A port of the equivalent method from GEOS, but with added support
for curved geometries and M values
Reorganizes the geometry into a normalized form (or "canonical" form).
Polygon rings will be rearranged so that their starting vertex is
the lower left and ring orientation follows the right hand rule, collections
are ordered by geometry type, and other normalization techniques are applied.
The resultant geometry will be geometrically equivalent to the original geometry.
Allows for comparison of geometry objects, e.g. to allow for stable
sorting of them.
Ported from the GEOS equivalent method, but with addition of support
for M values and curved geometry types
to transform the vertices of a QgsAbstractGeometry
E.g.
class Transformer(QgsAbstractGeometryTransformer):
def transformPoint(self, x, y, z, m):
return True, x * 2, y + 1, z, m
transformer = Transformer()
g = QgsGeometry.fromWkt('LineString(3 0, 10 0, 10 10)')
g.get().transform(transformer)
print(g.asWkt()) # 'LineString (6 1, 20 1, 20 11)'
Unlike QgsGeometry::asQPolygonF, this allows for correct handling
of multipolygons and rings, etc.
And potentially, the generated QPainterPaths could use arc segments
instead of segmentizing geometries. In fact, there's been disabled
code which seems to do this in place since the new geometry engine
was introduced back in 2.10! TODO: check if this code works correctly...
... you are too slow and QJson API is so ugly.
Now using this wonderful json lib:
https://github.com/nlohmann/json
Results in release mode (QJson tests are not shown but
QJson was even slower than string concat).
PASS : TestQgsJsonUtils::testExportAttributesJson(Use json)
RESULT : TestQgsJsonUtils::testExportAttributesJson():"Use json":
0.0022 msecs per iteration (total: 75, iterations: 32768)
PASS : TestQgsJsonUtils::testExportAttributesJson(Use old string concat)
RESULT : TestQgsJsonUtils::testExportAttributesJson():"Use old string concat":
0.0032 msecs per iteration (total: 54, iterations: 16384)
PASS : TestQgsJsonUtils::testExportFeatureJson(Use json)
RESULT : TestQgsJsonUtils::testExportFeatureJson():"Use json":
0.011 msecs per iteration (total: 96, iterations: 8192)
PASS : TestQgsJsonUtils::testExportFeatureJson(Use old string concat)
RESULT : TestQgsJsonUtils::testExportFeatureJson():"Use old string concat":
0.015 msecs per iteration (total: 64, iterations: 4096)
PASS : TestQgsJsonUtils::testExportGeomToJson(Use json)
RESULT : TestQgsJsonUtils::testExportGeomToJson():"Use json":
0.76 msecs per iteration (total: 98, iterations: 128)
PASS : TestQgsJsonUtils::testExportGeomToJson(Use old string concat)
RESULT : TestQgsJsonUtils::testExportGeomToJson():"Use old string concat":
0.85 msecs per iteration (total: 55, iterations: 64)
PASS : TestQgsJsonUtils::cleanupTestCase()
For non-point geometry subclasses (points are always valid!) we
now cache the results of a geometry validity check. Subsequent
checks utilise the cached result wherever possible.
Because QgsGeometry/QgsFeature objects are implicitly shared, this
means that we avoid a *lot* of duplicate validity checks as
features and geometries are thrown around during processing model
execution.
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."
