[Digikam-devel] [Bug 137320] Thumbnails should continue loading for images that are off-screen

[Marcel Wiesweg]

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http://bugs.kde.org/show_bug.cgi?id=137320         




------- Additional Comments From marcel.wiesweg gmx de  2008-03-21 17:19 -------
Thumbnails in the thumbnail thread are currently simply appended to the list of a single thread.
Note that in KDE4 parts of the above discussion does not apply, we can do more what we like.

We could e.g. use a precreation thread that creates thumbnails on disk, but does not care for pixmaps (thread->setPixmapRequested(false)) as a first step.
On album change, the old process can be stopped by thread->stopLoading(QString()), and all new thumbnail tasks can be appended as a whole.
For this solution to make sense, the thumbar should also apply the load-when-needed principle.

In the icon view, loading is also more straightforward: When an item is painted, it requests its pixmap from the thread. If the pixmap is cached, it is returned and painted. Else, a loading operation is initiated. AlbumIconView will then receive a signal in slotThumbnailLoaded, find out the affected item, and cause a repaint of this item.
Introducing pixmap preloading here for the next row/screen is another point. We need to think about finding the correct place for a hook for starting the preloading.