[QGIS-Developer] Qt 5.10 for QGIS devs - the short story

[Nyall Dawson]

Hi all!

Can't be bothered reading the full changelog of Qt 5.10 which was
released today??! No problem!! Here's the 2 second rundown on changes
which are relevant to us:

- The new QStringView class: cool stuff, but it's no use to us until
we require >= 5.10 and it works correctly with the sip bindings. Let's
revisit in 10 years when debian gets updated.

- QRandomGenerator: useful for us. Maybe we can #ifdef this in for our
various random number generation routines (like in expression
functions) to get better quality random numbers, falling back to the
current routines for < 5.10

- "QImages can now use more than 2GByte of pixel data.". This could
potentially be very good for us, but I can't find any info on whether
the pixel dimension limits have also been lifted (these are what's
blocking us from higher-res/larger composer/map exports).

- "Added AA_DisableWindowContextHelpButton attribute that prevents the
automatic" What's this" button on dialogs on Windows". Woohoo! I
remember discussing somewhere (Nodebo?) about how we could get rid of
all these useless "what's this" buttons on windows dialogs which give
no useful information at all. At the time there wasn't a solution.
https://github.com/qgis/QGIS/commit/15e7d57f adds support for this,
but requires Qt 5.10 windows builds.

- "QDockWidget acquired the ability to be dropped together side by
side". Sounds like a nice little UI benefit we get for free after
moving to 5.10 builds. I'm not sure how useful it will be for QGIS in
practice (I think most users would tend to want less docks visible at
once and more room for the actual map), but it's a nice option to have
available given that it takes no effort on our behalf.

- QtQuick/QML changes: meh. I'll let Matthias get excited about those.
I'm just glad that for once there's a Qt release that includes changes
outside of these modules...

- Qt3D changes: looks like some good stuff here, now that it's of use to us!

Nyall