threaded image provider might help On Thu, Aug 10, 2017 at 12:36 PM, Bernhard B <schluc...@gmail.com> wrote:
> Hi, > > yesterday, I also tried to replace the Base64ImageProvider approach with a > subclassed QQuickPaintedItem which paints the image in it's paint method. I > imagined that this approach might be faster es no bade64 decoding needs to > be done. But unfortunately it looks like as it's performing even worse that > way. > > Bernhard > > Am Mittwoch, 9. August 2017 schrieb Bernhard B : > >> Hi, >> >> I would need some help from you guys on how to improve the ListView's >> performance. The problem is, that scrolling through my ListView sometimes >> feels a little bit sluggish. >> >> If I only display some text in the ListView's delegate I can scroll >> smoothly through my list. But as soon as there is a picture in the >> ListView's delegate I notice that I can't scroll smoothly through my list >> anymore. That's especially noticable if I try to scroll fast through my >> list. Every time I hit a picture while scrolling through the list I can see >> that there is a noticable delay until the picture is fully loaded. My >> assumption is, that those pictures are the reason why he scrolling feels so >> sluggish. >> >> My application currently works like this: >> >> * load 20 pictures via REST (pictures are base64 encoded) >> * populate list model >> * the Image component in the delegate uses a Base64ImageProvider (self >> written) to access the model's base64 encoded content and displays the image >> * if the user scrolls past a threshold another batch of base64 encoded >> pictures is fetched from the server >> >> I also found this document: http://doc.qt.io/qt- >> 5/qtquick-performance.html#rendering and tried to apply as much as >> possible. In detail I applied the following changes: >> >> * removed complex bindings from delegate >> * set sourceSize property for Image >> * increased cacheBuffer a bit >> * profiled with QML profiler and improved a few things >> >> But still, the ListView feels a bit sluggish. The strange thing is, that >> it's most noticable on Android whereas on Windows and iOs it is better. >> >> Does anyone have an idea on how to improve that? >> >> >> Any help is really appreciated. >> Thanks a lot! >> > > _______________________________________________ > Interest mailing list > Interest@qt-project.org > http://lists.qt-project.org/mailman/listinfo/interest > > -- Best regards, Vlad
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