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
