[FEATURE] Tracing of features (digitizing)
Tracing can be now used in various capturing map tools (add feature, add part, ...) including reshape and split tools.
Tracing is simply a new mode for these tools - when tracing is not enabled, the tools work as usual. When tracing is enabled (by clicking the new magnet icon or pressing T key), tools switch to tracing behavior:
- first click on a vertex/edge (must be snapped!) will start tracing - moving mouse on top of the map continuously updates the trace
- next click will confirm the trace and mark start of a new trace Tracing can be enabled/disabled anytime even while digitizing one feature, so it is possible to digitize some parts of the feature with tracing enabled and other parts with tracing disabled.
Tracing respects snapping configuration for the list of traceable layers.
If there are too many features in map display, tracing is disabled to avoid potentially long tracing structure preparation and large memory overhead. After zooming in or disabling some layers the tracing is enabled again.
Internally, things work like this:
- when tracing is requested, linestrings are extracted from vector layers, then noded (using GEOSNode to resolve all intersections) and finally a simple planar graph is built (vertices + edges)
- when tracing, endpoints are temporarily added to the graph (if not equal to one of existing vertices already) and Dijkstra's algorithm is run to get shortest path
Original specs for the curious ones (the interaction with QGIS is slightly improved from what has been specified): http://www.lutraconsulting.co.uk/crowdfunding/autotrace-phase-2/specification.pdf
During rendering, two new variables will be available:
* `geometry_part_count`
* `geometry_part_num` (1-based index)
Useful to apply different styles to different parts of multipart
features
(only works with Cartographic point label placement). When this
setting is active, the label distance applies from the bounds
of the rendered symbol for a point, instead of the point itself.
It's especially useful when the symbol size isn't fixed, eg if
it's set by a data defined size or when using different symbols
in a categorised renderer.
Sponsored by Andreas Neumann
A new control for setting a label's "z-index" has been added to
the labeling properties dialog. This control (which also accepts
data-defined overrides for individual features) determines the order
in which label are rendered. Label layers with a higher z-index
are rendered on top of labels from a layer with lower z-index.
Additionally, the logic has been tweaks so that if 2 labels have
matching z-indexes, then:
- if they are from the same layer, a smaller label will be drawn
above a larger label
- if they are from different layers, the labels will be drawn in
the same order as the layers themselves (ie respecting the order
set in the legend)
Diagrams can also have their z-index set (but not data defined)
so that the order of labels and diagrams can be controlled.
Note that this does *NOT* allow labels to be drawn below the
features from other layers, it just controls the order in which
labels are drawn on top of all the layer's features.
Fix#13888, #13559
Now all classes and members are either exposed to bindings or marked
as "not available in Python bindings" in the docs.
Drop test thresholds to 0. Now it should be much easier to determine
what missing members have been added which are causing test
failures.
A number of elements have both a <Name> and a <Title>. The Name is a text string used for machine-to-machine
communication while the Title is for the benefit of humans. For example, a dataset might have the descriptive Title
“Maximum Atmospheric Temperature” and be requested using the abbreviated Name “ATMAX”.
User can already set title for layers, groups and project. OWS name is based on the name used in layer tree. This name is more a label for humans than a name for machine-to-machine communication.
To add the capability to users to define Name as a text string for machine-to-machine communication, this pull-request adds:
* short name line edits to layers properties
* WMS data dialog to layer tree group (short name, title, abstract)
* short name line edits to project properties
* add a regexp validator "^[A-Za-z][A-Za-z0-9\._-]*" to short name line edit accessible through a static method
* add a TreeName element in the fullProjectSettings
If a short name has been set for layers, groups and project it is used by QGIS Sever as the layer name.
- Setting exterior ring will force all interior rings to match
dimensionality of exterior ring
- add equality operator
- use correct WKB types for rings when creating polygon from WKB
- segmentize curves when setting exterior ring with curved segments
- fix export to GML2/3 (should use LinearRing, not LineString as
ring element tag)
