Qt 6.2 QImage JPG over 33,547,526 pixels no longer loads

Rory_1

My image viewer program, updated from Qt 5.15.2 to Qt 6.2, no longer will display jpg files over 33.5 million pixels. I also tried the Qt example application "imageviewer", which has the same issue. Qt has a web page https://doc.qt.io/qt-6/qtimageformats-changes-qt6.html suggesting something has changed, but all the page has is "ADD STUFF HERE".

I determined it is a size issue by resizing an image down until it would work.

The point of failure is QImage::load function. QImage::loadFromData also fails.

SGaist

Hi,

Can you provide a minimal compilable example along with such a file to show the issue ?

Rory_1

@SGaist said in Qt 6.2 QImage JPG over 33,547,526 pixels no longer loads:

Hi,

Can you provide a minimal compilable example along with such a file to show the issue ?

The imageviewer Qt example application. Any jpg greater than 33.6 million pixels.

Example jpg that does not work (8640x5760 pixels): https://drive.google.com/file/d/1ZwWEJCVP7Mdqtt_SWbEPHVm1a6HBnkri/view?usp=sharing

The same image, reduced in size to 7094x4729 pixels works: https://drive.google.com/file/d/1Jkpb2y527m066tGy1Y4O66Mcw8nhZ31Q/view?usp=sharing

SGaist

Which OS are you on ?

Rory_1

Both win10 and macos Big Sur 11.5.1.

hskoglund

Hi, don't know if it's relevant but 2**25 = 33554432 which seems pretty close to 33,547,526.

Rory_1

@hskoglund That was what I was thinking. The 33,547,526 number I gave is an estimate.

Christian Ehrlicher

See QImage::setAllocationLimit() and the warning output on your command line when you start your program:

qt.gui.imageio: QImageIOHandler: Rejecting image as it exceeds the current allocation limit of 128 megabytes

hskoglund

Also, as an alternative to calling QImage::setAllocationLimit() you can set an environment variable QT_IMAGEIO_MAXALLOC to some bigger value of megabytes than the default 128 :-)

Rory_1

@Christian-Ehrlicher @hskoglund @SGaist Thanks very much gentlemen!