Bug 209343

Summary: mouse-wheel should jump to next/previous picture if used when viewing a picture
Product: [Applications] digikam Reporter: S. Burmeister <sven.burmeister>
Component: Usability-MouseAssignee: Digikam Developers <digikam-bugs-null>
Status: RESOLVED WORKSFORME    
Severity: wishlist CC: caulier.gilles, emile.cordonnier+bugzilla, fest.in, toddrme2178
Priority: NOR    
Version: 0.10.0   
Target Milestone: ---   
Platform: openSUSE   
OS: Linux   
Latest Commit: Version Fixed In: 4.3.0
Sentry Crash Report:
Attachments: wheel browse without shift

Description S. Burmeister 2009-10-03 23:55:12 UTC
Version:           0.10 (using KDE 4.3.1)
OS:                Linux
Installed from:    SuSE RPMs

If one clicks on a picture in an album it is displayed, yet turning the mouse-wheel on it does not do anything. I think it would be very comfortable if the user could jump to the next/previous image by turning the mouse-wheel in the view mode when hovering the current picture.
Comment 1 caulier.gilles 2009-10-04 08:30:44 UTC
Note  : press CTRL with mouse wheel, and you zoom in/out with preview.

Try current code from svn (1.0.0-beta5) to see if CTRL alone behavior has been implemented...

Gilles Caulier
Comment 2 caulier.gilles 2009-10-04 09:56:19 UTC
Use SHIFT + Mouse wheel to switch between pictures.

As preview is a scroll view, mouse wheel alone is used to pan content, when zooming is up.

Gilles Caulier
Comment 3 S. Burmeister 2009-10-06 12:58:11 UTC
Ok, so there are two issues here.

1. The current previewer does not allow to use all its functionality without using the keyboard, although this would possible.
2. Within digikam the usage of the "viewers" is not consistent, i.e. the OpenGL viewer works differently.

The OpenGL viewer does the following: Mouse-wheel changes the picture, zooming is done with holding right-click (changing the cursor to a magnifying glass to signal the user that some new functionality is active) and moving the mouse. Double-click takes one back to "fit to screen".

So as those tools are not consistent within digikam and since pressing SHIFT for longer than a few seconds makes KDE prompt the user whether one wants to enable the accessibility features, I'd suggest to change the previewers handling of mouse-clicks and enable the user to access all its functionality without the need to use the keyboard.

- One (short) click on the picture would take the user back to the album view. Alternative: since there is always some space not used by the picture, i.e. either on the top and bottom or left and right, clicking on the empty space could take one back to the album-view, while clicking on the picture does not do anything. In the very rare cases of a picture fitting exactly into the space available for the preview, ESC would still work.

- Holding the left mouse button and moving the mouse would allow the user to grab the picture and move it around, as one is used to from apps like gwenview or google maps etc. This has the big advantage that paning only works in one direction per mouse-wheel, while grabbing+moving works in x and y direction simultaneously.

- Zooming can be done via the slider or holding right-click + mouse movement.

- Mouse-wheel jumps to the next/previous picture.

That way one can use all functionality without the keyboard, which is currently not possible and the viewers would work consistently within digikam.
Comment 4 S. Burmeister 2009-10-07 10:54:17 UTC
Just noticed that marble (within digikam) uses holding left mouse-button to grab+move as well, so this seems to be quite common and suited to replace scrolling for images as the latter is not as y-axis centric as text-scrolling.
Comment 5 Émile Cordonnier 2010-01-28 18:43:08 UTC
Couldn't it be possible to add a option in settings to let the user choose the mouse wheel behaviour ? In gwenview, you can choose between scroll and browse. 

Émile
Comment 6 caulier.gilles 2010-01-31 20:45:15 UTC
*** Bug 225029 has been marked as a duplicate of this bug. ***
Comment 7 Fest 2010-02-01 00:57:16 UTC
Created attachment 40427 [details]
wheel browse without shift

Tiny patch. Instead of shift+wheel, browse with mouse wheel.
Maybe it's not nice code, but it works.
Comment 8 caulier.gilles 2010-02-01 08:59:49 UTC
Fest,

Now zoom in to image and look like the vertical scroll feature from Qt widget is broken.

This is why shift notifier is user here to switch between images.

Gilles Caulier
Comment 9 Fest 2010-02-01 13:57:13 UTC
Strange. I compiled last svn version. Ctrl+wheel zoom work, vertical scroll to. Browsing between images with mouse wheel to.
I'm trying to understand program structure, to add variable that define mouse wheel behavior. Not sure about happy end with that, but i'm trying. :)
Comment 10 Émile Cordonnier 2010-03-08 19:24:29 UTC
A solution could be to change the behavior depending on whether the image is zoomed or not  : 
- switch between pictures (in fitted view),
- pan content when zooming is up (as it's already possible). 
(like the solution recently chosen for the behavior of right-click in the Preview Mode : https://bugs.kde.org/show_bug.cgi?id=225443)
Comment 11 Todd 2011-03-04 17:47:31 UTC
Gwenview has an option to switch between the modes.
Comment 12 caulier.gilles 2014-08-29 21:44:40 UTC
You can use already mouse wheel to change current image show in preview canvas. Just press SHIFT when you use mouse wheel over preview canvas.

This work perfectly with current implementation from git/master

Gilles Caulier