[Digikam-devel] camera interface improvements for 2.1.0 : thumbnails cache mechanism...

[Gilles Caulier]

Marcel,

I currently work on camera interface. The goal is to be able to port icon
view to Qt4 model view at end.

For the moment, i would to fix in first some several problem relevant of
thumbnails and speed-up connection.

There is an old bug in bugzilla about memory consumption in icon view (i
cannot find here), especially when camera contains a lots of items (1000
files for ex).

In 2.0.0 version all thumbs are processed at connection. This mangle memory
of course because thumb pixmap is stored in icon-view item. We don't control
how many memory will be used by icon view in this case.

In current implementation, it still true but thumbs are processed on the
fly, when user scroll icon view. This better but not optimal.

The ultimate solution is to use a thumb cache mechanism, where we can
control how many memory will be used to store thumbs for icon view.
When it's necessary, cache take thumb from camera and store it in cache.
Icon view item do not store thumbs pixmap and take it directly in cache. If
item is not stored in cache, this one take automatically it from camera and
store it in cache.

It work like thumb database for album GUI, but DB  is camera in this case.

My question is : we can use LoadingCache class here ? Perhaps we need to
adapt the implementation from camera gui ? We don't need a mechanism to
check if something is changed in path to thumnailize (KDirWatch). In fact
the cache for camera thumb is more simple here.

What do you think about ?

Thanks in advance

Gilles Caulier
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