The project layer filter allows you to quickly select a layer
from the current project and highlight it in the layer tree.
It's useful for complex project with lots of groups, where
it's easy to "lose" layers somewhere in the tree...
The composition filter allows searching for and opening
compositions from the current project
This is a completely wrong use of an algorithm that is meant to be used with *integer* values,
e.g. when dealing with pixels on screen, but not for coordinates that are floating point numbers.
The algorithm has a fixed tolerance of 1 unit.
QgsPoint(5,0.9).onSegment(QgsPoint(0,0), QgsPoint(10,0)) would return 2 (i.e. point is on line segment)
See the original code: https://github.com/erich666/GraphicsGems/blob/master/gems/PntOnLine.c
Historically the configuration used to be stored in layer's custom properties, but that does not scale
beyond simple rendering and so rule-based labeling introduced storage of configuration natively in XML elements.
That left us with two different ways of reading/writing labeling configurations. This work makes all configuration
to use native XML elements.
To keep compatibility of 2.x projects, reading of configuration from custom properties is preserved.
This commit also adds Python APIs for direct manipulation of labeling configuration through vector layer's
setLabeling() and labeling() calls.
This is necessary in order to be able to correctly translate between absolute and relative paths
deeper in the code - e.g. paths to SVG files used in marker or fill symbols.
Until now, relative paths were translated to absolute paths on the fly.
This is now changed - paths to files should be always absolute within QGIS objects - and paths
only get turned into relative when saving projects. When loading a project, relative paths
are translated to absolute paths immediately.
This should lower the overall confusion about relative/absolute paths within QGIS, and also
allow having different base directories for relative paths (e.g. QML or QPT files may use relative paths
to their directory - rather than to the project directory)
Since the majority of users of this class will be exporting
an existing map layer to a data provider, the QgsVectorLayerImport
name is misleading and suggests that this class is designed
just to bring layers "into" QGIS.
Explicitly naming the class "Exporter" should help API users
discover this class.
Also cleanup API and improve docs
