This allows easy iteration over all the parts of a geometry,
regardless of the geometry's type. E.g.
geometry = QgsGeometry.fromWkt( 'MultiPoint( 0 0, 1 1, 2 2)' )
for part in geometry.parts():
print(part.asWkt())
geometry = QgsGeometry.fromWkt( 'LineString( 0 0, 10 10 )' )
for part in geometry.parts():
print(part.asWkt())
There are two iterators available. QgsGeometry.parts() gives
a non-const iterator, allowing the parts to be modified in place:
geometry = QgsGeometry.fromWkt( 'MultiPoint( 0 0, 1 1, 2 2)' )
for part in geometry.parts():
part.transform(ct)
For a const iteration, calling .const_parts() gives a const
iterator, which cannot edit the parts but avoids a potentially expensive
QgsGeometry detach and clone
geometry = QgsGeometry.fromWkt( 'MultiPoint( 0 0, 1 1, 2 2)' )
for part in geometry.const_parts():
print(part.x())
All your uses of toUtf8().data() actually just need a const char*
So use constData() that is semantically more correct, and documented
to be faster.
From http://doc.qt.io/qt-5/qbytearray.html#data
"For read-only access, constData() is faster because it never
causes a deep copy to occur."
* make QgsWkbTypes a Q_GADGET and declare GeometryType as Q_ENUM
* include QObject
* remove extra include
* move QgsWkbTypes to moc headers
* run sip_include
Avoid conversion to/from WKB at OGR/QGIS side, and just directly
utilise OGR geometry API to construct QGIS geometries.
Shaves ~10% off rendering time for a large point layer (GPKG)
Because:
- Exactly follows curves and doesn't require segmentizing input geometry
- Also interpolates z/m values if they are present in input geometry
- Is faster
Returns a new curve representing a substring of a curve, from
a start distance and end distance.
If z or m values are present, the output z and m will be interpolated using
the existing vertices' z or m values.
Handles curved geometries without loss.
We never call this method using nullptrs, so there's no need
for this to be a pointer argument in the first place. And
having it a pointer encourages leaky code, such as the
leak this commit fixes in server.
Checks whether a function declaration has parameters that are
top level const.
const values in declarations do not affect the signature of a
function, so they should not be put there.
