this does leave digikam (which does indeed leave the large view,
>  but not in the way I wanted ...)

Here i use 3 flat screens with Xinerama. not reproductible.

>- And another one: I happen to press the left-mouse
>  (having panning in mind) quite frequently, which brings
>  me back to the thumbnail view (which I did not want;-) - not sure
>  if this is optimal from the useability point of view
>  (I know that the "return-on-left-click" was a wish brought
>   up a while ago...;-)

preview with zooming/scrooling work like old static preview mode : when you press on left mouse button, you go back to album view. F-spot work like this too.

The canvas preview use the same implementation than canvas from editor. You pan the image when you use central mouse buttom. Gimp work like this.

Some wishes:
>- When zoomed in: a pan-window widget in the lower-right corner
>  where the scroll-bars meet
>  (as in the image editor) would be nice

TODO

>- it would be nice if the position of the mouse would be
>  the center around which the zoom is done
>  (I also mentioned this as a wish for the image editor zoom,
>   but did not yet manage to look into the logic there, should
>   be fairly easy to implement...)

TODO

>There is maybe one very important point:
>the zoom as it is presently done, uses a reduced-size version of the
>underlying image, right?

yes

>So while it is nice to be able to zoom in, it does not allow for
>a judgement of the image quality (in contrast to the image editor).
>Do you think that there is a way to use the actual image
>(maybe from a certain zoom-level on?) But that would (quite
>certainly?) slow things down...

no. the implementation is not do in this way. All tool to change the image are in editor. Preview mode is not an editor.

>In particular for the upcoming light-table I think it is important
>to compare the real images, not just up-scaled ones

Light Table is planed (:=)))

Uups: I just realized that for zooming in, the image editor also
some interpolation is done, so that that one does not see the single
pixels, but some nicely interpolated version?

You want mean to have an option to disable interpolation with Zoom in (named antialiasing in editor) ?

Gilles