QgsSipUtils.isPyOwned will return True if an object is owned
by python, or False if ownership is held by another object
or c++ class.
This gives a way to test in advance if we can safely assign
an object to a method which takes ownership (which always results
in a crash).
Allows raster pixels to be labeled with the value taken from a raster
band.
Labels are registered with the labeling engine, so participate in
label conflict resolution and overlap avoidance
Options include
- Selection of band to take values from
- Using QgsNumericFormat to customise the number format for the labels
- Uses text renderer, so supports buffers, shadows, etc
- Label priority
- Scale dependant visibility
- Optional pixel size dependent visibilty, ie show only when pixels are
> 4mm in size
- Z index control, overlap avoidance mode
Fixes#14408
For multi-line labels, this allows use of either:
- HTML <p align="xxx"> attributes
- CSS "text-align: xxx"
- HTML <center>some text</center> tags
Supported alignments are left, right, center and justify
Horizontal alignment can be used in all contexts where
HTML text is rendered, EXCEPT for curved labels (since they
are restricted to single-line text)
Sponsored by City of Freiburg im Breisgau
See https://github.com/qgis/QGIS-Enhancement-Proposals/issues/299
Implements the API framework for setting advanced labeling engine
rules for a project, and implements 4 initial rule types:
- QgsLabelingEngineRuleMinimumDistanceLabelToFeature: prevents labels
being placed too *close* to features from a different layer
- QgsLabelingEngineRuleMaximumDistanceLabelToFeature: prevents labels
being placed too *far* from features from a different layer
- QgsLabelingEngineRuleMinimumDistanceLabelToLabel: prevents labels
being placed too close to labels from a different layer
- QgsLabelingEngineRuleAvoidLabelOverlapWithFeature: prevents labels
being placed overlapping features from a different layer
(note that the first 3 rules require a build based on GEOS >= 3.10,
they are not available for older GEOS builds)
Also implements a registry for storing available rule classes,
and serialization of rules and configuration in QGIS projects
This new symbol layer type allows placing text labels at regular
intervals along a line (or at positions corresponding to
existing vertices). Positions can be calculated using
Cartesian distances, or interpolated from z/m values.
Functionality includes:
- Labels can be placed using fixed cartesian 2d distances,
at regular linearly interpolated spacing calculated using
the Z or M values in geometries, or at existing vertices
- Labels can show either the running total distance, or
the linearly interpolated Z/M value
- Uses text rendered to draw labels, so the full range
of functionality is available for the labels (including
buffers, shadows, etc)
- Uses the QGIS numeric format classes to format numbers
as strings, so users have full range of customisation
options for eg decimal places
- An optional "skip multiples of" setting. If set, then
labels which are a multiple of this value will be skipped
over. This allows construction of complex referencing labels,
eg where a symbol has two linear referencing symbol layers,
one set to label every 100m in a small font, skipping multiples
of 1000, and a second set to label every 1000m in a big
bold font
- Labels are rendered using an angle calculated by averaging
the linestring, so sharp tiny jaggies don't result in
unslightly label rotation
- Optionally, markers can be placed at referenced points
in the line string, using a full QGIS marker symbol (this allows
eg showing a cross-hatch at the labeled point, for a "ruler"
style line)
- Data defined control over the placement intervals, skip
multiples setting, marker visibility and average angle
calculation length
Notes:
- When using the distance-based placement or labels, the
distances are calculated using 2D only, Cartesian calculations
based on the original layer CRS. This could potentially be
extended in future to expose options for 3D Cartesian distances,
or ellipsoidal distance calculations.
Sponsored by the Swiss QGIS User Group
This numeric format allows users to craft a custom QGIS expression
to format numbers. The expression can use the @value variable
to retrieve the value to be formatted, and then use any standard
QGIS expression function to format this as desired.
It can be used anywhere QgsNumericFormat is accepted, eg layout
scalebars, elevation plots, layout tables, and color ramp
legends
Sponsored by the Swiss QGIS User Group
This adds a new annotation item type for rendering paragraphs
of text inside a rectangle
Options are present for:
- Text format
- Horizontal and vertical alignment
- Margins
- Background and frame symbol
Can render SVG or raster images as items in an annotation layer.
Options are present for:
- Locking the picture's aspect ratio
- Drawing with a background symbol
- Drawing with a border symbol
- Linked or embedded pictures
And API mechanism to propagate these from layout exports down
to the render context
Gives us a place to specify fine-tuned control over masking
settings for map renders
We currently offer three renderer choices:
- Textured (default). Loads the texture image and paints the mesh using
these textures
- Texture color. Uses the center point color for rendering each mesh
triangle. Gives a clear visual overview of the mesh structure while
also providing some context via the texture color
- Mesh. Renders the scene's mesh using a fill symbol
This is an equivalent of the point cloud index class, with some
notable differences:
- The class is designed to be thread safe. There's a shallow copy
QgsTiledMeshIndex class, which contains an implicitly shared
QgsAbstractTiledMeshIndex object. Tiled mesh data providers will
be accompanied by a concrete class of QgsAbstractTiledMeshIndex.
- The QgsTiledMeshIndex class takes care of thread safety by
protecting the underlying QgsAbstractTiledMeshIndex via a read/write
lock
- Callers can request tiled mesh tiles from the index by calling
QgsTiledMeshIndex::getTiles along with a QgsTiledMeshRequest object.
This will return the unique IDs of tiles matching the request.
Currently only geometric error based filtering is supported
by QgsTiledMeshRequest, but bounding box based filtering will
also be introduced.
- Individual tile details are retrieved by calling
QgsTiledMeshIndex::getTile along with the tile's unique ID.
- A caller can determine whether a specific tile can be further
refined by checking QgsTiledMeshIndex::tileCanRefine. This allows
the caller to check whether more children are available for a
tile, but which haven't yet been fetched (eg due to a sub dataset
tileset which hasn't yet been retrieved)
- A tile can be refined by calling QgsTiledMeshIndex::refineAsync.
(Non async refinement will be introduced later)
- Clients can request tile content by calling
QgsTiledMeshIndex::retrieveContent. This will either return
a cached version of the content (if available), or retrieve and cache
the content for future retrieval. Currently this uses a custom caching
mechanism, but this will be replaced in future with
QgsTileDownloadManager. (Currently QgsTileDownloadManager lacks support
for blocking gets which is required by the index to avoid use
of local event loops)
The api is implemented by the cesium tiles data provider, which
builds the index upfront from the cesium tiles tileset.json definitions.
