width buffers
Adds:
- tapered_buffer
- buffer_by_m
expression functions. These expose the same functionality as the
equivalent processing algorithms but for use in expressions
such as geometry generators.
Adds geometry methods to create variable width buffers, including
tapered buffers (with a specified start and end diameter) and
variable width buffers from line string m values.
Also adds processing algorithms which expose these methods
to processing.
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
This pull request is a subset of #6490
This adds a new library for creation of applications based on Qt Quick
framework.
It contains reusable QML / Qt Quick components based on QGIS core
library.
The initial work introduces MapCanvas
To enable compilation of the library, use WITH_QUICK=TRUE
Further documentation of the library is located in doc/qgsquick.dox
For background information see the associated QEP:
qgis/QGIS-Enhancement-Proposals#109
The initial implementation is largely based on the work of Matthias Kuhn
and Marco Bernasocchi on QField probject - kudos to them for the great
job!
* [FEATURE][needs-docs] Rework expression parser for unknown functions
* Remove old comment
* Rename NAME and update tests
* Change COLUMN_REF to QUOTED_COLUMN_REF
This is a subclass of QgsProcessingParameterNumber, but specifically
for numeric parameters which represent distances. It is linked
to a parent parameter, from which the distance unit will
be determined, and is shown using a dedicated distance widget
within the processing parameters panel. This widget shows
the distance unit.
This avoids the confusion when running algorithms which
use distances where the unit depends on a layer or CRS parameter -
e.g. the distance parameter in the buffer algorithm gives
the distance in layer units... so now we can show those units
directly within the dialog. Hopefully this leads to less
user confusion and accidental "1000 degree buffers"!
Additionally - if the unit is in degrees, a small warning
icon is shown next to the parameter. The tooltip for this
icon advises users to reproject data into a suitable
projected local coordinate system.
Initially implemented for the native buffer and single
sided buffer algorithm only - but more will be added.
Fixes#16290
