Cache problem when preview picture use QAbstractItemDelegate in QListWidget.

[opengpu2]

i write a delegate to preview the picture in the QListWidget, but there are lots of pictures, and there should be a cache method to Only load and show the Items in the current viewRect.
how can i get the items in the current viewport?
and now i use QPixmap, is there any way to cache it? i know when construct it use: QPixmap ppp(strFilePath), it will be loaded and the file is read...so is there any way to use it in order to work with the Cache mechanism?

thank you

[SGaist]

Hi,

QPixmapCache and visualItemRect comes to mind for that

[opengpu2]

thank you, is it right to use QPixmap to open the image file in order to preview the images?
i found when there are lots of image files, it's very slow to load.
is there any good way to accelerate this?
or may i load there QListWidgetItems one by one, which will make the user feel a little better...

[SGaist]

You can create downscaled thumbnails of the images and load them rather than the original

[opengpu2]

u mean i manually downscale the original image to another image file whose resolution is smaller.

[SGaist]

Yes, that's it

[opengpu2]

@SGaist You can create downscaled thumbnails of the images and load them rather than the original

is there any way to use Qt to downscale various kind formats of pictures?

[SGaist]

@opengpu2 See @Chris-Kawa answer to your other thread