no, decrese the font size and see if it works. then you'll know whether you can change font size at all. If it works then that should be a hint as to why you cannot increase the size.

@SGaist got it.

@TheTrueGoofy said in Read and write QBrush (QPen, QFont) as XML:

Certainly this is also quite simple to implement, but I was hoping that there is a more elegant solution.

I think the only other way is to create feature request for QtGui, or implement a Qt patch yourself - to add a QBrush::toString() method (or QTextStream overload), with a corresponding QBrush::fromString().

@Asperamanca
Doc says "Returns the pixel size of the font if it was set with setPixelSize() ".
OP says " But I do not ever explicit used that methods in my program."
so it returns -1 for him always.

@Violet-Giraffe said:

Isn't any modern C++ compiler capable of doing that optimization implicitly (with optimizations enabled)?

In all probability, yes; it's just a stupid habit. Compilers weren't so smart before, but they are improving by the minute. You can safely replace it with left.height() / 2.

Weight is an enumeration and theres a corresponding getter

Ok, I found the solution for Windows-Side:
When opening a font with FontForge, there (in GridFitting-Options) one can set certain attributes for certain point-sizes, such as Antialiasing. There is even two special columns for giving attributes to ClearType. These settings will be respected by ClearType, so no need to switch it off.

On Linux based OS, I still am no further, except that I know that some sort of fontconfig is what Qt5 "reads" and therefore decides. Unfortunately the Linux-RenderEngine ignores the above mentioned internal font-attributes.