Include descriptive text with the specified parameter value
in error, and always check that sources were loaded to avoid
raw Python exceptions when they are not
and add new QgsGeometry::fromPolyline which uses QgsPoint
We want to encourage people not to use the QgsPointXY method, as it drops
Z/M values. So it's moved across to a different name to make way
for a new QgsGeometry::fromPolyline which uses a QgsPoint list
instead of QgsPointXY, thus keeping Z/M values intact.
Similarly, QgsPolyline now is a list of QgsPoint (keeping z/m values)
and the old 2d QgsPolyline type was renamed to QgsPolylineXY.
Making the QgsPoint method the "preferred" method and making linestrings
just as easy to create from z/m dimensioned points as 2d points is
important to push people to write code which does not discard
these important dimensions.
As a bonus, the QgsPoint methods are more efficient anyway, since
they don't require creation of a temporary list.
initAlgorithm() method
This allows 2 benefits:
- algorithms can be subclassed and have subclasses add additional
parameters/outputs to the algorithm. With the previous approach
of declaring parameters/outputs in the constructor, it's not
possible to call virtual methods to add additional parameters/
outputs (since you can't call virtual methods from a constructor).
- initAlgorithm takes a variant map argument, allowing the algorithm
to dynamically adjust its declared parameters and outputs according
to this configuration map. This potentially allows model algorithms which
can be configured to have variable numbers of parameters and
outputs at run time. E.g. a "router" algorithm which directs
features to one of any number of output sinks depending on some
user configured criteria.
have specific icons, instead of generic qgis icon
We consider these 'top level' algorithms, and using the
standard algorithm icon should help reflect this and
differentiate them from 3rd party algorithms.
Algorithms and other processing code should use this method
(instead of dataobjects.getLayerFromString) to
retrieve layers from a string, as it considers the processing
context and allows resolving strings to temporarily stored layers.
This permits processing models to function correctly when
intermediate results are stored as memory layers. Subsequent
model algorithms can then access these temporary layers as inputs.
All temporary layers will be removed when the context object
is destroyed after the model algorithm is run.
- setEllipsoidalMode() was removed. Ellipsoidal calculations are
now enabled whenever a valid ellipsoid() has been set. Set the
ellipsoid to 'NONE' to disable ellipsoidal calculations.
- ellipsoidalEnabled() was removed. Ellipsoidal calculations
are now enabled whenever a valid ellipsoid() is set. Check
willUseEllipsoid() to determine whether ellipsoidal
calculations will be performed.
- sourceCrs() and setSourceCrs() now always take and return
QgsCoordinateReferenceSystem objects. All string/ID based CRS
methods were removed.
- geographic() was removed. This was only used internally
in one place, so was replaced with sourceCrs().isGeographic() instead.
- some largely overlapping measurement functions were consolidated
Also
- simplify and add tests
- remove large memory leak (persistant store of all non-project layers)
- remove broken support for direct loading postgres/virtual layers
by string (Python version was very broken and would never match
a postgres/virtual layer)
- don't use setFilterFid() within loops to fetch features one
at time (as it's extremely slow), instead use setFilterFids()
outside the loop
- don't fetch unused attributes/geometry when it can be
avoided
