Why?
- no benefits to QScopedPointer over std::unique_ptr
- unlike QScopedPointer, std::unique_ptr has no overhead
over regular pointers
- using standard language features makes it more likely that
compilers can optimise this use and static analysers can
correctly handle code using unique_ptrs
- QScopedPointer has an (IMO) uncertain future (given that
Qt is dropping features which have become part of the c++
standard). Better to port now before wider use of QScopedPointer
in the codebase!
This changes the rendering of annotation frames to use QGIS' symbology
engine, which means that all the existing fill styles can now be
used to style annotation frames.
Also paint effects & data defined symbol parameters. Whee!
Splits the rendering component of annotations out from map
canvas item component.
A new core abstract base class QgsAnnotation handles the
management of the common properties associated with an
annotation, and handles rendering the annotation onto a
QgsRenderContext destination.
Existing annotation classes have been ported to this, and
with the exception of the form annotation moved into core.
Form annotations are dependant on editor widgets and must
remain in GUI.
A new QgsMapCanvasAnnotationItem item class implements
a QgsMapCanvasItem which draws an annotation inside the
canvas, and handles synchronising the position and size
of the canvas item with the QgsAnnotation position/size.
This allows annotations to be safely used in a multi-canvas
environment, with a single QgsAnnotation being displayed
in multiple canvases (even if the canvases have different
extent/crs/etc).
Additionally it allows annotations to be directly rendered
to a map (eg in composer) without going through the
gui based Qt graphics scene framework.
Also removes lots of duplicate code, and adds some basic
unit tests for annotations.
