Thanks Elvis for your reply, A compressed in-memory cache would be just perfect in my case.
So I can save a QPixmap in a QByteArray in let's say png format and use a regular QCache instead of QPixmapCache... I'll give it a shot for sure Thanks again, I think you made my day :) Philippe Le 25-10-2015 16:20, Elvis Stansvik a écrit : > 2015-10-25 15:53 GMT+01:00 maitai <[email protected]>: >> Hello, >> >> I have several relatively big pixmap I'd like to manage through cache. >> Big meaning 1024x1024 at a maximum (one edge is 1024 while the other >> is >> less or equal). I need to keep something like 10 of those in a cache >> system. Each image being quite heavy to paint, that would help a lot. >> >> I believe each pixmap uses a maximum of 1024 * 1024 * (32 / 8 byte) / >> 1024 / 1024 = 4 Mb, right? >> >> QPixmapCache is eating way too much memory for that (40MB + >> "whatever-is-needed-for-qt" on regular memory), on android and >> especially iOS it's a no go. Plus it's kind of shared with qt own >> needs >> so it's hard to decide which limit to give. >> >> What would you advise? Saving the pixmap on disk, with a "kind of >> cache" >> system to limit it to a given size, last used is dropped etc? Using >> opengl textures to store/restore img with a similar cache system? >> Using >> QPixmapCache anyway? Something else? >> >> I should add that in our case it's way faster to read the pixmap from >> a >> pre-saved png than to re-generate it, and that quality is ok for our >> needs. So a disk-cache might be ok. But 40mb on a mobile device is >> something expensive.... > > If you used a disk cache with PNG files, the images would be > compressed, so probably a lot less than the 4 MB per image you > calculated above. > > I guess you could also try to make a compressed in-memory cache. > > Cheers, > Elvis > >> >> Thanks >> Philippe Lelong >> _______________________________________________ >> Interest mailing list >> [email protected] >> http://lists.qt-project.org/mailman/listinfo/interest _______________________________________________ Interest mailing list [email protected] http://lists.qt-project.org/mailman/listinfo/interest
