how to get the picture's resolution, file's size quickly without open the file?

[opengpu2]

how to get the picture's resolution, file's size quickly without open the file?
i now use
QPixmap xxx(filePath);
int w = xxx.width();
int h = xxx.height();
...........
.........
as for file size, i use
QImage xxx(filePath);
int size = xxx.byteCount();
..........
..........

[mcosta]

Hi,

IMO you can't, these information are stored in the image file so you MUST open it to read them.

[opengpu2]

but i found that it's very slow when there are lots of image file...
is there any accelaration method?

[mcosta]

Hi,

you could write a method that opens the file a reads only these information instead of loading all data.
But in this case you have to handle manually the binary data of the different image formats.

[opengpu2]

ok, got it, thank you