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novomesk / qt-jpegxl-image-plugin

Qt plug-in to allow Qt and KDE based applications to read/write JXL images.
GNU General Public License v3.0
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Qt/C++: crash during encode/write jxl image #17

Closed dbermond closed 3 years ago

dbermond commented 3 years ago

After installing the plugin, this Qt/C++ code crashes:

// grab a screenshot (X11) and save it to jxl format
QPixmap pixmap(qApp->primaryScreen()->grabWindow(0).copy());
pixmap.save("screenshot.jxl", "JXL");

Console output:

/build/libjxl/src/libjxl/lib/jxl/enc_ac_strategy.h:52: JXL_DASSERT: masking_field_row[by * masking_field_stride + bx] > 0
Illegal instruction (core dumped)

But this code works fine and correctly writes a jxl image:

// load existing png file into a QPixmap and save it as a new jxl file
QPixmap pixmap("myimage.png");
pixmap.save("myimage.jxl", "JXL");

Tested with both Qt5 and Qt6, with the same result.

System information: OS: Arch Linux x86_64 Qt5: 5.15.2+kde+r211 Qt6: 6.1.2 libjxl: 0.5 Compiler: gcc 11.1.0

novomesk commented 3 years ago

I believe this a bug in libjxl.

Try to save the screenshot as PNG and then to convert the PNG to JXL using cjxl.

dbermond commented 3 years ago

Thank you for the reply.

Yes, saving a png file that was taken with qApp->primaryScreen()->grabWindow(0).copy() and then converting it to jxl through the cjxl command gives the same error of the crash in Qt/C++. So, looks like a libjxl bug.