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.
Remove QgsAbstractProperty and subclasses, and instead use a single
QgsProperty class which covers the use of QgsAbstractProperty
and its subclasses. This simplifies the API and avoids pointer
handling. QgsProperty is implicitly shared for memory efficiency
and inexpensive copies.
draw shape/arrow/nodes/paper symbols
This commit removes some more instances where changes in the
canvas affect compositions. Previously the symbols drawn
in shape/arrow/etc items were using the scale from the canvas.
This meant that the appearance of these items in composer
would change depending on canvas zoom if they used symbols
with map unit sizes.
Now they take their map scale from the composition's reference
map. While this has the nice side effect that now map units
can be used in the appearance of these items and they're
guaranteed to match up with the reference map item, the main
intention here is to remove more of the forced links between
compositions (core) and the main canvas (app).
Rationale:
- there was a lot of large objects passed by value, so potentially
there's a speed bump from this
- even for implicitly shared classes like QString/QList there's still
a (small) cost for copying the objects when there's no reason to
- it's the right thing to do!
- New class QgsComposerObject, which both QgsComposerItem and QgsComposerMultiFrame
derive from. This class contains the framework for data defined composition properties.
- New class QgsComposerUtils, containing helpful static functions previously in QgsComposerItem
- Test suites for data defined settings in QgsComposerObject and functions in QgsComposerUtils
