MeasureWidget: Warn about min size in combined symbols

[lpechacek]

This enhancement is especially useful when working with @mlerjen's "halo" symbol set (mentioned multiple times, e.g. in #1004). Please consider merging.

[lpechacek]

@mlerjen's "halo" symbol set (mentioned multiple times, e.g. in #1004)

I've just realized that it's actually the symbol set contributed in #2032.

[dl3sdo]

Libor, thank you for considering combined area symbols. Your commit works fine except in one case: if a new symbol part is just added to the combined symbol without specifying its type, Mapper will crash due to dereferencing a nullptr. Adding an additional check solves this issue:
if (part) { if (part->getType() == Symbol::Area) ........ }
See dl3sdo@c1b9ed8

[lpechacek]

Libor, thank you for considering combined area symbols. Your commit works fine except in one case: if a new symbol part is just added to the combined symbol without specifying its type, Mapper will crash due to dereferencing a nullptr. Adding an additional check solves this issue: if (part) { if (part->getType() == Symbol::Area) ........ }

Thanks, Matthias, for testing the commit and the fix! I agree with the approach, however, I'd avoid the additional indentation level induced by if (part) ... but rather skip the part in the loop with a continue. Otherwise, I agree with all the changes and I've merged them into my commit.