[Qt-interest] Limitations of QImage size

[Paul Miller]

M. Bashir Al-Noimi wrote:
> Hi All,
> 
> I'm working on NLP (natural human processing) project so I need to deal 
> with huge images for that I faced a problem with creating images more 
> than 1000w X 30000h !

 > Is there any way for creating images by QImage more than 1000w X 30000h
 > pixels?

That would use a chunk of memory that is 120MB in size. You're likely 
going to run into massive fragmentation issues unless you're running a 
64 bit OS and building a 64 bit app.

> I successfully created a huge image manually by Photoshop.

Photoshop is tile-based - so it's actually created a large number of 
256x256 (or some other small size) tiles and virtualizing them to disk. 
You could do this yourself but you'd probably have to build your own 
image I/O layer.

I've done this myself in photo editing apps - I don't use QImage to 
actually store the image except at lower-resolution proxy sizes, and all 
my I/O is done in strips that are much smaller than the image height.


-- 
Paul Miller | paul at fxtech.com | www.fxtech.com | Got Tivo?