Pretty much Qt. You can learn how different OSes have different way.
However, modern GUI programming is happening on the web and mobile phones. React is popular, but it's too high level and their XML-based approach is horrifically designed. Swift UI is nice, but it's Apple-only. Flutter is a good middle ground, but its Desktop capability is limited. You're going to shoot on your own foot several times.
Macs, or iTunes on Windows. There are two modes of a backup: actual one or backup in name only (like the names of the apps, I wish the latter fucks off).
At this point I'm not expert enough to explain more details. You can check font renderers.
Below is what's in my mind but it's just a guess.
In typical PC architectures you have IO between the storage and the RAM, and then there's the copying from the RAM to the VRAM, and editors maybe also want copying from the VRAM to RAM for decoration purposes etc.
AFAIK it's the copy cost for the memory. GPU makes sense only when the hardware allows this copy to go away. Generally, desktop PCs don't have such specialized hardware.
Therefore there is a real threat that the required majority for mass scanning of private communications may be achieved at any time under the current Hungarian presidency (Hungary being a supporter of the proposal).
Why did they let this Hungarian pro-Nazi idiot regime lead anything?
This IS bad. Btw they can ask the user to type the password rather than saving it in a plaintext. I can't believe comments on this thread defend Signal...
A similar system has been there to prevent Nazism rise. Sadly, AfD and other right wing parties found a loophole a decade ago.