Adds support for base64 encoded image decoding when the path
is a HTML data URL (in addition to the existing "base64:..."
format support)
Allows use of eg "data:image/jpeg;base64,XXXXXXXX" formats
for image paths, so that the image cache can correctly handle
embedded image paths from HTML/CSS content
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
We should be using the new name for the enum value instead
of the old one in the enum class docstring.
Move the old compatible name to an extra note
"Available as ``xx.yy`` in older QGIS releases."
Fixes#49171
