[Improvement] Use BoundingBoxes in labeling

[ahuarte47]

Use BoundingBoxes to check faster if clipping is necessary.

Now it uses directly the geometries to check if clipping is necessary. There is a performance bottleneck with this.

[ahuarte47]

I moved the topology validation to last item to verify because "isGeosValid" is a costly method

[nyalldawson]

I think this line should be left untouched. If a map is rotated then the extent geometry will be a rotated rectangle, so taking its bounding box will result in a larger extent then is actually visible. In this case we'd still need to clip. The geometryRequiresPreparation change is safe since it's already returned true if the map is rotated, but I think this second check should be left at the original version. What do you think?

[ahuarte47]

But this previous line covers it? no?

[nyalldawson]

@ahuarte47 Sorry, I don't quite understand. The changes to geometryRequiresPreparation are fine, no issue there. But we need to make sure the test before doing the actual clipping is still applied using the geometries themselves when rotation is applied. Maybe a better replacement for line 3947 would be:

  if ( clipGeometry &&
  ( ( qgsDoubleNear( m2p.mapRotation(), 0 ) && !clipGeometry->boundingBox().contains( geom->boundingBox() ) )
    || ( !qgsDoubleNear( m2p.mapRotation(), 0 ) && !clipGeometry->contains( geom ) ) ) )

Ie if no rotation, do the optimised bounding box check, but if rotation then do the full expensive check?

[ahuarte47]

@nyalldawson sorry, I mixed the code in my mind, my apologies, you are right!

Thanks for your pacience :-)

[nyalldawson]

@ahuarte47 no need to apologise - I'm just happy someone is looking to speed this stuff up!

[ahuarte47]

:-) thanks to you for your work. I am working in this work. I hope in right way.

[nyalldawson]

@ahuarte47 I noticed you're having issues with the indentation test - here's some tips getting this to pass:

Tips to prevent and resolve:

• Enable WITH_ASTYLE in your cmake configuration to format C++ code
• Install autopep8 (>= 1.2.1) to format python code
• Use "scripts/astyle.sh file" to fix the now badly indented files
• Consider using scripts/prepare-commit.sh as pre-commit hook to avoid this
  in the future (ln -s ../../scripts/prepare-commit.sh .git/hooks/pre-commit) or
  run it manually before each commit.

[ahuarte47]

Thanks @nyalldawson