QGraphicsScene - memory consumption

[mateuszzz88]

Hello
I want to create mobile program to display OpenStreetMap or similar (tiled) maps - something very like LightMaps demo. I consider using QGraphicsScene to display tiles. However I wonder: user can possibly load millions of 256x256 pixmaps on multiple layers (z-axis), first in one area of the scene, later in other. I worry about limited memory on smartphone. How should I address this problem? Or should I better create ordinary QWidget (as LightMaps)?

[wysota]

Whatever path you choose you will have to manage the memory yourself by removing the tiles that are not currently displayed from memory. You can cache the data on a permanent storage device to fetch it quickly when you need it.

[mateuszzz88]

Thank you for your answer.
I was told QGraphicsScene does some rendering optimizations (and I don't know this part of API yet), so I'll try it out.

[wysota]

I was told QGraphicsScene does some rendering optimizations (and I don't know this part of API yet), so I'll try it out.

Yes, at a cost of increased memory consumption.